3D Test Research Articles

High order recovery of geometric interfaces from cell-average data

We consider the problem of recovering multivariate characteristic functions u := χΩ from cell-average data on a coarse grid, motivated in particular by the accurate treatment of interfaces in finite volume schemes. While linear recovery methods are known to perform poorly, nonlinear strategies based on local reconstructions of the jump interface Γ := ∂Ω by geometrically simpler interfaces may offer significant improvements. We study two main families of local reconstruction schemes the first one based on nonlinear least-squares fitting, the second one based on the explicit computation of a polynomial-shaped curve fitting the data, which yields simpler numerical computations and high order geometric fitting. For each of them, we derive a general theoretical framework which allows us to control the recovery error by the error of best approximation up to a fixed multiplicative constant. Numerical tests in 2d illustrate the expected approximation order of these strategies. Several extensions are discussed, in particular the treatment of piecewise smooth interfaces with corners.

Solving crystallization/precipitation population balance models in CADET, Part II: Size-based Smoluchowski coagulation and fragmentation equations in batch and continuous modes

A particle size-based Smoluchowski coagulation and fragmentation equation was solved in the free and open source process modeling package CADET. The WFV and MCNP schemes were selected to discretize the internal particle size coordinate. Weights in these schemes were modified to preserve and conserve the zeroth and third moments for size-based equations. Modified propositions and proofs for the scheme are provided. Analytical Jacobians were derived and implemented to reduce the solver’s runtime. A two-dimensional Smoluchowski coagulation and fragmentation equation with axial position as external coordinate was formulated and discretized to support simulations of continuous particulate processes in dispersive plug flow reactors. Five 1D and four 2D test cases were used to validate the implementation and benchmark the solver’s performance. The runtime, L1 error norm, L1 error rate, particle size distribution moments up to sixth order and several scalar metrics were analyzed in detail.

Discretisations of mixed-dimensional Thermo-Hydro-Mechanical models preserving energy estimates

In this study, we explore mixed-dimensional Thermo-Hydro-Mechanical (THM) models in fractured porous media accounting for Coulomb frictional contact at matrix fracture interfaces. The simulation of such models plays an important role in many applications such as hydraulic stimulation in deep geothermal systems and assessing induced seismic risks in CO2 storage. We first extend to the mixed-dimensional framework the thermodynamically consistent THM models derived in [19] based on first and second principles of thermodynamics. Two formulations of the energy equation will be considered based either on energy conservation or on the entropy balance, assuming a vanishing thermo-poro-elastic dissipation. Our focus is on space time discretisations preserving energy estimates for both types of formulations and for a general single phase fluid thermodynamical model. This is achieved by a Finite Volume discretisation of the non-isothermal flow based on coercive fluxes and a tailored discretisation of the non-conservative convective terms. It is combined with a mixed Finite Element formulation of the contact-mechanical model with face-wise constant Lagrange multipliers accounting for the surface tractions, which preserves the dissipative properties of the contact terms. The discretisations of both THM formulations are investigated and compared in terms of convergence, accuracy and robustness on 2D test cases. It includes a Discrete Fracture Matrix model with a convection dominated thermal regime, and either a weakly compressible liquid or a highly compressible gas thermodynamical model.

Numerical implementation of an extended multi-resolution SPH-PD coupling model for fluid-structure interaction problem with impacting failure

Considering the fluid-structure impacting failure problems with large size, this paper presents an extended multi-resolution smoothed particle hydrodynamics (SPH)-peridynamics (PD) coupling model. The influence domain and the interpolation smoothing length are innovatively introduced to reconstruct governing equations for interactions between particles of diverse resolutions, ensuring system-wide momentum conservation. Then, an adaptive multi-level cell neighborhood search (AMCNS) algorithm is presented, designed to reduce the time of neighborhood search in multi-resolution simulations. Several 2D and 3D validation tests demonstrate the accuracy of the multi-resolution SPH-PD model in describing solid deformation and fluid impact pressure. The multi-resolution SPH-PD model significantly enhances computational efficiency and can depict the process of structural failure under conditions where a wide difference in scale between waves and structures.

