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Examines the numerical instability of the smeared-crack approach in the non-linear modelling of concrete structures. Assessment of the high shear retention function; Instability of the artificial attraction of loading; Simulation of the post-failure regime.

The article discusses a feasibility study of a numerical technique to analyze the gas-diffusion layer (GDL) of a polymer electrolyte fuel cell (PEFC). The technique combines a digitally reconstructed three-dimensional (3-D) model of carbon paper GDL and 3-D two-phase lattice Boltzmann numerical model. A description of the X-ray nanotomography image generation and digital reconstruction process is presented. The study showed the effect of liquid intrusion pressures on intruded volume.

ABSTRACT The next-generation seismic imaging algorithms will consider multiple scattering as indispensable information, being referred to as Full-Wavefield Migration. In addition, these algorithms will also include autonomous velocity updating in the migration process, being referred to as Joint Migration Inversion. Full-Wavefield Migration and Joint Migration Inversion address the industrial needs to improve images of very complex reservoirs as well as the industrial ambition to produce these images in a more automatic manner (automation in seismic processing). In this vision paper on seismic imaging, Full-Wavefield Migration and Joint Migration Inversion are formulated in terms of a closed-loop estimation algorithm that can be physically explained by an iterative double focusing process (full-wavefield common-focus-point technology). A critical module in this formulation is forward modelling, allowing feedback from migrated output to unmigrated input (closing the loop). For this purpose, a full-wavefield modelling module has been developed, which utilizes an operator description of complex geology. The full-wavefield modelling module is pre-eminently suited to function in the feedback path of a closed-loop migration algorithm. 'The Future of Seismic Imaging' is presented as a coherent trilogy, proposing the migration framework of the future in three consecutive parts. In Part I, it was shown that the proposed full-wavefield modelling module algorithm differs fundamentally from finite-difference modelling because velocities and densities need not be provided. Instead, an operator description of the subsurface is used. In addition, the concept of reverse modelling was introduced. In Part II, it is shown how the theory of Primary Wavefield Migration can be extended to Full-Wavefield Migration by correcting for angle-dependent transmission effects and by utilizing multiple scattering. The potential of the Full-Wavefield Migration algorithm is illustrated with numerical examples. A multidirectional migration strategy is proposed that navigates the Full-Wavefield Migration algorithm through the seismic data cube in different directions. [ABSTRACT FROM AUTHOR]

ABSTRACT The next generation seismic imaging algorithms will consider multiple scattering as indispensable information, referred to as Full Wavefield Migration. In addition, these algorithms will also include autonomous velocity updating in the migration process, referred to as Joint Migration Inversion. Full wavefield migration and joint migration inversion address the industrial needs of improving images of very complex reservoirs as well as the industry ambition of producing these images in a more automatic manner ('automation in seismic processing'). In this vision paper on seismic imaging, full wavefield migration and joint migration inversion are formulated in terms of a closed-loop, estimation algorithm that can be physically explained by an iterative double focusing process (full wavefield Common-Focus-Point technology). A critical module in this formulation is forward modelling, allowing feedback from migrated output to unmigrated input ('closing the loop'). For this purpose a full wavefield modelling module has been developed that utilizes an operator description of complex geology. Full wavefield modelling module is pre-eminently suited to function in the feedback path of a closed-loop migration algorithm. 'The Future of Seismic Imaging' is presented as a coherent trilogy, proposing in three consecutive parts the migration framework of the future. In part I it was shown that the proposed full wavefield modelling module algorithm differs fundamentally from finite difference modelling, as velocities and densities need not be provided. Instead, full wavefield modelling module uses an operator description of the subsurface. In Part II it was shown how the theory of Primary Wavefield Migration can be extended to Full Wavefield Migration by correcting for elastic transmission effects and by utilizing multiple scattering. In Part III it is shown how the full wavefield migration technology can be extended to Joint Migration Inversion, allowing full wavefield migration of blended data without knowledge of the velocity. Velocities are part of the joint migration inversion output, being obtained by an operator-driven parametric inversion process. The potential of the proposed joint migration inversion algorithm is illustrated with numerical examples. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigates the skiving and cutting stock problem (SCSP) encountered in the paper and plastic film industries, in which a set of nonstandard reels generated from previous cutting processes are used to produce finished rolls through the skiving and cutting process. First, reels are skived together lengthwise to form a reel‐pyramid (a polygon), and then the reel‐pyramid is cut into finished rolls of small widths. Depending on if a reel can be divided lengthwise into subreels to form the reel‐pyramid, the problem can be classified into divisible SCSP (DSCSP) and indivisible SCSP (ISCSP). In this paper, two integer programming (IP) models are proposed for DSCSP and ISCSP, respectively. A sequential value correction procedure combined with the two IP models (SVCTIP) is developed to solve the two SCSPs. The effectiveness of the SVCTIP is demonstrated through extensive computational tests. [ABSTRACT FROM AUTHOR]

We show abstract versions for Banach couples of several limiting compact interpolation theorems established by Edmunds and Opic for couples of [ABSTRACT FROM AUTHOR]

