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In molecular physics, it is often necessary to average over the orientation of molecules when calculating observables, in particular when modeling experiments in the liquid or gas phase. Evaluated in terms of Euler angles, this is closely related to integration over two- or three-dimensional unit spheres, a common problem discussed in numerical analysis. The computational cost of the integration depends significantly on the quadrature method, making the selection of an appropriate method crucial for the feasibility of simulations. After reviewing several classes of spherical quadrature methods in terms of their efficiency and error distribution, we derive guidelines for choosing the best quadrature method for orientation averages and illustrate these with three examples from chiral molecule physics. While Gauss quadratures allow for achieving numerically exact integration for a wide range of applications, other methods offer advantages in specific circumstances. Our guidelines can also be applied to higher-dimensional spherical domains and other geometries. We also present a Python package providing a flexible interface to a variety of quadrature methods. [ABSTRACT FROM AUTHOR]

We investigate the numerical accuracy of the extended Koopmans's theorem (EKT) in reproducing the full configuration interaction (FCI) and complete active-space configuration interaction (CAS-CI) ionization energies (IEs) of atomic and molecular systems calculated as the difference between the energies of N and (N − 1) electron states. In particular, we study the convergence of the EKT IEs to their exact values as the basis set and the active space sizes vary. We find that the first FCI EKT IEs approach their exact counterparts as the basis set size increases. However, increasing the basis set or the active space sizes does not always lead to more accurate CAS-CI EKT IEs. Our investigation supports the observation of Davidson et al. [J. Chem. Phys. 155, 051102 (2021)] that the FCI EKT IEs can be systematically improved with arbitrary numerical accuracy by supplementing the basis set with diffuse functions of appropriate symmetry, which allow the detached electron to travel far away from the reference system. By changing the exponent and the center of the diffuse functions, our results delineate a complex pattern for the CAS-CI EKT IE of LiH, which can be important for the spectroscopic studies of small molecules. [ABSTRACT FROM AUTHOR]

Kitaev chain is one of the important physical models for studying topological quantum states and quantum computing. We here propose an approach to simulate the one-dimensional Kitaev chain via a circuit of superconducting qubits. In our approach, all coupling parameters can be controlled independently, and a nontrivial gauge phase is constructed. We also study the environmental effects on the topological states of the Kitaev chain. In addition to the independent environment surrounding each qubit, we consider the common environment shared by neighboring qubits. Such an environment can generate effective non-Hermitian dissipative coupling between qubits. Through analysis and numerical calculation, we demonstrate that the common environment can significantly affect the topological properties of the qubit chain. Moreover, we observe that dissipative couplings at the edges of the Kitaev chain affect the topological states more strongly than those located elsewhere. Our work may provide a new way to explore topological phase transitions and environmental effects on topological physics using superconducting qubit circuits. [ABSTRACT FROM AUTHOR]

It has been recently shown that 2D systems can exhibit crystalline phases with long-range translational order showcasing a striking violation of the Hohenberg–Mermin–Wagner (HMW) theorem, which is valid at equilibrium. This is made possible by athermal driving mechanisms that inject energy into the system without exciting long wavelength modes of the density field, thereby inducing hyperuniformity. However, as thermal fluctuations are superimposed on the non-equilibrium driving, long-range translational order is inevitably lost. Here, we discuss the possibility of exploiting non-equilibrium effects to suppress arbitrarily large density fluctuations even when a global thermal bath is coupled to the system. We introduce a model of a harmonic crystal driven both by a global thermal bath and by a momentum conserving noise, where the typical observables related to density fluctuations and long-range translational order can be analytically derived and put in relation. This model allows us to rationalize the violation of the HMW theorem observed in previous studies through the prediction of large-wavelength phonons, which thermalize at a vanishing effective temperature when the global bath is switched off. The conceptual framework introduced through this theory is then applied to numerical simulations of a hard-disk solid in contact with a thermal bath and driven out-of-equilibrium by active collisions. Our numerical analysis demonstrates how varying driving and dissipative parameters can lead to an arbitrary enhancement of the quasi-long-range order in the system regardless of the applied global noise amplitude. Finally, we outline a possible experimental procedure to apply our results to a realistic granular system. [ABSTRACT FROM AUTHOR]

Thermal activation of a particle from a deep potential trap follows the Arrhenius law. Recently, this result has been generalized for interacting diffusive particles in the trap, revealing two universality classes—the Arrhenius class and the excluded volume class. The result was demonstrated with the aid of numerical analysis. Here, we present a perturbative hydrodynamic approach to analytically validate the existence and range of validity for the two universality classes. [ABSTRACT FROM AUTHOR]

Higher-order topological states, as emergent topological phases of matter, originating from condensed matter physics, have sparked a vibrant exploration of topological insulators. Their topologically protected multidimensional localized states are typically associated with nontrivial bulk band topology, and the significant impact of lattice geometry is unconsciously overlooked. Here, we construct coupled acoustic cavities on a two-dimensional honeycomb lattice to investigate the sensitivity of higher-order topological modes to the variations of edge contour. Fractional charge is utilized to accurately predict topological modes with distinct topological orders, in spite of the minimal bulk bandgaps inherent in the honeycomb lattice and bound states in the continuum. It is found that the presence and absence of the first-order and higher-order topological modes in the same topological phase are tightly linked to the sample boundaries, which can be demonstrated by both theoretical analysis and numerical calculation. Our study also discusses potential physical realization of geometry-dependent topological states across different platforms, providing inspiration for the prospective application of topological devices in acoustics. [ABSTRACT FROM AUTHOR]

