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Highlights Permeability quantifies the flow conductivity of fabric reinforcements and is key to predicting mold filling times and resin flow in liquid composite molding (LCM). Flow depends on the micron‐level channels within the tows and the millimeter‐level channels between them. This study presents a general multi‐scale permeability prediction framework for fabrics considering realistic inter‐ and intra‐tow geometry. A misaligned fiber representative volume element model was constructed by a random perturbation method at the micro‐scale with orientation parameters identified from microscopic images of the cross‐section. At the meso‐scale, a tow cross‐section wrapping algorithm and an interference elimination algorithm were proposed to construct continuous as‐woven tows from the virtual fiber compression simulation. The governing fluid dynamics equations were solved to obtain the flow field within the multi‐scale gaps and compute the permeability. The simplified model's permeability predictions differed from experimental results by 12.7% to 16%. This work provides valuable insights for further research and development in LCM. Fabric permeability framework considers realistic tow geometry for prediction. Microscale misaligned fiber SVE model predicts tow permeability. Adaptive winding & interference algorithms aid tow description transition. A simplified model predicts permeability reasonably without 3D measurements. [ABSTRACT FROM AUTHOR]

Highlights This paper presents the experimental, analytical, and numerical extensive investigation into the flexural creep performance of pultruded glass fiber reinforced polymer (pGFRP) composites at elevated service temperatures. The experimental phase involved a physical testing program on pGFRP coupons in a four‐point bending setup covering a wide range of loads (12%, 24%, and 37% stress levels) and temperature conditions (20, 40, and 60°C) over a long test duration of 720 h. The analytical Burgers model was employed to provide theoretical insights into the time‐dependent deformation behaviors, while the finite element analysis (FEA) simulations using derived reduction factor validated the accuracy of the proposed procedure. Burgers model was able to capture the experimental data very well and reached the ultimate strain failure limit within about 1.4–50 years depending on the case. The proposed simple FEA procedure yielded a pattern closely resembling the one observed from Burgers model in which they resulted in estimated endurance times with a roughly 15% difference between them. The higher stress and/or temperature, the longer the primary creep stage is. Burgers model is able to capture the experimental data very well in all conditions. Burgers general equation is able to predict failure within about 1.4–50 years. A proposed reduction factor based on Burgers model is utilized in FEA The FEA procedure shows a roughly 15% difference compared to Burgers model. [ABSTRACT FROM AUTHOR]

The regulation of energy associated with heat transfer is the most important problem in the food processing, chemical and biomedical engineering industries. Therefore, this investigation explores the heat transfer qualities of micropolar hybrid-nanofluid also considering entropy generation which has recently become central focus of research in the field of heat transfer processes. The purpose of this analysis is to explore the influence of magnetohydrodynamics (MHD), viscous dissipation, and heat radiation on the flow of hybrid-nanofluid with micropolar properties above an exponentially shrinking/stretching sheet. A mathematical model is constructed and the solution is acquired by utilizing numerical technique bvp-4c in MATLAB. The befitting usage of the second law of thermal physics helped in conducting the entropy production analysis. The study obtains numerical results for the governing equations, which reveal dual solutions when analyzing a shrinking sheet, contrary to a stretching sheet. The paper presents graphical depictions of the influence of different attributes upon micro-rotation, velocity, surface-friction, temperature, Nusselt number and also the entropy generation plus the Bejan number. Moreover, a comparison of heat transfer rates between conventional nanomaterial and hybrid-nanofluid is provided. The study concludes that dual solutions appear and the wall shear stress coefficient decreases as the values of micropolar parameter R 1 increase with critical values of λ being λ c = − 1. 2 8 , − 1. 3 4 and − 1. 3 7. Also thermal irreversibility, which results from fluid friction near the sheet rather than far from it, is more dominant than total entropy generation. [ABSTRACT FROM AUTHOR]

Numerous studies have indicated that turbulence typically initiates along the boundary layer of the stationary disk within a rotor–stator cavity. To describe the transition process to turbulence on the stationary side of a closed rotor–stator cavity, a comprehensive approach combining global linear stability analysis with direct numerical simulation was adopted in the present study. The proposed model aligns with that of Yim et al. (J. Fluid Mech. , vol. 848, 2018, pp. 631–647), who investigated the stability characteristics of the rotating-disk boundary layer in a rotor–stator cavity. In order to achieve a stable inflow for the stationary-disk boundary layer, we rotate the shroud together with the rotating disk. Through careful global stability analysis, the predominant spiral mode exhibiting the highest instability in the boundary layer of the stationary disk was discerned, corroborating observations from simulations. Initially, the spiral mode undergoes linear amplification, reaches a state of linear saturation and enters the nonlinear regime. Following nonlinear saturation in the flow field, a circular wave mode arises due to the influence of mean flow distortion. As the Reynolds number attained a sufficiently high level, the interplay between the downstream-propagating circular mode and spiral mode amplified disturbances in the boundary layer of the stationary disk, ultimately leading to the development of localised turbulence at the mid-radius of the rotor–stator cavity. Notably, the present study is the first to elucidate the coexistence of laminar–transitional–turbulent flow states in the stationary-disk boundary layer through direct numerical simulations. [ABSTRACT FROM AUTHOR]

The dynamics of wind turbine (WT) behavior and the identification of factors influencing its performance are both highly complex and challenging. Additionally, component damage, along with sensor and actuator failures, can lead to system faults that significantly reduce performance. Understanding these impacts provides control system designers with valuable insights to develop strategies for mitigating faults and enhancing WT performance. This study presents a novel evaluation of rotor fault effects on output power and measured variables in WTs using Monte Carlo simulation and sensitivity analysis. Through comprehensive simulation and numerical analysis, the faults with the greatest impact on WT performance are identified. The results of this research not only provide a better understanding of the WT performance during faults but also identify the significant effects of these faults on the performance of wind turbines and specifically identify and prioritize the main faults. These results are instrumental in improving control strategies, developing preventive maintenance programs, and offering practical solutions to reduce operational costs and extend the equipment's useful life. [ABSTRACT FROM AUTHOR]

Summary In this paper, computational analysis of a Caputo fractional variable‐order system with inductor‐capacitor (LC) and resistor‐capacitor (RC) electrical circuit models is presented. The existence and uniqueness of solutions to the given problem are determined using Schaefer's fixed point theorem and the Banach contraction principle, respectively. The proposed problem's computational consequences are addressed and analyzed using modified Euler and Runge–Kutta fourth‐order techniques. Furthermore, the suggested model compares several orders, including integer, fractional, and variable orders. To demonstrate the utility of the proposed approach, computational simulations are carried out on LC and RC circuit models of various orders. Furthermore, a comparative analysis with previous investigations has been carried. For the given problem, the numerical solution results in high‐precision approximations. [ABSTRACT FROM AUTHOR]

