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Engineering Nano/Microscale Chiral Self‑Assembly in 3D Printed Constructs

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Nano-Micro Letters 2024年第3期16卷 313-332页

作者： Mohsen Esmaeili Ehsan Akbari Kyle George Gelareh Rezvan Nader Taheri‑Qazvini Monirosadat Sadati Department of Chemical Engineering University of South CarolinaColumbiaSC 29208USA TA Instruments Waters LLCNew CastleDE 19720USA Biomedical Engineering Program University of South CarolinaColumbiaSC 29208USA

Helical hierarchy found in biomolecules like cellulose,chitin,and collagen underpins the remarkable mechanical strength and vibrant colors observed in living *** study advances the integration of helical/chiral assembly and 3D printing technology,providing precise spatial control over chiral nano/microstructures of rod-shaped colloidal nanoparticles in intricate *** designed reactive chiral inks based on cellulose nanocrystal(CNC)suspensions and acrylamide monomers,enabling the chiral assembly at nano/microscale,beyond the resolution seen in printed *** employed a range of complementary techniques including Orthogonal Superposition rheometry and in situ rheo-optic measurements under steady shear rate *** techniques help us to understand the nature of the nonlinear flow behavior of the chiral inks,and directly probe the flow-induced microstructural dynamics and phase transitions at constant shear rates,as well as their post-flow ***,we analyzed the photo-curing process to identify key parameters affecting gelation kinetics and structural integrity of the printed object within the supporting *** insights into the interplay between the chiral inks self-assembly dynamics,3D printing flow kinematics and photopolymerization kinetics provide a roadmap to direct the out-of-equilibrium arrangement of CNC particles in the 3D printed filaments,ranging from uniform nematic to 3D concentric chiral structures with controlled pitch length,as well as random orientation of chiral *** biomimetic approach can pave the way for the creation of materials with superior mechanical properties or programable photonic responses that arise from 3D nano/microstructure and can be translated into larger scale 3D printed designs.

关键词： Directed chiral self-assembly Cellulose nanocrystals Bioinspired nanocomposite 3D printing Rheology

Sn-doped cobalt containing perovskite as the air electrode for highly active and durable reversible protonic ceramic electrochemical cells

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Journal of Advanced Ceramics 2024年第1期13卷 63-72页

作者： Min Fu Wenjing Hu Hua Tong Xin Ling Linggui Tan Fanglin Chen Zetian Tao School of Resources Environment and Safety EngineeringUniversity of South ChinaHengyang 421001China Department of Mechanical Engineering University of South CarolinaColumbia 29208USA

One potential solution to the problems of energy storage and conversion is the use of reversible protonic ceramic electrochemical cells(R-PCEC),which are based on the solid oxide fuel cell(SOFC)technology and offer a flexible route to the generation of renewable ***,the R-PCEC development faces a range of significant challenges,including slow oxygen reaction kinetics,inadequate durability,and poor round-trip efficiency resulting from the inadequacy of an air *** address these issues,we report novel B-sites doped Pr_(0.5)Ba_(0.5)Co_(0.7)Fe_(0.3)O_(3−δ)(PBCF)with varying amounts of Sn as the air electrode for R-PCEC to further enhance electrochemical performance at lower *** 600℃,R-PCEC with an air electrode consisting of Pr_(0.5)Ba_(0.5)Co_(0.7)Fe_(0.25)Sn_(0.05)O_(3+δ)has achieved peak power density of 1.12 W∙cm^(−2) in the fuel cell mode and current density of 1.79 A∙cm^(−2) in the electrolysis mode at a voltage of 1.3 ***,R-PCECs have shown good stability in the electrolysis mode of 100 *** study presents a practical method for developing durable high-performance air electrodes for R-PCECs.

关键词： triple conducting oxide dual-element doping protonic ceramic electrochemical cells(PCECs) catalytic

Direct Pointwise Comparison of FE Predictions to StereoDIC Measurements:Developments and Validation Using Double Edge-Notched Tensile Specimen

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Computer Modeling in Engineering & Sciences 2024年第8期140卷 1263-1298页

作者： Troy Myers Michael A.Sutton Hubert Schreier Alistair Tofts Sreehari Rajan Kattil Department of Mechanical Engineering University of South CarolinaColumbiaSC29208USA Correlated Solutions Incorporated 121 Dutchman BlvdColumbiaSC29063USA

To compare finite element analysis(FEA)predictions and stereovision digital image correlation(StereoDIC)strain measurements at the same spatial positions throughout a region of interest,a field comparison procedure is *** procedure includes(a)conversion of the finite element data into a triangular mesh,(b)selection of a common coordinate system,(c)determination of the rigid body transformation to place both measurements and FEA data in the same system and(d)interpolation of the FEA nodal information to the same spatial locations as the StereoDIC measurements using barycentric *** an aluminum Al-6061 double edge notched tensile specimen,FEA results are obtained using both the von Mises isotropic yield criterion and Hill’s quadratic anisotropic yield criterion,with the unknown Hill model parameters determined using full-field specimen strain measurements for the nominally plane stress *** Hill’s quadratic anisotropic yield criterion,the point-by-point comparison of experimentally based full-field strains and stresses to finite element predictions are shown to be in excellent agreement,confirming the effectiveness of the field comparison process.

