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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]

In this paper, we numerically study the influence of saturable absorber parameters, namely, modulation depth, recovery time, and saturation energy, on the performance of an ultrafast fiber laser that is mode-locked by a hybrid scheme of a saturation absorber (SA) and a nonlinear polarization rotation (NPR). Maps of mode-locked states related to intracavity wave-plates are created to evaluate the operation of hybrid mode-locking under different modulation depths of the SA. Along with the improvement of modulation depth of the SA, the mode-locked pulse results from a combination effect of the SA and NPR. The numerical analysis reveals that the SA parameters can significantly impact the pulse profile, peak power, and operation state. Moreover, they can also impact the selection of NPR mode-locked points, resulting in variation in stable single pulse output. A higher modulation depth can suppress the unstable multiple pulses' operation and convert them into harmonic mode-locked pulses. The obtained results indicate that the selection of appropriate SA parameters can effectively improve the output characteristics of hybrid mode-locked fiber lasers. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the potential of replacing fly ash (FA) with bauxite tailing (BT) slurry for geopolymer synthesis and investigate the long-term leaching behaviour of BT slurry/FA geopolymers (BFGs) for heavy metal immobilisation. The mechanical properties and heavy metal immobilisation efficiency of BFGs were tested, and numerical simulations were conducted to assess their environmental impact as a backfill material. The results showed that the incorporation of 5 Wt.% BT increased the early compressive strength of the geopolymer without any additional treatment. A small quantity of Cu2+ improved the mechanical strength, while excess heavy metals harmed the geopolymer. Heavy metal immobilisation efficiency decreased with increased heavy metal addition and exceeded 99.9% for Pb2+ and Cu2+ when simulating acid rain leachate. The modified Elovich equation described the leaching kinetics of Cu2+ well, and the leaching rate decreased with time. Numerical analysis indicated that Cu2+ leaching from landfill leachate occurred in three phases, with an initial increase followed by a gradual decrease, stabilisation, and diffusion into the surrounding soil layer. This study provides insight into the material's long-term stability and environmental performance, offering a scientific basis for relevant engineering applications. Highlights: Direct utilisation of unprocessed tailing slurry to synthesise geopolymer. The leaching pattern of Pb2+ and Cu2+ under acidic conditions was explored. The modified Elovich equation effectively describes the leaching kinetics of Cu2+. The environmental impact of bauxite tailings slurry-based geopolymers was evaluated. [ABSTRACT FROM AUTHOR]

In water‐assisted injection molding processes, it is crucial to understand the mechanisms governing the formation of hollow structures and identify the key factors influencing their morphology and dimensional accuracy. This work combined experimental analysis and numerical simulation to investigate the influence of different mold cavities and main processing parameters on hollow structures in overflow water‐assisted injection molded parts of short‐glass‐fiber‐reinforced polypropylene, that is, hollow shape and hollow ratio. The results show that the hollow shape and hollow ratio depended not only on the cross‐sectional location but also on the cross‐sectional shape of the mold cavity. For the circular parts, the hollow shape resembled the cross‐sectional shape of the mold cavity, with a relatively small and uniform hollow ratio across cross‐sectional locations. For the noncircular parts, the hollow shape varied considerably with increasing distance from the water inlet. Moreover, the results also show that except for the influence of water‐injection delay time on the uniformity of the hollow ratio, higher melt temperature (250°C), shorter water‐injection delay time (0 s), and higher water pressure (10 MPa) contributed to the hollow shape being closer to the cross‐sectional shape of mold cavities and made hollow ratios relatively larger and more uniform. [ABSTRACT FROM AUTHOR]

