Numerical Validation Research Articles

Assessment of medical information on irritable bowel syndrome information in Wikipedia and Baidu Encyclopedia: comparative study.

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder (FGID) with heterogeneous clinical presentations. There are no clear testing parameters for its diagnosis, and the complex pathophysiology of IBS and the limited time that doctors have to spend with patients makes it difficult to adequately educate patients in the outpatient setting. An increased awareness of IBS means that patients are more likely to self-diagnose and self-manage IBS based on their own symptoms. These factors may make patients more likely to turn to Internet resources. Wikipedia is the most popular online encyclopedia among English-speaking users, with numerous validations. However, in Mandarin-speaking regions, the Baidu Encyclopedia is most commonly used. There have been no studies on the reliability, readability, and objectivity of IBS information on the two sites. This is an urgent issue as these platforms are accessed by approximately 1.45 billion people. We compared the IBS content on Wikipedia (in English) and Baidu Baike (in Chinese), two online encyclopedias, in terms of reliability, readability, and objectivity. The Baidu Encyclopedia (in Chinese) and Wikipedia (in English) were evaluated based on the Rome IV IBS definitions and diagnoses. All possible synonyms and derivatives for IBS and IBS-related FGIDs were screened and identified. Two gastroenterology experts evaluated the scores of articles for both sites using the DISCERN instrument, the Journal of the American Medical Association scoring system (JAMA), and the Global Quality Score (GQS). Wikipedia scored higher overall with DISCERN (p<.0001), JAMA (p<.0001) and GQS (p<.05) than the Baidu Encyclopedia. Specifically, Wikipedia scored higher in DISCERN Section 1 (p<.0001), DISCERN Section 2 (p<.01), DISCERN Section 3 (p<.001), and the General DISCERN score (p<.0001) than the Baidu Encyclopedia. Both sites had low DISCERN Section 2 scores (p=.18). Wikipedia also had a larger percentage of high quality scores in total DISCERN, DISCERN Section 1, and DISCERN Section 3 (p<.0001, P<.0001, P<.0004, respectively, based on the above 3 (60%) rule). Wikipedia provides more reliable, higher quality, and more objective IBS-related health information than the Baidu Encyclopedia. However, there should be improvements in the information quality for both sites. Medical professionals and institutions should collaborate with these online platforms to offer better health information for IBS.

Numerical Validation of Fully Coupled Nonlinear Seismic Soil–Pile–Structure Interaction

While many researchers have broadly studied soil–structure interaction (SSI) problems to comprehend SSI effects on the overall system’s behavior, some critical numerical modeling issues have not been sufficiently investigated to achieve the most accurate results. Furthermore, most scholars have not provided detailed explanations of the validation process for their proposed numerical models. Modeling pile foundations in a three-dimensional (3D) continuum system in a fully coupled manner is often challenging for engineers who do not specialize in structural and geotechnical earthquake engineering, as it can be very time-consuming and complicated. Therefore, this work aims to validate a finite element model of seismic soil–pile–structure interaction (SPSI) problems in a continuum soil body by comparing the results of numerical models with those of a centrifuge test and computed numerical simulations available in the literature. In this regard, several newly developed elements in OpenSees (Version 3.6.0) are tested. The results of this work demonstrate a closer alignment with prior experimental research findings. It is believed that providing detailed numerical modeling and validation processes will assist researchers in better understanding crucial issues in modeling soil–pile–structure interaction problems.

Numerical simulation and entropy optimization of hybrid nanofluid flow in an inclined wavy enclosure subjected to thermal radiation

The current study investigates two-dimensional natural convective heat transference and entropy production in a tilted wavy-walled enclosure under the magnetic field and thermal radiation effect. The enclosure is filled with Cu–Al2O3/H2O hybrid nanofluid and subjected to a non-uniformly heated curved left wall, constant cold right curved side, uniformly heated bottom side, and insulated upper side. The regulating formulas in the non-dimensional form are reduced to streaming function-velocity expression and are numerically solved based on the Bi-CGStab method. The simulations are behaved with diverse Rayleigh amounts, Hartmann numbers, an incline angle of the enclosure, radiation parameters, diverse amplitude of the curved wall, and volume fraction of hybrid nanoparticles. Numerical code validation with other published results agrees well with the present outcomes. Heat and entropy generation were improved with the change in dimensionless parameters, and the findings have been clarified through discussion. The observations indicate that the Rayleigh numbers, nanoparticle fractional size, amplitude, and radiation parameter influence the convective effect and entropy production inside the enclosure. In contrast, the Hartmann number detracts from the convective effect. The findings suggest that a rise in the cavity angle may result in a corresponding boost or decline in heat transference. The minimum Nusselt numbers is obtained at [Formula: see text], as the angle of incline of the enclosure restraints the fluid rapidity and diminishes the heat transference rates. To design heat exchangers, this particular study may serve as a guide.