关键词： StereoDIC spatial co-registration data transformation finite element simulations point-wise comparison of measurements and FEA predictions double edge notch specimen model validation

Exponential Time Differencing Method for a Reaction-Diffusion System with Free Boundary

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Communications on Applied Mathematics and Computation 2024年第1期6卷 354-371页

作者： Shuang Liu Xinfeng Liu Department of Mathematics University of CaliforniaSan Diego9500 Gilman DriveLa JollaCalifornia92093-0112USA Department of Mathematics University of South CarolinaColumbiaSouth Carolina29208USA

For reaction-diffusion equations in irregular domains with moving boundaries,the numerical stability constraints from the reaction and diffusion terms often require very restricted time step sizes,while complex geometries may lead to difficulties in the accuracy when discretizing the high-order derivatives on grid points near the *** is very challenging to design numerical methods that can efficiently and accurately handle both *** an implicit scheme may be able to remove the stability constraints on the time step,however,it usually requires solving a large global system of nonlinear equations for each time step,and the computational cost could be *** factor(IF)or exponential time differencing(ETD)methods are one of the popular methods for temporal partial differential equations(PDEs)among many other *** our paper,we couple ETD methods with an embedded boundary method to solve a system of reaction-diffusion equations with complex *** particular,we rewrite all ETD schemes into a linear combination of specificФ-functions and apply one state-of-the-art algorithm to compute the matrix-vector multiplications,which offers significant computational advantages with adaptive Krylov *** addition,we extend this method by incorporating the level set method to solve the free boundary *** accuracy,stability,and efficiency of the developed method are demonstrated by numerical examples.

关键词： Reaction diffusion equations Free boundary Integrating factor method Level set method

High-speed railway track components inspection framework based on YOLOv8 with high-performance model deployment

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High-Speed Railway 2024年第1期2卷 42-50页

作者： Youzhi Tang Yu Qian Department of Civil and Environmental Engineering University of South CarolinaColumbia 29208USA

Railway inspection poses significant challenges due to the extensive use of various components in vast railway networks,especially in the case of high-speed *** networks demand high maintenance but offer only limited inspection *** response,this study focuses on developing a high-performance rail inspection system tailored for high-speed railways and railroads with constrained inspection *** system leverages the latest artificial intelligence advancements,incorporating YOLOv8 for *** research introduces an efficient model inference pipeline based on a producer-consumer model,effectively utilizing parallel processing and concurrent computing to enhance *** deployment of this pipeline,implemented using C++,TensorRT,float16 quantization,and oneTBB,represents a significant departure from traditional sequential processing *** results are remarkable,showcasing a substantial increase in processing speed:from 38.93 Frames Per Second(FPS)to 281.06 FPS on a desktop system equipped with an Nvidia RTX A6000 GPU and from 19.50 FPS to 200.26 FPS on the Nvidia Jetson AGX Orin edge computing *** proposed framework has the potential to meet the real-time inspection requirements of high-speed railways.

关键词： High-speed railway Track inspection Computer vision Deep learning Edge computing Real-time decision making

Comprehensive cross cancer analyses reveal mutational signature cancer specificity

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Quantitative Biology 2024年第3期12卷 245-254页

作者： Rui Xin Limin Jiang Hui Yu Fengyao Yan Jijun Tang Yan Guo Department of Computer Science University of South CarolinaColumbiaSouth CarolinaUSA Department of Public Health and Sciences Sylvester Comprehensive Cancer CenterUniversity of MiamiMiamiFloridaUSA

Mutational signatures refer to distinct patterns of DNA mutations that occur in a specific context or under certain *** is a powerful tool to describe cancer *** conducted a study to show cancer heterogeneity and cancer specificity from the aspect of mutational signatures through collinearity analysis and machine learning *** thorough training and independent validation,our results show that while the majority of the mutational signatures are distinct,similarities between certain mutational signature pairs can be observed through both mutation patterns and mutational signature *** observation can potentially assist to determine the etiology of yet elusive mutational *** analysis using machine learning approaches demonstrated moderate mutational signature cancer *** cancer among all cancer types demonstrated the strongest mutational signature specificity.

关键词： cancer specificity collinearity analysis DNA mutational signatures machine learning

Efficient fully-decoupled and fully-discrete explicit-IEQ numerical algorithm for the two-phase incompressible flow-coupled Cahn-Hilliard phase-field model

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Science China Mathematics 2024年第9期67卷 2171-2194页

作者： Chuanjun Chen Xiaofeng Yang School of Mathematics and Information Sciences Yantai UniversityYantai 264005China Department of Mathematics University of South CarolinaColumbiaSC 29208USA

In this paper,an efficient fully-decoupled and fully-discrete numerical scheme with second-order temporal accuracy is developed to solve the incompressible hydrodynamically coupled Cahn-Hilliard model for simulating the two-phase fluid flow *** scheme is developed by combining the finite element method for spatial discretization and several effective time marching approaches,including the pressure-correction projection method for dealing with fluid equations and the explicit-invariant energy quadratization(explicit-IEQ)approach for dealing with coupled nonlinear *** obtained scheme is very efficient since it only needs to solve several decoupled,linear elliptic equations with constant coefficients at each time *** also strictly prove the solvability and unconditional energy stability of the scheme,and verify the accuracy and stability of the scheme through plenty of numerical examples.