In this paper, a one-level operator splitting method (OOSM) and a two-level operator splitting method (TOSM) for the two-dimensional or three-dimensional (2D/3D) unsteady incompressible micropolar fluid equations with double diffusion convection (IMFDDC) are proposed and analyzed. Firstly, a OOSM is constructed, which consists of five steps. The projection strategy is adopted to get the values of linear velocity and pressure in the first two steps, then the three elliptic subproblems about the angular velocity, the temperature, and the concentration variables are solved in the last three steps. The original variables with the predefined boundary conditions need to be solved separately in each step. Next, in order to solve the problem efficiently, a TOSM is presented, which only solves the nonlinear equations in the coarse level subspaces and the Oseen type linearized equations in the fine level. The numerical analysis of stability and error estimates of the fully discrete methods show that TOSM can reach the same accuracy as the OOSM with H ∼ O (h 2 / 3). Numerical examples are provided to confirm the effectiveness and reliability of the proposed methods. [ABSTRACT FROM AUTHOR]

Continuous fibre reinforced ceramic matrix composites (CMCs) are increasingly being employed in safety critical applications. As a result, their use in these applications requires the adoption of appropriate design methodologies that are able to consider their complex non-linear mechanical behaviour. In this paper, a simple but robust formulation for continuum damage model, thermodynamically consistent and written under plane stress condition, is proposed for a laminated 2D woven composite material. This model is implemented via the Classical Laminate Theory (CLT) extended to non-linear behaviour to predict the behaviour of different stacking sequences. In-plane tensile tests were performed on an oxide/oxide composite up to 1000 °C to fully identify the model. The procedure is described and used on tests at room temperature before being extended higher temperature tests. Finally, the law and its coupling with the CLT are validated by means of tests on quasi-isotropic and cross-ply laminates at different temperatures. [ABSTRACT FROM AUTHOR]

This study presented a novel analytical method to investigate the coupled dynamic behavior of a supercritical helicopter tail transmission system, taking into account the friction-induced self-excitation of the floating spline, the rubbing between the limiting ring device and the shaft, and the time-varying meshing excitation experienced by multiple spiral bevel gear pairs. The tail transmission shaft was first modeled using Timoshenko beam elements in local coordinates. Subsequently, the centralized parameter method was employed to build dynamic models of critical components such as the floating spline, limiting ring devices, and multiple spiral bevel gear pairs. Finally, the system's dynamic equations were derived utilizing the interface coordination principle and spatial coordinate transformation. Numerical analyses were conducted to examine the dynamic behavior of the system, including the coupled vibration properties and the impact laws of the limiting ring device and floating spline on the system's response. The findings indicated that the limiting ring device resulted in a cross-critical vibration reduction in the tail horizontal shaft, achieved through the mechanisms of dry friction and rubbing impact. However, as a consequence, the natural and rubbing frequencies of the other shafts were generated. The self-excited vibration of the system, brought about by the friction of the spline tooth surface, had a significant impact on the shaft that was directly connected. The emergence of the self-excited vibration occurred when the speed surpassed the first-order natural speed of the directly connected shaft, with the corresponding self-excited frequency being the first-order natural frequency of said shaft. With the increase in the tooth surface friction coefficient of the spline, it even caused continuous rubbing between the shaft and the limiting ring device under a supercritical condition. The proposed dynamic analysis approach holds promise in offering theoretical guidance for the reduction of vibration and noise generated in supercritical tail transmission systems. [ABSTRACT FROM AUTHOR]

In recent times, various real word problems including infectious diseases, engineering problems, and chemical processes, etc are modelled by using differential equations with fractals and fractional orders. The mentioned area provides a powerful tool to investigate the aforesaid problems from different perspectives like analysis, numerical investigation, and qualitative theory. Similarly, one of the global issue is devoted to re-infection of viral diseases like COVID-19. The said behaviour has produced very saviour impact on human life worldwide. Also, this is very critical for health system of a country as well as for its economics situation. To study the aforesaid phenomenon of re-infection, a hybrid type fractal–fractional three compartments model is formulated. The basic results related to boundedness, positivity, equilibrium points, basic reproductive number, and sensitivity analysis of the basic threshold are included in the theoretical aspect. Additionally, the Volterra–Lyapunov approach is used to establish both local and global stability analysis under fractals and fractional derivative. Furthermore, utilizing techniques from numerical functional analysis and fixed point theory, the existence and Hyers–Ulam stability of the solutions are also examined. A numerical algorithm based on Lagrange's interpolation polynomials is extended to simulate the results of various compartments. Graphical interpretations corresponding to different fractals–fractional order values are presented. For verification of our numerical results, a comparison is provided between the real and simulated data. Here it should be kept in mind that the differential operator of fractals–fractional order is considered with Mittag-Leffler kernel. The mentioned operator is more general among the available fractals fractional differential operators in literature. [ABSTRACT FROM AUTHOR]