Induction heating is a clear, cheap, and highly effective technology used for many industrial and commercial applications. Generally, a time-varying magnetic field produces the required heat in the workpiece with a specially designed coil. The efficiency of the heating process depends highly on the coil design and the geometrical arrangement. A detailed and accurate finite element analysis of the induction heating process usually needs to resolve a coupled thermoelastic–magnetic problem, whose parameters values depend on the solution of another field. The paper deals with a shrink-fitting process design problem: a gear should be assembled with an axe. The interesting part of this case study is given the prescribed low limits for critical stress, the temperature of the gear material, and the heat-treated wearing surfaces. A coupled finite-element-based model and a genetic algorithm-based parameter determination methodology were presented. A thermal imaging-based measurement validated the presented numerical model and parameter determination task. The results show that the proposed methodology can be used to calibrate and validate the numerical model and optimize an induction heating process. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) microgrids comprise a multitude of small PV power stations distributed across a specific geographical area in a decentralized manner. Computational services for forecasting the output power of power stations are crucial for optimizing resource deployment. This paper proposes a deep-learning-based architecture for short-term prediction of PV power. Firstly, in order to make full use of the spatial information between different power stations, a spatio–temporal feature fusion method is proposed. This method is capable of exploiting both the power information of neighboring power stations with strong correlations and meteorological information with the PV feature data of the target power station. By using a multiscale convolutional neural network–long short-term memory (CNN-LSTM) network model, it is capable of generating a PV feature dataset containing spatio–temporal attributes that expand the data source and enhance the feature constraints. It is capable of predicting the output power sequences of power stations in PV microgrids with high model generalization and responsiveness. To validate the effectiveness of the proposed framework, an extensive numerical analysis is also conducted based on a real-world PV dataset. [ABSTRACT FROM AUTHOR]

For the purpose of improving performance and reducing the fabrication difficulty of terahertz traveling wave tubes (TWTs), this paper proposes a novel single-section high-gain slow wave structure (SWS), which is named the symmetrical quasi-synchronous step-transition (SQSST) folded waveguide (FW). The SQSST-FW SWS has an artificially designed quasi-synchronous region (QSR) to suppress self-oscillations for sustaining a high gain in an untruncated circuit. Simultaneously, a symmetrical design can improve the efficiency performance to some extent. A prototype of the SQSST-FW SWS for 650 GHz TWTs is designed based on small-signal analysis and numerical simulation. The simulation results indicate that the maximum saturation gain of the designed 650 GHz SQSST-FW TWT is 39.1 dB in a 34.3 mm slow wave circuit, occurring at the 645 GHz point when a 25.4 kV 15 mA electron beam and a 0.43 mW sinusoidal input signal are applied. In addition, a maximum output power exceeding 4 W is observed at the 648 GHz point using the same beam with an increased input power of around 2.8 mW. [ABSTRACT FROM AUTHOR]

Fractured crystalline rocks have been chosen or are under consideration by several countries as host rock formations for deep geological repositories for spent nuclear fuel. In such geological formations, flow and solute transport are mostly controlled by a network of connected natural fractures, each of them being characterised by internal heterogeneity, also denoted as roughness. Fractures are, in turn, subject to variable load caused by various factors, such as the presence of thick ice sheets formed during glaciation periods. Understanding how coupled hydro-mechanical (HM) processes affect flow and transport at the scale of a single natural fracture is crucial for a robust parameterisation of large-scale discrete fracture network models, which are not only used for nuclear waste disposal applications but are also of interest to problems related to geothermics, oil and gas production or groundwater remediation. In this work, we analyse and model an HM experiment carried out in a single natural fracture and use the results of both, the experimental and the modelling work, to get insights into fundamental questions such as the applicability of local cubic law or the effect of normal load on channeling. The initial fracture aperture was obtained from laser scanning of the two fracture surfaces and an equivalent initial aperture was then defined by moving the two fracture surfaces together and comparing the results obtained using a Navier–Stokes based computational fluid dynamics (CFD) model with the experimental flowrate obtained for unloaded conditions. The mechanical effect of the different loading stages was simulated using a high-resolution contact model. The different computed fracture apertures were then used to run groundwater flow simulations using a modified Reynolds equation. The results show that, without correction, local cubic law largely overestimates flowrates. Instead, we show that by explicitly acknowledging the difference between the mechanical aperture and the hydraulic aperture and setting the latter equal to 1/5 of the former, cubic law provides a very reasonable approximation of the experimental flowrates over the entire loading cycle. A positive correlation between fluid flow channeling and normal load is also found. [ABSTRACT FROM AUTHOR]

A dual-phase lattice structure composed of mixed units with hard and soft phase characteristics is proposed in this work. The proposed lattice structure has high specific energy absorption and high compressive strength. The load response and energy absorption characteristics under bending loads were studied through three-point bending tests and numerical analysis methods. The research results indicate that although the deformation modes of the given lattice structure are the same, the dual-phase design strategy significantly improves the bending performance of the lattice structure: the bending modulus is increased by 744.7%, and the specific energy absorption is increased by 243.5%. [ABSTRACT FROM AUTHOR]

In this study, a numerical dynamic analysis of ceiling raster panels was performed. The analysis was conducted on panels designed with inspiration from bionics. The purpose of the analysis was to enable optimisation of the location of the holes in the designed slabs in order to achieve the preferred dynamic properties, including the natural frequencies of the slabs and an appropriate airflow to avoid the occurrence of resonance. Three different types of panels were used and a total of fifteen panels were designed in terms of their geometry, with circular, elliptical, and hexagonal perforations, made of different materials: polypropylene PP, wood, and aluminium. Then, using the finite element method and ANSYS 2023 R1 software, the airflow over the ceiling panels and their natural frequencies and vibration modes were analysed. The analysis took into account not only the shape of the openings, but also their percentage area relative to the total panel area and different airflow velocities. In addition, the results were compared in an analytical way with those obtained for a solid slab. The results obtained include findings on the mode shapes and values of the vibration frequencies of the plates, air pressure maps, histograms, and plots of the pressure dependence on the surface area of the plate openings. [ABSTRACT FROM AUTHOR]

The Diffusion Peterlin Viscoelastic Fluid (DPVF) model describes the movement of specific incompressible polymeric fluids. In this paper, we introduce and evaluate a new low-complexity linear-time filter finite element (FE) method for the DPVF model. In order to avoid the value at time t = − Δ t , the proposed time filter method consists of three steps, including a post-processing step. Firstly, a first-order Euler backward nonlinear fully discrete mixed FE scheme is employed to compute the numerical solutions at time t 1 = Δ t. For n ≥ 1 , we obtain the intermediate values ( u ˜ h n + 1 , p ˜ h n + 1 , d ˜ h n + 1) in Step II using a fully implicit backward Euler scheme. At the same time level, we proceed with these intermediate values ( u ˜ h n + 1 , p ˜ h n + 1 , d ˜ h n + 1) using the linear time filters. The linear time filters step does not significantly increase computational complexity. However, it can enhance temporal convergence accuracy from first order to second order for backward Euler time filter (BE time filter), and from second order to three order for BDF2 time filter. We demonstrate the almost unconditional stability of the scheme. Error estimates for the time filter method are derived and presented. Several numerical experiments are conducted to validate the theoretical findings and showcase the efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

