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This work deals with fracture mechanisms in quasi-brittle materials, focusing on the characterization of the Fracture Process Zone (FPZ) of specimens under tensile load. Particularly, paper was used as model material. Experiments were conducted on notched and unnotched specimens. Based on an image analysis of these observations, a stochastic finite element model was developed, using both a nonlocal stress-based approach and a discretized random field modeling of the Young's modulus. The proposed methodology allowed characterizing the damage zone and the size of the FPZ, analyzing the influence of the mesostructure, composed of flocs (fiber aggregates where the basis weight is larger than the average one) and antiflocs (complement of flocs). The area of the active FPZ and the normalized stress drop were linked using a surface energy dissipated in the active FPZ. The stress drop, until limiting value, increased with the width of the active FPZ. Finally, a relationship between the surface energy and the nonlocal internal length was established. [ABSTRACT FROM AUTHOR]

Some errors exist in the above paper. [ABSTRACT FROM AUTHOR]

As the main structural bodies of underground facilities such as subway stations, frame tunnel structures play an important role in urban development and construction. In recent years, with the frequent occurrence of explosions after vehicle impacts in tunnels, which have caused severe damage to frame tunnels, the lack of relevant papers makes it necessary to develop a dynamic response analysis of frame tunnels. In this paper, by optimizing the design of an original frame tunnel structure, a dynamic response numerical model of the frame tunnel considering the impact effect of a 3D solidified vehicle and the joint effect is investigated. The deformation trend and damage evolution of the frame tunnel are analysed under different collision masses (1.4, 2.4, 6 and 15 t), collision angles (5, 10, 15 and 75°), collision speeds (60, 80 and 100 km/h), blast delay times (10, 20 and 30 ms) and blast equivalents (50, 100 and 200 kg TNT). This paper improves the active and passive robustness of frame tunnels using both improved operational management and the optimal design of the tunnel structure as a way to ensure the structural safety and functional resilience of frame tunnels. [ABSTRACT FROM AUTHOR]

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The aim of this Authors’ Reply is to examine critically certain assertions by Logo in a Discussion and in two conference papers about a publication by Rozvany and Maute on a reliability based benchmark example [ABSTRACT FROM AUTHOR]

Data from natural sources show counter-intuitive distribution patterns for the leading digits to the left of the decimal point and the digit 1 is observed more frequently than all other numbers. This pattern, which was first described by Newcomb and later confirmed by Benford, is used in financial and tax auditing to detect fraud. Deviations from the pattern indicate possible falsifications. Anesthesiology journals are affected not only by ghostwriting and plagiarism but also by counterfeiting. In the present study 20 publications in anesthesiology known to be falsified by an author were investigated for irregularities with respect to Benford's law using the χ-test and the Z-test. In the 20 retracted publications an average first-digit frequency of 243.1 (standard deviation SD ±118.2, range: 30-592) and an average second-digit frequency of 132.3 (SD ±72.2, range: 15-383) were found. The observed distribution of the first and second digits to the left of the decimal point differed significantly (p< 0.01) from the expected distribution described by Benford. Only the observed absolute frequencies for digits 3, 4 and 5 did not differ significantly from the expected values. In an analysis of each paper 17 out of 20 studies differed significantly from the expected value for the first digit and 18 out of 20 studies varied significantly from the expected value of the second digit. Only one paper did not vary significantly from expected values for the digits to the left of the decimal. For comparison, a meta-analysis using complex mathematical procedures was chosen as a control. The analysis showed a first-digit distribution consistent with the Benford distribution. Thus, the method used in the present study seems to be sensitive for detecting fraud. Additional statements of specificity cannot yet be made as this requires further analysis of data that is definitely not falsified. Future studies exploring conformity might help prevent falsified studies from being published. [ABSTRACT FROM AUTHOR]

Abstract  A web is continuous, flexible materials such as paper, plastic film, metal foil, textiles, etc. Web wrinkle is a problem which plagues the process industries. Most webs are very thin and prone to buckle or wrinkle. The effects of wrinkling can range from compromised product quality to down time of a processing operation, leading to less profitability in the manufacturing operation. The web wrinkles which will be treated in this paper are those that can be affected by roller misalignment and friction characteristics between web and roller. In this paper, observation method is presented for paper-web wrinkling and the prediction model of wrinkling is proposed with experimental verifications. [ABSTRACT FROM AUTHOR]

In the recent paper [1], a new scaling theory of electron localization was proposed. We show that numerical data for the quasi-one-dimensional Anderson model do not support predictions of this theory. [ABSTRACT FROM AUTHOR]

Recently, Al-Odat and Al-Hussien presented consideration of the critical energy of a composite superconductor in this journal. Various numerical and other deficiencies have been identified in this paper. These problems are discussed and clarified in this Comment. [ABSTRACT FROM AUTHOR]

This paper shows the construction of a growth model that includes public infrastructure and a related externality and investigates the dynamic properties of the model for a specific endogenous time preference function. After suggesting a saddle-path stability for long-term equilibrium under an endogenous time preference, numerical analysis of the model then reveals an unexpected relation between the strength of the externality, the magnitude of the rate of time preference, and the growth rate of the economy. In addition, it is found that multiple equilibria are unlikely to be supported empirically by the model in this paper. [ABSTRACT FROM AUTHOR]