Arnold, L. J. & Roberts, R. G. 2011: Paper I - Optically stimulated luminescence (OSL) dating of perennially frozen deposits in north−central Siberia: OSL characteristics of quartz grains and methodological considerations regarding their suitability for dating. Boreas, Vol. 40, pp. 389-416. 10.1111/j.1502-3885.2011.00209.x. ISSN 0300−9483. Optically stimulated luminescence (OSL) dating of coarse-grained quartz is increasingly being used as the main chronological tool in late Quaternary palaeoenvironmental reconstructions of Siberia. However, relatively little information has been published on the suitability of OSL dating for the various types of perennially frozen sediments found in this region. Here we provide a systematic examination of the quartz luminescence characteristics of 21 perennially frozen samples from the Taimyr Peninsula and adjacent coastal lowlands of north-central Siberia, and discuss their implications for the reliability of single-grain and multi-grain OSL chronologies in such contexts. The results of this study suggest that the quartz luminescence characteristics of these samples are, in principle, favourable for OSL dating but, in practice, require that a series of validation checks are made of the chosen experimental conditions. If these tests are satisfied, then reliable OSL chronologies should be obtained for sedimentary deposits in this region. Importantly, however, the single-grain and multi-grain aliquot equivalent dose (D) distribution characteristics for our samples reveal that there are advantages in targeting certain types of depositional settings for OSL dating studies of Siberian sediments. We also show that samples from the same depositional settings, and even from the same sites, do not necessarily display similar D distribution characteristics. The latter complication favours the use of single-grain analysis to unravel the bleaching and burial histories of young (mid- to late Holocene) sediments in these Arctic environments. [ABSTRACT FROM AUTHOR]

This paper introduces a new scheme for the numerical computation involving shock waves. The essence of the scheme is to adaptively implement a conjugate low-pass filter to effectively remove the accumulated numerical errors produced by a set of high-pass filters. The advantages of using such an adaptive algorithm are its controllable accuracy, relatively low cost and easy implementation. Numerical examples in one and two space dimensions are presented to illustrate the proposed scheme. Copyright © 2003 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Summary This paper discusses visualization methods for discriminant analysis. It does not address numerical methods for classification per se, but rather focuses on graphical methods that can be viewed as pre-processors, aiding the analyst's understanding of the data and the choice of a final classifier. The methods are adaptations of recent results in dimension reduction for regression, including sliced inverse regression and sliced average variance estimation. A permutation test is suggested as a means of determining dimension, and examples are given throughout the discussion. [ABSTRACT FROM AUTHOR]

Summary: Many efforts have been made to improve the accuracy of the conventional weighted essentially nonoscillatory (WENO) scheme at transition points (connecting a smooth region and a discontinuity point). This paper analyzes these works and further develops a more effective multistep WENO scheme. Theoretical analysis and numerical results show that the new scheme not only improves the accuracy by one order higher than the traditional fifth‐order WENO schemes at transition point but also maintains the fifth‐order accuracy in smooth regions even at critical point where the first derivative vanishes. [ABSTRACT FROM AUTHOR]

The focus of this paper is on the solution of Maxwell's equations for time-harmonic fields on triangular, possibly non-orthogonal meshes. The method described was first introduced in References 1 and 2 for eigenvalue problems arising in the design of accelerator components and dielectric loaded waveguides. It is based on the well-known Finite Integration Technique (FIT) which is a proven consistent discretization method for the computation of electromagnetic fields. The FIT-discretization on non-orthogonal 2D grids has close relations to the Nédélec elements or edge elements in the Finite Element Method. Revisiting FIT on triangular grids this paper intends to stimulate thorough studies of the latter subject which is well worth further investigations. Copyright © 1999 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Earlier work using the time dependent Poynting theorem has shown that the complete description of power in a multimodal radiation field requires the use of three numbers; two are sufficient only with a single modal field. Where three numbers are required it is not possible to correctly represent power as a complex number. In the common notation the third number is a suppressed phase angle; when multiple power fields are combined to form a single one it is essential to account for the suppressed phase angles. The differences in power calculations using the time and frequency domain power theorems are manifest in determination of the energy flow that remains local to the source, oscillating between the near field and source, which does not form part of the far field power. In this paper we numerically model, using commonly accepted frequency and time domain techniques, the simplest antenna design that clearly illustrates the differences between time and frequency domain representations of reactive power. We calculate and contrast the instantaneous and the steady-state far field and local powers emitted from two identical, perpendicularly oriented electrically small TM dipoles as a function of relative phase between the two dipoles. Copyright © 1999 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The analysis of structures which contain thin wires or narrow microstrips using the FDTD method and without resorting to a very fine mesh, has been an area of intensive research for many years. Despite this activity, however, the problem is still not definitively solved. In this paper the problem is attacked by investigating the properties of the FDTD mesh when the material parameters of a single cell, or a small group of cells, are altered. From this, formulae are derived by which these parameters may be chosen in order to accurately represent a conductor of small cross-section. Results are presented which show that accurate results for wire and microstrip transmission lines can be achieved with little or no computational overhead and without the problems of late time instability or spurious field divergence. Copyright © 1999 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In recent years, the finite-difference time-domain (FDTD) method has been used to simulate a wide range of frequency dependent media. The accuracy of these simulations often depends on how accurately the complex dielectric constant is simulated in the sampled time domain used by FDTD. This paper describes the process of modelling the complex dielectric constant as a digital filtering problem and uses Z transforms to convert the frequency domain expression to a sampled time domain expression. Copyright © 1999 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

For the simulation of acoustic-structure interaction problems, the coupled field equations must be solved. The structure is commonly discretized using finite elements, whereas for the acoustic field the boundary element method (BEM) is favorable. A mortar BEM-FEM coupling algorithm is developed that allows the combination of non-conforming meshes. The high flexibility for the choice of discretizations offers a high efficiency, since specialized shape functions and adaptive mesh refinement can be used in the subdomains. The mortar coupling algorithm yields a saddle point problem that is solved using a preconditioned inexact Uzawa algorithm. The iterative solver enables the use of the fast multipole BEM and thus coupled simulations on large boundary element models. [ABSTRACT FROM AUTHOR]