We propose a novel and simple spectral method based on the semi-discrete Fourier transforms to discretize the fractional Laplacian (− Δ) α 2 . Numerical analysis and experiments are provided to study its performance. Our method has the same symbol | ξ | α as the fractional Laplacian (− Δ) α 2 at the discrete level, and thus it can be viewed as the exact discrete analogue of the fractional Laplacian. This unique feature distinguishes our method from other existing methods for the fractional Laplacian. Note that our method is different from the Fourier pseudospectral methods in the literature which are usually limited to periodic boundary conditions (see Remark 1.1). Numerical analysis shows that our method can achieve a spectral accuracy. The stability and convergence of our method in solving the fractional Poisson equations were analyzed. Our scheme yields a multilevel Toeplitz stiffness matrix, and thus fast algorithms can be developed for efficient matrix-vector multiplications. The computational complexity is O (2 N log ⁡ (2 N)) , and the memory storage is O (N) with N the total number of points. Extensive numerical experiments verify our analytical results and demonstrate the effectiveness of our method in solving various problems. [ABSTRACT FROM AUTHOR]

Standard Galerkin methods often perform poorly for problems with low diffusion. In particular for purely convective transport, least-squares (LS) formulations provide a good alternative. While spatial stability is relatively straightforward in a least-squares finite element framework, estimates in time are restricted, in most cases, to one dimension. This article presents temporal stability proofs for the LS formulation of θ -schemes, including unconditional stability for the backward Euler and Crank-Nicolson methods in two or three dimensions. The theory includes also the linear advection-reaction equation. A series of numerical experiments confirm that the new stability estimates are sharp. [ABSTRACT FROM AUTHOR]

Elastomeric materials are widely used in different industries due to their excellent capability to withstand different loading types. There are significant challenges to the efficient design of elastomeric structures because of the rate-dependent and highly nonlinear behavior of this type of material. In this study, a damage zone model was employed to simulate the material behavior and damage evolution in polyurethane (PU) elastomers with different shore hardness. This model consists of three sections, hyper viscoelastic constitutive model, damage initiation, and damage evolution using a hyper viscoelastic traction-separation law. To simulate the nonlinear behavior of PU, a dynamic increase factor (DIF) implemented into the Mooney–Rivlin strain density function with 9 parameters. The material characteristics are specified by performing the experimental tests for three different shore hardness. In this study, a user-defined subroutine (VUMAT) was developed to predict the damage evolution in the pure shear tearing specimen of PU elastomers. The results verification proves a good agreement between the FEA simulation and experimental data. Therefore, the developed numerical analysis procedure can be used to investigate the damage initiation and evolution in elastomeric materials. [ABSTRACT FROM AUTHOR]

This paper examined the mechanical properties of wrist–hand orthoses made from polylactic acid (PLA) and polyethylene terephthalate glycol (PETG), produced through material extrusion with infill densities of 55% and 80%. These orthoses, commonly prescribed for wrist injuries, were 3D-printed flat and subsequently thermoformed to fit the user's hand. Experimental and numerical analyses assessed their mechanical resistance to flexion after typical wear conditions, including moisture and long-term aging, as well as their moldability. Digital Imaging Correlation investigations were performed on PLA and PETG specimens for determining the characteristics required for running numerical analysis of the mechanical behavior of the orthoses. The results indicated that even the orthoses with the lower infill density maintained suitable rigidity for wrist immobilization, despite a decrease in their mechanical properties after over one year of shelf life. PLA orthoses with 55% infill density failed at a mean load of 336 N (before aging) and 215 N (after aging), while PETG orthoses did not break during tests. Interestingly, PLA and PETG orthoses with 55% infill density were less influenced by aging compared to their 80% density counterparts. Additionally, moisture and aging affected the PLA orthoses more, with thermoforming, ongoing curing, and stress relaxation as possible explanations related to PETG behavior. Both materials proved viable for daily use, with PETG offering better flexural resistance but posing greater thermoforming challenges. [ABSTRACT FROM AUTHOR]

Accurately simulating the deployment process of coupled systems in deep-sea environments remains a significant challenge. This study employs the Absolute Nodal Coordinate Formulation (ANCF) to dynamically model and analyze multi-body systems based on the Pendant Installation Method (PIM). Utilizing the principle of energy conversion, this study calculates the stiffness, generalized elastic forces, mass matrices, and Morison equation, formulating a motion equation for the dynamic coupling of nonlinear time-domain forces in cables during pendulum deployment, which is numerically solved using the implicit generalized-α method. By comparing the simulation results of this model with those from the catenary theory model, the advanced modeling capabilities of this model are validated. Lastly, the sensitivity of the multi-body system under various boundary conditions is analyzed. The results indicate that deployment operations are more effective in environments with strong ocean currents. Furthermore, upon comparing the impacts of structural mass and deployment depth on the system, it was found that deployment depth has a more significant effect. Consequently, the findings of this study provide a scientific basis for formulating subsequent optimization strategies. [ABSTRACT FROM AUTHOR]

Featured Application: The work reported in this paper contributes to the further improvement of the reverse-time migration imaging accuracy of VSP data, which has broad application prospects for oil and gas exploration of unconventional reservoirs. Vertical seismic profiling has garnered widespread attention in the industry as a supplement to seismic exploration due to its higher data quality compared to surface seismic data. However, its unique observation system in which geophones are only distributed within observation wells results in uneven coverage of subsurface structures. This can lead to significant noise when directly applying conventional reverse-time migration techniques used in surface seismic imaging. This study addresses the issue of noise suppression in reverse-time migration imaging associated with walk-away vertical seismic profiling and presents two main innovations. First, a common-receiver reverse-time migration imaging method is proposed, which uses the observation signals as excitation signals for the corresponding shots after reverse-time processing. Second, an excitation-time-constrained cross-correlation imaging condition is introduced to eliminate non-contributing portions of the wavefield, thereby modifying the traditional cross-correlation imaging condition to include an excitation time constraint. The combination of these methods enhances imaging quality by effectively suppressing noise, as demonstrated through theoretical analysis and numerical simulations with synthetic models. [ABSTRACT FROM AUTHOR]