Dual-stage Acting Dendrimeric Nanoparticle for Deepened Chemotherapeutic Drug Delivery to Tumor Cells.

We report on the design of hypoxia-induced dual-stage acting dendrimeric nanoparticles (NPs) for selective delivery of two chemotherapeutic model drugs doxorubicin (DOX) and tirapazamin (TPZ) for deepened drug delivery into hypoxic tumors in vitro. PAMAM G5 dendrimers were crosslinked with a hypoxic azo linker, attached to a mPEG to form a detachable corona on the dendrimer surface (PAP NPs). NPs were characterized by Zeta sizer, transmission electron microscope (TEM), Fourier transforms infrared (FTIR) and drug release kinetics. The anti-cancer performance of PAPs was evaluated by numerous tests in 2D and 3D cultured MDA-MB-231 breast cancer cells. MTT assay showed a significant difference between PAP and PAMAMG5 in terms of biocompatibility, and the effect of PAP@DOX was significantly greater than free DOX in hypoxic conditions. The results of DAPI and Annexin V-FITC/PI cell staining also confirmed uniform drug penetration as validated by induction of 90% cell apoptosis in spheroids and a high level of PAP@DOX-induced ROS generation under hypoxia conditions. Mechanistically, PAP@DOX significantly reduced the expression of mTOR, and Notch1, while the expression of Bax and Caspase3 was considerably unregulated, compared to the controls. Importantly, hypoxia-responsive disintegration and hypoxia-induced activation of HAP drug were synergized to promote deep and homogenous HAP distribution in whole microtumor regions to efficiently eliminate residual tumor cells. Our results indicate the safety and high therapeutic potential of PAP system for targeted drug delivery of chemotherapeutics in particular HAPs which show maximum anti-cancer activity against hypoxic solid tumors.

Frozen-field Modeling of Coronal Condensations with MPI-AMRVAC. I. Demonstration in Two-dimensional Models

Large-scale coronal plasma evolutions can be adequately described by magnetohydrodynamics (MHD) equations. However, full multidimensional MHD simulations require substantial computational resources. Given the low plasma β in the solar corona, in many coronal studies, it suffices to approximate the magnetic field to remain topologically fixed and effectively conduct one-dimensional (1D) hydrodynamic (HD) simulations instead. This approach is often employed in studies of coronal loops and their liability to form condensations related to thermal instability. While 1D HD simulations along given and fixed field line shapes are convenient and fast, they are difficult to directly compare with multidimensional phenomena. Therefore, it is more convenient to solve volume-filling, multidimensional versions of the MHD equations where we freeze the magnetic field, transforming it into frozen-field HD (ffHD) equations for simulation. We have incorporated this ffHD module into our open-source MPI-AMRVAC code and tested it using a two-dimensional (2D) evaporation–condensation model to study prominence formation due to radiative losses. The 2D ffHD results are compared with those from actual 2D MHD and pseudo-2D HD simulations, analyzing the differences and their causes. Pseudo-2D studies account for the known flux tube expansion effects. Overall, the performance of 2D ffHD is close to that of 2D MHD and pseudo-2D HD. The 2D tests conducted in this paper will be extended in follow-up studies to 3D simulations based on analytical or observational approaches.

Modal effects of span-layout types on coupled flutter of long-span suspension bridges

This study provides a theoretical explanation for a perplexing experimental phenomenon observed frequently in suspension bridge flutter testing, where the flutter critical wind speed (Ucr) predicted by two-dimensional (2D) section model testing is higher than that predicted by three-dimensional (3D) full aeroelastic model testing. Six long-span suspension bridges with either a single simply supported span or multiple continuously supported spans were taken as research examples, then the comparative studies on the flutter critical wind speeds, flutter frequencies, modal energy ratios and aerodynamic damping corresponding to 2D and 3D coupled flutter states were carried out to illustrate the flutter modal effects. The research findings indicate that the Ucr of 2D testing being higher than that of 3D testing is an inherent characteristic for single-span simply-supported suspension bridges, which can be attributed to the prominent aerodynamic negative damping associated with 2nd-order vertical bending mode. However, due to the aerodynamic positive damping associated with 3rd-order vertical bending mode, the Ucr of 2D testing is consistently lower than that of 3D testing in the cases of multi-spans continuously-supported suspension bridges. Additionally, to eliminate unsafe 2D evaluations, a reasonable modal matching principle is recommended for section model testing of single-span simply-supported suspension bridges.