The report of the 20th National Congress of the Communist Party of China pointed out that it is necessary to accelerate the construction of digital China, and actively develop equipment intelligence, digitalization, and high‐end equipment manufacturing. With the construction of a new round of digital China, the safety of digital technology and high‐end equipment is particularly important for power grid. Transformer is an important link of power grid operation. The destructive thermal failure of transformer has become a hot research issue in the power industry. At the same time, there are more and more power electronic equipment in the power grid, which makes the regulation and control more and more complicated. Taking a 1000 kVA oil‐immersed transformer as an example, the magnetic, current, and thermal multi field coupling numerical analysis method is first used to simulate and analyse the operation status of the transformer. By comparing the simulation results with the monitoring data results, the error of the results is controlled within 5%. Finally, the multi‐state characteristic parameters of the transformer are monitored through sensors, and the numerical simulation analysis results are integrated with the state monitoring results to build a transformer thermal life loss assessment system. The method in this paper can evaluate and analyse the running state of transformer in real time, which is of great significance for the power company to formulate the treatment measures. [ABSTRACT FROM AUTHOR]

Frequency domain transfer functions of microwave systems are usually calculated either directly in the frequency domain or in the time domain in combination with a Fourier analysis. The computation of loss-free linear devices based on eigenfields (resonant fields) offers an alternative to obtaining broadband frequency characteristics with a high accuracy. Such methods are very effective for problems with multiple narrow resonances as many points in frequency domain have to be calculated to sample the maximas, or time domain computations have to deal with long transients. We describe a method of this type and then an improvement that leads directly to transfer functions, which are very accurate even if only modes in the chosen frequency range are taken into account. Generalized macroscopic parameters are introduced as input and output quantities, which are related to conventional quantities such as discrete currents and voltages, wave parameters, or even beam currents and voltages (as defined in accelerator physics for beams of ultra-relativistic charged particles). When the generalized input/output parameters are causal they are related to each other and to state parameters of the eletromagnetic fields by a differential equation with time independent system matrices. The input/output transfer matrix in the frequency domain is an impedance matrix, which is derived from the system matrices of the discretization as well as from a series expansion using eigensolutions. The number of eigenmodes is typically three times the number of meshpoints, but good approximations can be achieved even with a much smaller set of eigenvalues around the frequency range of interest. Another approach to characterizing the system response is based on the output/input relation described by an admittance matrix. Combining both approaches, the error of the approximations can be estimated and significantly reduced. The application of the method is shown for several examples. Copyright © 1999 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A new approach using FIT-formulation (Finite Integration Technique) (T. Weiland, Electron. Commun., 31, 116–120 (1977); Int. J. Numer. Model., 9, 295–319 (1996)) for simulating waveguide propagation of optical pulses is presented. FIT-methods are widespread in use for broadband linear simulations. In recent years, several attempts have been made to describe different dispersive material-characteristics such as Drude, Debye or Lorentz dispersion. Today advanced FDTD-formulations (Finite Difference Time Domain) also consider non-linear effects (P. M. Goorjian and A. Taflove, IEEE Opt. Lett., 17(3), 180–182 (1992); D. M. Sullivan, IEEE Trans. Microwave Theory Techniques, 43(3), 676–682 (1995)). In the following presented method third-order non-linear effects were described, which can be observed in isotropic media in frequency ranges of optical pulses, by updating material polarization terms using classical descriptions of Lorentz dispersion, Raman scattering and the Kerr effect. The basic idea is transforming these description formulas into sets of linear differential equations and solving them with the help of the general exponential solution. Copyright © 1999 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The simulation of slowly varying electromagnetic fields is possible for very large, realistic problems with finite-difference implicit time-domain (FDiTD) and frequency-domain (FDFD) formulations on the basis of the consistent Finite-Integration Technique (FIT). Magneto-quasistatic time-domain formulations combined with implicit time marching schemes require the repeated solution of real-valued symmetric systems. The solution of driven frequency domain problems usually consists in the solution of one non-Hermitean system. Preconditioned conjugate gradient-type methods are well-suited for this task. They allow the efficient solution even for consistent singular or near-singular systems, which typically arise from formulations for slowly varying electromagnetic fields using the Maxwell-Grid-Equations of the FI-Method. Numerical results for TEAM workshop 11 benchmark problem and for a large practical problem, a shading ring sensor, show that the presented algorithms are capable of solving realistic problems for large numbers of unknowns in acceptable calculation times on contemporary medium sized workstations. Copyright © 1999 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper presents a 4th-order accurate implicit multistage finite-difference time-domain (IMS-FDTD) method. The analysis of the stability shows that this IMS-FDTD method is unconditionally stable. In addition, its numerical-dispersion relation is derived and the analysis shows that its performance is better than those of conventional unconditionally-stable implicit FDTD methods and is even better than those of some conditionally-stable explicit FDTD methods, such as the Fang(2, 4)-FDTD method. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1383–1385, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21646 [ABSTRACT FROM AUTHOR]

The next generation of low observable (LO) unmanned combat aerial vehicle (UCAV) with highly autonomy to implement a penetration mission requires advanced methods for flyable and safe route planning (i.e., respecting physical capability of vehicle and threat coverage by hostile air defense radars) at a real‐time manner. Currently, the main challenge of real‐time route planning for LO UCAV is to achieve computationally efficiency under dynamic (pop‐up/moving) threats by air defense radars. In this paper, a real‐time planning paradigm in compliance with complex penetration requirements is proposed, and a complete modeling of route planning for LO UCAV's penetration as an optimal control problem is designed. The paper at first devises a direct method to transform the optimal control problem into a nonlinear programming (NLP) problem and then solves the formulated NLP problem under a moving planning horizon. The proposed method can give computationally efficient route planning results for LO UCAV's penetration under multiple kinds of radar threats. Numerical test results based on F‐16 uninhabited platform demonstrate the effectiveness of the proposed method. [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]