This study presents the dynamic capillary pressure model (Hassanizadeh and Gray, Adv Water Resour 13:169-186, ; Water Resour Res 29:3389-3405, ) adapted for the needs of paper manufacturing process simulations. The dynamic capillary pressure-saturation relation is included in a one-dimensional simulation model for the pressing section of a paper machine. The one-dimensional model is derived from a two-dimensional model by averaging with respect to the vertical direction. Then, the model is discretized by the finite volume method and solved by Newton's method. The numerical experiments are carried out for parameters typical for the paper layer. The dynamic capillary pressure-saturation relation shows significant influence on the distribution of water pressure. The behavior of the solution agrees with laboratory experiments (Beck, Fluid pressure in a press nip: measurements and conclusions, ). [ABSTRACT FROM AUTHOR]

Layered rock slope exists widely. Because of its special slope structure, it is prone to bending deformation and toppling failure, which is a serious threat to engineering construction and safety operation. At present, the research of layered rock slope still has great innovation potential. During the construction of Wudongde Hydropower Station on Jinsha River, safety and stability problems such as slope geological structure development, face rock unloading and relaxation, and even slip and large deformation were encountered. Through field exploration, it is found that the rock and soil stratification of the slope on both sides of Wudongde Hydropower Station is highly obvious. At present, there is a lack of research on-site long-term displacement monitoring of layered rock high-steep slope, especially for layered slope in complex hydrogeology and construction environment. In order to strengthen the research on the deformation and stability of layered rock slope, this paper analyzes the measured displacement data of Wudongde hydropower station slope, and establishes three-dimensional geological finite element model with the help of numerical simulation software. The stability of the slope is calculated by combining the finite difference method and the strength reduction method. Finally, the evolution mechanism of the deformation of the layered rock slope is explained according to the geological structure characteristics. The main conclusions of this paper are as follows: the layered slope in the dam reservoir area is prone to deformation under the combined action of long-term construction disturbance and fissure water seepage, and the construction disturbance has a strong influence on the artificial excavation area below 1070 m, and the maximum rock mass deformation and surface displacement in the artificial excavation area of the slope reach 92.2 mm and 312.5 mm, respectively. However, the influence of construction disturbance on the natural mountain above 1070 m is limited, the valley deformation of the natural mountain on the left bank of the reservoir area is higher than that on the right bank, and the cumulative deformation is still less than 20 mm. The influence of seepage on the displacement of the area with higher elevation at the top of the slope is more obvious, and the influence of excavation and other disturbances on the displacement of the artificial excavation area with lower elevation is more obvious. The deformation of the river valley in the water cushion pond behind the dam increases slowly, and the change trend of the field deformation data is mostly consistent with that of the numerical calculation. The horizontal shrinkage of the mountains on both sides shows a contraction trend on the whole, and the maximum horizontal shrinkage calculated by numerical simulation is close to 20 mm, which is located at the elevation of 990 m. [ABSTRACT FROM AUTHOR]

Clustered group nail connectors are key connecting components for the full lifecycle construction and safe operation of steel–concrete composite structural bridges. To thoroughly investigate the stress mechanism of clustered group nail connectors in steel–concrete composite structures, this paper conducts a detailed numerical analysis on 100 sets of such connectors. It analyzes the stress mechanism of individual nail connectors and quantitatively calculates the group nail effect under the coupled action of multiple factors (nail spacing between layers, number of nail layers, concrete strength). Based on clarifying the force transmission patterns of nails and concrete in different layers during the loading process, this paper proposes a method for calculating the average bearing capacity reduction coefficient and the load-slip curve of single nails in clustered group nail connectors under the coupled action of multiple factors, which has been validated by experimental data. This research provides a theoretical basis for the design and calculation of group nail connectors in steel–concrete composite structural bridges. [ABSTRACT FROM AUTHOR]

O. Einstein (2008) proved Bollobás-type theorems on intersecting families of ordered sets of finite sets and subspaces. Unfortunately, we report that the proof of a theorem on ordered sets of subspaces had a mistake. We prove two weaker variants. [ABSTRACT FROM AUTHOR]

Because of the increased mobility of vehicle users, it might be difficult to keep communication services in vehicle networks effective and dependable. Huge hurdles have been presented to vehicular networks as a result of the meteoric rise in the amount of data, which comes with the needs of high dependability and low latency. The deployment of access point servers at geographic locations that are closer to the vehicles in order to provide real-time service to applications that are based on the vehicles is one possible option. However, there is a limited amount of cache store space, and there is also a lack of a tractable access mode allocation method. As a result of these factors, it is very difficult to strike a compromise between the network transmission performance and fronthaul savings. Because the signal-to-interference-ratio (SIR) can be enhanced with switching mode in vehicular infrastructure, it may be possible to achieve higher levels of dependability. To serve all of the vehicles, the conventional allocation in vehicular network may not be sufficient on its own for two reasons: (1) the number of vehicles exceeds the number of paths, and (2) a vehicle may be located outside of the coverage path. Therefore, the implementation of switching mode allocation in vehicular communication is very necessary in order to increase the number of vehicles that can be supplied. In this paper, allocation using V2I, V2V, and V2X modes have been analyzed to provide dependable coverage for vehicles. These methods are used for communicating with other vehicles. In this paper, the numerical analysis has been performed such that SIR is optimized. In switching mode allocation, it has been shown that establishing a variable SIR threshold is helpful in achieving a path coverage that can be relied upon. It has been shown beyond a reasonable doubt that the coverage probability is likewise directly dependent on SIR thresholds. The theoretical analysis is verified, and it is confirmed that the suggested method is capable of achieving significant performance improvement in terms of coverage probability and data rate. [ABSTRACT FROM AUTHOR]