The flow rate is a significant factor in the operation of centrifugal pumps. The characteristic curve of the pump head is frequently employed in the calculation of the flow rate. Nevertheless, this may be subject to alteration because of prewhirl on the suction side of the pump. Calculating the changes in the head's characteristic curve reveals a change in hydraulic losses. The impact of prewhirl on hydraulic losses is investigated by experimental and numerical analysis of two radial centrifugal pumps. It is demonstrated that the primary changes occur in the pump impeller losses. Relative velocity is a significant factor in this context. Alterations in the pumps' configurations result in a range of secondary flows and shock losses at the leading edge of the blades. A physical model, derived on the basis of the relative velocity, is used to predict the characteristic curves of radial centrifugal pumps with prewhirl with a high degree of accuracy. The results demonstrate a notable enhancement in comparison to modelling techniques that do not incorporate the fluctuating hydraulic losses. [ABSTRACT FROM AUTHOR]

This study investigates the effectiveness of positive position feedback (PPF) in reducing vibration amplitudes in an electric vehicle generator, specifically at super harmonic resonance (SHR) with 1:1 Internal Resonance (IR). Here is a breakdown. Simplified Model: The study uses a simplified nonlinear dynamic model (one degree of freedom, up to fifth-order nonlinear components) with external force, analyzed using the Multiple Time Scales Method (MTSM) with a first-order approximation. Focus on Resonance: The primary focus is on understanding the system's behavior at SHR with 1:1 IR and how PPF can mitigate vibrations in this specific scenario. Frequency Response and Controller Influence: Frequency response functions are used to analyze the system's stability with PPF, examining how different controller parameters affect the main system's dynamics. Validation: Numerical solutions, obtained using the fourth-order Runge–Kutta method ('RK-4'), are used to demonstrate and evaluate the system's amplitude with and without PPF. The analytical and numerical results show strong agreement, validating the model's accuracy. In essence, the research explores using PPF as a vibration control strategy in a specific resonance condition within an electric vehicle generator, using a combination of analytical and numerical methods for analysis and validation. [ABSTRACT FROM AUTHOR]

Prestressed spun high-strength concrete (PHC) piles are commonly used in various types of structures, including bridges, buildings and marine infrastructures. However, piles installed in aggressive environments are vulnerable to corrosion of the steel, which can lead to rapid degradation of the piles. As a corrosion-resistant material, carbon fiber-reinforced polymer (CFRP) is considered an alternative to steel tendons for durability enhancement. In this study, a new pile system with CFRP was proposed. Experimental tests of three full-scale piles and a numerical analysis of eight piles with various parameters were performed to investigate the flexural performance of CFRP prestressed spun high-strength concrete pile. The proposed piles were loaded under four-point bending after prestressing. The experimental and numerical results verified the feasibility of the proposed system, and the CFRP pile exhibited twice of flexural capacity of that of steel-reinforced piles. The flexural performance of the CFRP PHC pile was significantly affected by the reinforcement ratio, prestressing level and modulus of the CFRP. An analytical approach predicting the flexural capacity of the CFRP PHC pile was proposed based on the parametric study. Ninety percent accuracy was achieved for the proposed analytical approach. The presented study can significantly promote the application of CFRP in pile foundations and improve the durability of PHC piles. [ABSTRACT FROM AUTHOR]

Transonic buffet flow is a classical complex and unstable flow that has a negative effect on aircraft fly safety. Therefore, it is crucial to study the unsteady characteristics of buffet flow. The numerical analysis method is very useful in achieving the aforementioned goal. In this paper, focused on the typical supercritical airfoil OAT15A in fixed and pitching conditions, unsteady Reynolds averaged Navier–Stokes (URANS) closed with the sst-kω turbulence mode, coupled with the structure dynamical equation, is utilized to investigate the transonic buffet flow. Firstly, from the perspective of coherent flow structure, flow velocity divergence snapshots constructed from unsteady flow solutions are used to analyze the feature of transonic buffets in the two cases mentioned. Then, DMD modes are extracted by the dynamic mode decomposition technique from the velocity snapshots and adopted to analyze the flow modes of the two distinct flow fields. The numerical simulation results show that, in the fixed case, the regular motion feature of the buffet is present, the shock oscillation is closely related to the vortex structure, and the durations of rearward and forward movements of the shock are both equal to half of the buffet period. In the pitching case, the duration of the rearward motion of the primary shock is approximately five eighths of one buffet period, and the secondary shock appears with the primary one moving downstream, and they interact with each other. The region of the shock movement is larger than that of the fixed case, and there is chaotic flow rather than periodic flow in its wake. Structural elastic oscillation changes the characteristics of the aerodynamic response, which is solely affected by the frequency of the pitching oscillation. [ABSTRACT FROM AUTHOR]

In light of the limitation that passive suspension can only provide vibration isolation within a specific range, a magnetorheological suspension in extrusion mode was developed. The reliability of structural parameters was ensured through theoretical analysis and numerical simulation, building upon traditional hydraulic suspension. A model linking static stiffness to the diameter of the upper extrusion plate, as well as the heights of the upper and lower liquid chambers, was established using Simulink as an evaluation index. The static stiffness performance of the magnetorheological suspension was then optimized using this model. Results indicate that while meeting the static stiffness requirements, the optimized Magnetorheological Suspension demonstrated a 29.22% increase in static stiffness (approximately 57.71 N/mm) compared to its previous state, validating the effectiveness of stiffness optimization for this system. [ABSTRACT FROM AUTHOR]

Water inrush from separation layers is a special type of water inrush disaster that occurs during coal mining. It is characterized by the absence of precursors before the inrush, a sudden and massive influx of water, strong destructive power, and significant difficulty in prevention and control. This disaster causes substantial economic losses and casualties in mines. To study the dynamic evolution characteristics of the overlying rock strata in Guojiahe coal mine, field investigations, theoretical analysis, physical simulations, and numerical simulations were conducted. The development state of the overlying rock strata and the height of the water-conducting fractures in the 1304 working face during continuous mining were analyzed, and the spatial position of the strata where water hazards could form was determined. Through theoretical calculations, the height of the water-conducting fracture zone was found to be approximately 205 m, forming a water-storable separation space about 248 m above the coal seam roof. A physical similarity model was constructed to study the development state of overlying rock strata separation in the 1304 working face. Experimental results indicate that, as the working face advances, the rock strata gradually develop lateral separation spaces from bottom to top, and vertical fractures increase progressively in a similar manner. The spaces and fractures formed in the early stages of the working face advance gradually close and form a compaction zone. However, new fractures develop near the working face side. As mining continues, the asynchronous movement of the overlying rock promotes the development of vertical fractures, providing water-conducting channels for water inrush from the separation. Based on numerical simulation analysis of the development state of overlying rock strata separation and the height of the water-conducting fracture zone, it can be concluded that the water-storable separation space develops between the 8th layer of the formation of sandy mudstone and the 9th layer of the Yijun Formation conglomerate, which is 248 m from the coal seam roof. When excavated to 280 m, the separation space reaches its maximum, with a width of about 19 m and a height of about 1.2 m, and the water storage capacity increases to its maximum. The height of the water-conducting fracture zone eventually increases to 202 m. [ABSTRACT FROM AUTHOR]