In this paper, we develop and analyze a mathematical model for spreading malaria, including treatment with transmission‐blocking drugs (TBDs). The paper's main aim is to demonstrate the impact the chosen model for demographic growth has on the disease's transmission and the effect of its treatment with TBDs. We calculate the model's control reproduction number and equilibria and perform a global stability analysis of the disease‐free equilibrium point. The mathematical analysis reveals that, depending on the model's demography, the model can exhibit forward, backward, and even some unconventional types of bifurcation, where disease elimination can occur for both small and large values of the reproduction number. We also conduct a numerical analysis to explore the short‐time behavior of the model. A key finding is that for one type of demographic growth, the population experienced a significantly higher disease burden than the others, and when exposed to high levels of treatment with TBDs, only this population succeeded in effectively eliminating the disease within a reasonable timeframe. [ABSTRACT FROM AUTHOR]

Highlights Textile composites are advanced materials composed of preforms combined with matrix materials. The fiber structure in the preform has a significant impact on the mechanical properties of the composite. Precise control over preform dimensions and internal fiber structural uniformity, termed ‘accurate shape control’, is essential to ensure reliable and stable composite component mechanical properties. This paper reviews current research progress on fabric deformation mechanisms, focusing on experimental characterization and numerical simulation. Experimental methods for fabric deformation include tensile, compression, bending, and shear deformation, whereas numerical methods encompass macroscopic continuum, discrete, and semi‐discrete models. The insights offered in this paper will aid a greater understanding of fabric deformation mechanisms, enabling an accurate prediction of complex shape molding and effective process parameter design, ultimately facilitating the structural design and engineering applications of textile composites. Recent trends and challenges in the study of fabric deformation mechanisms are presented. The experimental methods for fabric deformation were summarized and evaluated. Representative numerical modeling techniques and simulation methods are discussed. Some recommendations on potential future research directions are detailed. [ABSTRACT FROM AUTHOR]

In the process of lower coal roadway support under double gobs in close coal seams, there are problems such as the whole destruction of the lower coal seam and the intermediate strata, the thin roof of the lower coal roadway with the smaller support space, the upper rock of the lower coal roadway without anchor bearing layer, the roof falling, the anchor cable offing, and so on. On the basis of the engineering background of No. 11103 haulage roadway in Fenxi coal mine, the research methods of theoretical modeling analysis, numerical simulation analysis and field engineering test are comprehensively adopted. In this paper, the layout of the roadway with floor insertion in the lower coal seam, the distribution characteristics of surrounding rock deviatoric stress, the control principle of broken surrounding rock and the coupling support method of shed–cable–prop are systematically studied. The study shows that many measures are needed to ensure the stability of the surrounding rock in the strong mining roadway of the lower coal seam. The lower coal seam roadway section was modified from the original rectangular section to adopt an arched section to counteract the broken roof. The staggered position of the lower coal seam roadway layout was modified from the original coal roadway position to a coal–rock roadway, so as to avoid the area of high deviatoric stress in the coal pillar and the area of crushed coal body, and to leave an effective support space for the roof. The support scheme of the lower coal seam roadway was improved to use anchor cable and single prop to support the weak section of U‐type steel shed with local coupling, and realize unequal force coupling by adjusting the size of the force at different coupling points. In the field monitoring the deformation of the roadway is small, and the support effect is good. [ABSTRACT FROM AUTHOR]

Inadequate knowledge regarding specific local and interactive behavior of slender high‐strength steel (HSS) hollow sections presents an obstacle in implementing these sections in the construction practice. The current approach in the standard is simplified and offers overly conservative results. Dealing with non‐standard cross‐sections only expands on these difficulties. This paper contributes to the on‐going RFCS project "HOLLOSSTAB", which has been dealing with the aforementioned issues. The project design proposal is based on the "Overall interaction concept" (OIC), and a new set of design rules for hollow sections is currently being developed. In this concept, linear buckling analysis (LBA) is used to obtain the slenderness of the member, and Geometrically and Materially Non‐linear Imperfection Analysis (GMNIA) is used to determine an "overall" buckling reduction factor. Extensive experimental tests are used to validate the method, by correlating the experimental results with numerical test results (GMNIA‐real) and statistically analyzing them. The focus of the tests in this paper is the use of high‐strength steel, ranging from S500 to S890, used for rectangular hollow‐sections and hexagonal‐hollow sections. The state‐of‐the‐art measuring tools available, offer the possibility of precise reverse‐engineering process, creating numerical models based on experimental test, which allows an accurate prediction of the ultimate load capacity of the specimens. Digital image correlation (DIC) allows a review of the buckling shape, comparing numerical model with real shape of tested specimen. The paper aims to validate the numerical models, as well as validity of assumptions on imperfection amplitude. [ABSTRACT FROM AUTHOR]

Recently, a novel approach has been proposed to produce ultrashort, fully coherent high-repetition-rate EUVand X-ray radiation by combining an energy recovery linac (ERL) with the angular-dispersion-induced microbunching methodology. It is critical to maintain microbunching when the beam passes through bending magnets between the undulators, which results in difficulties supporting multiple beamlines. In this paper, the design of a multiplexed emitting system consisting of multi-bend achromats, matching sections and radiators to facilitate the multi-beamline operation is presented. Theoretical analysis and numerical simulations have been carried out and the results show that the microbunching and beam quality can be well maintained after four times of bending. Five radiation pulses with a central wavelength of 13.5 nm and peak power at theMW level have been produced by the same electron beam via this multiplexed emitting system. The proposed method holds potential in the multi-beamline operation of ERL- or storage-ring-based coherent light sources. [ABSTRACT FROM AUTHOR]