This paper investigates the performance of a single and a group of laterally loaded barrettes using a series of numerical models in a three-dimensional finite element software. The simulation of laterally loaded barrettes in both directions is verified by comparing numerical predictions to field measurements previously published in the literature. This paper defines the soil wedge around the barrette sheared at a strain equivalent to the minimum shear strain value at the barrette side or higher as the effective strain wedge. The results from a suite of numerical experiments show that the size of the effective shear strain wedge remains constant at different lateral loads, soil density, barrette shape (aspect ratio), and barrette stiffness. This paper also delineates the effect of spacing in a group of barrettes on the mobilized strain wedges and the associated lateral deformations. The paper then suggests equivalent dimensions for laterally loaded barrettes to be used as input parameters in analyses using p-y curves based on the shape of the effective strain wedge. The predictions from p-y analyses are improved in all the studied cases when equivalent dimensions are used compared to the finite element computations. The paper studies the appropriate design multipliers recommended in literature to be used in the p-y curves method for laterally loaded barrette groups in single and multiple rows. Comparisons with finite element results show the validity of employing the equivalent shape dimensions in determining suitable p-multipliers. [ABSTRACT FROM AUTHOR]

The performance of a permissioned blockchain, namely, Hyperledger Fabric, is modeled and analyzed in a quantitative manner in this paper. Various types of nodes contribute to the performance of Hyperledger Fabric, and each of those is modeled and tracked along the operational flow of the permissioned blockchain. There are nodes for endorsement, ordering, and commitment to realize the due decentralized network operations. A quantitative model for each type of nodes has been proposed in Ke and Park (Performance study on various Hyperledger Fabric node types and transaction flow, IEEE BCCA, 2021) along with numerical analysis. Each type of the nodes is characterized in terms of transaction/block queue size and waiting time, and the transaction/block arrival rates and the transaction/block service rates are considered for simulation purposes. The analysis is extended beyond the analysis in Ke and Park (Performance study on various Hyperledger Fabric node types and transaction flow, IEEE BCCA, 2021) in this paper to particularly demonstrate how the arrival rates and the service rates co-influence the performance and how the number of channels impacts the performance, in order to ultimately facilitate a more dynamic way of optimization, taking the co-relation across different types of nodes into account. The major contribution of this paper to the field of computer science by creating a series of queuing models to evaluate the performance of different types of nodes: Chaincode Execution and Endorsement, Block Creation and Delivery, Transaction Validation and Block Committing, and Transaction Processing. [ABSTRACT FROM AUTHOR]

This paper deals with precipitation events, particularly the problem of recognising events individually, of distinguishing one local meteorological/precipitation event from another. The final aim was to arrive at a more appropriate conceptualization of "distance" between individual annual events. A criterion for identifying annual precipitation events, inside a 5 min-timestep series of pluviometric data, was proposed. Using this numerical criterion, a series of annual distances between events were obtained and compared with those obtained by other two known and applied statistical methods. This comparison would be important for linking the so-called statistical methods to the real data of the series, analysed through a numerical process. This would make it possible to provide a kind of "measure" for the understanding of real data via a statistical model. Results showed that distances between events, obtained through numerical analyses, are almost always different from those obtained by statistical methods. The supposed Poisson-process, generally matched to, and widely applied in the field of rainfall data, showed some contradiction with the analysis conducted in this paper. The so-called Lag method shows a numerical method type distribution, but produces some important internal deviations from numerical results. It seems that the method proposed in this paper can reproduce the real distances between events more realistically compared to the statistical methods considered here. Exponential distribution does not seem highly performing, at least in the case of the annual analysis, with series of a 5-min time-step resolution, obtained from rain gauges installed in the Veneto Region of Italy. It is believed that the numerical criterion presented in this paper can be considered adequate for determining the distances between events, within an annual time-window. [ABSTRACT FROM AUTHOR]

The selection of materials for the protective coating of a crusher's feed chute significantly influences the mean time between failures (MTBF) and operational costs associated with the mass production of sulfuric acid at MMG/Kinsevere. Neglecting the condition of the protective coating can pose a serious challenge to production efficiency and result in increased downtime. This study focuses on enhancing industrial productivity in Sulfuric Acid production with minimal maintenance. The investigation explores the quality and type of materials used for the protective coating of the feed chute in the mining industry, particularly at MMG/Kinsevere, utilizing Ansys Fluent and SOLIDWORKS Software for analysis. The paper proposes a Ceramic protective liner for the crusher feed chute due to its superior resistance to erosion compared to other liners. Different feed chute models, constructed with materials like halogenated butyl rubber, 316 stainless steel, and ceramic, underwent analysis. The evaluation of the potential impact on the mean time between failures (MTBF) for different materials used in a protective coating, considering the rate of erosion through computational fluid dynamics (CFD) with ANSYS FLUENT software, is a central aspect of this study. The detailed modeling and simulation reveal that the ceramic material exhibits the most favorable protective coating characteristics, with an erosion rate density of 06.636753 kg/m2s, outperforming halogenated butyl rubber (3.326576 kg/m2s) and 316 stainless steel (2.186633 kg/m2s). The simulation yielded results corresponding to flow rates of 284.19 kg/s for the solid phase and 123.14 kg/s for the liquid phase. [ABSTRACT FROM AUTHOR]