Numerical and experimental validation of tribological phenomenon in wind turbine brake pads using novel Archard's wear coefficient

Designing effective mechanical brakes for wind turbines has been hindered by the historical reliance on simplistic criteria such as wear rate and friction coefficient for material selection. In this study, a novel approach to predicting wear rate was proposed, utilizing Archard's wear coefficient and considering factors such as material composition, hardness, sliding distance, and axial load. Furthermore, we developed a numerical model to simulate the tribological behavior of wind turbine brake pads, integrating the novel wear coefficient derived from a hybrid mathematical model with cubic and radial basis functions. This comprehensive approach bridges the gap between experimental data and theoretical insights, offering a robust framework for optimizing brake pad design and performance.

Fortifying Slab Resilience against Touch-Off Explosions: Integration of Innovative Stud Reinforcements and Computational Analysis

Explosions, once limited to military and accidental contexts, now occur frequently due to advances in warfare, local disputes, and global conflicts. Recent incidents, like urban bombings, emphasize the urgent need for infrastructure to withstand explosions. Slabs, critical in architectural frameworks, are vulnerable to explosive forces due to their slimness, making them prime targets for sabotage. Scholars have explored various strategies to fortify slabs, including the use of advanced materials like CFRP laminates/strips, steel sheets and ultra-high-strength concrete, along with reinforcement techniques such as two-mesh and diagonal reinforcements. A novel approach introduced in current research involves integrating vertical short bars, or studs, to enhance slab resilience against touch-off explosions. The aim of this research endeavor is to assess the impact of studs and their utilization in bolstering the anti-contact-blast capabilities of a concrete slab. To achieve this goal, a specialized framework within the ABAQUS/Explicit 2020 software is employed for comprehensive analysis. Initially, a conventionally reinforced slab devoid of studs serves as the benchmark model for numerical validation, facilitating a comparative assessment of its anti-contact-blast effectiveness against the findings outlined by Zhao and colleagues in 2019. Following successful validation, six additional distinct slab models are formulated utilizing sophisticated software, incorporating studs of varying heights, namely, 15 mm and 10 mm. Each configuration encompasses three distinct welding scenarios: (i) integration with upper-layer bars, (ii) attachment to bottom-layer bars, and (iii) connection to both upper- and bottom-layer bars. The comparative merits of the slabs are evaluated and deliberated upon through the examination of diverse response parameters. The research revealed that the incorporation of studs within slabs yielded notable enhancements in blast resistance. Specifically, taller studs demonstrated exceptional resilience against deformation, cracking, and perforation, while also diminishing plastic damage energy. Particularly noteworthy was the superior performance observed in slabs with studs welded to both upper and lower layers of re-bars. This highlights the critical significance of both the integration of studs and their precise positioning in fortifying structural integrity against blast-induced loadings.

A Novel Adjoint-Based Reduced-Order Model for Depletion Calculations in Nuclear Reactor Physics

The licensing of new reactors implies the use of verified and validated neutronic codes. Numerical validation can rely on sensitivity and uncertainty studies, but they require repeated execution of time-consuming neutron flux and depletion calculations. The computational costs can be reduced by using perturbation theories. However, the uncoupled Depletion Perturbation Theory is restricted to single integral values such as nuclide density. Relying on reduced-basis approaches, which reconstruct all nuclide densities at once, is one way to get around this restriction. Furthermore, the adjoint-based reduced-order model uses the direct and adjoint equations for projection. For diffusion or transport calculations, the Exact-to-Precision Generalized Perturbation Theory was developed. Still, no models for depletion calculations are readily available. Therefore, this paper describes a novel adjoint-based reduced-order model for the Bateman Equation. It uses a range-finding algorithm to create the basis and the uncoupled Depletion Perturbation Theory for the reconstruction of the first order replaced by with a first order formulation. Our paper shows that for several perturbed cases, the depletion reduced-order model successfully reconstructs the nuclide densities. As a result, this serves as a proof of concept for our adjoint-based reduced-order model, which can perform sensitivity and uncertainty burn-up analysis in a shorter time.