Bidirectional power flow is becoming increasingly commonplace in modern distribution systems with the integration Renewable Energy Sources (RESs) and Energy Storage Systems (ESSs). This has facilitated in bringing generation closer to end‐consumers, thus leading to the emergence and rapid growth of microgrids. Additionally, due to the technological revolution in Information and Communications Technology (ICT), innovative business models have developed where willing and able participants of the power system can participate in the electricity market. In line with this evolution of both the electric power system and its participants, Energy‐as‐a‐Service (EaaS) is emerging as an increasingly prominent business model to address electrical grid challenges economically. EaaS encourages electricity grid customers to play a more active role and participate in different electricity markets. This paper introduces and simulates a variant of a Transactive Energy (TE) trading algorithm for microgrids. The paper describes the model in brief how multiple microgrids assets can trade electricity to ensure more efficient and economical local resource utilization. The main motivations of this research paper is to validate and test the suitability of the TE trading algorithm for a variety of conditions. The coordinated TE trading model can optimize expansion and investment planning especially at the distribution level. [ABSTRACT FROM AUTHOR]

Conventional mooring systems contribute significantly to the cost of floating wind projects, and innovative solutions with cost‐saving potentials are desired. In the present paper, we investigate the fundamental dynamic behavior of an innovative tethered‐buoy mooring system for a prototype wind farm in which two spar floating offshore wind turbines (FOWTs) are moored to five submerged tethered buoys. Numerical decay tests are used to characterize the fundamental frequencies and oscillatory modes of the system. The influence of net buoyancy is established through a parametric study. Finally, the dynamic response of the tethered‐buoy mooring system is compared against two alternative shared mooring configurations with catenary mooring lines. Time‐domain simulations are carried out for one accidental scenario with a parked and an operational FOWT, and one extreme scenario with two parked FOWTs. The results show that net buoyancy has a significant influence on platform motions and mooring loads. Compared to alternative configurations with catenary mooring lines, the tethered‐buoy mooring system exhibits substantially lower mooring tension loads and practically eliminates the threat of snap events. The reduction in the maximum characteristic fairlead tension is up to 85%. The mean positional offset of the wind turbines in the loading direction is larger, up to 36% of the water depth, however, the relative motions are comparable. The mean distance between the FOWTs is even smaller for the tethered‐buoy system. With the application of dynamic inter‐array cables, the proposed tethered‐buoy system can be a promising mooring solution for floating offshore wind farms. [ABSTRACT FROM AUTHOR]

The evolution of Artificial Intelligence of Things (AIoT) pushes connectivity from human‐to‐things and things‐to‐things, to AI‐to‐things, has resulted in more complex physical networks and logical associations. This has driven the demand for Internet of Things (IoT) devices with powerful edge data processing capabilities, leading to exponential growth in device quantity and data generation. However, conventional data preprocessing methods, such as data compression and encoding, often require edge devices to allocate computational resources for decoding. Additionally, some lossy compression methods, like JPEG, may result in the loss of important information, which has negative impact on the AI training. To address these challenges, this paper proposes a two‐step attribute reduction approach, targeting devices and dimensions, to reduce the massive amount of data in the AIoT network while avoiding unnecessary utilization of edge device resources for decoding. The device‐oriented and dimension‐oriented attribute reductions identify important devices and dimensions, respectively, to mitigate the multimodal interference caused by the large‐scale devices in the AIoT network and the curse of dimensionality associated with high‐dimensional AIoT data. Numerical results and analysis show that this approach effectively eliminates redundant devices and numerous dimensions in the AIoT network while maintaining the basic data correlation. [ABSTRACT FROM AUTHOR]

This paper focuses on the Y type perfobond shear connectors of steel‐concrete composite beams with the aim to investigate the influence of the structural parameter of the connection to the resistance and ductility of the structures. The Y shaped shear connections are a new shape developed with the benefits of resisting a higher shear force by the transversal bars and a bigger area of the concrete dowels surrounded by the Y shaped plate. This type of shear connection has significant resistance against vertical separation. In this paper, an advanced finite element model for a push‐out test with a Y type perfobond shear connector has been developed and validated by the experimental test. The aim of this research is to investigate different parameters such as the concrete strength, perfobond yield stress, the existence of the transversal bars on the structural behavior. The results showed that the concrete strength has a major effect as using a higher concrete resistance gave a higher ultimate resistance with a higher ductility. The existence of the transverse bars shows a major effect on the ductility load level. On the contrary, the effect of changing the diameter of the bars on the ductility load level was slightly noticeable. While using deferent steel grades for the perfobond plate significantly affected the ultimate resistance, but not the ductility load level. In further studies more parameters will be checked, and a formula and a guideline could be developed for a design purpose. [ABSTRACT FROM AUTHOR]

This paper is concerned with the behaviour of stainless steel cellular beams during a fire. Stainless steel has become increasingly popular in recent years for structural applications, mainly due to its excellent corrosion resistance, as well as its other attractive physical and mechanical attributes. During a fire, stainless steel generally retains a higher proportion of their room temperature strength (above temperatures of 550°C) and stiffness (all temperatures) compared with carbon steel. In the current paper, the focus is on the fire behaviour of stainless steel cellular beams. There are no specific design rules available for these members and the carbon steel design rules for cellular beams are typically used with the stainless steel material properties. This work aims to investigate the validity of this approach by analysing the behaviour of stainless steel cellular beams with stiffened webs under fire conditions. A nonlinear finite element (FE) model is developed using the ABAQUS software, and is validated using fire test data. Then, the model is employed to conduct parametric studies in order to determine the most salient factors. Finally, design guidance is provided for stainless steel cellular beams in fire conditions, which consider the most influential geometric and material characteristics. [ABSTRACT FROM AUTHOR]

This paper deals with a Finite Element (FE) numerical analysis of an electromagnetic stirring system for composite plastic materials with ferromagnetic particles. The electromagnetic stirring process is ensured by the magnetic forces acting on the ferromagnetic particles spread in the plastic matrix. These forces are produced by the rotating magnetic field of the stator of a three‐phase induction motor supplied from an inverter. The analysis is carried out using the professional software package Flux for electromagnetic field computation based on the FE method. The 2D computations allowed to estimate the magnetic forces and their orientation acting on micrometric particles spread in a fluid plastic material. A preliminary experimental setup is also built for studying the proposed solution. [ABSTRACT FROM AUTHOR]

The article invites submissions for research papers about numerical methods in engineering.