Pile driving can trigger slope failure, specifically in sensitive soil deposits or marginally stable slopes. Cases of slope failure during pile installation have been reported in countries such as Norway, Sweden and Canada where soft sensitive clay deposits are prevalent. Although a few approaches have been suggested to assess the factor of safety of a slope during pile driving, there is currently no standard method recognized by the geotechnical society to account for the reduction of safety factor of a slope as an effect of pile installation. Some approaches suggest using the excess pore pressure generated during pile driving to account for the reduction in soil strength (by reducing effective stresses), neglecting the change in total stresses. This paper discusses the accuracy of stability analysis methods currently in use for this problem by looking at stress changes in the soil during pile driving as well as using numerical analysis results. Importantly, the paper identifies the shortcomings regarding these approaches, thus allowing geo-engineers to understand the limitations of their analysis and the uncertainties in the models. [ABSTRACT FROM AUTHOR]

Particle morphology is a crucial determining factor in the physicochemical properties of geological materials. Currently, there are still substantial challenges with the characterization and reconstruction of the morphology of irregular particles. Most currently used characterization and reconstruction methods were developed separately, and lack cohesive integration of parameters between the two processes. This limitation hinders the comprehensive characterization of the multiscale geometric features and impedes a clear relation between geometrical features and reconstruction parameters. Therefore, a unified 2D and 3D morphological characterization method for irregular particles is developed in this paper, enabling a systematic morphology quantification across three relative scales. Furthermore, a geometric parameters-driven particle reconstruction approach is proposed, which is the reverse of the quantification process, achieving precise and controllable 2D and 3D irregular morphology reconstruction. The proposed methods achieve, for the first time, an integrated quantification and reconstruction framework of irregular particle morphology, as well as a unified 2D and 3D morphology characterization. Notably, the proposed approach exhibits strong robustness and computational efficiency when performing 2D and 3D particle morphology quantification and precisely controllable virtual particle reconstruction, which are the bases for accurate mechanical analyses and numerical simulations. [ABSTRACT FROM AUTHOR]

With the development of cloud computing, users are more inclined to outsource complex computing tasks to cloud servers with strong computing capacity, and the cloud returns the final calculation results. However, the cloud is not completely trustworthy, which may leak the data of user and even return incorrect calculations on purpose. Therefore, it is important to verify the results of computing tasks without revealing the privacy of the users. Among all the computing tasks, the polynomial calculation is widely used in information security, linear algebra, signal processing and other fields. Most existing polynomial-based verifiable computation schemes require that the input of the polynomial function must come from a single data source, which means that the data must be signed by a single user. However, the input of the polynomial may come from multiple users in the practical application. In order to solve this problem, the researchers have proposed some schemes for multi-source outsourced data, but these schemes have the common problem of low efficiency. To improve the efficiency, this paper proposes an efficient polynomial-based verifiable computation scheme on multi-source outsourced data. We optimize the polynomials using Horner's method to increase the speed of verification, in which the addition gate and the multiplication gate can be interleaved to represent the polynomial function. In order to adapt to this structure, we design the corresponding homomorphic verification tag, so that the input of the polynomial can come from multiple data sources. We prove the correctness and rationality of the scheme, and carry out numerical analysis and evaluation research to verify the efficiency of the scheme. The experimental indicate that data contributors can sign 1000 new data in merely 2 s, while the verification of a delegated polynomial function with a power of 100 requires only 18 ms. These results confirm that the proposed scheme is better than the existing scheme. [ABSTRACT FROM AUTHOR]

This paper presents a novel approach to analyzing the dynamics of COVID-19 using nonstandard finite difference (NSFD) schemes. Our model incorporates both asymptomatic and symptomatic infected individuals, allowing for a more comprehensive understanding of the epidemic's spread. We introduce an unconditionally stable NSFD system that eliminates the need for traditional Runge–Kutta methods, ensuring dynamical consistency and numerical accuracy. Through rigorous numerical analysis, we evaluate the performance of different NSFD strategies and validate our analytical findings. Our work demonstrates the benefits of using NSFD schemes for modeling infectious diseases, offering advantages in terms of stability and efficiency. We further illustrate the dynamic behavior of COVID-19 under various conditions using numerical simulations. The results from these simulations demonstrate the effectiveness of the proposed approach in capturing the epidemic's complex dynamics. [ABSTRACT FROM AUTHOR]

Enhancing information security has become increasingly significant in the digital age. This paper investigates the concept of physical layer security (PLS) within a relay-aided power line communication (PLC) system operating over a multiple-input multiple-output (MIMO) channel based on MK model. Specifically, we examine the transmission of confidential signals between a source and a distant destination while accounting for the presence of multiple eavesdroppers, both colluding and non-colluding. We propose a two-phase jamming scheme that leverages a full-duplex (FD) amplify-and-forward (AF) relay to address this challenge. Our primary objective is to maximize the secrecy rate, which necessitates the optimization of the jamming precoding and transmitting precoding matrices at both the source and the relay while adhering to transmit power constraints. We present a formulation of this problem and demonstrate that it can be efficiently solved using an effective block coordinate descent (BCD) algorithm. Simulation results are conducted to validate the convergence and performance of the proposed algorithm. These findings confirm the effectiveness of our approach. Furthermore, the numerical analysis reveals that our proposed algorithm surpasses traditional schemes that lack jamming to achieve higher secrecy rates. As a result, the proposed algorithm offers the benefit of guaranteeing secure communications in a realistic channel model, even in scenarios involving colluding eavesdroppers. [ABSTRACT FROM AUTHOR]