Open‐type Sabo dam captures the advantage of solids mitigating the potential energy of fluids, but the disadvantage is that a small amount of debris flow passes through the dam, the reason for this comes from the grid size of the dam, the inclination angle of the dam, the stone size among the debris flow, etc. This study aims to investigate the influence of the inclination angle on the capture performance of the open‐type Sabo dam. A model experiment is conducted based on the centrifuge machine. Three open‐type Sabo dam models reflecting different inclination angles of 0° (vertical form), 20°, and 40° are used to capture the debris flow. The concentration of the large particle (CLP) for the debris flow configuration is set to 20% and 33%, respectively. The experimental results indicate that the open‐type Sabo dam with 0° inclination angle has the best capture rate, 93%–94%. An increase in inclination decreases the capture rate for debris flows. A 40° inclination angle decreases the capture rate by 2%–8%, and this decrease is exacerbated by an increase in CLP of the debris flow. Additionally, the smoothed‐particle hydrodynamics–distributed contact distinct element method (SPH–DCDEM) has a good reproduction for the experimental result of the capture rate, with an error of 12%–25%. [ABSTRACT FROM AUTHOR]

Geologic fractures such as joints, faults, and slip surfaces govern the stability and performance of many subsurface systems in the built environment. As such, a variety of approaches have been developed for computational modeling of geologic fractures. Yet none of them lends itself to a straightforward utilization with the classical finite element method widely used in practice. Over the past decade, phase-field modeling has become a popular approach for simulating fracture, because it can be implemented simply with the standard finite element method without any surface-tracking algorithms. However, the standard phase-field formulations do not incorporate several critical features of geologic fractures, including frictional contact, pressure-dependence, quasibrittleness, mode-mixity, and their combined impacts on cracking. This article provides a brief report of a novel phase-field model that incorporates these features of geologic fractures in a well-verified and validated manner. Remarkably, the phase-field model allows one to simulate the combination of cohesive tensile fracture and frictional shear fracture without any algorithms for surface tracking and contact constraints. It is also demonstrated how phase-field modeling enables us to gain insights into geologic fractures that are challenging to investigate experimentally. [ABSTRACT FROM AUTHOR]

Introduction: Soil organic carbon (SOC) content can vary significantly across a given plot. Therefore, a representative sampling is a prerequisite to obtain meaningful results from analysis and of utter importance when SOC quantification is used to quantify (temporary) carbon dioxide removal (CDR). However, certain management practices aiming to increase SOC further increase the level of heterogeneity and may challenge representative sampling schemes. This includes concentrated root-zone application of biochar, which immediately increases SOC with the input of biochar-C and may promote the local enrichment of non-biochar SOC over time. Methods: Here, we used numerical modelling to quantify the number of single sampling points (soil cores) needed to achieve a representative sample of biochar-C and total SOC on a plot after application of biochar in rows, e.g., for growing vegetables, or in the circumference of trees in agroforestry systems. Results: After row application of 5 t ha-1 biochar in soil with rather low SOC content (26 t ha-1), 140 soil cores (per 0.25 ha plot) where necessary to achieve representative sampling of C-stocks (±5% error) in 90% of the repeated sampling simulation cases. Compared to realistic and cost-effective soil sampling scenarios in agronomic practice, we conclude that concentrated root zone application of biochar makes representative sampling for quantification of SOC in soils with low baseline C-stocks virtually impossible. Discussion: This finding calls into question the soil-sampling and SOC-analysisbased ("result-based") monitoring of SOC as a (temporary) CDR when biochar might have been applied. Considering the rapid scaling of biochar production and use in agriculture, this is a considerable challenge for SOC certification. Instead, action-based incentives, rewarding farmers for carrying out specific practices, could be applied to promote carbon farming practices. [ABSTRACT FROM AUTHOR]

This paper focuses on the finite‐time synchronization issue for reaction‐diffusion competitive neural networks (RCNNs) with different time scales and time‐varying delays. To reduce the waste of network resources, a periodically intermittent control strategy is presented based on two time scales (short and long memory) and time‐varying delay. By constructing the Lyapunov–Krasovskii functional, with the help of Lyapunov stability theory and auxiliary inequality technique, the finite‐time synchronization can be guaranteed and the settling time is exactly estimated. Finally, an exhaustive numerical analysis is presented to illustrate the effectiveness of the controller and the correctness of theoretical results. [ABSTRACT FROM AUTHOR]

Rock slope failures pose significant challenges in geotechnical engineering due to the intricate nature of rock masses, discontinuities, and various destabilizing factors during and after excavation. In mining industries, such as national cement factories, multi-benched excavation systems are commonly used for quarrying. However, cut slopes are often designed with steep angles to maximize economic benefits, inadvertently neglecting critical slope stability issues. This oversight can lead to slope instability, endangering human lives and property. This study focuses on analyzing the stability of existing quarry cut slopes, estimating their final depth, and conducting a parametric study of geometric profiles including bench height, width, face angle, and rump width. Kinematic analysis helps identify potential failure modes. The results reveal that the existing quarry cut slope is prone to toppling, wedge failure, and planar failure with probabilities of 42.68%, 19.53%, and 14.23%, respectively. Numerical modeling using the finite element method (Phase2 8.0 software) was performed under both static and dynamic loading conditions. The shear reduction factor (SRF) of the existing quarry cut slope was 1.01 under static loading and 0.86 under dynamic loading. Similarly, for the estimated depth, the SRF was 0.82 under static loading and 0.7 under dynamic loading. These values indicate that the slope stability falls significantly below the minimum acceptable SRF, rendering it unstable. The parametric study highlights the face angle of the bench as the most influential parameter in slope stability. By adjusting the bench face angle from 90° to 75°, 70°, and 65°, the SRF increased by 31.6%, 35.4%, and 37.9%, respectively. Among these, a 70° bench face angle is recommended for optimal stability with a SRF of 1.27 under static loading and 1.18 under dynamic loading. [ABSTRACT FROM AUTHOR]

This study aims to address the issue of high energy consumption in the hydrocyclone separation process. By introducing a novel slotted overflow pipe structure and utilizing experimental and response surface optimization methods, the optimal parameters were determined. The research results indicate that the number of slots, slot angles, and positioning dimensions significantly influence the performance of the hydrocyclone separator. The optimal combination was found to be three layers of slots, a positioning dimension of 5.3 mm, and a slot angle of 58°. In a Φ100mm hydrocyclone separator, validated through multiple experiments, the separation efficiency increased by 0.26% and the pressure drop reduced by 24.88% under a flow rate of 900 ml/s. CFD simulation verified the reduction in internal flow field velocity and pressure drop due to the slotted structure. Therefore, this study provides an effective reference for designing efficient and low-energy hydrocyclone separators. [ABSTRACT FROM AUTHOR]