In this work, we investigate the possibilities of performing charge and spin current rectifications using graphene nano-ribbon in the presence of Rashba spin–orbit (SO) interaction. More specifically, we explore the specific role of mechanical strain on these two different types of current rectifications. The system is simulated by a tight-binding framework, where all the results are worked out based on the standard Green's function formalism. In order to have current rectification, an asymmetry is required, which is incorporated through uncorrelated disorder among the constituent lattice points. From our extensive numerical analysis, we find that reasonably large charge and spin current rectifications can be obtained under strained conditions, and all the physical pictures are valid for a broad range of tight-binding parameters. The rectification properties are studied mostly for zigzag graphene nano-ribbons; however, an armchair ribbon is also taken into account for a clear comparison. Our work may provide a new direction of getting strain-controlled current rectifications in similar kinds of other physical systems as well. [ABSTRACT FROM AUTHOR]

The excitation and tuning of multiple resonances with narrow spectral width based on Brewster's effect is possible in an ultrathin dual-band terahertz absorber. The angular variation establishes a monotonic relation with the frequency of some generated resonances offering tunability. Moreover, burying a graphene ring resonator beneath the metallic ring splits the resonance for providing the triple narrow absorption windows. The electrical modulation offers the feature of independent tunability in the generated third absorption band. Thus, the frequency ratio of the upper to lower spectral absorption peak can be modulated by the electrically tunable Fermi energy of graphene. Engraving the graphene resonator also enhances the incident angle based tunability by affecting a greater number of Brewster generated resonance peaks. The narrow line shape of the triple band absorption can enable refractive index sensing and the detection of extraneous elements in localized analyte samples. The detection of imidacloprid pesticide in wheat flour is performed by the implemented sensor. The numerical analysis is done for the design and analysis of the absorber structures to report the above facts. [ABSTRACT FROM AUTHOR]

Lot splitting is one of the effective technologies of time-based strategy and has been widely studied in a variety of production environments. Nevertheless, the literature on its application in seru production has been highly scarce until now. Seru system is composed of simple equipment and multi-skilled workers, which can be quickly converted from the traditional assembly line to seru units. As an innovative production mode, seru production inevitably allows applying lot splitting in the real world. Therefore, a multi-objective model is studied for line–cell conversion with lot splitting, aiming at determining the trade-off among makespan, inter-seru system balancing, and intra-seru system balancing. Due to the proposed model's NP-hard nature, an improved NSGA-II was developed to solve it. Finally, extensive numerical simulations are conducted. Compared to no lot splitting, lot splitting is improved by 4.2% and 3.7% in terms of inter-seru system balancing and makespan respectively. The better efficiency and effectiveness of the improved NSGA-II are proved by comparisons with other state-of-the-art algorithms. Additionally, a sensitivity analysis is conducted to ascertain the degree of contribution of the model parameters towards the value of objectives, which provides management implications to support the decision-making of seru production for the enterprise. [ABSTRACT FROM AUTHOR]

The Unitary Group Adaptation (UGA) offers a very compact and efficient spin adaptation strategy for any spin-free Hamiltonian in a many body framework. Our use of UGA in the context of state-specific (SS) Jeziorski–Monkhorst Ansatz based multireference coupled cluster (MRCC) theory obviates the non-commutativity between the spin-free cluster operators via a normal ordered exponential parametrization in the wave operator. A previous formulation of UGA-SSMRCC by us [R. Maitra, D. Sinha, and D. Mukherjee, J. Chem. Phys. 137, 024105 (2012)], using the same ansatz, employed certain sufficiency conditions to reach the final working equations, which cannot be improved systematically. In this article, we will present a more rigorous formulation that follows from an exact factorization of the unlinked terms of the Bloch equation, resulting in equations on which a hierarchy of approximations can be systematically performed on the emergent additional terms. This derivation was shown in our recent article [D. Chakravarti, S. Sen, and D. Mukherjee, Mol. Phys. 119, e1979676 (2021)] in the context of a single open shell CC formalism and was applied to spectroscopic energy differences where the contribution of the new terms was found to be of the order of ∼0.001 eV for ionization potential, electron affinity, and excitation energy. In the current work, we will present a comparison between the earlier and current formulations via both a theoretical analysis and a numerical demonstration of the dramatic effect of the additional terms brought in by the factorization on potential energy curves. The contribution of such terms was found to gain importance with an increase in the number of singly occupied active orbitals in the model space functions. [ABSTRACT FROM AUTHOR]

The kernel polynomial method (KPM) is a powerful numerical method for approximating spectral densities. Typical implementations of the KPM require an a prior estimate for an interval containing the support of the target spectral density, and while such estimates can be obtained by classical techniques, this incurs addition computational costs. We propose a spectrum adaptive KPM based on the Lanczos algorithm without reorthogonalization, which allows the selection of KPM parameters to be deferred to after the expensive computation is finished. Theoretical results from numerical analysis are given to justify the suitability of the Lanczos algorithm for our approach, even in finite precision arithmetic. While conceptually simple, the paradigm of decoupling computation from approximation has a number of practical and pedagogical benefits, which we highlight with numerical examples. [ABSTRACT FROM AUTHOR]

Angular and spectral differential imaging is an observational technique of choice to investigate the immediate vicinity of stars. By leveraging the relative angular motion and spectral scaling between on-axis and off-axis sources, post-processing techniques can separate residual star light from light emitted by surrounding objects such as circumstellar discs or point-like objects. This paper introduces a new algorithm that jointly unmixes these components and deconvolves disc images. The proposed algorithm is based on a statistical model of the residual star light, accounting for its spatial and spectral correlations. These correlations are crucial yet remain inadequately modelled by existing reconstruction algorithms. We employ dedicated shrinkage techniques to estimate the large number of parameters of our correlation model in a data-driven fashion. We show that the resulting separable model of the spatial and spectral covariances captures very accurately the star light, enabling its efficient suppression. We apply our method to data sets from the Very Large Telescope/Spectro-Polarimetry High-contrast Exoplanet REsearch instrument and compare its performance with standard algorithms (median subtraction, PCA, PACO). We demonstrate that considering the multiple correlations within the data significantly improves reconstruction quality, resulting in better preservation of both disc morphology and photometry. With its unique joint spectral modelling, the proposed algorithm can reconstruct discs with circular symmetry (e.g. rings, spirals) at intensities one million times fainter than the star, without needing additional reference data sets free from off-axis objects. [ABSTRACT FROM AUTHOR]