A Simple, Sensitive, and Greener HPLC-DAD Method for the Simultaneous Analysis of Two Novel Orexin Receptor Antagonists.

The orexin receptor antagonist (ORA) is one of the new psychopharmacological agents used in the treatment of insomnia. There are currently no documented greener high-performance liquid chromatography-diode array detector (HPLC-DAD) methods for the analysis of ORA antagonists, lemborexant (LMB) and suvorexant (SUV) simultaneously. Therefore, in this study, a simple, sensitive, and greener HPLC-DAD method has been developed for the simultaneous quantitative analysis of LMB and SUV in bulk and laboratory-prepared mixture. The developed method was validated for numerous validation parameters and evaluated for greenness. The C18 Waters Spherisorb CN (4.6 × 250 mm2; 5 μm) column was used for the chromatographic separation. The mobile phase composition was ethanol: 10 mM KH2PO4 buffer in a ratio of (60:40 v/v). The DAD detection was performed at 253 nm using a Waters DAD detector. The greenness was evaluated using the analytical Eco-Scale (AES), ChlorTox, and analytical GREEnness (AGREE) techniques. The calibration curves showed excellent linearity for LMB and SUV between the concentration range of 125-5000 ng/mL and 250-10,000 ng/mL, respectively. In addition, the proposed HPLC-DAD method was accurate, precise, robust, highly sensitive, and greener. AES, ChlorTox, and AGREE scales were predicted by the HPLC-DAD method to be 91, 1.14 g, and 0.79, respectively, showing an excellent greenness profile. The greener HPLC-DAD method was successfully used to analyze both medicines quantitatively in bulk and laboratory-prepared synthetic mixtures. The findings of this study indicated that the proposed HPLC-DAD method may be consistently applied to evaluate LMB and SUV in bulk and dosage forms.

Albumin Nanoparticles Increase the Efficacy of Doxorubicin Hydrochloride Liposome Injection Based on Threshold Theory.

One of the most significant reasons hindering the clinical translation of nanomedicines is the rapid clearance of intravenously injected nanoparticles by the mononuclear phagocyte system, particularly by Kupffer cells in the liver, leading to an inefficient delivery of nanomedicines for tumor treatment. The threshold theory suggests that the liver's capacity to clear nanoparticles is limited, and a single high dose of nanoparticles can reduce the hepatic clearance efficiency, allowing more nanomedicines to reach tumor tissues and enhance therapeutic efficacy. Building upon this theory, researchers have conducted numerous validation studies based on the same nanoparticle carrier systems. These studies involve the use of albumin nanoparticles to improve the therapeutic efficacy of albumin nanomedicines as well as polyethylene glycol (PEG)-modified liposomal nanoparticles to enhance the efficacy of PEGylated liposomal nanomedicines. However, there is no research indicating the feasibility of the threshold theory when blank nanoparticles and nanomedicine belong to different nanoparticle carrier systems currently. In this study, we prepared two different sizes of albumin nanoparticles by using bovine serum albumin. We used the marketed nanomedicine liposomal doxorubicin hydrochloride injection (trade name: LIBOD, manufacturer: Shanghai Fudan-zhangjiang Biopharmaceutical Co., Ltd.), as the representative nanomedicine. Through in vivo experiments, we found that using threshold doses of albumin nanoparticles still can reduce the clearance rate of LIBOD, prolong its time in vivo, increase the area under the plasma concentration-time curve (AUC), and also lead to an increased accumulation of the drug at the tumor site. Furthermore, evaluation of in vivo efficacy and safety further indicates that threshold doses of 100 nm albumin nanoparticles can enhance the antitumor effect of LIBOD without causing harm to the animals. During the study, we found that the particle size of albumin nanoparticles influenced the in vivo distribution of the nanomedicine at the same threshold dose. Compared with 200 nm albumin nanoparticles, 100 nm albumin nanoparticles more effectively reduce the clearance efficiency of LIBOD and enhance nanomedicine accumulation at the tumor site, warranting further investigation. This study utilized albumin nanoparticles to reduce hepatic clearance efficiency and enhance the delivery efficiency of nonalbumin nanocarrier liposomal nanomedicine, providing a new avenue to improve the efficacy and clinical translation of nanomedicines with different carrier systems.

