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arXiv 2021年

作者： Zhang, Chunyi Tang, Fujie Chen, Mohan Zhang, Linfeng Qiu, Diana Y. Perdew, John P. Klein, Michael L. Wu, Xifan Department of Physics Temple University PhiladelphiaPA19122 United States HEDPS Center for Applied Physics and Technology College of Engineering Peking University Beijing100871 China Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States Department of Mechanical Engineering and Materials Science Yale University New HavenCT06520 United States Department of Chemistry Temple University PhiladelphiaPA19122 United States Institute for Computational Molecular Science Temple University PhiladelphiaPA19122 United States

Within the framework of Kohn-Sham density functional theory (DFT), the ability to provide good predictions of water properties by employing a strongly constrained and appropriately normed (SCAN) functional has been extensively demonstrated in recent years. Here, we further advance the modeling of water by building a more accurate model on the fourth rung of Jacob’s ladder with the hybrid functional, SCAN0. In particular, we carry out both classical and Feynman path-integral molecular dynamics calculations of water with the SCAN0 functional and the isobaric-isothermal ensemble. In order to generate the equilibrated structure of water, a deep neural network potential is trained from the atomic potential energy surface based on ab initio data obtained from SCAN0 DFT calculations. For the electronic properties of water, a separate deep neural network potential is trained using the Deep Wannier method based on the maximally localized Wannier functions of the equilibrated trajectory at the SCAN0 level. The structural, dynamic, and electric properties of water were analyzed. The hydrogen-bond structures, density, infrared spectra, diffusion coefficients, and dielectric constants of water, in the electronic ground state, are computed using a large simulation box and long simulation time. For the properties involving electronic excitations, we apply the GW approximation within many-body perturbation theory to calculate the quasiparticle density of states and bandgap of water. Compared to the SCAN functional, mixing exact exchange mitigates the self-interaction error in the meta-generalized-gradient approximation and further softens liquid water towards the experimental direction. For most of the water properties, the SCAN0 functional shows a systematic improvement over the SCAN functional. © 2021, CC BY.

关键词： Deep neural networks

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Hierarchical Construction of Higher-Order Exceptional Points

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Physical Review Letters 2020年第20期125卷 203602-203602页

作者： Q. Zhong J. Kou Ş. K. Özdemir R. El-Ganainy Department of Physics Michigan Technological University Houghton Michigan 49931 USA Henes Center for Quantum Phenomena Michigan Technological University Houghton Michigan 49931 USA Division of Engineering and Applied Science California Institute of Technology Pasadena California 91125 USA Department of Engineering Science and Mechanics and Materials Research Institute The Pennsylvania State University University Park Pennsylvania 16802 USA

The realization of higher-order exceptional points (HOEPs) can lead to orders of magnitude enhancement in light-matter interactions beyond the current fundamental limits. Unfortunately, implementing HOEPs in the existing schemes is a rather difficult task, due to the complexity and sensitivity to fabrication imperfections. Here we introduce a hierarchical approach for engineering photonic structures having HOEPs that are easier to build and more resilient to experimental uncertainties. We demonstrate our technique by an example that involves parity-time symmetric optical microring resonators with chiral coupling among the internal optical modes of each resonator. Interestingly, we find that the uniform coupling profile is not required to achieve HOEPs in this system—a feature that implies the emergence of HOEPs from disorder and provides resilience against some fabrication errors. Our results are confirmed by using full-wave simulations based on Maxwell’s equation in realistic optical material systems.

关键词： Light-matter interaction Photonics PT-symmetry Whispering gallery mode resonators

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Polar state memory in active fluids

arXiv

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arXiv 2021年

作者： Zhang, Bo Yuan, Hang Sokolov, Andrey De La Cruz, Monica Olvera Snezhko, Alexey Materials Science Division Argonne National Laboratory 9700 South Cass Avenue ArgonneIL60439 United States Applied Physics Graduate Program Northwestern University 2145 Sheridan Road EvanstonIL60208 United States Department of Materials Science and Engineering Northwestern University 2220 Campus Drive EvanstonIL60208 United States Department of Physics and Astronomy Northwestern University 2145 Sheridan Road EvanstonIL60208 United States

Spontaneous emergence of correlated states such as flocks and vortices are prime examples of remarkable collective dynamics and self-organization observed in active matter [1–6]. The formation of globally correlated polar states in geometrically confined systems proceeds through the emergence of a macroscopic steadily rotating vortex that spontaneously selects a clockwise or counterclockwise global chiral state [7, 8]. Here, we reveal that a global vortex formed by colloidal rollers exhibits state memory. The information remains stored even when the energy injection is ceased and the activity is terminated. We show that a subsequent formation of the collective states upon re-energizing the system is not random. We combine experiments and simulations to elucidate how a combination of hydrodynamic and electrostatic interactions leads to hidden asymmetries in the local particle positional order encoding the chiral state of the system. The stored information can be accessed and exploited to systematically command subsequent polar states of active liquid through temporal control of the activity. With the chirality of the emergent collective states controlled on-demand, active liquids offer new possibilities for flow manipulation, transport, and mixing at the microscale. Copyright © 2021, The Authors. All rights reserved.