Exploiting the Persistent Homology technique and its complementary representations, we examine the footprint of summed neutrino mass (⁠|$M_{\nu }$|⁠) in the various density fields simulated by the publicly available Quijote suite. The evolution of topological features by utilizing the superlevel filtration on three-dimensional density fields at zero redshift, reveals a remarkable benchmark for constraining the cosmological parameters, particularly |$M_{\nu }$| and |$\sigma _8$|⁠. The abundance of independent closed surfaces (voids) compared to the connected components (clusters) and independent loops (filaments), is more sensitive to the presence of |$M_{\nu }$| for |$R=5$| Mpc  |$h^{-1}$| irrespective of whether using the total matter density field (m) or cold dark matter + baryons field (⁠|$\mathrm{ \mathrm{cb}}$|⁠). Reducing the degeneracy between |$M_{\nu }$| and |$\sigma _8$| is achieved via Persistent Homology for the m field but not for the |$\mathrm{cb}$| field. The uncertainty of |$M_{\nu }$| at |$1\sigma$| confidenc interval from the joint analysis of Persistent Homology vectorization for the m and |$\mathrm{cb}$| fields smoothed by |$R=5$| Mpc  |$h^{-1}$| at |$z=0$| reaches 0.0152 and 0.1242 eV, respectively. Noticing the use of the three-dimensional underlying density field at |$z=0$|⁠ , the mentioned uncertainties can be treated as the theoretical lower limits. [ABSTRACT FROM AUTHOR]

The indirect method for bridge modal identification based on the response of moving vehicles has attracted widespread attention in recent years. However, most existing studies only focus on the simply supported bridge, while continuous girder bridges are widely used in practical engineering. Therefore, this study proposes an indirect frequency identification method for continuous girder bridges. First, the mode shape formula of the equal-span continuous beam is deduced using the three-moment equations, and the analytical solution of the vehicle vibration response is deduced via the vehicle–bridge coupled vibration theory. Second, the derived analytical solution is verified through numerical analysis results and field test results. Finally, the effects of bridge and vehicle parameters on the frequency identification accuracy are analyzed. The results show that a reasonable frequency of the trailer should be selected to avoid the resonance between the vehicle and the bridge for better performance. The research findings can provide a reference for the indirect identification of continuous girder bridges based on the response of moving vehicles. [ABSTRACT FROM AUTHOR]

This study elucidates the impact of the types and blending ratios of low-carbon alkanes (methane and ethane, C1/C2) on the combustion and emission performance of NH₃ and analyzes the reasons for the differences in the effects of C1/C2 from the elementary reaction. The experimental and numerical analysis results show that C1/C2 reduces the temperature dependence of NH₃ oxidation and promotes the formation of combustion-promoting (CP) radicals. The concentration of CP is determined by the strength of the H-abstraction reactions of C1/C2. The initial H-abstraction product of C1, CH₃, exhibits reaction inertness, whereas the inert radicals of C2 (C₂H₄, C₂H₃, and C₂H₂) appear after three main H-abstraction steps. Additionally, C1/C2 intensifies the NH→N→NO reaction, worsening thermal-NO emissions; this study classifies it as a thermal-NO generation pathway. Although NH₂ and NH significantly reduce fuel-NO, their effect on thermal-NO is less pronounced. The consumption of thermal-NO primarily depends on the reverse direction of the reaction N 2 +O N + NO. • The introduction of C1/C2 reduces the temperature dependence of NH 3 oxidation reactions. • The dehydrogenation reactions of C1/C2 produce different types of inert radicals that limit subsequent dehydrogenation reactions. • C1's inert radicals form after the first dehydrogenation, while C2's form after the third dehydrogenation. • For the HC(O)/NH 3 , NH.→N→NO should be classified as one of the thermal-NO generation pathways. • Thermal-NO consumption depends on N accumulation, driving the reaction N 2 +O=N+NO. [ABSTRACT FROM AUTHOR]

Skin cancer is one of the most common cancers, and is primarily caused by long-term exposure to ultraviolet (UV) radiation. Understanding these dynamics is critical for the development of effective preventive and treatment measures. In this study, we examined a mathematical model of skin cancer induced by UV rays, categorizing the total population into four compartments: susceptible S(t), infected I(t), recovered R(t), and UV radiation U(t). To solve the system of nonlinear differential equations and obtain a numerical solution for the SIRU model, we employed three semi-analytical methods: the differential transform method (DTM), Shehu transformation–Akbari–Ganjis–Pade approximation method (SAGPM), and higher-order inverse polynomial method (HOIPM). Each method was effective in providing highly accurate solutions with minimal computational effort. Compared to the ode45 solver, these semi-analytical methods have been validated for their accuracy, confirming their reliability and efficiency in solving complex real-world problems, leading to interesting findings. This study also investigated the impact of key parameters, offering valuable insights into the response and behavior of the skin cancer model under various conditions. These findings enhance our understanding of the dynamics of skin cancer. [ABSTRACT FROM AUTHOR]