关键词： finite element method decoupled scheme two-phase fow Cahn-Hilliard equation Navier-Stokes equations energystability

Introducing the n^th-Order Features Adjoint Sensitivity Analysis Methodology for Nonlinear Systems (n^th-FASAM-N): II. Illustrative Example

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American Journal of Computational Mathematics 2024年第1期14卷 43-95页

作者： Dan Gabriel Cacuci Center for Nuclear Science and Energy University of South Carolina Columbia USA

This work highlights the unparalleled efficiency of the “nth-Order Function/ Feature Adjoint Sensitivity Analysis Methodology for Nonlinear Systems” (nth-FASAM-N) by considering the well-known Nordheim-Fuchs reactor dynamics/safety model. This model describes a short-time self-limiting power excursion in a nuclear reactor system having a negative temperature coefficient in which a large amount of reactivity is suddenly inserted, either intentionally or by accident. This nonlinear paradigm model is sufficiently complex to model realistically self-limiting power excursions for short times yet admits closed-form exact expressions for the time-dependent neutron flux, temperature distribution and energy released during the transient power burst. The nth-FASAM-N methodology is compared to the extant “nth-Order Comprehensive Adjoint Sensitivity Analysis Methodology for Nonlinear Systems” (nth-CASAM-N) showing that: (i) the 1st-FASAM-N and the 1st-CASAM-N methodologies are equally efficient for computing the first-order sensitivities;each methodology requires a single large-scale computation for solving the “First-Level Adjoint Sensitivity System” (1st-LASS);(ii) the 2nd-FASAM-N methodology is considerably more efficient than the 2nd-CASAM-N methodology for computing the second-order sensitivities since the number of feature-functions is much smaller than the number of primary parameters;specifically for the Nordheim-Fuchs model, the 2nd-FASAM-N methodology requires 2 large-scale computations to obtain all of the exact expressions of the 28 distinct second-order response sensitivities with respect to the model parameters while the 2nd-CASAM-N methodology requires 7 large-scale computations for obtaining these 28 second-order sensitivities;(iii) the 3rd-FASAM-N methodology is even more efficient than the 3rd-CASAM-N methodo

关键词： Nordheim-Fuchs Reactor Safety Model Feature Functions of Model Parameters High-Order Response Sensitivities to Parameters Adjoint Sensitivity Systems

Volumetric lattice Boltzmann method for pore-scale mass diffusionadvection process in geopolymer porous structures

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2126-2136页

作者： Xiaoyu Zhang Zirui Mao Floyd W.Hilty Yulan Li Agnes Grandjean Robert Montgomery Hans-Conrad zur Loye Huidan Yu Shenyang Hu Purdue University IndianapolisIN46202USA Pacific Northwest National Laboratory RichlandWA99352USA CEA DESISECDMRCUniv.MontpellierMarcouleFrance Department of Chemistry and Biochemistry University of South CarolinaColumbiaSC29208USA

Porous materials present significant advantages for absorbing radioactive isotopes in nuclear waste *** improve absorption efficiency in nuclear waste treatment,a thorough understanding of the diffusion-advection process within porous structures is essential for material *** this study,we present advancements in the volumetric lattice Boltzmann method(VLBM)for modeling and simulating pore-scale diffusion-advection of radioactive isotopes within geopolymer porous *** structures are created using the phase field method(PFM)to precisely control pore *** our VLBM approach,we introduce a concentration field of an isotope seamlessly coupled with the velocity field and solve it by the time evolution of its particle population *** address the computational intensity inherent in the coupled lattice Boltzmann equations for velocity and concentration fields,we implement graphics processing unit(GPU)*** of the developed model involves examining the flow and diffusion fields in porous ***,good agreement is observed for both the velocity field from VLBM and multiphysics object-oriented simulation environment(MOOSE),and the concentration field from VLBM and the finite difference method(FDM).Furthermore,we investigate the effects of background flow,species diffusivity,and porosity on the diffusion-advection behavior by varying the background flow velocity,diffusion coefficient,and pore volume fraction,***,all three parameters exert an influence on the diffusion-advection *** background flow and diffusivity markedly accelerate the process due to increased advection intensity and enhanced diffusion capability,***,increasing the porosity has a less significant effect,causing a slight slowdown of the diffusion-advection process due to the expanded pore *** comprehensive parametric study provides valuable insights into the kinetics of isotope

关键词： Volumetric lattice Boltzmann method(VLBM) Phase field method(PFM) Pore-scale diffusion-advection Nuclear waste treatment Porous media flow Graphics processing unit(GPU) parallelization