关键词： Vortex flow

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Understanding viscoelastic flow instabilities: Oldroyd-B and beyond

arXiv

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arXiv 2022年

作者： Sánchez, Hugo A. Castillo Jovanović, Mihailo R. Kumar, Satish Morozov, Alexander Shankar, V. Subramanian, Ganesh Wilson, Helen J. Department Of Applied Mathematics And Statistics Institute Of Mathematics And Computational Sciences University Of Sao Paulo Brazil Ming Hsieh Department Of Electrical And Computer Engineering University Of Southern California Los AngelesCA90089 United States Department Of Chemical Engineering And Materials Science University Of Minnesota MinneapolisMN55455 United States SUPA School Of Physics And Astronomy The University Of Edinburgh EdinburghEH9 3FD United Kingdom Department Of Chemical Engineering Indian Institute Of Technology Kanpur208016 India Engineering Mechanics Unit Jawaharlal Nehru Center For Advanced Scientific Research Bangalore560064 India Mathematics Department University College London Gower Street LondonWC1E 6BT United Kingdom

The Oldroyd-B model has been used extensively to predict a host of instabilities in shearing flows of viscoelastic fluids, often realized experimentally using polymer solutions. The present review, written on the occasion of the birth centenary of James Oldroyd, provides an overview of instabilities found across major classes of shearing flows. These comprise (i) the canonical rectilinear shearing flows including plane Couette, plane and pipe Poiseuille flows;(ii) viscometric shearing flows with curved streamlines such as those in the TaylorCouette, cone-and-plate and parallel-plate geometries;(iii) non-viscometric shearing flows with an underlying extensional flow topology such as the flow in a cross-slot device;and (iv) multilayer shearing flows. While the underlying focus in all these cases is on results obtained using the Oldroyd-B model, we also discuss their relation to the actual instability, and as to how the shortcomings of the Oldroyd-B model may be overcome by the use of more realistic constitutive models. All the three commonly used tools of stability analysis, viz., modal linear stability, nonmodal stability, and weakly nonlinear stability analyses are discussed, with supporting evidence from experiments and numerical simulations as appropriate. Despite only accounting for a shear-rate-independent viscosity and first normal stress coefficient, the Oldroyd-B model is able to qualitatively predict the majority of instabilities in the aforementioned shearing flows. The review also highlights, where appropriate, open questions in the area of viscoelastic stability. © 2022, CC BY.

关键词： Stability

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Thermal analysis of ternary hybrid nanofluid flow in convergent/divergent channel using Box-Behnken design of response surface methodology

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Results in Physics 2025年 74.0卷

作者： Mahariq, Ibrahim Mohana, C.M. Kumar, B. Rushi Mohamed, Kezzar SARI, Mohamed Rafik El-Wahed Khalifa, Hamiden Abd Nagarathnam, Sunitha University College Korea University Seoul 02481 South Korea Najjad Zeenni Faculty of Engineering Al Quds University Jerusalem Palestine Department of Medical Research China Medical University Hospital China Medical University Taichung Taiwan Applied Science Research Center Applied Science Private University Amman Jordan GUST Engineering and Applied Innovation Research Center (GEAR) Gulf University for Science and Technology Mishref Kuwait Department of Mathematics School of Advanced Sciences Vellore Institute of Technology Tamil Nadu Vellore India Materials and Energy Engineering Laboratory (LMGE) Technology Department Faculty of Technology 20 Aout 1955 University of Skikda PO Box 26 Skikda 21000 Algeria Mechanics of Materials and Plant Maintenance Research Laboratory (LR3MI) Mechanical Engineering Department Faculty of Engineering Badji Mokhtar University of Annaba (UBMA) PO Box 12 Annaba 23052 Algeria Department of Operations and Management Research Faculty of Graduate Studies for Statistical Research Cairo University Giza 12613 Egypt Centre for Research in Computational and Applied Mechanics University of Cape Town Rondebosch 7701 South Africa