We analyse the fourth data release of the Kilo Degree Survey (KiDS-1000) and extract cosmological parameter constraints based on the cosmic shear peak count statistics. Peaks are identified in aperture mass maps in which the filter is maximally sensitive to angular scales in the range 2–4 arcmin, probing deep into the non-linear regime of structure formation. We interpret our results with a simulation-based inference pipeline, sampling over a broad w CDM prior volume and marginalizing over uncertainties on shape calibration, photometric redshift distribution, intrinsic alignment, and baryonic feedback. Our measurements constrain the structure growth parameter and the amplitude of the non-linear intrinsic alignment model to |$\Sigma _8 \equiv \sigma _8\left[\Omega _{\rm m}/0.3\right]^{0.60}=0.765^{+0.030}_{-0.030}$| and |$A_{\rm IA}= 0.71^{+0.42}_{-0.42}$|⁠ , respectively, in agreement with previous KiDS-1000 results based on two-point shear statistics. These results are robust against modelling of the non-linear physics, different scale cuts, and selections of tomographic bins. The posterior is also consistent with that from the Dark Energy Survey Year-1 peak count analysis presented in Harnois-Déraps et al. and hence we jointly analyse both surveys with a common pipeline. We obtain |$\Sigma _8^{\rm joint} \equiv \sigma _8\left[\Omega _{\rm m}/0.3\right]^{0.57}=0.759^{+0.020}_{-0.017}$|⁠ , in agreement with the Planckw CDM results. The shear-CMB tension on this parameter increases to |$3.1\sigma$| when forcing |$w=-1.0$|⁠ , and to |$4.1\sigma$| if comparing instead with |$S_{8,\Lambda {\rm CDM}}^{\rm joint} = 0.736^{+0.016}_{-0.018}$|⁠ , one of the tightest constraints to date on this quantity. Residual biases in the photometric redshifts of the DES-Y1 data and in the modelling of small scales physics could lower this tension, however it is robust against other systematics. Limits in the accuracy of our emulator prevent us from constraining |$\Omega _{\rm m}$|⁠. [ABSTRACT FROM AUTHOR]

Aiming at the problems of large deviation of plastic machining accuracy and different buckling instability loads of bionic egg-shaped shells under different flexible medium forming technologies, it is proposed to adopt unidirectional loading rubber bulging and granular medium bulging technologies of bionic egg-shaped shells. By comparing the plastic machining accuracy, geometric accuracy, and strength of bionic egg-shaped shells with different flexible mediums, the machining accuracy and overall quality of bionic egg-shaped shells can be improved. In order to explore the stress and strain conditions at different stages and in different regions of the egg-shaped shell flexible medium forming technologies under the ideal case considering the thick directional stress conditions, a mechanical analysis of the egg-shaped shell flexible medium forming technologies is carried out. The combination of numerical analysis and experiment is used to analyze the forming process of egg-shaped shell under the action of different flexible mediums, and the accuracy of the numerical analysis model is verified. And then, through the study of the influence of different flexible medium forming technologies on the plastic processing accuracy, geometric accuracy, and strength of the egg-shaped shells, the plastic deformation and quality of the egg-shaped shell is mastered by the influence law of the flexible medium forming technology. The study shows that the results of the numerical analysis of the egg-shaped shell flexible medium forming technology have an average error of no more than 11% with the test, and the numerical analysis model can be considered accurate. Moreover, the plastic machining accuracy of egg-shaped shell process parts and egg-shaped parts with granular medium is better than that of rubber medium. The geometric accuracy deviation of the egg-shaped part of the egg-shaped shell with the granular medium is 10% smaller than that of the rubber medium, and the process parts are also superior to the rubber medium. The buckling load of the egg-shaped shell process parts under granular medium are higher than that of the rubber medium, while the egg-shaped parts are slightly smaller. Considering the experiment error and the overall buckling load distribution, the overall strength of the egg-shaped shell is higher under the action of granular medium. [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]

This study investigated the thermomechanical behavior of an alumina calciner's lining, a critical component in alumina processing, often susceptible to maintenance issues arising from refractory failure due to erosion and cracking. Based on numerical analyses via the finite element method, the design of a refractory panel was modeled. Furthermore, the influence of geometric parameters and friction level between lining layers on the thermal and mechanical behavior of the system was evaluated. Key findings highlighted how the curvature changed the stress profiles, resulting in particular cracking patterns, where curved panels showed higher stress concentrations at the center of their edges. Empirical validation through in-situ crack pattern observations further validated the model's predictive capability. Additionally, the study evaluated the influence of friction coefficients on resulting stresses, showing their small effect relative to other factors. Analyses on design parameters indicated that stress levels generally increased with the size-to-thickness ratio, highlighting the trade-off between reducing installation time and ensuring structural integrity in panel design and application. An alternative for enhancing lining performance was explored by selecting the material, where decreasing the insulating thermal conductivity reduced the likelihood of failure of the castable layer. Ultimately, the computational numerical method developed in this study offers a robust framework for exploring various geometries and materials, providing engineers with a versatile tool for optimizing lining designs in various operational scenarios. • Panel curvature influenced stress distributions and cracking patterns in calciner linings. • Friction modestly affected tensile stresses; 0.5 is reasonable for simulations. • Stress levels increased with panel size-to-thickness ratio, affecting installation efficiency. • Lower insulating thermal conductivity reduced failure risk in the castable layer. • The developed method provides a framework for exploring various geometries and scenarios. [ABSTRACT FROM AUTHOR]

A sub-wavelength particle with a total scattering cross section that exceeds the single channel limit is referred to as a superscatterer, which can provide ability to control light in nanoscale. A variety of superscatter structures have been suggested, most of them are typically constructed with strong forward scattering but minor backscattering. This unusual behavior can be attributed to the superposition of resonant modes in adjacent angular momentum channels. We reveal the mechanism of super backscattering for subwavelength column, which can be formed by recombining non-adjacent resonant modes, as confirmed by our numerical analysis. [ABSTRACT FROM AUTHOR]