The rock mechanics parameters are important indicators for risk assessment in tunnel construction. However, rock mechanical parameters estimated by traditional mechanical testing in the field are subject to considerable uncertainties due to limitations testing technology, which can directly lead to unreliable risk assessment results. Deformation data for parametric back analysis is a reliable and efficient method for estimating mechanical parameters of rock masses. Deformation monitoring data used for parameter back analysis is an efficient and reliable method for estimating rock mechanical parameters, but the current research generally suffers from inaccurate constitutive models, confusing selection of input data, and failure to consider the intrinsic correlation of mechanical parameters. In this paper, a deformation-based back analysis method for rock mechanical parameters was proposed by XGBoost with RC. Taking the Changning Tunnel in Yunnan Province, China, as an example, the construction process of the back analysis model was described in detail. To improve the reliability of the sample data, the Ubiquitous-Joint constitutive model was used and a more characteristic deformed data selection method was proposed. Furthermore, the performance of the back analysis model was improved through Bayesian Optimization of hyperparameters and order filtering of Regressor Chain, and the intrinsic correlation of the parameters was effectively considered through the Regressor Chain. The results showed that applying the rock mechanics parameters obtained from the back analysis model to numerical simulation can effectively predict deformation during tunnel construction, and the error rate of deformation prediction was within 10%, which demonstrates the reliability of the method in this paper. This method can be extended to other heavily fractured tunnels. Highlights: Summarized the technical process of back analysis of mechanics parameters based on machine learning, analyzed the current research status, and put forward the existing problems. Through the spatial–temporal effect analysis of deformation of rock mass, a reasonable selection method of the surrounding rock deformation index in the sample data is proposed. The performance of the back analysis model of rock mechanics parameters is effectively improved by hyperparameter optimization of Bayesian and order filtering of Regressor Chains. [ABSTRACT FROM AUTHOR]

The main goal of this paper is to investigate the hydrodynamic and vibrational behavior of the 2000 mm diameter Howell Bunger valve that will be installed in the Khodaafrin dam. The existence of a historical bridge downstream of this dam makes it important to investigate the vibration and hydrodynamic behavior of the valve, so that its design and operation should be in such a way that the historical bridge located downstream will not be damaged. In order to achieve this goal, the valves are considered to have submerged discharge, and this has raised the need to investigate the hydrodynamic behavior of the valve and compare it with the non-submerged state. To investigate the behavior of the valve, a 1:20 model of the valve, hood and discharge pool were designed and built. Then, the experimental rig was designed and equipped with measuring equipment, and the model valve was subjected to hydrodynamic and vibration tests with different opening percentages in non-submerged and submerged states with different downstream pool depths. These experiments have been repeated for the valve with hood and without hood and the results have been compared. Then, the finite element model of the 1:20 model valve was developed and hydrodynamically analyzed and the numerical results were compared with the experimental data. After ensuring the correctness of the numerical model, it was used to investigate the behavior of the valve in different conditions. The results show that there is not much change in the flow rate when the valve is submerged, but the range of vibrations decreases significantly. This decrease in the amplitude of vibrations becomes more dominant with increasing the depth of the pool. Also, it has been shown that the range of vibrations in the case without the hood is lower than the case with the hood. [ABSTRACT FROM AUTHOR]

In this paper, the authors discuss a three-dimensional problem of the semiconductor device type involved its mathematical description, numerical simulation and theoretical analysis. Two important factors, heat and magnetic influences are involved. The mathematical model is formulated by four nonlinear partial differential equations (PDEs), determining four major physical variables. The influences of magnetic fields are supposed to be weak, and the strength is parallel to the z-axis. The elliptic equation is treated by a block-centered method, and the law of conservation is preserved. The computational accuracy is improved one order. Other equations are convection-dominated, thus are approximated by upwind block-centered differences. Upwind difference can eliminate numerical dispersion and nonphysical oscillation. The diffusion is approximated by the block-centered difference, while the convection term is treated by upwind approximation. Furthermore, the unknowns and adjoint functions are computed at the same time. These characters play important roles in numerical computations of conductor device problems. Using the theories of priori analysis such as energy estimates, the principle of duality and mathematical inductions, an optimal estimates result is obtained. Then a composite numerical method is shown for solving this problem. [ABSTRACT FROM AUTHOR]

This paper introduces a novel approach for analyzing efficient numerical solution of a class of singularly perturbed parabolic convection-diffusion PDEs having a finite jump discontinuity mostly in the source function at the interior of the spatial domain. These PDEs often appear in mathematical modeling of the semiconductor devices; and solutions of such problems usually exhibit a weak interior layer at one side of the point of discontinuity along with a boundary layer at one side of the spatial domain. The prime objectives of this paper are to overcome the theoretical challenge related to the monotonocity of the finite difference operator which utilizes one-sided second-order difference operators at the interface point; and also to establish higher-order numerical approximation in space, regardless of smaller and larger values of the parameter ε. Proving discrete maximum principle of the proposed difference operator is found to be challenging task on the standard Shishkin mesh adapted to both boundary and weak interior layers. We overcome this difficulty by constructing a special non-uniform mesh, called modified layer-adapted mesh; and hereby establish the stability as well as the parameter-uniform error estimate in the discrete supremum norm. Finally, the theoretical estimate is verified with numerical results for test examples with and without the exact solution. Moreover, numerical results are obtained for the semilinear PDEs and also compared with the implicit upwind scheme to exhibit the efficiency of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Concrete slabs are widely used in modern railways to increase the inherent resilient quality of the tracks, provide safe and smooth rides, and reduce the maintenance frequency. In this paper, the elastic performance of a novel slab trackform for high-speed railways is investigated using three-dimensional finite element modelling in Abaqus. It is then compared to the performance of a ballasted track. First, slab and ballasted track models are developed to replicate the full-scale testing of track sections. Once the models are calibrated with the experimental results, the novel slab model is developed and compared against the calibrated slab track results. The slab and ballasted track models are then extended to create linear dynamic models, considering the track geodynamics, and simulating train passages at various speeds, for which the Ledsgård documented case was used to validate the models. Trains travelling at low and high speeds are analysed to investigate the track deflections and the wave propagation in the soil, considering the issues associated with critical speeds. Various train loading methods are discussed, and the most practical approach is retained and described. Moreover, correlations are made between the geotechnical parameters of modern high-speed rail and conventional standards. It is found that considering the same ground condition, the slab track deflections are considerably smaller than those of the ballasted track at high speeds, while they show similar behaviour at low speeds. [ABSTRACT FROM AUTHOR]