Interfacial debonding in a thin plate bonded to a rigid substrate with a circular hole

Mode I fracture is a prevalent failure mode in adhesively bonded joints. This paper presents analytical and numerical solutions for the mechanical interaction of a thin plate bonded to a rigid substrate with a circular hole. Utilizing the bilinear cohesive law, the proposed solution is designed for the bonded joints subjected to uniformly distributed load and point load, respectively. The interfacial normal stress distribution and load-displacement response undergo three distinct stages: the initial elastic stage, followed by the elastic-softening stage, and culminating in the elastic-softening-debonding stage. The load-displacement response of the joints subjected to uniformly distributed load and point load diverges after debonding occurs. The load-carrying capacity of the former decreases rapidly, while the latter exhibits an opposite trend. Finite element (FE) simulation is conducted for numerical validation, demonstrating excellent agreement between the proposed model and FE results. The paper concludes by discussing the influences of hole radius, bond length, and the properties of the adhesive layer and thin plate on load-displacement response and the ultimate load. The findings suggest that higher bond strength and larger fracture energy of the adhesive, along with thicker and stiffer thin plates, contribute to achieving higher load-carrying capacity in bonded joints. Additionally, a longer bond length improves the load-carrying capacity for the joint subjected to the point load, with minimal impact for uniformly distributed loads once the bond length exceeds the effective bond length.

A boundary element analysis of quasi-potential inviscid incompressible flow in multiply connected airfoil wing

AbstractThe quasi-potential flow in a doubly linked airfoil wing with a sharp trailing edge can be solved using a high-order boundary-element method (BEM). A bicubic Hermite spline interpolation is used to express the unknown, with node derivatives given by finite difference method. The revolutionary traits apply to bleeding-edge settings; specifically, challenges relating to the three-dimensional problem of multiply connected domains are investigated. Numerical validation examples were utilized to assess the implemented BEM approach.

The Surviwec Project: An Open-Source Experimental Database For Extreme Loads On A Moored Cylinder Under Regular And Focused Waves

In this work, we introduce a novel open-source experimental database focused on the dynamic response of a moored floater under both regular and focused waves. The database provides detailed information about the motion (6 DOF) of a cylindrical floating body anchored using two distinct mooring configurations. The former configuration employs four tension legs evenly distributed around the perimeter of the float. The latter, utilizes catenary connections made of steel chains. This database holds significance in three key aspects. Firstly, by leveraging one of the largest wave facilities in Europe for wave generation, the wave-structure interaction is studied on a large scale (approx. 1:10 ratio). Due to this, scale effects are minimized. Secondly, the database captures critical hydrodynamic loads, including slamming and overtopping induced by extreme waves, as well as snap loads in the mooring lines. These represent unique features of the dataset. Lastly, the tests are conducted with meticulous consideration for subsequent analytical or numerical validations: preliminary tests with regular waves are followed by investigations under extreme sea states represented by focused waves.

Effect of layup sequence on cure deformation and accurate prediction of composite pressure vessels

The application of composite winding pressure vessels is becoming more and more widespread, and the magnitude of deformation during curing can have a significant impact on service performance, but there are fewer studies on the accurate prediction of the numerical and experimental validation of the deformation during the curing process of pressure vessels. To accurately predict the effect of different angles of layup on the curing deformation of high-pressure hydrogen storage vessels made of T700S-12 K/4251A4B2 carbon fiber/epoxy composites in cylindrical and dome sections. In this paper, WCM-ABAQUS segmented pressure vessel accurate modeling method is proposed for the first time, using the method of converting the chemical shrinkage coefficient of epoxy resin into thermal expansion coefficient equivalently, the finite element prediction of the deformation of the pressure vessel during the curing process in different layup sequences was carried out, and the deformation values of the pressure vessel in different layup sequences were analyzed comparatively. Finally, the winding curing experiments were carried out on pressure vessels with different layup sequences, and the curing deformation values of the experimental tests on pressure vessels with different layup sequences were compared with the finite element simulation values, respectively, and the minimum error value 13.07%. It provides a reliable basis for accurately predicting the deformation value of the pressure vessel curing process, and also provides a reference for subsequent experiments to reduce the curing deformation value.