Ensemble variational Bayesian approximation for the inversion and uncertainty quantification of Darcy flows in heterogeneous porous media with random parameters

The inversion and uncertainty quantification of physical parameters are important for many science and engineering problems. For nonlinear parameter inversion problems of flows in hydrocarbon reservoirs, estimating the true posterior probability distribution function for the random parameter is difficult when the dimension of the parameter is relatively high. Inversion methods such as gradient-based or heuristic optimization methods searching for the maximum a posterior are generally point-estimate, while uncertainty quantification using MCMC is computationally expensive. In the current study, a new ensemble variational Bayesian approximation method is developed to estimate the posterior probability density using an ensemble of realizations regarded as a trial sample distribution. The objective is to optimize the trial sample distribution such that the evidence lower bound is maximized indicating that the distance between the trial and true posterior distribution is minimized. A subspace is built using principle component analysis based on finite samples to obtain a diagonal positive-definite covariance matrix, and ensemble-based data assimilation is used to optimize the trial distribution efficiently. Heterogeneous 2D and 3D test cases of transient single- and two-phase Darcy flows are presented for validation.

An operator-splitting numerical scheme for relativistic magnetohydrodynamics

We describe a novel operator-splitting approach to numerical relativistic magnetohydrodynamics designed to expand its applicability to the domain of ultra-high magnetisation. In this approach, the electromagnetic field is split into the force-free component, governed by the equations of force-free degenerate electrodynamics (FFDE), and the perturbation component, governed by the perturbation equations derived from the full system of relativistic magnetohydrodynamics (RMHD). The combined system of the FFDE and perturbation equations is integrated simultaneously, for which various numerical techniques developed for hyperbolic conservation laws can be used. At the end of every time-step of numerical integration, the force-free and the perturbation components of the electromagnetic field are recombined and the result is regarded as the initial value of the force-free component for the next time-step, whereas the initial value of the perturbation component is set to zero. To explore the potential of this approach, we build a 3rd-order WENO code, which was used to carry out 1D and 2D test simulations. Their results show that this operator-splitting approach allows us to bypass the stiffness of RMHD in the ultra-high-magnetisation regime where the perturbation component becomes very small. At the same time, the code performs very well in problems with moderate and low magnetisation too.

Abstract 4236: PDX-derived organoids (PDXO) are valuable tools to unveil the shortcomings of new anti-cancer drug candidates

Abstract Introduction: Tumor organoids are increasingly being used as predictive preclinical cancer models, as they reflect the original tumor features and patient drug responses. However, systematic comparisons between organoids and traditional 2D cell lines or 3D spheroids are lacking. Method: We established over 30 PDX-derived organoid (PDXO) models with KRAS mutations and tested three inhibitors targeting the KRAS pathway: VS-6766(RAF/MEK inhibitor), Trametinib (MEK inhibitor), and MRTX1133 (a Phase II drug targeting KRASG12D) against these models. Results: IC50 results indicated that most models responded to treatment. For some cell lines we detected differential drug responses in 2D vs. 3D testing with 3Dspheroids being more sensitive to inhibitors than 2D cell lines (on average ~10 fold). PDXO models exhibited greater individual differences in drug response, with a subset of models demonstrating no sensitivity to MRTX1133. This is consistent with published results showing that some KRASG12D-mutant PDX models were less sensitive to MRTX11331. Similarly, the clinical trial data for the KRASG12C inhibitor Adagrasib revealed distinctions in the response of patients2. Further analysis with WES (whole exome sequencing) and RNA-sequencing identified potential genotypic mutations and differential expressions of signaling pathways related to drug resistance. Subsequent drug combination testing showed that targeting these pathways could enhance the MRTX1133 efficacy in the resistant PDXO models. Summary: Our research confirms that drug testing on organoids predicts responses in mouse models and clinical trials. In combination with multi-omics and bioinformatics analysis, the platform can be used for evaluating drug resistances, identifying new targets, developing new drug combination therapies, and ultimately improving the creation of new cancer therapeutics. Citation Format: Yuhui Wang, Lin Feng, Han Liu, Junwen Zhang, Kaiqiang Hu, Pengwei Pan, Fang He. PDX-derived organoids (PDXO) are valuable tools to unveil the shortcomings of new anti-cancer drug candidates [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4236.