Continuous monitoring of the structural health of strategic structures and transport infrastructures plays a crucial role in providing an effective assessment of the safety conditions and in timely planning of the ordinary and extraordinary maintenance programme. Deformation monitoring and dynamic characteristic identification are some commonly used strategies for this purpose. One of the main challenges of recent years in the field of structural health monitoring is the use of data deriving from satellite interferometry, capable of providing information on structural deformations at a local and territorial scale. Despite the solidity and dependability of satellite-based methods for assessing ground deformation over time, when it comes to structural surveillance, there are certain circumstances under which satellites are incapable of accurately assessing displacements. This is particularly true for structures that are sensitive to temperature variations. The paper uses the "Ponte della Musica–Armando Trovajoli" in Rome as a case study to explore these aspects in more depth. This bridge has a steel arch structure with a prestressed concrete deck below it. It represents an example in which satellite differential interferometry does not allow obtaining useful information on displacement, at least for the most deformable portion of the deck, and therefore also on any pathological movements. This work proposes a 3D digital twin of the bridge, appropriately calibrated through experimental measurements of the environmental vibrations performed on the bridge. This will allow to evaluate the role played by thermal deformations related to air temperature variations and thus better understand the connection between physiological deformations and satellite limits. [ABSTRACT FROM AUTHOR]

The simulation of rubber-like materials is usually based on hyperelasticity. If strain-rate dependency has to be considered viscous dampers also have to be taken into account in the rheological model. A disadvantage of such a description is time-consuming parameter identification associated with the damping constants. In this paper, a tabulated formulation is presented which allows the fast generation of input data based on uniaxial static and dynamic tensile tests at different strain rates. Unloading, i.e. forming a hysteresis loop, can also be modeled easily based on a damage formulation. We show the theoretical background and algorithmic setup of our model that has been implemented in the explicit finite element program LS-DYNA [1-3]. Apart from purely numerical examples, the validation of a soft and a hard rubber under loading and subsequent unloading at different strain rates is shown. [ABSTRACT FROM AUTHOR]

The convergence of the integral smoothed particle hydrodynamics (SPH) solution to the advection-diffusion equation in two dimensions in the particular case of a rigid rotation transport velocity field, is established in this paper. The approximation to the Laplacian operator is considered (Morris et al. 1997). The convergence of the SPH solution to the exact one is established in Fourier space. It is shown that convergence is guaranteed if a certain condition on the Fourier transform of the kernel, that we call positivity condition, is fulfilled. This condition is that the first moment of the radial profile of the kernel’s Fourier transform is positive. The analytical result is illustrated with a numerical verification. The numerical solutions obtained with different kernels, including those more commonly used by the SPH community (namely, the Wendland kernels and the cubic and linear spline kernels), are compared in terms of both the L2 norm and the norm of the maximum. In addition to that, a pathological kernel, for which the positivity condition is not satisfied, is presented and tested, leading to non convergent results. This fact suggests that the Positivity condition is not only a sufficient but a necessary condition for convergence, in the case of the advection-diffusion equation. Moreover, the derivation of the exact solution for one of the numerical examples discussed in the paper is presented in detail in an appendix. This is an interesting test case for the advection-diffusion equation due to its discontinuous nature, therefore, the authors consider it useful to thoroughly present the obtaining of its exact solution. The paper is closed with conclusions and future work. [ABSTRACT FROM AUTHOR]

In this note we will show that finitely generated condition is necessary in Theorem 1.2 of the above mentioned paper. [ABSTRACT FROM AUTHOR]

Fire resistance is one of the essential requirements to be fulfilled in the design of timber structures. For this purpose, a reduced cross-section method is given in the European standards, Eurocodes. The method is based on the assumption that an initial, rectangular timber cross-section exposed to fire conditions reduces to an effective cross-section, which has material properties as at a room temperature. The reduced part of the cross-section with no resistance is determined by a sum of two parameters, namely a charring depth and a thickness of zero-strength layer. Eurocodes give a value of the latter only for the standard fire exposure, which is only one of the fire curves proposed in the same standards. Therefore, the present paper examines the thickness of zero-strength layer in case of 46 different fuel-controlled parametric fire exposures applied to a timber beam from three sides. A four-phase numerical analysis is applied for this purpose that includes the use of a hygro-thermal model and a mechanical model to determine temperatures of timber over the cross-section and the mechanical resistance of timber beam in fire conditions, respectively. The results show that the thickness of zero-strength layer takes the values between 7.9 and 18.4 mm for the fuel-controlled parametric fire exposures. Since it is clearly dependent on the parameters describing the parametric fire curve, five equations are proposed that can be used for determination of the thickness of zero-strength layer in case of parametric fire exposures. [ABSTRACT FROM AUTHOR]