ABSTRACT The severe deformation of the surrounding rock of the coal floor in Shanghaimiao mining area is affecting the safe, efficient production of mine wells in this region. In this study, the heave mechanism and control of the roadway floor were investigated through laboratory experiments, field research, theoretical analysis, numerical simulation, and on‐site testing. The results showed that the main reason for the serious damage to the roadway floor was the low strength of the surrounding rock of the roadway floor, and floor damage was exacerbated by the low support strength, hydraulic effects, and mining impact. A mechanical model of the asymmetric floor heave was established, and it was found that the stability of the roadway floor was positively correlated with the floor rock type, the stress concentration coefficients on the two sides of the roadway, and the burial depth, whereas it was negatively correlated with the cohesive force and internal friction angle of the floor rock mass. Expressions for the upward resultant force R of the roadway floor and the stress concentration coefficients K and K′ on both sides of the roadway were derived. The results of a FLAC3D numerical simulation analysis showed that the stress peak in front of the working face was 36 MPa, with a stress concentration factor of 3.7. After the floor support was reinforced, the floor heave was remarkably reduced, with a maximum value of approximately 600 mm, and the floor deformation became somewhat asymmetric. Finally, a double‐seal floor‐reinforcing “inverted arch” control technique was proposed and tested on‐site. The new system could efficiently and stably support the surrounding rock of the roadway. [ABSTRACT FROM AUTHOR]

The paper presents experimental investigations and numerical analysis of bearing type lap joint behaviour with one bolt and two shear planes joining thin-walled steel parts. The aim of the study is to describe the actual force-displacement F-Δ relationship for the tested joints and to represent it numerically by validated models with varying degrees of geometry detailing in the finite element analysis. Validation involves determining properties of plates, bolts and the entire shear joint based on individual experimental testing. The obtained shear characteristic include all main stages of F-Δ connection behaviour, as elastic phase, friction, slip and bearing. Although bearing joints are analysed, friction-slip mechanism resulting from tightening of the bolts is also examined. Analyses also take into account existence of threaded portion of the bolt shank in bearing. FEA model with bolt thread confirmed its validity in terms of predicting load-bearing capacity with an overestimation of 1% with respect to the experimental average. However, simplified cylindrical model of the bolt shank appeared to be more reliable in terms of initial bearing stiffness, where the value was 20% higher comparing to the empirical results. An analytical characteristic of the considered joint was also derived based on the component method, which required certain assumptions and adjustments to include the actual phases of connection behaviour. This approach provided a satisfactory match to the experimental results, characterised by underestimations of maximum force and initial bearing stiffness of 2.5 and 7.6% respectively. [ABSTRACT FROM AUTHOR]

In many countries, public transport (PT) services are offered by multiple operators with different modes, such as trains, metros, and buses, which are interchangeable across a single journey. This paper presents a model with one origin (O)-destination(D) path operated by two operators, each of which is responsible for different parts of the OD journey. One operator competes with potential third-party transport companies by offering discount incentives. Such an abstract settings has not been discussed in the literature. We explore how prices, demand, profits, and social welfare change with discounts through a theoretical analysis and numerical simulations under five scenarios. The results indicate that in all the scenarios the operator offering a discount incentive can always attract more passengers and increase its profits. Moreover, reducing the service time of operators offering discounts contributes to an increase in social welfare. Notably, this paper deduces for the first time that the demand scenario aimed at maximizing social welfare is twice as high as that aimed at maximizing total profit. However, in the scenario of maximum social welfare, the profitability of operators becomes challenging. [ABSTRACT FROM AUTHOR]

Characteristics like mission cycle, failure number, and failure mode act as crucial metrics for evaluating the reliabilities of products subject to various failure modes. As a result, this study develops two distinct strategies to manage product reliabilities. The first strategy focuses on managing warranty-stage reliability and employs renewable-free replacements to enhance warranty appeal. Using either the criterion of “whichever occurs first” or “whichever occurs last”, this strategy is called a three-dimensional random warranty-first-or-last approach with renewable-free replacement. The second strategy involves various replacements, providing comprehensive management of post-warranty reliability. The first approach within this second type of strategy is called the bivariate random periodic replacement-first-with-corrective-replacement method. The proposed warranty can identify reliability heterogeneities, which serves as the basis for adapting the second approach within the second type of strategy. Time and cost factors are used to quantify the proposed strategies. Numerical analyses are carried out focusing on key parameters. [ABSTRACT FROM AUTHOR]

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. Highlights: 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]

Acoustic black hole (ABH), as a new wave manipulation technique, shows excellent applications in vibration and noise reduction of structures. Nowadays, most ABHs use materials with a fixed elastic modulus, limiting their low-frequency performance. Herein ABH plates with variable elastic modulus (VM-ABH) is designed, and its vibration and acoustic radiation characteristics are investigated by using numerical analysis. The results show that the vibration response of VM-ABH has a decrease of 5–13.2 dB relative to that of the uniform texture ABH (UT-ABH) in the frequency range of 10–5000 Hz, and the degree of energy aggregation is significantly improved. Moreover, the sound pressure level was reduced by 3.6 dB. Meanwhile, by linearly varying the elastic modulus in the center region of the VM-ABH, the effects of gradient index and terminal elastic modulus on the damping characteristics and dynamic response are revealed. The research results provide new objects for the study of vibration and noise reduction of ABH. [ABSTRACT FROM AUTHOR]

The effects of random dislocations on the vibrational properties of finite-length RNA and DNA macro-structures have been investigated by means of a harmonic Hamiltonian and the Green's function method. The RNA molecule has been modeled using a half ladder model, and three models (a fishbone model and two different strand models) have been employed to model the structure of DNA. The lengths of the finite and cyclic systems are gradually increased to more accurately approximate the structures of RNA and DNA. Springs whose behaviors are governed by Hooke's constitutive law have been used to represent the bonds between the masses, with the stiffness of the vertical springs randomly changing along the length of each model. This results in a more realistic representation of the inherent randomness of the studied structures. To investigate the effect of random dislocations on the mechanical response of the studied systems, it has been assumed that a random mass-spring ensemble has been knocked out of place by an external force. It has been found that increasing the number of building blocks along the length of the models suppresses the influence of dislocations on the vibration spectra of RNA and DNA. It was also observed that at low frequencies, the influence of dislocations becomes more pronounced. Besides, taking into account the collective mass of the sugar-phosphate backbone results in the appearance of gaps in the vibration spectra. By introducing dislocations into the models, additional dislocation-induced vibrational states appear in the DOS curves. What stands out from the results is that the responses of the studied systems to these changes are strictly nonlinear. The employed methodology can be applied to investigate the mechanical response of damaged RNA and DNA. [ABSTRACT FROM AUTHOR]