The aim of this paper is to introduce a novel approach for estimating the fixed points of multi-valued non-expansive mappings using the AR-iteration scheme in the context of uniformly convex Banach spaces. We establish strong and weak convergence results, providing rigorous analytical proofs and illustrating the results with a detailed example. Our approach showcases the potential of the AR-iteration scheme in solving real-world problems, particularly in addressing two-point boundary value problems. We demonstrate the applicability and effectiveness of the AR-iteration scheme in numerical analysis and computational mathematics. Our results contribute significantly to the advancement of numerical methods in solving boundary value problems, offering new insights and directions for future research in this area. Furthermore, we provide a detailed explanation of Green’s function approach and its implications for various scientific and engineering applications, paving the way for future research in this area. [ABSTRACT FROM AUTHOR]

Determining the thermal profile of ignition is important because the desired ignition behavior varies with the objective. For example, extended ignition prolongs the time that the engine runs; however, fast ignition offers a higher power gain. The pollution caused by undesirable chemical reactions, as determined by the ignition profile, is another important aspect. Based on a previously developed method, we examined the impact of different theoretical particle size distributions (PSDs) on the thermal ignition profile. We compared different PSDs of polydispersed fuel spray with normal distributions with various means, each corresponding to the same fuel volume. Our results revealed a significant dependence of thermal ignition on the PSD. Systems that comprised only low-radius droplets did not reach ignition, whereas systems with only high-radius droplets required a long time to establish ignition. Moreover, the change in the mean droplet radius unexpectedly resulted in a double hump in the maximum temperature of the combustion process. [ABSTRACT FROM AUTHOR]

This paper introduces a novel numerical method for investigating the dynamic stability of a flutter panel exposed to a supersonic gas flow and a fluctuating axial excitation force. Initially, the system equation of motion was derived using Lagrange’s equation, where the first two modes are coupled Mathieu–Hill equations with damping, constituting a system of linear second-order differential equations with periodically variable coefficients. Subsequently, a new numerical method was proposed to analyze the dynamic stability of coupled Mathieu–Hill equations with damping. This method involves breaking down an arbitrary parametric load into discrete segments to approximate the variable excitation function using a step function. The system responses of each segment are then accumulated in matrix form. The proposed numerical method proves particularly effective for dynamic systems whose parameters cannot be treated as small. In practical application, the method allows the construction of instability regions corresponding to natural frequencies, subharmonics, and combination frequencies. Dynamic stability diagrams were generated based on dynamic pressure ratio, air/panel density ratio, Mach number, panel thickness—length ratio, and excitation frequency. The results demonstrated general agreement with those obtained through Hsu’s perturbation method, however, our numerical results have proven more accurate. The paper concludes by offering suggestions for suppressing panel flutter through appropriate parameter combinations. [ABSTRACT FROM AUTHOR]

This paper introduces a novel stochastic inverse method that utilizes perturbation theory and advanced intelligence techniques to solve the multi‐parameter identification problem of concrete dams using displacement field monitoring data. The proposed method considers the uncertainties associated with the dam displacement monitoring data, which are comprised of two distinct sources: the first is related to stochastic mechanical properties of the dam, and the second is due to observation errors. The displacements at different measuring points generated by dam mechanical properties exhibit spatial correlation, while the observation errors at different points can be considered statistically random. In this context, the inversion formulas are derived for unknown stochastic parameters of the dam by combining perturbation equations and Taylor expansion methods. An improved meta‐heuristic optimization method is employed to identify the mean of stochastic parameters, while mathematical and statistical methods are used to determine the variance of stochastic parameters. The feasibility of the proposed method is verified through numerical examples of a typical dam section under different conditions. Additionally, the paper discusses and demonstrates the applicability of this method in a practical dam project. Results indicate that this method can effectively capture the uncertainty of dam's mechanical properties and separates them from observation errors. [ABSTRACT FROM AUTHOR]

For the polarization multiplexing requirements in all-optical networks, this work presents a compact all-fiber polarization beam splitter (PBS) based on dual-core photonic crystal fiber (PCF) and an elliptical gold layer. Numerical analysis using the finite element method (FEM) demonstrates that the mode modulation effect of the central gold layer effectively reduces the dimensions of the proposed PBS. By determining reasonable structural parameters of the proposed PCF, the coupling length ratio (CLR) between X- and Y-polarized super-modes can approach 2, achieving a minimal device length of 0.122 mm. The PBS exhibits a maximum extinction ratio (ER) of − 65 dB at 1.55 μm, with an operating bandwidth spanning 100 nm (1.5–1.6 μm) and a stable insertion loss (IL) of ~ 1.5 dB at 1.55 μm. Furthermore, the manufacture feasibility and performance verification scheme are also investigated. It is widely anticipated that the designed PBS will play a crucial role in the ongoing development process of miniaturization and integration of photonic devices. [ABSTRACT FROM AUTHOR]

To investigate the dynamic mechanical response and damage mechanisms of I‐shaped steel‐concrete composite beams under explosive loads, experimental research and numerical simulations were conducted on steel‐concrete composite structures. The accuracy of the numerical analysis model was validated by comparing the damage characteristics of the structures obtained from explosive tests on the steel‐concrete composite components. Based on this, numerical simulations were performed on steel‐concrete composite beams using the explicit dynamic analysis software ANSYS/LS‐DYNA, and a study on their damage mechanisms was conducted. This study resulted in the acquisition of dynamic mechanical response patterns, including time‐dependent stress, strain, displacement, acceleration, and so on. Different structural damage characteristics under various explosive conditions were summarized, and key parameters affecting the blast resistance of the structure were analyzed. The research findings indicated that, in contrast to the failure characteristics of I‐shaped reinforced concrete (RC) beams, the failure characteristics of I‐shaped steel‐concrete composite beams mainly include punching and shearing failure of the steel‐RC slab and local buckling of the steel beam. Under the same explosive conditions, steel‐concrete composite structures exhibit superior blast resistance, with certain changes in structural parameters significantly improving blast resistance. The research results can provide theoretical support and a scientific basis for the proactive design of blast protection in steel‐concrete beams. [ABSTRACT FROM AUTHOR]

Among the different hydrogen premixed combustion concepts, direct injection (DI) is one of the most promising for internal combustion engine (ICE) applications. However, to fully exploit the benefits of this solution, the optimization of the mixture preparation process is a crucial factor. In the present work, a study of the hydrogen-air mixture formation process in a DI H 2 -ICE for off-road applications was performed through 3D-CFD simulations. First, a sensitivity analysis on the injection timing was carried out to select the optimal injection operating window, capable of maximizing mixture homogeneity, without a significant volumetric efficiency reduction. Then, different spray injector guiding caps were tested to assess their effect on in-cylinder dynamics and mixture characteristics consequently. Finally, the impact of swirl intensity on hydrogen distribution has been assessed. The optimization of the combustion chamber geometry has allowed the achievement of significant improvements in terms of mixture homogeneity. • Diesel engines have high retrofit potential in H2 conversion. • Early injection timings increase uniformity, H2 backflow has to be avoided. • Injector cap properly guide hydrogen jet; not sufficient as a stand-alone solution. • Intense swirl severely reduces mixture homogeneity into the cylinder. • Combination of spray cap and swirl chamfers design improves homogeneity. [ABSTRACT FROM AUTHOR]