Formerly the geometry was based on shapes, but since the last centuries this founding mathematical science deals with transformations, projections, and mappings. Projective geometry identifies a line with a single point, like the perspective on the horizon line and, due to this fact, it requires a restructuring of the real mathematical and numerical analysis. In particular, the problem of interpolating data must be refocused. In this paper, we define a linear structure along with a metric on a projective space, and prove that the space thus constructed is complete. Then, we consider an iterated function system giving rise to a fractal interpolation function of a set of data. [ABSTRACT FROM AUTHOR]

This paper presents results obtained using three numerical approaches for the basal heave analysis of a hypothetical circular shaft: the Finite Element Method (FEM), Numerical Limit Analysis (NLA), and the Material Point Method (MPM). The Strength Reduction Factor (SRF) methodology was used in conjunction with the MPM, NLA, and FEM to analyze the stability of this structure under dry and saturated conditions. In this paper, we introduced a methodology for applying the SRF technique within the framework of the MPM in a three-dimensional (3D) context. The paper compares and discusses results from the three analysis methods concerning the factor of safety and failure mechanisms. In particular, the failure surface and the run-out condition were also evaluated for a hypothetical case with large deformations using MPM. The results obtained from the three numerical methods exhibited good consistency. Regarding FEM, NLA required the least computational cost to get the safety factor, being a more appealing tool for its estimation, and the MPM allowed consideration of large deformations in the simulations without any additional numerical treatments like remeshing. The current work demonstrates a potential strategy for combining MPM, NLA, and FEM approaches to determine the failure mechanism and the post-rupture processes with large deformations. [ABSTRACT FROM AUTHOR]

In this study, geomechanical behavior of fractures and faults in rocks as a saturated deformable discrete fracture-porous medium has been evaluated using coupled fluid flow-geomechanics numerical modeling. The purpose of this paper is to observe and evaluate the effects of fractures and faults on the pore pressures during fluid flow through reservoirs. This issue involves solving the equations that have been derived from the Biot consolidation theory such as fluid mass balance equation, Darcy law and momentum balance equations. Govern coupled equations were solved using the standard Galerkin finite element method for continuous porous medium. Elements called "zero-thickness elements" were also used to discretize the fault as a discontinuous part of the porous medium. In compared with the previous and similar methods, the method introduced in this paper, made modifications in either the choice of the element and the method of solving the governing equations. The main advantage of this paper is providing clear precise formulations of the double node zero-thickness element in hydro-mechanical modeling of fractures and faults. Verification of the proposed process and models presented in this paper were done by providing three index problems which their analytical and numerical solutions are available. The results of our model provide a good agreement to these reference solutions which indicates the accuracy of the method presented in this paper. [ABSTRACT FROM AUTHOR]

The article focuses on the call for paper for special issue of the journal "Finance and Stochastics" on topic related to the probabilistic methods for solving computational problems in financial mathematics. The paper to be submitted to the journal could focus on new methods/algorithms or significant improvements in solving computational problems in financial mathematics. Furthermore, all submitted papers will be reviewed in the usual way so that only papers which meet the high standards of the journal.

This paper presents a numerical analysis of different rheology models during the encapsulation of moulded underfill (MUF) for flip-chip package. Robust computational fluid dynamics of finite volume analysis software; ANSYS FLUENT Workbench 14.5 was utilised in three-dimensional. A remarkable analysis was carried out by considering three distinctions among rheology models, namely Power Law, Cross, and Castro-Macosko. Nevertheless, a unique function has been written for the Castro–Macosko model since it considers the curing effect using user-defined functions. The volume of fluid technique was utilised to track the flow front of epoxy moulding compound (EMC). Beforehand, the flow visualization for the tray cavity has been verified by both experiment and simulation qualitatively, and it has been found to be in good agreement. It also conformed to the rheological properties, i.e., viscosity and shear rate. For MUF encapsulation, the 3D views of the melt front profile during encapsulation were presented. In addition, the viscosity-shear rate and void formation versus rows of multi-flip chips for all models were plotted and discussed. The numerical results have shown that the best rheology model for EMC during encapsulation was the Castro-Macosko model with consideration of curing effect. It was clearly found that the retardation flow occurred since the conversion of EMC took place, i.e., the curing effect. The present numerical analysis is expected to grant a good understanding of epoxy behaviour for engineers and designers in the electronic packaging industry. [ABSTRACT FROM AUTHOR]

In this paper, finite element method is used to calculate the static performance of gas journal bearing, in which rotation speed term is introduced into the stiffness matrix of linear triangular element to realize the performance calculation of the bearing with rotation speed. The results indicate that the average gas film thicknesses corresponding to the maximum load capacity and stiffness, and the minimum attitude angle increase with the growth of orifice diameter. Load capacity and stiffness significantly improved with the increase of rotation speed, eccentricity ratio and supply pressure when the bearing has thin average gas film thickness. Attitude angle increases with the growth of rotation speed, while the growth rate slows down or even decreases at high speed. The most effective way of reducing attitude angle is to increase supply pressure. It can be found that rotation speed affects attitude angle through changing gas pressure difference between two orifices, while other parameters have the same effect by changing gas pressure at orifice outlet. Article Highlights: Analyzing performances of gas journal bearings by solving Reynolds equation with FEM. Solving Reynolds equation with speed term using FEM. Investigating the effect of bearing parameters on attitude angle, stiffness, and load capacity. [ABSTRACT FROM AUTHOR]