A bubble VEM-fully discrete polytopal scheme for mixed-dimensional poromechanics with frictional contact at matrix–fracture interfaces

This article addresses the discretisation of fractured/faulted poromechanical models using 3D polyhedral meshes in order to cope with the geometrical complexity of faulted geological models. A new polytopal scheme is proposed for contact-mechanics, based on a mixed formulation combining a fully discrete space and suitable reconstruction operators for the displacement field together with a face-wise constant approximation of the Lagrange multiplier, accounting for the surface tractions along the fracture/fault network. To ensure the inf–sup stability of the mixed formulation, a bubble-like degree of freedom is included in the discrete space of displacements and used in the reconstruction operators. This fully discrete scheme for the displacement is equivalent to a low-order Virtual Element scheme, with a bubble enrichment of the virtual space. This P1-bubble VEM–P0 mixed discretisation is combined with an Hybrid Finite Volume scheme for the Darcy flow. The proposed approach is adapted to complex geometry with a network of planar faults/fractures which can include corners, tips and intersections; it leads to efficient semi-smooth Newton solvers for the contact-mechanics, and preserves the dissipative properties of the fully coupled model. The scheme is numerically investigated in terms of convergence and robustness on several 2D and 3D test cases, using either analytical or numerical reference solutions and considering both the stand alone static contact-mechanics model and the fully coupled poromechanical model.

Modeling and numerical simulation of a type of pure-viscoacoustic-wave equation in attenuated transversely isotropic media

The anisotropy and attenuation features of subsurface media significantly affect seismic data processing. Ignoring anisotropy and attenuation in seismic wave propagation may result in inaccurate reflector positions, dimming amplitudes, and reduced spatial resolution in the imaging results. Therefore, accurate seismic wave modeling of anisotropy and attenuation is essential for understanding wave propagation in the earth’s interior. This paper derives three pure-viscoacoustic-wave equations from characterizing the earth’s frequency-independent Q behavior in transversely isotropic (TI) media. First, we develop three time-space domain pure-qP-wave equations in TI media based on different approximation methods, whose coefficients can be determined by different approximation methods and Thomsen’s anisotropic parameters [Formula: see text], [Formula: see text]. Subsequently, we introduce the Kelvin-Voigt attenuation model into our derived three time-space domain pure-qP-wave equations and then obtain three pure-viscoacoustic-wave equations. To further demonstrate the effectiveness and accuracy of our methods, we provide some 2D and 3D numerical tests. The numerical results indicate that the wavefield generated by pure-qP-wave equations and pure-viscoacoustic-wave equations have accurate kinematic characteristics of qP-wave in TI media and attenuated TI media and are free of S-wave artifacts while remaining stable under Thomsen’s anisotropic parameters [Formula: see text], so our methods have broader applicability compared with some existing methods. At the same time, the simulation results of pure-viscoacoustic-wave equations also reflect the absorption and attenuation characteristics of qP-waves in attenuated TI media.

Three Virtual Reality Environments for the Assessment of Executive Functioning Using Performance Scores and Kinematics: An Embodied and Ecological Approach to Cognition.