We study hedonic editing principles that aim to find individuals' maximum utility when confronted with multiple outcomes Thaler (Mark Sci 4:199–214, 1985). These principles have been primarily defined and studied for only two outcomes. However, when dealing with more than two outcomes, the principles become more ambiguous, and some of them may not continue to be valid. To address this, we present an algorithm designed to find the best solution over a partition set of a given vector of n outcomes. We demonstrate that this algorithm identifies the best-majorized vector for up to four outcomes and establish the conditions under which this vector is optimal for n outcomes. Our algorithm is fast since it requires at most n - 1 steps. We provide a detailed analysis of the algorithm's performance, characterizing the conditions that guarantee the optimal solution and identifying cases where the algorithm may not converge to the optimal solution. Nevertheless, in these cases, we demonstrate through numerical analysis that it can find the optimal solution with a high accuracy rate in most 'practical' instances, making it a reliable tool for solving hedonic editing problems. [ABSTRACT FROM AUTHOR]

Intermodal four-wave mixing (FWM) in photonic waveguides offers a promising approach for efficient terahertz (THz) wave generation, crucial for advanced photonic systems. This study explores the potential of germanium (Ge) waveguides, leveraging their distinct dispersion profiles in transverse electric (TE), and transverse magnetic (TM) modes to achieve phase-matching for FWM. We conducted a numerical analysis of two waveguide geometries, ridge and plane, to optimize THz generation efficiency. Also, by optimizing waveguide geometry, it is possible to achieve higher conversion efficiency and broader THz bandwidth. The results demonstrate that Ge waveguides, particularly when utilizing same-phase laser pulses, can significantly enhance THz radiation and exhibit lower losses compared to traditional silicon-based designs. The findings suggest that integrating these optimized Ge waveguides with existing photonic components could lead to more versatile and efficient THz systems. [ABSTRACT FROM AUTHOR]

In order to study the overall seepage field and stability changes of the soil slopes during rainfall and after the rain stops, numerical simulation analysis is carried out by using FLAC3D, and the simulation results are verified by using outdoor rainfall simulation tests. The results of the study show that rainfall infiltration process from the foot of the slope began to damage, mainly in the form of shallow sliding; during the rainfall cessation of the initial period, the rain will continue to infiltrate, the depth of the wetting peak continues to move downward, and the coefficient of safety still has a tendency to decline; In the mid to late rainy season, the factor of safety begins to pick up as the soil moisture decreases; the increase in rainfall intensity and slope gradient is detrimental to slope stability. The research results provide a new idea for solving the unsaturated soil flow-consolidation coupling problem. [ABSTRACT FROM AUTHOR]

Most studies on open-pit mine stability have been performed in two-dimensional (2D) mode, which neglects the effect of the circular shape and thus the effect of third-direction boundary conditions. The aim of this work was to study the effect of the third dimension on static and dynamic stability analyses of pit slopes by comparing results from two- and three-dimensional (3D) numerical and limit equilibrium analyses. Geomechanical data from Choghart open-pit mine, located in the seismically active area of central Iran, were considered under a historical earthquake (M = 6.4). Kinematic analyses showed that two tectonic blocks of the mine – BL1 and BL2 – are susceptible to wedge and planar failures, respectively. The 2D and 3D static analyses showed that both blocks are stable, with higher safety factors (SFs) obtained using numerical 3D analyses. In the dynamic analyses, both 2D and 3D analyses showed wedge instability for BL1. However, for BL2, the 2D numerical analyses showed instability whereas the 3D numerical and pseudo-static analyses indicated block stability. The results revealed that the 3D SFs are generally 20–40% greater than those from 2D analyses. This can be explained by the consideration of the third-direction effect, verifying the importance of 3D analyses. [ABSTRACT FROM AUTHOR]

This study applies random field theory to simulate the spatial variability of the ground where a tunnel was excavated in a granitic soil mass, in the city of Porto (Portugal). Numerical analyses are performed using the finite-element method combined with random field theory to simulate tunnel excavation. A parametric study to analyse the influence of the correlation coefficient is performed. The results are compared with the measured values and the values obtained with the deterministic computation. The performance of the models is evaluated using two measures of error: root mean squared error (RMSE) and mean absolute deviation (MAD). With the random fields approach (correlation length equal to 0.5) values of MAD equal to 2.18 and RMSE equal to 4.16 were obtained, whereas with the deterministic approach values of MAD equal to 2.29 and RMSE equal to 4.26 were obtained. Furthermore, the performance of the models improves as far as the correlation coefficient increases. Therefore, it is concluded that the results obtained using random fields are better than those obtained using the deterministic analysis. [ABSTRACT FROM AUTHOR]

This paper presents a research attempt towards frequency-based crack effect study in laminated composite beams (LCBs) through combined computational and experimental work. The focused objective of the undertaken research is to quantify the crack effects on the frequency behavior of LCBs. Towards achieving the objective, carbon/epoxy LCBs are the subject materials under consideration and to achieve the natural frequencies for the LCBs under free vibration, a combination of numerical simulation and experimental tests are conducted. ABAQUS, a powerful finite element (FE) simulation software is employed to develop precise numerical models representing the LCB's mechanical behavior and response to crack propagation. The free vibration experiments on LCB samples are conducted through a Fast Fourier Transform (FFT) analyzer under controlled crack scenarios aligning with the numerical simulation model. Through the frequency analysis, critical crack depths and positions that significantly influence the dynamic impact are identified. The study also explores the correlation between the computational and experimental results, enhancing the confidence in simulation models. The results from the study can aid in the early detection of damage and the optimization of repair strategies to ensure the structural reliability and safety of LCBs or alike composite components. [ABSTRACT FROM AUTHOR]