In this paper, we develop algorithms to independently draw from a family of conjugate posterior distributions over the structural parameterization when sign and zero restrictions are used to identify structural vector autoregressions (SVARs). We call this family of conjugate posteriors normal‐generalized‐normal. Our algorithms draw from a conjugate uniform‐normal‐inverse‐Wishart posterior over the orthogonal reduced‐form parameterization and transform the draws into the structural parameterization; this transformation induces a normal‐generalized‐normal posterior over the structural parameterization. The uniform‐normal‐inverse‐Wishart posterior over the orthogonal reduced‐form parameterization has been prominent after the work of Uhlig (2005). We use Beaudry, Nam, and Wang's (2011) work on the relevance of optimism shocks to show the dangers of using alternative approaches to implementing sign and zero restrictions to identify SVARs like the penalty function approach. In particular, we analytically show that the penalty function approach adds restrictions to the ones described in the identification scheme. [ABSTRACT FROM AUTHOR]

The QZ algorithm computes the generalized Schur form of a matrix pencil. It is an iterative algorithm and, at some point, it must decide when to deflate, that is when a generalized eigenvalue has converged and to move on to another one. Choosing a deflation criterion that makes this decision is nontrivial. If it is too strict, the algorithm might waste iterations on already converged eigenvalues. If it is not strict enough, the computed eigenvalues might not have full accuracy. Additionally, the criterion should not be computationally expensive to evaluate. There are two commonly used criteria: the elementwise criterion and the normwise criterion. This paper introduces a new deflation criterion based on the size of and the gap between the eigenvalues. We call this new deflation criterion the strict criterion. This new criterion for QZ is analogous to the criterion derived by Ahues and Tisseur for the QR algorithm. Theoretical arguments and numerical experiments suggest that the strict criterion outperforms the normwise and elementwise criteria in terms of accuracy. We also provide an example where the accuracy of the generalized eigenvalues using the elementwise or the normwise criteria is less than two digits whereas the strict criterion leads to generalized eigenvalues which are almost accurate to the working precision. Additionally, this paper evaluates some commonly used criteria for infinite eigenvalues. [ABSTRACT FROM AUTHOR]

Climate change will lead to prolonged droughts in various regions of the world, which may significantly affect agricultural production. This is particularly problematic for soils with low water retention capacity, which cannot store sufficient water for crops. In this paper, we investigate how a change in the water‐holding capacity of the soil material, as could be achieved by increasing the soil organic carbon (SOC) amount, affects the components of the soil water balance (evaporation, transpiration, and groundwater recharge). Specifically, we state the hypothesis that an increased water‐holding capacity in a shallow soil layer, as it is achieved through SOC enrichment at the soil surface, will result in more water being stored near the soil surface and lost to unproductive evaporation, thereby reducing the amount of water available to plants and groundwater recharge. The hypothesis was tested by numerical simulations, employing the Hydrus‐1D program package to model the water balance in a soil–plant–atmosphere system for an arable crop in hydrologically contrasting years. The study considered soils with varying textures and different depths of a soil layer with increased SOC content. The soil hydraulic properties (SHP) of the soil material, including the effect of SOC on the SHP, were determined using a recently developed pedotransfer model based on data from over 500 samples. We showed that both the improved water retention by SOC and its vertical distribution affect the soil water balance in a complex manner. In sandy soils, increasing the water‐holding capacity in shallow layers up to 0.1 m led to enhanced evaporation and thus a decrease in water availability for crops. However, deeper incorporated SOC could ameliorate these negative effects. Our findings suggest that not only the amount but also the vertical SOC distribution should be considered if enrichment of SOC shall be applied to mitigate the effect of droughts. Core Ideas: Addition of soil organic carbon (SOC) alters soil material's hydraulic properties.This, in turn, impacts the water balance of soils under agricultural use.The depth at which SOC is incorporated into soils plays a crucial role in the partitioning of evapotranspiration (ET) into evaporation (E) and transpiration (T).Deeper incorporation of SOC results in greater water availability for plants. [ABSTRACT FROM AUTHOR]

Reinforced concrete flat slab projects usually require openings close to the columns for electrical and hydraulic installations. Since such openings reduce the punching shear of slabs, a comprehensive study is needed. In this paper, numerical models of slabs tested in literature were elaborated upon, using the commercial software in finite elements DIANA. The physical nonlinearity of the materials was considered. After the calibration and validation of the numerical parameters related to concrete and reinforcement, 62 numerical models were created for performing a parametric analysis. The numerical analysis aimed to study the effect of openings close to the columns and verify the punching resistance reduction. In this parametric study, the main variables were the compressive strength of the concrete, the bending reinforcement ratio, the number of openings, and the distance from the openings to the column's face. Finally, the numerical results obtained were compared with the punching strength values provided by the main structural design codes, viz., NBR 6118 (2014), Eurocode 2 (2004), ACI 318 (2019), fib Model Code (2010), and the next generation of Eurocode 2, which are constantly questioned in academic papers regarding their safety. [ABSTRACT FROM AUTHOR]