Virtual reality (VR) is an attractive technology for cognitive assessment, as it provides a more embodied experience compared with typical test situations, such as those using paper and pencil. In addition, VR can immerse individuals in complex situations similar to real-life ones, thereby improving the ecological validity (i.e., face validity) of the assessment. VR also offers improved scoring of tests as it facilitates the tracking of kinematic information and the temporal tracking of activities. This study assesses the correlation between scores on executive function assessments using standard neuropsychological tasks in paper-and-pencil format, on a tablet, and in three immersive VR environments, each designed to involve specific aspects of executive function. This study also aims to assess the correlation between these performance scores and a set of kinematic measures (speed, duration, and distance traveled by the hand) collected in VR. The outcomes, including performance scores and kinematic measures, correlate both with traditional assessment methods (such as paper and pencil, and computerized 2D tests) and with each other, suggesting their potential usefulness in clinical and research contexts. The discussion focuses on the advantages of embodied, situated, and spatialized tests for cognitive assessment and the benefits of kinematic tracking in VR tests for the quality of this assessment.

On the convergence of 2D P4+$$ {P}_{4+} $$ triangular and 3D P6+$$ {P}_{6+} $$ tetrahedral divergence‐free finite elements

AbstractWe show that the discrete velocity solution converges at the optimal order when solving the steady state Stokes equations by the ‐ mixed finite element method for on 2D triangular grids or on tetrahedral grids, even in the case the inf‐sup condition fails. By a simple ‐projection of the discrete pressure to the space of continuous polynomials, we show this post‐processed pressure solution also converges at the optimal order. Both 2D and 3D numerical tests are presented, verifying the theory.

In situ analysis of plastic flow near interfaces and free surfaces

Spatio–temporal analysis of large strain plastic flow at or near interfaces and free surfaces is important for understanding practical problems in the cutting and sliding of metals. In this context, the use of direct in situ imaging, coupled with digital image correlation (DIC), has gained popularity in the past couple of decades since it does not require a priori assumptions about the nature of the deformation field. Moreover, the application of DIC to dynamically evolving interfaces remains challenging. Common techniques such as hierarchical grid refinement or post analysis interpolation are either spatially restrictive or can lead to significant data loss. In this work, we present an alternative experimental method -termed ensemble averaged DIC- that circumvents both these limitations by resorting to ensemble averaging of deformation fields over a number of related, yet independent, unstructured grids. The resulting fields are accurate to second order and are benchmarked against standard 1D and 2D test cases, before being applied to two plastic flow fields arising in deformation processing—frictional sliding and orthogonal machining. We benchmark our scheme against commercially available packages to demonstrate its enhanced ability to resolve plastic flow near interface and free surface. The scheme is shown to accurately estimate residual surface strains on the cut/processed material surface without any a priori information about the flow field.

Quantum control based on three forms of Lyapunov functions

This paper introduces the quantum control of Lyapunov functions based on the state distance, the mean of imaginary quantities and state errors. In this paper, the specific control laws under the three forms are given. Stability is analyzed by the LaSalle invariance principle and the numerical simulation is carried out in a 2D test system. The calculation process for the Lyapunov function is based on a combination of the average of virtual mechanical quantities, the particle swarm algorithm and a simulated annealing algorithm. Finally, a unified form of the control laws under the three forms is given.

An efficient bilinear interface reconstruction algorithm and consistent multidimensional unsplit advection scheme for accurate capturing of highly-curved interfacial shapes on structured grids

A new bilinear interface reconstruction algorithm (BLIC) is presented to capture highly-curved interfaces more accurately on structured grids without a significant increase in computational costs compared to the standard piecewise linear interface calculation (PLIC) methods. The new reconstruction algorithm uses the initial PLIC segment and improves continuity of the interface using an averaging method. A curvature-weighted method improves the repositioning of the linear segments.A new unsplit donating quadrant advection (DQA) scheme is introduced that is conservative and can create consistency with the momentum flux for two-phase flow models with a staggered MAC arrangement of variables within a grid cell. The consistent discretization of the fluxes prevents spurious interface velocities, negative densities, and instabilities. Standard 2D test cases and benchmarks demonstrate the performance of the BLIC and the DQA scheme, showing high accuracy and low costs compared to other available methods.