Convergent/divergent channels represent a critical advancement in thermal management systems, offering enhanced heat transfer capabilities through geometrically optimized flow paths. This study investigates the thermal and hydrodynamic characteristics of UO₂-ZnO-Fe₃O₄/EG-water ternary hybrid nanofluid in rotating convergent/divergent channels with magnetohydrodynamic and radiation effects, a critical area for enhancing heat transfer efficiency in modern thermal management systems. Employing the Runge-Kutta-Fehlberg method coupled with a Box-Behnken design approach, we analyzed how key parameters affect flow behavior and heat transfer performance. The numerical simulations reveal that increasing the nanoparticle volume fraction from 0.01 to 0.06 enhances the Nusselt number by 27.3 %, while an increase in the magnetic parameter reduces the friction coefficient by 41.2 %. The Reynolds number demonstrates a strong positive correlation with the Nusselt number (R² = 0.978). Maximum heat transfer (Nu = 33.4859) achieved at: α = 1°, Re = 40, φ = 3 %, Ha = 50, Rd = 1, Kn = 0.04, De = 0.5, Ro = 50, ε = 0, λ = 0.5 whereas a minimum flow resistance (Cf = -2.60454) occurred at: α = -3°, Re = 60, φ = 6 %, Ha = 25, Rd = 1, Kn = 0, De = 0.5, Ro = 50, ε = 0.2, λ = 0.5. For the convergent channel configuration (α = -3°), the friction coefficient was 28.3 % higher than in the divergent channel (α = 5°) under identical flow conditions. This work advances the field beyond previous studies by comprehensively analyzing the synergistic effects of rotation, magnetohydrodynamic, radiation, and channel geometry on the performance of ternary hybrid nanofluids, providing crucial insights for designing more efficient thermal systems in electronics cooling, heat exchangers, and industrial processing applications. © 2025 The Authors

关键词： Box-Behnken Design Convergent/Divergent Channels Heat Transfer Enhancement Non-linear Solar Radiation Ternary Hybrid Nanofluids Variable thermal conductivity

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Critical pore radius and transport properties of disordered hard- and overlapping-sphere models

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Physical Review E 2021年第1期104卷 014127-014127页

作者： Michael A. Klatt Robert M. Ziff Salvatore Torquato Department of Physics Princeton University Princeton New Jersey 08544 USA Institut für Theoretische Physik FAU Erlangen-Nürnberg Staudtstr. 7 91058 Erlangen Germany Center for the Study of Complex Systems and Department of Chemical Engineering University of Michigan Ann Arbor Michigan 48109 USA Department of Chemistry Princeton Institute for the Science and Technology of Materials and Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

Transport properties of porous media are intimately linked to their pore-space microstructures. We quantify geometrical and topological descriptors of the pore space of certain disordered and ordered distributions of spheres, including pore-size functions and the critical pore radius δc. We focus on models of porous media derived from maximally random jammed sphere packings, overlapping spheres, equilibrium hard spheres, quantizer sphere packings, and crystalline sphere packings. For precise estimates of the percolation thresholds, we use a strict relation of the void percolation around sphere configurations to weighted bond percolation on the corresponding Voronoi networks. We use the Newman-Ziff algorithm to determine the percolation threshold using universal properties of the cluster size distribution. The critical pore radius δc is often used as the key characteristic length scale that determines the fluid permeability k. A recent study [Torquato, Adv. Wat. Resour. 140, 103565 (2020)] suggested for porous media with a well-connected pore space an alternative estimate of k based on the second moment of the pore size 〈δ2〉, which is easier to determine than δc. Here, we compare δc to the second moment of the pore size 〈δ2〉, and indeed confirm that, for all porosities and all models considered, δc2 is to a good approximation proportional to 〈δ2〉. However, unlike 〈δ2〉, the permeability estimate based on δc2 does not predict the correct ranking of k for our models. Thus, we confirm 〈δ2〉 to be a promising candidate for convenient and reliable estimates of the fluid permeability for porous media with a well-connected pore space. Moreover, we compare the fluid permeability of our models with varying degrees of order, as measured by the τ order metric. We find that (effectively) hyperuniform models tend to have lower values of k than their nonhyperuniform counterparts. Our findings could facilitate the design of porous media with desirable transport properties via targete

关键词： Geophysical networks materials Patterns in complex systems

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Electrochemical and quantum chemical investigation on the adsorption behavior of a schiff base and its metal complex for corrosion protection of mild steel in 15 wt% HCl solution

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Heliyon 2024年第23期10卷 e40662页