The paper deals with numerical analysis of the effect of stress state and loading direction with respect to the rolling direction on damage and fracture behavior of anisotropic metals. The continuum damage model has been enhanced to take into account the influence of production-induced anisotropies and loading direction on damage criteria and on evolution equations of damage strains. Constitutive parameters are determined using experimental results taken from tests with uni- and biaxially loaded specimens. The focus of the paper is on three-dimensional micro-mechanical numerical analyses of micro-defect-containing representative volume elements covering a wide range of stress states. These calculations lead to more insight in the different damage and failure processes on the micro-scale and their influence on the macroscopic damage laws. With the obtained numerical results it is possible to detect general trends, to propose governing equations for the damage criteria, to develop evolution equations for the damage strains, and to identify constitutive parameters of the anisotropic material model. It is shown that the anisotropic behavior and the loading direction with respect to the principal axes of anisotropy affect the evolution of damage mechanisms on the micro-level as well as the corresponding damage strains. [ABSTRACT FROM AUTHOR]

Propped cantilever truss is not a common bridge construction technique. The performance of such bridges under operational and extreme loading is not reported in the literature either. In this paper, failure mechanisms in a propped cantilever truss bridge are reported using field investigation. The field observations are supplemented by numerical analysis to identify the causes of failure. A a systematic account of damage mechanisms in bridge components is also reported. The failure of the Lamgadi Bridge over the Seti River in Nepal is used as a case study example. The loading and construction protocols are detailed, and numerical analysis results are juxtaposed with the field observations to explain the failure mechanisms. Field observations and numerical results show that lack in adequate design is the most likely cause of the bridge collapse. Numerical results also indicate that the roller support at the propped end, unlike the hinged pot bearing used in the as constructed bridge would have been a safer choice. The failure could have been easily prevented with proper numerical simulation of the bridge response during the design phase. [ABSTRACT FROM AUTHOR]

This paper presents the results of an analysis of the porous structure of spherical activated carbons obtained from cation-exchange resin beads subjected to ion exchange prior to activation. The study investigated the effects of the type of cation exchange resin, the concentration of potassium cations in the resin beads and the temperature of the activation process on the adsorption properties of the resulting spherical activated carbons. The numerical clustering-based adsorption analysis method and the quenched solid density functional theory were used to analyse the porous structure of spherical activated carbons. Based on original calculations and unique analyses, complex relationships between preparation conditions and the porous structure properties of the obtained spherical activated carbons were demonstrated. The results of the study indicated the need for simultaneous analyses using advanced methods for the analysis of porous structures, i.e., the numerical clustering-based adsorption analysis method and the quenched solid density functional theory. This approach allows a reliable and precise determination of the adsorption properties of the materials analysed, including, among other things, surface heterogeneities, and thus an appropriate selection of production conditions to obtain materials with the expected adsorption properties required for a given industrial process. [ABSTRACT FROM AUTHOR]

In this paper, we study the phase tranisions in the extended holographic thermodynamics of Born–Infeld AdS black holes. The extended gravitational thermodynamics of black holes is related to the thermodynamics of the dual field theory by varying both cosmological constant and Newton's constant. With topological analysis and numerical calculation, we find that the reentrant large-small-large black hole phase transition still exists in D = 4 . Interestingly, a similar reentrant phase transition is also observed in the dual field theory, between the high-, low- and high-entropy thermal states. For higher dimension D > 4 , only the van der Waals like phase transition is observed, both in the bulk and the dual field theory. [ABSTRACT FROM AUTHOR]

In this paper, we provide a numerical solution for the nonlinear tempered fractional integrodifferential equation in three dimensions. We use the trapezoidal convolution rule with backward differences (BDF2) for temporal discretization, and develop an alternating direction implicit difference scheme for spatial discretization. A novel fast approximation is applied to tackle the nonlinear term. The stability and convergence analysis of the numerical scheme are analyzed. Furthermore, some numerical experiments are provided to confirm the theoretical results. [ABSTRACT FROM AUTHOR]

This paper is concerned with the numerical analysis of linear and nonlinear Schrödinger equations with periodic analytic potentials. We prove that, for linear equations, when the potential is analytic in a strip of width A of the complex plane, the solution is analytic in the same strip, ensuring an exponential convergence of the planewave discretization of the equation with rate A. On the other hand, for nonlinear equations, we find that the solution may be analytic only in a strip of width smaller than A. This behavior is illustrated by two examples using a combination of numerical and analytical arguments. [ABSTRACT FROM AUTHOR]

Reservoir computing (RC) is a popular class of recurrent neural networks (RNNs) with untrained dynamics. Recently, advancements on deep RC architectures have shown a great impact in time-series applications, showing a convenient trade-off between predictive performance and required training complexity. In this paper, we go more in depth into the analysis of untrained RNNs by studying the quality of recurrent dynamics developed by the layers of deep RC neural networks. We do so by assessing the richness of the neural representations in the different levels of the architecture, using measures originating from the fields of dynamical systems, numerical analysis and information theory. Our experiments, on both synthetic and real-world datasets, show that depth—as an architectural factor of RNNs design—has a natural effect on the quality of RNN dynamics (even without learning of the internal connections). The interplay between depth and the values of RC scaling hyper-parameters, especially the scaling of inter-layer connections, is crucial to design rich untrained recurrent neural systems. [ABSTRACT FROM AUTHOR]

Applying the gradient discretisation method (GDM), the paper develops a comprehensive numerical analysis for nonlinear equations called the reaction–diffusion model. Using only three properties, this analysis provides convergence results for several conforming and non-conforming numerical schemes that align with the GDM. As an application of this analysis, the hybrid mimetic mixed (HMM) method for the reaction–diffusion model is designed, and its convergence is established. Numerical experiments using the HMM method are presented to facilitate the study of the creation of spiral waves in the Barkley model and the ways in which the waves behave when interacting with the boundaries of their generating medium. [ABSTRACT FROM AUTHOR]