The Navier-Stokes system with temperature and salinity for free surface flows. Numerical scheme and validation

In this paper, we propose and study a numerical scheme for the Navier-Stokes-Fourier system derived and studied by the authors in [12]. This system models hydrostatic free surface flows with density variations depending on temperature or salinity. We show that the finite volume/finite element scheme presented – based on a layer averaged formulation of the model – is well-balanced with regards to the steady state of the lake at rest and preserves the nonnegativity of the water height. A maximum principle on the density is also proved as well as a discrete entropy inequality (when the thermal and viscous effects are neglected). Some numerical validations are finally shown with comparisons to 3D analytical solutions and experiments.

Simplified method and numerical simulation analysis of pipe-group long-term heat transfer in deep-ground heat exchangers

Deep-buried pipe-group heat transfer is a primary form of utilizing geothermal energy in the middle and deep ground layers. This study introduces a methodology to simplify the heat transfer process of a pipe-group into a single borehole within a finite computational domain. The proposed methodology allows for rapid and accurate assessment of the heat transfer performance of the pipe-group with coaxial deep-ground heat exchangers (C-DGHEs). The feasibility of this simplified method is supported by numerical validation. Consequently, a 20-year numerical computation is performed for pipe-group models with spacings of 15, 20, 30, and 40 m, alongside a comparative study on the heat transfer of a single borehole C-DGHE with a computational domain radius of 200 m. For a pipe-group spacing of 15 m, the results demonstrated that the heat transfer boundary is exceeded in the first year of heat extraction but stabilized into a steady decline. For a spacing of 40 m, the decrease in heat transfer over 20 years was less than 15 % compared to the single C-DGHE. This research effectively evaluates the heat transfer performance of pipe groups, providing theoretical support and technical guidance to develop and promote the applications of deep geothermal energy.

Porous structures inspired by porcupine quill: multiscale design optimization approach

This paper presents a novel approach for designing a freeform bending-resistant structure from the combination of explicit discrete component-based topology optimization (TO) and the porcupine quill-inspired features. To embed the porcupine quill’s features into the TO formulations, the method involves constructing discrete components at various scales to imitate features including solid shell, stochastically distributed pores, and graded stiffeners. The components are iteratively updated, and the optimization process allows for the grading of quill-inspired features while achieving optimal structural compliance under bending loads. The proposed approach is demonstrated to be effective through the resolution of Messershmitt–Bolkow–Blohm (MBB) beam designs, parameterized studies of geometric parameters, and numerical validation of long-span and short-span quill-inspired beam designs. By examining the von Mises stress distribution, the study highlights the mitigation of material yielding at the shell region brought by the geometric features of porcupine quills, leading to the potential theory support for the bending resistance. The optimized MBB beams are manufactured using the material extrusion technique, and three-point bending tests are conducted to explore the failure mitigation capability of the quill-inspired beam under large deformation. Consequently, the study concludes that the proposed quill-inspired component-based TO approach can design a structure with excellent bending resistance according to the improved energy absorption as well as increased deformation after reaching 75% peak load.

Numerical investigation of gyroid heat exchanger

A novel cylindrical gyroid surface-based tube is designed to investigate fluid flow and heat transfer characteristics numerically. The simulations are carried out using finite volume based CFD software Ansys Fluent. The numerical validation is performed to verify the robustness of the solver and grid independence study are also carried out to compute the simulations using optimum mesh. The heat exchanger (HX) tubes with gyroid surfaces are manufactured using additive manufacturing and a crossflow HX is fabricated with a bank of gyroid tubes where the experiments were conducted. The numerical results of the Realizable k-ε turbulence model with enhanced wall treatment is validated with in-house experimental data. The thermal performance of the gyroid tube HX is also compared with a conventional circular tube (CCT). Parametric analysis is also carried out by varying the gyroid design parameter and an optimum HX design is proposed. The results show that due to larger surface area and enhanced fluid mixing, the gyroid tube-based HXs show better thermal performance compared to CCT-based HX.