To provide convenient access to service ducts, beam and girder web openings are very prevalent in practice. The insertion of a reinforced concrete (RC) beam into the web, however, reduces the stiffness and strength of the beam because of the local cracking around the aperture. The employ of fiber-reinforced polymer (FRP) laminas in general and not a specific type of them for reinforcing the holes was showed in this paper including their dimension and some design parameters change, such as the number and placement of (FRP) sheets near the opening. The experimental work was presented by comprised the testing of ten reinforced concrete beams, four of them were tested without reinforcement, five of which had (FRP) sheets around the opening for reinforcement, and the remaining beam was solid. The (FE) program consists of ten beams were modelled by using Abaqus, one of them was control solid beam and other nine beams were with hollow. The load-deflection relationships were evaluated before failure, and crack patterns were obtained and compared with the experimental results available. The numerical and experimental results agreed well. Reinforced concrete beams are the cornerstone of modern infrastructure, carrying heavy loads and forming the basic structure of buildings and structures. However, these beams may be damaged or deteriorated over time due to multiple factors such as corrosion, overload, moisture, and fire. In addition, the need to make modifications or openings in these beams for maintenance or service installation purposes may negatively affect their load-bearing capacity. To overcome these challenges, modern techniques have emerged to strengthen concrete elements, the most important of which is the technique of strengthening concrete with fiber reinforced polymer (FRP). This technique is highly effective in increasing the load-bearing capacity of concrete beams, improving their performance under different loads, and extending their service life. A brief critique of the limitations of existing studies should be included to highlight the significance of the present work. Inadequate studies on the interaction between FRP and concrete: There are still gaps in our understanding of the interaction between FRP and concrete at the microscopic level, which affects the accuracy of computational models. The research focused on the behavior of FRP-reinforced concrete hollow core beams under different loads, filling a gap in previous research. The research combined computer simulations and laboratory tests to ensure the accuracy of the results and provide a comprehensive picture of the behavior of the beams. The research identified the best methods for applying FRP sheets to improve the load-bearing capacity of beams around openings, providing practical guidance for engineers. [ABSTRACT FROM AUTHOR]

A SEND toxicology data transformation, harmonization, and analysis platform were created to improve the identification of unique findings related to the intended target, species, and duration of dosing using data from multiple studies. The lack of a standardized digital format for data analysis had impeded large-scale analysis of in vivo toxicology studies. The CDISC SEND standard enables the analysis of data from multiple studies performed by different laboratories. This work describes methods to analyze data and automate cross-study analysis of toxicology studies. Cross-study analysis can be used to understand a single compound's toxicity profile across all studies performed and/or to evaluate on-target versus off-target toxicity for multiple compounds intended for the same pharmacological target. This work involved development of data harmonization/transformation strategies to enable cross-study analysis of both numerical and categorical SEND data. Four de-identified SEND datasets from the BioCelerate database were used for the analyses. Toxicity profiles for key organ systems were developed for liver, kidney, male reproductive tract, endocrine system, and hematopoietic system using SEND domains. A cross-study analysis dashboard with a built-in user-defined scoring system was created for custom analyses, including visualizations to evaluate data at the organ system level and drill down into individual animal data. This data analysis provides the tools for scientists to compare toxicity profiles across multiple studies using SEND. A cross-study analysis of 2 different compounds intended for the same pharmacological target is described and the analyses indicate potential on-target effects to liver, kidney, and hematopoietic systems. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive three-dimensional numerical investigation of horizontal square anchors embedded in geogrid-reinforced sand. Prior experimental studies have demonstrated notable enhancements in anchor uplift capacity when placed below geogrid reinforcement in soil. However, these results are limited to small anchor plates tested in laboratory conditions with over-reinforced sand. In contrast, this study focuses on large field-scale anchors and explores the influence of anchor width, embedment depth, reinforcement size, stiffness, and tensile strength on uplift capacity. The findings reveal that the optimal size for geogrid reinforcement is three times the anchor width. A diminishing improvement in uplift capacity with increasing anchor width was observed. Additionally, deeper anchor embedment reduces the uplift capacity improvement in geogrid-reinforced sand. The geogrid reinforcement is found to be more efficient in the case of shallow anchors placed in loose sand. The major contribution of this paper lies in the response analysis of large anchors and providing a better understanding of the uplift mechanism in geogrid-reinforced sand. • This paper presents a three-dimensional numerical investigation of large field-scale horizontal square anchors embedded in geogrid-reinforced sand. • The findings reveal that the optimal size for geogrid reinforcement is three times the anchor width (B) in contrary to the 5B value reported in the previous literature. • A diminishing improvement in uplift capacity with increasing anchor width was observed. • Deeper anchor embedment reduced the uplift capacity improvement in geogrid-reinforced sand. • The geogrid reinforcement is found to be more efficient in the case of shallow anchors. [ABSTRACT FROM AUTHOR]

We consider a model convection-diffusion problem and present our recent analysis and numerical results regarding mixed finite element formulation and discretization in the singular perturbed case when the convection term dominates the problem. Using the concepts of optimal norm and saddle point reformulation, we found new error estimates for the case of uniform meshes. We compare the standard linear Galerkin discretization to a saddle point least square discretization that uses quadratic test functions, and explain the non-physical oscillations of the discrete solutions. We also relate a known upwinding Petrov–Galerkin method and the stream-line diffusion discretization method, by emphasizing the resulting linear systems and by comparing appropriate error norms. The results can be extended to the multidimensional case in order to find efficient approximations for more general singular perturbed problems including convection dominated models. [ABSTRACT FROM AUTHOR]

In this paper, an experimental, numerical and analytical study is conducted on a 2 × 1 bored pile group on saturated sand under combined loading. Initially, a single-degree-of-freedom system founded on the pile group is tested at the ETH Zurich drum centrifuge under vertical, lateral and pushover loading, gaining insights and deriving benchmark results for validation of finite-element (FE) models. The latter account for non-linear soil–pile interaction, using hypoplasticity for sand and appropriate modelling of interfaces and pile response. Combining centrifuge and FE modelling, the governing resistance mechanisms are identified and quantified. The transition from model to prototype scale is achieved after careful consideration of scale effects. The concrete damaged plasticity model is employed to model the non-linear response of the reinforced concrete (RC) piles, accounting for axial load dependency of bending moment capacity. The prototype problem is studied parametrically, deriving failure envelopes for different levels of vertical loading. Distinguishable failure modes are identified, and the contribution of different resistance mechanisms is quantified. Finally, analytical failure envelopes are derived based on limit equilibrium, expanding Broms' theory to pile groups under combined loading. Accounting for the axial load dependency of RC bending moment capacity, the proposed closed-form solutions provide a useful design tool for engineering practice. [ABSTRACT FROM AUTHOR]

The influence of design parameters on the thermal performance of a packed bed thermocline thermal energy storage (TES) system was analyzed. Both one-dimensional (1D) and two-dimensional (2D) in-house codes were developed in MATLAB environment. The diameter of solid filler, height of storage tank, and fluid velocity were varied. The thermal performance of the system, such as discharging time, thermocline thickness, and energy efficiency was calculated. As the diameter of the solid filler and fluid velocity increased, and the height of the storage tank decreased, the discharging time decreased. As the diameter of the solid filler and the height of storage tank increased, the thermocline generally became thicker. The thermocline thickness according to the fluid velocity showed non-monotonic behavior: initially increasing and then decreasing, since it affected heat transfer coefficient, fluid-solid contact time and discharging time, which affected thermocline expansion. The 2D model exhibited higher energy efficiency than the 1D model, due to the consideration of the additional wall heating to the fluid, resulting in extended discharging time except for very low flow velocities. [ABSTRACT FROM AUTHOR]