Nowadays, fracture characterization of dissimilar materials adhesively bonded structures still generally refers to standards for fiber‐reinforced plastic composites. Moreover, the calculation methods of fracture energy release rate specified in these standards often lead to great deviation due to the differences in material properties and geometry. In this paper, dissimilar materials corrected beam theory with effective crack length (DM‐CBTE) method for calculation of mode II fracture energy release rate of dissimilar materials adhesively bonded structures was proposed. The differences in material properties and geometry as well as the effect of clamp were all considered. The experimental and J‐integral numerical analysis results showed that the maximum deviation of the GIIC calculated by the methods recommended in standard from the J‐integral result is 28% while that by the DM‐CBTE method is only 5%, which proved good feasibility of the DM‐CBTE method for evaluation of mode II fracture performance of dissimilar materials adhesively bonded structures. Highlights: DM‐CBTE method for GII of dissimilar materials adhesively bonded samples was proposed.The differences in material, geometry, and clamp correction were all considered.Good feasibility of the DM‐CBTE method for evaluation of GII was validated. [ABSTRACT FROM AUTHOR]

This paper proposes a multiaxial macroelement for bridge abutments that can be included in the global structural model of a bridge to carry out nonlinear dynamic analyses with very much smaller computational effort than can be achieved using continuum representations of embankment and foundation soil behaviour. The proposed macroelement derives a constitutive force–displacement relationship within a rigorous thermodynamic framework and includes important features of non‐linearity and directional coupling in characterizing the interactions of the abutment with the soil. In a dynamic analysis, the frequency‐dependent response of the system is simulated through the combination of the macroelement with appropriate participating masses. The calibration procedure of the macroelement is based on the assessment of its ultimate capacity and of its response at small displacements, and it is shown that these ingredients can be derived through standardised procedures. In the paper, the macroelement response is validated against the results of fully coupled continuum numerical analyses for a reference soil–abutment system, under both static and seismic loading conditions. We show that the two models achieve similar predictions of maximum and permanent abutment deformations (less than 10–14% difference, respectively) for a suite of three‐axis seismic loading events. [ABSTRACT FROM AUTHOR]

In this paper, attention is devoted to the analysis of the detection threshold based on the multi‐frame integration in heavy‐tailed clutter for the radar with high resolution and even smaller grazing angle. The closed‐form expressions of both the probability of the detection and the probability of false alarm for the heavy‐tailed clutter background, which can be used for the theoretical analysis of constant false alarm rate (CFAR) detectors, are derived with the multi‐frame integration technique. Accordingly, an improved CFAR detector is designed to work well with the presence of target‐like outliers in the heavy‐tailed clutter. In addition, the proposed CFAR detector is capable to alleviate the masking‐effect resorting to the additive feedback operation when a target is large enough to cross several cells in multi‐target case. The theoretical analysis and numerical simulations demonstrate that the proposed CFAR detector based on multi‐frame integration can improve the signal‐to‐clutter rate of the targets exhibiting better performance than ones based on single frame in heavy‐tailed clutter background. It is validated from the simulations that the proposed CFAR detector with additive feedback operation can deal with masking‐effect for large target occupying several cells. [ABSTRACT FROM AUTHOR]

It is difficult to separate Luer lock adapters during the external ventricular drainage (EVD) since they are often connected by a threaded connection, and the infusion needle put into the patient's body gets pulled out when extubation occurs unexpectedly. The paper described a new magnetic connection assembly made up of ring magnetic permanents and a Hall sensor that could be used to replace Luer lock adapters for quicker disconnection and reconnection of the drainage catheter. For the design and analysis of the device, the finite element method magnetics (FEMM) was used to estimate the size of magnetic permanents and the best detection site of the Hall sensor for detecting whether the magnetic permanents were closely attracted and/or pulled apart. Then an experiment was conducted to confirm our findings. Both simulation and experiment revealed that a pair of hollow cylindrical magnetic permanents, each with height 10 mm, outer diameter 8 mm, and inner diameter 4 mm, could achieve the same force as the Luer lock adapters held, and that the best Hall sensor detection position was in the middle of the permanent magnets, with a radial distance of about 2 mm. [ABSTRACT FROM AUTHOR]

As part of the ongoing revision of the Eurocodes, design provisions in EN 1999‐1‐1 on the buckling of longitudinally welded aluminium compression members have been subjected to a critical review. The numerical investigations described in part 1 of the paper were conducted because a need for improvement was identified. In part 2 of the paper, the main observations are presented in qualitative terms. Those observations are: the influence of the allocation of the materials to buckling classes, the influence of the imperfections plus the cross‐section geometry including the position and size of the HAZ within the cross‐section. Part 3 will conclude this paper by discussing the proposed design approaches in detail. [ABSTRACT FROM AUTHOR]

The fiscal governance framework includes the rules and regulations that discipline the preparation, approval, and implementation of public budgets. It results from the power struggle of the actors that participate in the process of allocating public resources. Despite relevant studies published on the subject, this study aimed to provide background information on determinant factors in the choice and effects of fiscal governance framework adopted by governments in the scholarly conversation. For this, the systematic literature review method was adopted with the development of five steps: selecting a review topic, searching the literature, gathering, reading, and analyzing the scientific papers published in the last 10 years on the subject. Results show that fiscal crises and pressures and rewards of external bodies were the preponderant factors for reforms in the framework of fiscal governance adopted by governments. In another view, impacts of this framework on national public finances were investigated primarily by analysis of numerical fiscal rules. The research gaps identified indicate directions for future research. [ABSTRACT FROM AUTHOR]