作者： El-Haitout, Badr Sardjono, Ratnaningsih Eko Es-Sounni, Bouchra Chafiq, Maryam Salghi, Rachid Bakhouch, Mohamed Al-Moubaraki, Aisha H. Al-Ahmari, Jamilah M. Al-Ghamdi, Azza A. Fahim, Mohammed Hammouti, Belkheir Chaouiki, Abdelkarim Ko, Young Gun Laboratory of Applied Chemistry and Environment ENSA University Ibn Zohr PO Box 1136 Agadir 80000 Morocco Chemistry Program Universitas Pendidikan Indonesia Setiabudi 229 Bandung 40154 Indonesia Laboratory of Innovative Material and Biotechnology of Naturel Resources Faculty of Sciences of Meknes Moulay Ismail University Morocco Integrated Materials Chemistry Laboratory School of Materials Science and Engineering Yeungnam University Gyeongsan 38541 South Korea Euromed University of Fes UEMF Morocco Laboratory of Bioorganic Chemistry Department of Chemistry Faculty of Sciences Chouaïb Doukkali University P.O. Box 24 El Jadida M-24000 Morocco Department of Chemistry Faculty of Sciences–Alfaisaliah Campus University of Jeddah Jeddah 21589 Saudi Arabia

This work evaluates the effectiveness of Schiff base derivatives, namely, 2,2'-((1E,1′E)-((2,2-dimethylpropane-1,3-diyl)bis(azaneylylidene))bis(methaneylylidene))diphenol (DAMD) and (2-((E)-((3-(((E)-2-hydroxybenzylidene)amino)-2,2dimethylpropyl)imino)methyl)phenoxy) zinc (HDMZ), as corrosion inhibitors for mild steel in a 15 % HCl solution. By employing a blend of experimental assessments and theoretical computations, such as electrochemical tests, morphological observations, and theoretical simulations, the study achieved an impressive up to 94.6 % inhibition efficiency. Notably, HDMZ exhibited significant protective properties. The results of PDP showed that both inhibitors act as mixed-type corrosion inhibitors. SEM surface analysis of the uninhibited and inhibited samples revealed the formation of a protective layer of inhibitor molecules on the mild steel surface to mitigate its corrosion. The Langmuir adsorption model verified the occurrence of dual adsorption, while theoretical simulations offered insights into the underlying interaction mechanisms. The identification of Schiff-based inhibitors reveals a pronounced synergistic effect in corrosion inhibition, marking a significant advancement in understanding corrosion control mechanisms. This study illuminates the process of forming covalent bonds between inhibitor molecules and iron atoms, presenting a hopeful path towards the advancement of corrosion inhibitors tailored for industrial use. The parallel adsorption configuration and mutual interactions form a stable structure, reinforcing the organic-metal bonds and enhancing both chemical and physical adhesion to the steel surface. These findings indicate that the synergistic effect of molecular interactions and polar-rich regions offers a promising strategy for designing functional hybrid materials. © 2024 The Authors

关键词： Adsorption behavior Corrosion inhibitor Electrochemistry Molecular modelling Schiff base metal complex

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Controlled synthetic chirality in macroscopic assemblies of carbon nanotubes

arXiv

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arXiv 2023年

作者： Doumani, Jacques Lou, Minhan Dewey, Oliver Hong, Nina Fan, Jichao Baydin, Andrey Yomogida, Yohei Yanagi, Kazuhiro Pasquali, Matteo Saito, Riichiro Kono, Junichiro Gao, Weilu Department of Electrical and Computer Engineering Rice University HoustonTX United States Applied Physics Graduate Program Smalley–Curl Institute Rice University HoustonTX United States Department of Electrical and Computer Engineering The University of Utah Salt Lake CityUT United States Carbon Hub Rice University HoustonTX United States Department of Chemical and Biomolecular Engineering Rice University HoustonTX United States J.A. Woollam Co. Inc. LincolnNE United States Smalley–Curl Institute Rice University HoustonTX United States Department of Physics Tokyo Metropolitan University Tokyo Japan Department of Chemistry Rice University HoustonTX United States Department of Materials Science and NanoEngineering Rice University HoustonTX United States Department of Physics Tohoku University Sendai Japan Department Physics and Astronomy Rice University HoustonTX United States