Improvement of the modelling of the conduction-radiation flash method by a fully stochastic approach. A numerical validation

Three different numerical models for simulating the well-known experimental flash method are presented and compared. These models consider conduction-radiation coupling and are applied within a one-dimensional grey semi-transparent slab enclosed between two opaque surfaces. The first model (A) is deterministic, dating back to about a decade, and is based on three assumptions regarding radiation transfer: isotropic intensity within each of the two hemispheres, the scattering phenomenon is supposed to be isotropic, and linearization of terms involving differences of temperatures to the fourth power. The other two models are completely new and do not make these assumptions. While the first one (B) is purely deterministic and serves as a reference for validation, the other one (C) is fully stochastic, and is the focus of this paper. A comparison shows excellent agreement between (B) and (C), validating our new model of interest (C). On the other hand, (A) exhibits significant discrepancies with the other two, highlighting the importance of its limiting assumptions.

A modification of production term for the shear stress transport turbulence model based on a new wall-law for adverse pressure gradient

This paper presents an attempt to improve the predictive accuracy of the Menter shear stress transport (SST) turbulence model for adverse pressure gradient (APG) flows. The foundation of this work lies in the newly modified law of the wall and turbulent kinetic energy (TKE) transport equation within the APG turbulent boundary layer. The modification of the law of the wall is achieved through a newly proposed variable λ, which is derived theoretically and calibrated using direct numerical simulation data. Based on the new law of the wall, we analyze the TKE transport equation of the SST model at APG and demonstrate that the analytical solution satisfying the law of the wall cannot achieve equilibrium in the current SST model. Further theoretical analysis reveals that this imbalance is caused by the TKE production term Pk, and the decomposition of the wall friction coefficient Cf indicates that Pk directly affects the prediction of flow separation. Based on the analysis and the new law of the wall, an additional term for Pk is suggested to correct Pk and improve the model's predictive accuracy for APG flows. Numerical validation results show that the correction leads to an increase in Pk within the APG turbulent boundary layer, resulting in more accurate predictions of Cf and the mean velocity profile in the inner layer of the turbulent boundary layer.

Numerical validation of Yukawa fluid excitations within the quasilocalized charge approximation (QLCA) theory

AbstractA first principle molecular dynamics (MD) simulation study on the nonlinear excitations in a quasi‐localized state of a Yukawa system is presented to validate the findings of the nonlinear quasi‐localized charge approximation (QLCA) model. Unlike solids or gases, quasi‐localized states lack certain simplifying features, such as the ability to assume a fixed shape or volume, and they combine large displacements with strong interactions, further complicating the theoretical underpinnings of their behavior. In a recent paper [P. Kumar and D. Sharma, Physics of Plasmas 30 (2023)], the nonlinear QLCA model was applied to characterize the nonlinear excitations in a quasi‐localized state of a Yukawa system, as existing continuum models have shown limited success in this regime. The simulation data presented with the screening and coupling parameters show a close agreement with the QLCA model findings. The MD simulations validate the prediction made by the QLCA model that the properties of a soliton remain unaffected by variations in the coupling parameter. The prediction made by QLCA regarding the formation of multiple solitons at higher screening parameter values has also been confirmed by the MD simulation data. The possibility of the formation of rarefactive solitons at relatively high screening parameter values within the QLCA model is also discussed.

Transmittance spectra expression for dye-doped cholesteric liquid crystal with large optical activity

ABSTRACT Dye-doped cholesteric liquid crystals (DDCLCs) with a homeotropic initial state are more practical due to their lower power consumption and higher security. However, achieving the homeotropic initial state necessitates the use of long-pitch DDCLCs. The conventional formula for determining the planar (P) state transmittance of DDCLCs is inadequate for calculating the P state transmittance of long-pitch DDCLCs with pronounced optical activity. Therefore, in the experimental calculations and fitting, optical activity was introduced to amend the conventional formula and expand the calculation range to include visible wavelengths (400 nm-800 nm). Following numerous validations, a modified formula for calculating the P-state transmittance of DDCLCs was derived, which yields results closer to the actual values when optical activity is significant. This modification is of great significance in the design of long-pitch DDCLCs.