Effect of Different Modalities of Facial Images on ASD Diagnosis using Deep Learning-Based Neural Network

This paper aims to investigate the effectiveness of different modalities of facial images for diagnosing Autism Spectrum Disorder (ASD) using deep learning-based neural networks. The motivation behind this study is the potential of advanced technologies to aid in accurately diagnosing ASD. The research revolves around the need to explore the performance of deep learning models on different modalities of facial images and to identify the challenges and potential solutions associated with each modality. The methodology involves training and testing the models on the respective datasets and analysing their accuracy and performance. ResNet50V2 achieved a 100% accuracy on the 2D test dataset, while Xception achieved an accuracy of 93.75% on the 3D test set. The detection accuracy suggests that neural networks-based deep learning methods have the potential to diagnose ASD using facial images accurately. However, the models perform better on 2D data, highlighting the need for additional training on larger 3D datasets to improve accuracy on 3D images. The study contributes to the field by providing insights into the performance of different modalities of facial images, emphasizing the need for robust datasets, and suggesting future research directions to enhance the accuracy and efficiency of ASD diagnosis using deep learning techniques.

Capturing photoionization shadows in streamer simulations using the discrete ordinates method

Numerical simulations of streamer propagation involving photoionization are presented, utilizing an ANSYS Fluent implementation that employs unstructured meshes and automatic mesh refinement. Two approximate methods for radiative transfer, used to handle computation of the photoionization source terms, are compared: the Eddington approximation and the discrete ordinates (DOs) method. The former is commonly employed in streamer simulations, while the latter is well-established in other branches of computational physics, such as radiative heat transfer. A 2D test case with two distinct regions, where streamer propagation can be triggered thanks to the protruded electrodes, is introduced. The two regions are partially separated by an opaque solid insulator barrier to study the effects of photoionization shadows on streamer inception and propagation. The primary positive streamer is initiated by placing a neutral plasma patch close to one of the electrode protrusions, while the secondary positive streamer, in the other region of the computational domain, is initiated by photoionization originating from the primary streamer zone. The Eddington approximation results in an excessively high photoionization source in the secondary streamer inception zone, as it fails to capture the shadowing effects of the opaque dielectric barrier. Consequently, this leads to a fast secondary streamer inception process, followed by rapid streamer propagation. On the other hand, the DOs method accurately captures the shadow, leading to a delayed secondary streamer inception. It is also shown that both methods exhibit very similar results when the dielectric barrier is transparent and the shadow is absent. This work demonstrates that using the DOs method for streamer simulations offers considerable advantages over the Eddington approximation, especially in cases involving more complex geometries where shadows need to be captured for accurate streamer inception and dynamics.

An accurate, robust and efficient convection-pressure flux splitting scheme for compressible Euler flows

The popular Roe's flux difference splitting scheme has high resolution for various types of discontinuities but it fails to satisfy the entropy condition and will encounter different forms of instability while calculating shock waves, such as the post-shock oscillation of the slowly moving shock waves and the carbuncle phenomenon of the multidimensional strong shock waves. In the present work, a simple flux difference splitting scheme based on the idea of convection-pressure splitting is proposed. With application of the Toro-Vázquez splitting procedure, the flux of the 3D Euler equations is split into the convection part and the pressure part. Due to having a complete set of linearly independent eigenvectors, the pressure subsystem can be solved by the conventional flux difference splitting method. The weakly hyperbolic convection subsystem, however, does not have a complete set of linearly independent eigenvectors and thus is solved by the flux difference splitting scheme based on the generalized eigenvectors [1]. In addition, a strategy that combines the THINC reconstruction with the BVD algorithm is employed on the numerical dissipation term of the convection flux to further improve the resolution for contact discontinuities. A comprehensive range of numerical simulations for classical 1D, 2D and 3D benchmark test problems demonstrate the good performance of the proposed scheme.