In the energy harvesting field, it is critical to efficiently convert ambient vibrations into usable electrical energy, especially under conditions characterized by low amplitude and random excitations. This study introduces a novel hybrid bistable piezoelectric energy harvester (HBPEH) designed to optimize energy conversion in challenging environmental conditions. The HBPEH features a unique piezoelectric cantilever beam integrated with a dynamic amplifier at the fixed end, significantly enhancing both rotational and lateral displacements of the beam. This innovation lowers the threshold for snap-through events, crucial for maximizing energy transfer in bistable systems, and enables superior energy harvesting capabilities. Furthermore, the HBPEH demonstrates significantly higher power outputs when subjected to excitation intensities beyond critical levels, outperforming conventional energy harvesters. Extensive numerical and theoretical analyses confirm that the HBPEH offers a promising solution for applications hindered by suboptimal energy conversion rates. Its ability to operate effectively under diverse and unpredictable excitation conditions underscores the HBPEH's robustness and superiority in advanced energy harvesting scenarios. The design improvements introduced in this study highlight the potential of the HBPEH to transform energy harvesting approaches. By addressing the limitations of traditional harvesters, the HBPEH provides enhanced efficiency and reliability, making it suitable for a broader range of practical applications in variable environmental conditions. [ABSTRACT FROM AUTHOR]

In this study, a numerical model for unilateral quasi-static contact between a rigid sphere and an elastic coating has been developed. The contact problem was solved using a numerical procedure based on the FFT technique, considering various coatings with different thicknesses and mechanical properties, implemented through a Matlab code. The model calculates the contact surface deformation and pressure field through a double iteration process. The first iteration solves the contact problem for a given indenter penetration, while the second iteration refines this penetration by minimizing the difference between the fixed and calculated loads. To achieve this, influence coefficients are derived from the elasto-static equations using the Papkovich-Neuber potentials. The study discusses the influence of coating thickness and friction coefficient value on the tribological behavior of the coating. The results indicate that contact pressure increases (ranging from 1.9 to 2.5) as the coating becomes thicker or more rigid (0.02 mm to 0.2 mm). Additionally, the tribological behavior of the coated surface is affected by the coating's thickness, hardness, and friction coefficient value. Importantly, this model demonstrates versatility by being applicable to both smooth and rough surfaces. [ABSTRACT FROM AUTHOR]

This paper discusses the design process toward new lumped chaotic systems that originates in higher-order ordinary differential equations commonly used as description of ideal oscillators. In investigated third-order case, two chaotic oscillators were constructed. These systems are dual in the sense of vector field geometry local to fixed points. The existence of robust chaos was proved by both standard routines of numerical analysis and practical measurement. For the fourth-order oscillatory equation, the concept based on interaction between superinductor and supercapacitor was examined in detail. Since both "superelements" are active, the nonlinearity essential to the evolution of chaos is fully passive. It is demonstrated that complex motion is robust and does not represent long transient behavior or numerical artefact. The existence of chaos was verified using standard quantifiers of the flow, such as the largest Lyapunov exponents, recurrence plots, approximate entropy and sensitivity calculation. A good final agreement between theoretical assumptions and practical results will be concluded, on a visual comparison basis. [ABSTRACT FROM AUTHOR]