As part of the ongoing revision of the Eurocodes, design provisions in EN 1999‐1‐1 on the buckling of longitudinally welded aluminium compression members have been subjected to a critical review. Numerical investigations were conducted because a need for improvement was identified. This part 1 of the paper describes the individual steps of the revision and the modifications discussed, which include the introduction of longitudinally welded members. Before going into the numerical investigations in more detail, previous observations are presented regarding buckling classes and plateau lengths. In part 1 of the paper, explanations of the numerical investigations are limited to presenting the modelling of the geometry, the mechanical properties and the imperfections as well as their respective variation in the context of the parametric studies. The results of the numerical investigations and the proposed design approaches will be presented in detail in parts 2 and 3. [ABSTRACT FROM AUTHOR]

This paper investigates the behaviour and design of duplex stainless steel stub columns with a circular hollow cross‐section (CHS) at elevated temperature. A numerical model is developed to supplement the limited number of test results available in the literature. Following validation, the numerical approach is employed to gain an understanding of the critical behavioural characteristics which have not previously been studied. In addition, the paper considers and extends the continuous strength method (CSM) to include duplex stainless steel for CHS stub columns in fire. This approach employs a base curve linking the cross‐sectional resistance to the deformation capacity and is implemented herein using an elastic, linear hardening material model. The cross‐sectional resistances obtained from the CSM are compared with those from the numerical analysis, as well as with the standardised procedures in the European, American and Australia/New Zealand design standards. It is demonstrated that the proposed design method can lead to more accurate and less scattered strength predictions compared with current design codes. [ABSTRACT FROM AUTHOR]

This paper focuses on the flexural strength of steel wide‐flange members that have holes in the tension flange. A comparison of the scant experimental data in literature with the strength predicted using the 2016 American Institute of Steel Construction (AISC) Specification shows that the predictions are not very accurate and most of the time are quite conservative. The research presented in this paper discusses a parametric analysis performed numerically in an effort to develop a design equation that better fits experimental data, without compromising the safety of flexural members. Extant literature already attempted proposing replacement design equations to address this issue. This paper proposes new design equations and compares all proposed replacements against experimental data augmented by the results of a series of numerical analyses aimed at filling the gaps in the available experimental datasets. These analyses were performed accounting for damage initiation in the finite element models, in an attempt to establish the bending moment at which fracture initiates and were calibrated against known experimental results. It is concluded that the introduction of the concept of a net plastic section modulus, calculated across the cross‐section containing the tension flange holes, provides the best practical approach to attain an accurate, yet conservative, estimate of the effective flexural capacity of a beam with holes in the tension flange. [ABSTRACT FROM AUTHOR]

Following the experimental study on EN 1.4003 ferritic stainless steel T‐stubs in tension discussed in the companion paper, this study reports the development and validation of an advanced FE model that can predict the overall behaviour and failure modes of ferritic stainless steel bolted T‐stubs subjected to tension. Key simulation strategies regarding the modelling of bolt geometry and overcoming numerical instabilities are discussed. Following the determination of material properties in the longitudinal, transverse and diagonal direction reported in the companion paper, the effect of allowing for anisotropy in the FE simulations is investigated and modelling recommendations for its inclusion in FE models are made. Moreover, the effect of bolt end and edge spacing on the joint plastic resistance, ultimate capacity, ductility as well as overall response is comprehensively discussed by inspecting the stress distribution through the plate thickness at various locations along the T‐stub, thus revealing both the flexural and the membrane component of the load transfer mechanism. The numerical results were validated against the experimental results reported in the companion paper in terms of predicted plastic and ultimate resistance, ductility and obtained failure modes. On the basis of the obtained results and the discussion, modeling recommendations for the simulation of stainless steel T‐stubs are made. [ABSTRACT FROM AUTHOR]

This paper investigates pricing decisions with different time sequences in a cross‐border dual‐channel supply chain, in which the manufacturer produces products in country A and sells them to country B via a retail channel and an online channel. Meanwhile, we design three scenarios, the manufacturer‐led earlier scenario, the manufacturer‐led later scenario, and the retailer‐led scenario, to analyze the effects of time sequences when the manufacturer is risk neutral or risk averse. Through modeling and analysis, it is concluded that whether the manufacturer is risk averse or not, the manufacturer prefers the manufacturer‐led earlier scenario and the retailer's preference is the retailer‐led scenario. That is, when considering the time sequences, the players are encouraged to make all decisions in the first stage. Moreover, this paper analyzes the effects of the exchange rate and delivery lead time on the players' pricing decisions. The theoretical and numerical analyses also show that the effects of an increasing exchange rate on the profits of the manufacturer and retailer are associated with the cost of the online channel. Additionally, while reducing the delivery lead time can attract customers, a moderate delivery lead time is more advantageous for the manufacturer. Finally, we further verify the robustness of the impacts of time sequences when the manufacturer is risk averse. Interestingly, if the cost of the online channel is higher, then the risk‐averse behavior benefits the retailer. [ABSTRACT FROM AUTHOR]

In this research the effect of prebuckling in‐plane deflections on the critical moment to lateral‐torsional buckling of beams is investigated. Though this topic is already discussed in the literature, the relevant papers show that there are some discrepancies in the proposals and results from the various authors. In this paper a numerical parametric study is reported, conducted on doubly symmetric simple supported I‐shaped beams. The critical moment values were calculated with and without considering the effect of prebuckling deflections. Various methods were considered, including analytical formulae, thin‐walled beam finite element, and shell finite element calculations. The results justify that the in‐plane deflection has a positive effect on the critical moments, and that the effect is essentially determined by the ratio of in‐plane and lateral rigidities. However, the results highlight that the moment‐increasing effect of the prebuckling deformations can be much smaller compared to the prediction of the analytical formulae, if a shell finite element model is employed. [ABSTRACT FROM AUTHOR]