AbstractA (T,N,n) preventive replacement first (PRF) policy is proposed in this article to investigate a parallel system with two independent parts where the secondary part is in a cold-standby state initially. Before the system fails completely, a preventive replacement is carried out at the planned time T, the time when the system successively completes N jobs or the time when the system suffers the n-th type-I failure, whichever occurs first. The system deteriorates stochastically, and it may experience two types of failures: type-I (repairable or minor) failure and type-II (non repairable or catastrophic) failure. When the system suffers a type-II failure, it’s correctively replaced. This model is widely applied in real-life scenarios, especially in the aviation industry. Under the single-parameter optimization scenario, both cost-minimal N and n exhibit favorable convexity characteristics. This indicates that we can uniquely determine the optimal N and n under the principle of minimizing the mean cost rate. Furthermore, we find that the mean cost rate cannot be minimized as T is less than a certain threshold, which implies that the planned time of the preventive replacement should not be implemented too early. In addition, the optimal multi-dimensional replacement policy that minimizes the mean cost rate can be uniquely obtained by theoretical or numerical analysis. Our proposed model provides a versatile formulation for analyzing a large variety of replacement policies. Compared with previous literature, the PRF policy adopted in this article integrates T-, N- and n- control policies, making it more comprehensive. It’s of practical significance for relevant enterprises to make decisions, assisting them in minimizing the mean cost rate while enhancing system reliability. [ABSTRACT FROM AUTHOR]

Translation abstract Numerical analysis of soil vibrations due to vibrating foundations: Guidance for model designGeotechnical engineers are increasingly concerned with wave propagation problems. Manufacturers of geotechnical analysis software added features for soil dynamic analyses to their products initially devised for static geotechnical analyses. Though, users often lack the experience for conducting such advanced numerical analyses. Working groups 1.4 “Soil dynamics” and 1.6 “Numerical analyses in geotechnical engineering” of DGGT German Society for Geotechnical Engineering established a joint subgroup “Numerical analyses in soil dynamics” to address this shortcoming. The present paper presents the work of the subgroup so far and provides some guidance on conducting numerical analyses in soil dynamics. [ABSTRACT FROM AUTHOR]

In recent years, the technology of the gob‐side entry retaining by roof cutting and pressure releasing (GERRC) has been widely used in coal mining. However, the stability of the roadway surrounding rock structure during GERRC in the coal seam with high dip angles is a major concern, limiting the widespread application of this technology. In this study, we analyzed the deformation and stress evolution of roadway surrounding rock during GERRC in the 011810‐working face of Jinfeng Coal Mine using theoretical analysis and numerical simulation. The results show that in coal seams with high dip angles, the gangue in the gob will slide down the lower trough, providing enough support for the upper rock layer and limiting rotation deformation along the gob‐side entry roof during GERRC. This weakens the impact of mining pressure on the roadway and promotes the stability of the surrounding rock structure. However, the stress in the coal of the lower roadway in the advanced influence area is the largest, reaching 16.3 MPa due to the influence of buried depth. The stress of the surrounding rock of the gob‐side entry tends to be stable at 110 m behind the working face in the lower roadways. There is also an obvious pressure relief zone in the coal in front of the working face, 10 m away from the cutting line, during GERRC. Its maximum stress is only 61.3% of the advanced coal and 10.0 MPa, indicating that the pressure relief effect of the roof cutting on the inclined coal seam is significant. [ABSTRACT FROM AUTHOR]

This paper aims to investigate new coincidence point theorems for self‐maps under an extended rational contraction. Our approach uses the p‐adic distance in partially ordered ultrametric spaces. Furthermore, to illustrate our major discoveries, we give a comprehensive numerical analysis. This study expands on prior research in partially ordered ultrametric spaces to provide a more comprehensive understanding of such spaces using rational contraction. [ABSTRACT FROM AUTHOR]

In this paper, we study a robust, dynamic, continuous-time optimal consumption and portfolio allocation problem for investors with recursive preferences who have access to both stock and derivatives markets. We assume the stock price process follows a stochastic volatility model, with instantaneous precision as the unique state variable, allowing for discontinuities in all the dynamics. We obtain a closed-form approximate solution up to a system of ODEs to the optimization problem for a non-unitary value of the elasticity of intertemporal substitution of consumption, being able to derive an exact solution as a particular case. Our theoretical findings show that the optimal policies are remarkably affected by the ambiguity-aversion parameters to diffusive and jump risks. A detailed numerical analysis confirms the effectiveness of our theoretical results on real data. Finally, we prove that investors who do not believe in ambiguity may suffer considerable wealth losses. [ABSTRACT FROM AUTHOR]

The geodynamic evolution of the Liguro-Provençal Basin and its crust and upper mantle structure remain debated, especially regarding the role of rifting in continental break-up and seafloor spreading. Our study incorporates updated datasets, including new gravity maps from the AlpArray Gravity Working Group (complete Bouguer, free air, and isostatic anomalies) for 3D modeling and gravity field analysis, seismic data from Lobster offshore campaigns for direct comparison, and geodynamic models, supplemented by seismic profiles from previous French and Italian campaigns to constrain the interpretation. We used GFZ's IGMAS + software for interactive 3D modeling, creating a density model extending to 300 km depth that includes crustal and upper mantle inhomogeneities based on prior geodynamic models. This hybrid approach, with polygonal structures for the crust and voxels for the upper mantle, clarifies individual contributions to the gravity field. Extending initial gravity modeling from the SPP MB4D project INTEGRATE, our work provides a consistent 3D density model for the Alps and Ligurian Basin. The constrained 3D modeling and numerical analyses (terracing, clustering, filtering, curvature), along with vertical stress and gravitational potential energy calculations, suggest that rifting has significantly influenced the basin's geological evolution. [ABSTRACT FROM AUTHOR]