There is an emerging recognition that successful utilization of chiral degrees of freedom can bring new scientific and technological opportunities to diverse research areas. Hence, methods are being sought for creating artificial matter with controllable chirality in an uncomplicated and reproducible manner. Here, we report the development of two straightforward methods for fabricating wafer-scale chiral architectures of ordered carbon nanotubes (CNTs) with tunable and giant circular dichroism (CD). Both methods employ simple approaches, (i) mechanical rotation and (ii) twist-stacking, based on controlled vacuum filtration and do not involve any sophisticated nanofabrication processes. We used a racemic mixture of CNTs as the starting material, so the intrinsic chirality of chiral CNTs is not responsible for the observed chirality. In particular, by controlling the stacking angle and handedness in (ii), we were able to maximize the CD response and achieve a record-high deep-ultraviolet ellipticity of 40 ± 1 mdeg/nm. Our theoretical simulations using the transfer matrix method reproduce the salient features of the experimentally observed CD spectra and further predict that a film of twist-stacked CNTs with an optimized thickness will exhibit an ellipticity as high as 150 mdeg/nm. The created wafer-scale objects represent a new class of synthetic chiral matter consisting of ordered quantum wires whose macroscopic properties are governed by nanoscopic electronic signatures such as van Hove singularities. These artificial structures with engineered chirality will not only provide playgrounds for uncovering new chiral phenomena but also open up new opportunities for developing high-performance chiral photonic and optoelectronic devices. © 2023, CC BY.

关键词： Carbon nanotubes

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A deep potential model with long-range electrostatic interactions

arXiv

引用

arXiv 2021年

作者： Zhang, Linfeng Wang, Han Muniz, Maria Carolina Panagiotopoulos, Athanassios Z. Car, Roberto Weinan, E. DP Technology Beijing China Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Fenghao East Road 2 Beijing100094 China HEDPS CAPT College of Engineering Peking University Beijing100871 China Department of Chemical and Biological Engineering Princeton University PrincetonNJ08544 United States Department of Chemistry Department of Physics Program in Applied and Computational Mathematics Princeton Institute for the Science and Technology of Materials Princeton University PrincetonNJ08544 United States School of Mathematical Sciences Peking University Beijing100871 China AI for Science Institute Beijing China Department of Mathematics and Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States

Machine learning models for the potential energy of multi-atomic systems, such as the deep potential (DP) model, make possible molecular simulations with the accuracy of quantum mechanical density functional theory, at a cost only moderately higher than that of empirical force fields. However, the majority of these models lack explicit long-range interactions and fail to describe properties that derive from the Coulombic tail of the forces. To overcome this limitation we extend the DP model by approximating the long-range electrostatic interaction between ions (nuclei+core electrons) and valence electrons with that of distributions of spherical Gaussian charges located at ionic and electronic sites. The latter are rigorously defined in terms of the centers of the maximally localized Wannier distributions, whose dependence on the local atomic environment is modeled accurately by a deep neural network. In the deep potential long-range (DPLR) model, the electrostatic energy of the Gaussian charge system is added to short-range interactions that are represented as in the standard DP model. The resulting potential energy surface is smooth and possesses analytical forces and virial. Missing effects in the standard DP scheme are recovered, improving on accuracy and predictive power. By including long-range electrostatics, DPLR correctly extrapolates to large systems the potential energy surface learned from quantum mechanical calculations on smaller systems. We illustrate the approach with three examples, the potential energy profile of the water dimer, the free energy of interaction of a water molecule with a liquid water slab, and the phonon dispersion curves of the NaCl crystal. © 2021, CC BY.

关键词： Electrostatics

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Stress state of unbonded flexible pipe’s tensile armour wires inside end-fittings 29th

Stress state of unbonded flexible pipe’s tensile armour wir...

引用

29th International Ocean and Polar engineering Conference, ISOPE 2019

作者： Theotokoglou, Efstathios E. Anastasiadis, Panagiotis S. Michailides, Constantine Department of Mechanics Laboratory of Testing and Materials School of Applied Mathematical and Physical Science National Technical University of Athens Attica Athens Greece Department of Civil Engineering and Geomatics Cyprus University of Technology Limassol Cyprus

ISBN: (纸本)9781880653852

The present paper addresses the stresses developing, inside the End-Fitting (EF), on the tensile armour wires of a metal based unbonded flexible pipe under axial tensile operational loads. To this end, a bi-dimensional finite element model that estimates the stress state of tensile armour wires inside the EF is developed. The stresses induced during the EF assembling procedure as well as the Factory Acceptance Test (FAT) are considered in the developed numerical model. An analytical approach to this problem, suggested by Campello (2014) and Campello et al. (2016), is utilized as a benchmarking tool in order to evaluate the developed numerical model’s performance. The results obtained show good agreement between the developed model and the analytical approach. A high concentration of stresses on the tensile armour wires inside the EF, at a key point near the EF’s entrance, is observed under all operational load cases. Moreover, the results suggest that the EF assembly procedure and the FAT test need to be indeed considered, as they yield significant residual stresses on the tensile armour wires inside the EF. © 2019 by the International Society of Offshore and Polar Engineers (ISOPE).

关键词： Finite element method

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