This paper investigates the dynamics of a four-dimensional plankton-fish system that contains three communities of plankton: non-toxic phytoplankton, toxic-producing phytoplankton, and zooplankton. The zooplankton consumes both non-toxic and toxic-producing phytoplankton. First, the positivity and boundedness of the solutions in the plankton-fish model are evaluated. Then, we derive the conditions for the existence of ecologically possible equilibria and their local and global asymptotic nature. Furthermore, we evaluate the criteria for the existence of Hopf-bifurcation and transcritical bifurcation. By applying Pontryagin’s maximum principle, we investigate the optimal control of fish harvesting, where fishing effort is taken as a control parameter. By using phase-space diagrams, time responses, bifurcation diagrams, and numerical analyses validate the theoretical results. The numerical results including maximum Lyapunov exponent verify chaotic dynamics of the system. We notice that a suitable choice of harvesting, phytoplankton growth rate, and additional food parameters can control the chaotic behavior of the presented model. The proposed novel mathematical model gives deeper insights to theoretical ecologists on how toxic-producing phytoplankton affects zooplankton and fish populations in aquatic systems. Furthermore, the proposed model is more appropriate for fish harvesting to maximize profit as well as species conversion in the presence of toxic phytoplankton. [ABSTRACT FROM AUTHOR]

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

This paper focuses on developing and analyzing a new AR-iterative scheme designed for estimating fixed points of generalized non-expansive mappings of the Suzuki kind. The scheme’s stability and convergence properties are rigorously proven, highlighting its superior convergence rate for non-expansive mappings when compared to existing schemes in the literature. Additionally, an application of the AR-iterative scheme to differential equations is presented. These findings underscore the effectiveness and versatility of the proposed scheme in numerical analysis and computational mathematics. [ABSTRACT FROM AUTHOR]

We are examining a mathematical model of second-grade Casson fluid flow over a Riga surface. This analysis takes into account the effects of heat generation on a second-grade Casson fluid. Additionally, we have discussed the impacts of Soret and Dufour in the presence of thermal radiation. The study also includes an analysis of the influences of thermal and concentration slip. By considering these factors in the fluid flow, we have constructed a set of partial differential equations. Furthermore, these differential equations have been transformed into dimensionless ordinary differential equations. We have presented the influences of relevant parameters through tables and graphs. Velocity curve reveals declining behavior due to larger values of magnetic field factor. A high magnetic field coefficient means a strong magnetic field. As a result, the force acting on the charged particle increases, causing it to slow down or change direction. This change in force can cause the particle's velocity to decrease. [ABSTRACT FROM AUTHOR]

The response amplification technology, which enhances the efficiency of shock absorption apparatuses, has been widely applied in the field of shock absorption control for engineering structures. Researchers have proposed and verified through numerical analysis and experiments more structural forms of this technology as applicable. The functions are also more comprehensive, such as increased utilization rate of structural space and economy. The development of its theoretical foundation has progressed from constant solutions based on small deformations to solutions that reflect the time-varying characteristics of the amplification factor of the brace-damping system. Simultaneously, the influencing factors of the amplification factor have been analyzed in detail to provide better theoretical guidance for engineering practice. This paper provides a detailed discussion on the research overview of the response amplification technology and the influencing factors of the amplification factor. The conclusion introduces the significance of using this technology, comprehensively analyzes the deficiencies and limitations of existing response amplification technology, and points out the research and development direction, with the expectation of providing ideas for further development. [ABSTRACT FROM AUTHOR]