To meet the demand for non‐contact displacement detection of magnetic levitation spheres, single‐ended and differential variable electrode distance capacitance displacement detection schemes are designed in this paper. For these two schemes, finite element simulation models are established in COMSOL Multiphysics software to obtain the relationship between the test capacitance and the displacement of the magnetic levitation sphere. In the single‐ended scheme, there is a non‐linear relationship between the test capacitance and the position of the levitated sphere, and this non‐linearity becomes more significant as the sphere moves away from the electrode plate. In contrast, in the differential scheme, the test capacitance and the displacement of the levitated sphere follow a linear relationship, but the test sensitivity decreases with the expansion of the measuring range. The simulation results of the differential scheme have been verified by building a spherical displacement detection simulator, and thanks to the mature development of capacitive detection circuits, the scheme is expected to achieve better than nanoscale displacement detection resolution in the 6.6 mm displacement range of a magnetic levitation sphere in the future. [ABSTRACT FROM AUTHOR]

This paper introduces finite difference delay modelling (FDDM) for computing the shielding effectiveness (SE) of a conductive enclosure with an aperture against electromagnetic pulses. FDDM offers optimal accuracy and stability for analysing complex structures. The time domain electric field integral equation (TD‐EFIE) for the conductive enclosure is derived by imposing boundary conditions on the perfect electrical conductor (PEC) surface in the Laplace domain. Time discretization is based on finite differences, and the Laplace‐to‐Z transform mapping is utilized. Fast Fourier Transform (FFT) is employed to expedite the FDDM solution process. Both frequency domain shielding effectiveness (FD‐SE) and time domain shielding effectiveness (TD‐SE) are evaluated using this approach. Finally, to validate the accuracy of the proposed method, results are compared with simulations using CST‐MWS software and the frequency domain moment method. [ABSTRACT FROM AUTHOR]

Shape optimization with respect to eigenvalues of a cavity plays an important role in the design of new resonators or in the optimization of existing ones. This paper proposes a gradient‐based optimization scheme, which is enhanced with closed‐form shape derivatives of the system matrices. Based on these, accurate derivatives of eigenvalues, eigenmodes, and the cost function can be computed with respect to the geometry, which significantly reduces the computational effort of the optimizer. The work is demonstrated by applying it to the 9‐cell TESLA cavity, for which the design parameters of the computational model are considered as optimization variables to match the design criteria for devices in realistic use cases. Since eigenvalues may cross during the shape optimization of a cavity, a new algorithm based on an eigenvalue matching procedure is proposed, to ensure the optimization of the desired mode in order to also enable successful matching along large shape variations. [ABSTRACT FROM AUTHOR]

In this paper, the performance of aluminum-based nanofluids with a possible application in pressurized water reactors is numerically investigated. A 605 mm long 4-rod array square (2 × 2) subchannel geometry with a uniform heat flux of 50 kW/m2 has been used in CFD simulation. This analysis has been carried out using the RNG k-epsilon turbulence model with standard wall function in ANSYS FLUENT 2022R1. The impact of various flow conditions and nanofluid concentrations has been examined. The effects of variable velocities on nanofluid performance have been studied using different Reynolds numbers of 20,000, 40,000, 60,000, and 80,000. The analysis was conducted with Al2O3/water nanofluid concentrations of 1%, 2%, 3%, and 4%. A comparison of the Nusselt number based on five different correlations was conducted, and deviations from each correlation were then presented. The homogeneous single-phase mixer approach has been adopted to model nanofluid characteristics. The result shows a gradual enhancement in the heat transfer coefficient with increasing volume concentrations and Reynolds numbers. A maximum heat transfer coefficient has been calculated for nanofluid at maximum volume concentrations (ϕ = 4%) and highest velocities (Re = 80,000). Compared to the base fluid, heat transfer was enhanced by a factor of 1.09 using 4% Al2O3. The Nusselt number was calculated with a minimal error of 3.62% when compared to the Presser correlation and the maximum deviation has been found from the Dittus–Boelter correlation (13.77%). Overall, the findings suggest that aluminum-based nanofluids could offer enhanced heat transfer capabilities in pressurized water reactors. [ABSTRACT FROM AUTHOR]

The bedding structure of layered tunnels has a significant impact on the evolution of excavation damage, yet research on the relevant evolution mechanisms is scarce. In view of this, this paper develops a mesh-free numerical method to simulate the progressive damage process of tunnel excavation and proposes a method for applying stress boundaries within the SPH framework. Through this method, simulations of tunnel excavation damage under different bedding dip angles and stress ratios are conducted. The results show that the following: in the simulation of excavation damage of a tunnel without bedding structures, specific areas around the tunnel exhibit characteristics of tensile–shear composite failure and shear failure, verifying the rationality of the algorithm; under different bedding dip angles, a damage zone is first generated around the tunnel, and shear cracks appear at the tangent of the bedding plane and the tunnel, with the damage degree being the largest when α = 30° and the smallest when α = 45°; and under different stress ratios, the damage starts around the tunnel, continuously evolves, and finally forms a failure zone inside the bedding plane joints tangent to the tunnel, and the damage degree increases with the increase in the stress ratio. This study discusses the damage mechanisms under different calculation schemes and provides a reference for understanding the excavation damage mechanisms of layered tunnels. [ABSTRACT FROM AUTHOR]

This study employs secondary ion mass spectrometry (SIMS) to investigate the diffusion behavior of hydrogen and carbon in a CdxZn1−xO:Eu multilayer at different annealing temperatures (500–900 °C). The SIMS results reveal a significant out-diffusion of these elements toward the surface and diffusion to the interface region. The diffusion flow rates are asymmetric and favor the interface direction. The depth profiles of diffused elements are fitted using the forward timecentered space (FTCS) iteration method. The activation energies are determined to be 0.35 ± 0.06 eV for hydrogen and 0.33 ± 0.09 eV for carbon, suggesting an interstitial mechanism in CdxZn1−xO. The results indicate that increasing the annealing temperatures leads to a significant decrease in impurity concentrations. [ABSTRACT FROM AUTHOR]

Functionally graded materials (FGMs) are heterogeneous composites characterized by outstanding properties. They are built from two or more components with a gradient distribution of chemical composition along a given direction. A promising graded material for biomedical engineering as an implant could be a FGM made of titanium (Ti) and hydroxyapatite (HAP). It would allow us to counteract the difference between the stiffness modulus of pure titanium and bone tissue. Moreover, it can be a good solution to the problem of stress shielding for bone fixation plates made of conventional titanium or steel. The presented paper aims to perform micromechanical modeling and optimization of a functionally Ti-HAP graded plate, followed by numerical analysis of a fractured tibia stabilization system under specific boundary conditions. Finite element analysis was performed using ANSYS Workbench 2021 software. The models of the FGM plate and tibial fixation system were made using the Space Claim tool. The ANSYS software allowed the optimization of the model considered and the selection of the appropriate structural parameters of the FGM Ti-HAP material. In general, the results proved that the osteosynthesis plate built of graded Ti-HAP material resulted in lower bone stress compared to titanium and steel plates. The results obtained confirmed the validity of the design and the possibility to use functionally graded Ti-HAP bone fixation plates. [ABSTRACT FROM AUTHOR]

The aim of this paper is to revisit propagation of chaos for a Langevin‐type interacting particle system recently proposed as a method to sample probability measures. The interacting particle system we consider coincides, in the setting of a log‐quadratic target distribution, with the ensemble Kalman sampler [SIAM J. Appl. Dyn. Syst. 19 (2020), no. 1, 412–441], for which propagation of chaos was first proved by Ding and Li in [SIAM J. Math. Anal. 53 (2021), no. 2, 1546–1578]. Like these authors, we prove propagation of chaos with an approach based on a synchronous coupling, as in Sznitman's classical argument. Instead of relying on a boostrapping argument, however, we use a technique based on stopping times in order to handle the presence of the empirical covariance in the coefficients of the dynamics. The use of stopping times to handle the lack of global Lipschitz continuity in the coefficients of stochastic dynamics originates from numerical analysis [SIAM J. Numer. Anal. 40 (2002), no. 3, 1041–1063] and was recently employed to prove mean‐field limits for consensus‐based optimization and related interacting particle systems [arXiv:2312.07373, 2023; Math. Models Methods Appl. Sci. 33 (2023), no. 2, 289–339]. In the context of ensemble Langevin sampling, this technique enables proving pathwise propagation of chaos with optimal rate, whereas previous results were optimal only up to a positive ε$\varepsilon$. [ABSTRACT FROM AUTHOR]

An embankment with a fill thickness of 7.5 m was built on a soil–cement column-slab system improved about 15.8 m thick soft subsoil. The embankment was stable for about 5 months after construction, and then, its settlement rate increased rapidly. To avoid the failure of the embankment, 1.0 m thick fill was removed and the embankment was stabilized again. The results of field investigation using all-core boring through a cement deep mixing (CDM) column under the central of the embankment and 3D finite element analysis (FEA) indicate that the most likely mechanism for the observed field behavior is progressive yielding/softening of the upper part of the columns. In FEA, the yielding/softening of the upper part of columns was simulated using strength reduction option and the start of the softening was triggered manually at the time of observed rapid increase in the settlement rate. This case history indicates that in field quality control of CDM columns, identifying local weak part(s) by continuous measuring the strength of the column samples retrieved from all-core boring is important. It is suggested that combination of unconfined compression test as well as needle penetration tests for the cores retrieved can be an economic and practical way to do this. [ABSTRACT FROM AUTHOR]

This paper studies the optimal investment and benefit payment strategies for target benefit (TB) pension plans. The pension fund receives contributions from active members and pays benefits to retirees. Meanwhile, the accumulated wealth is invested in financial market consisting of one risk-free asset and one risky asset, in which the risk-free interest rate is described by the Vasicek model. The general hyperbolic absolute risk aversion (HARA) utility is adopted to describe pension fund managers' risk preferences. Using the dynamic programming approach, we construct the Hamilton–Jacobi–Bellman (HJB) equation and obtain explicit expressions for optimal investment and benefit payment strategies using the Legendre transform-dual technique. Finally, numerical analysis is presented to illustrate the sensitivity of the optimal strategies to model parameters. [ABSTRACT FROM AUTHOR]

Different explosive materials have been studied numerically and experimentally to assess the efficiency of a small diameter shaped charge in terms of produced jet characteristics and penetration depth into RHA steel targets. 26 different explosives have been simulated numerically using Autodyn hydrocode, whereas recommended explosives have been loaded into small diameter shaped charges by pressing technique and tested by static firing against RHA targets in order to validate the numerical calculations. The numerical analysis has presented an intensive global view about the variation of the shaped charge jets as a potential of the loaded explosive charge efficiencies. A successful trial has been performed to measure the shaped charge jet velocity using detonation velocity VOD 812 apparatus, where its measured value was only 3.6% different from the numerical one for HMX-V5 explosive. Besides, TITAN (L3) flash X-ray radiograph has also been implemented to explore the jet profile using the same explosive type and to measure its jet tip velocity, which has only 2.1% different from that estimated numerically. Extensive fragmentation analysis has been presented, which showed increase in both the fragment number and the fragment speed when the used explosive charge is of high detonation velocity. CL-20 explosive exhibited the largest jet tip velocity and its scaled collapse velocity was found to be 140% of TNT explosive. The calculated average fragment speed has been validated and the measured fragment speed has only 2.3% difference when compared to the SPH calculations. [ABSTRACT FROM AUTHOR]