Broadband near-infrared (NIR) light sources cover unique optical wavelengths and are valuable in the fields of bioimaging and photodynamic therapy, night vision lighting and security monitoring. NIR phosphor converted light-emitting diode (NIR pc-LED) devices have attractive features such as tunable emission peak, low cost of production, compact in sizes and high luminous efficiency. However, heat accumulation during operation due to poor thermal conductivity of the organic resin used in packaging often causes serious reduction in luminous efficiency and accelerated degradation of the device. In present work, we developed a Cr3+-doped transparent CaF 2 -based oxy-fluoride glass-ceramic (GC) that showed a broadband emission of 700∼1400 nm under 470 nm excitation. The emission peaked at ∼880 nm, the full-width at half maximum was about ∼297 nm, and the photoluminescence quantum yield reached ∼31.19 %. The emission was derived from the electronic transition of Cr3+ ions from the 4T 2 (F) to 4A 2 (F). Through structural analysis and numerical simulation, we showed that during the heat treatment process, Cr3+ ions were enriched into the CaF 2 crystal phase and replaced the Ca2+ in the GC host with occupied the center position of the polyhedrons, which provided a weak crystal field and led to NIR emission. We built NIR pc-LED devices using optimized GC and commercial blue LED chips, and we demonstrated the application of this NIR pc-LED in night-vision lighting. Our approaches to prepare simple and stable inorganic NIR luminous materials sealed in bulk in a transparent CaF 2 -based oxy-fluoride GC and to construct pc-LED devices could provide new concept to the field and have practical implications to applications in related fields. [ABSTRACT FROM AUTHOR]

The work addresses the topic of the thermal study of high-voltage power cables installed inside plastic pipes in the absence of filling. The presence of air inside the pipe creates an insulating layer that does not favor heat exchange and makes the calculation of the flow rate more complex, as it is necessary to take into account the thermal phenomena of natural convection and radiation between the surface of the cable and the internal surface of the tube. The numerical model based on the finite element calculation was compared with the experimental results obtained on a simulacrum in which the temperatures on the different layers of the cable were measured. After this validation, some typical installation configurations of single and double energy transport triads were analyzed. [ABSTRACT FROM AUTHOR]

The effect of cyclic loading is an essential factor leading to progressive soil strength degradation. Therefore, a comprehensive analysis of the pile‐soil system behavior under cyclic loading is required to ensure the stability of pile group. There is room for improvement in the inherent constraint of the conventional numerical model in terms of approximating the soil resistance distribution along the pile by point loads at element nodes, necessitating a specific element that integrates considerations of pile group effect and cyclic loading within a unified framework. This study aims to develop a newly specific type of element for efficiently predicting nonlinear behavior within the pile‐soil system, addressing simulations involving nonlinear pile‐soil interaction, pile group effect, and cyclic loading. Modified element formulations based on soil stiffness matrices and soil resistance vectors specifically address pile group effect and consider parameters that influence pile behavior under cyclic lateral loading. The numerical solution procedure with Newton‐Raphson iteration allows the calculation of pile responses in geometric and material nonlinear analyses. The validation of the proposed method includes several examples, comparing it with existing numerical solutions and experimental tests of single piles and pile groups under cyclic loading. These comparisons further support the consistency of the proposed method with measured data and validate its accuracy in considering group effect and cyclic loading. The parametric study illustrates the ability of the proposed method to capture cyclic loading parameters while considering the influence of the number and magnitude of load cycles, the cyclic load direction, and the installation methods. [ABSTRACT FROM AUTHOR]

A hypersonic airborne radome must possess multiband electromagnetic transparency, high specific strength, and thermomechanical resistance to ensure proper antenna operation. However, achieving these multifunctional properties in radome wall design is challenging due to conflicting material requirements. Moreover, existing design methods for arbitrary multiband and broadband hypersonic radomes are insufficient. This paper presents an efficient method that integrates artificial intelligence and an evolutionary algorithm to enable the multidisciplinary synchronous design of the radome wall. The designed radome walls using multilayered porous silicon-nitride ceramics achieve power transmission efficiency exceeding 90% in a broadband of 30 GHz or arbitrary multiple bands with bandwidths of 5 GHz, covering the centimeter-to-millimeter wave range. Moreover, the designed laminate also meets requirements of flexural strength surpassing 60 MPa and a maximum thermal stress-strength ratio below 1. Notably, the utilization of artificial intelligence accelerates the design process by at least 1093 times compared to conventional methods. [ABSTRACT FROM AUTHOR]

In soft soil layers, piles are frequently loaded laterally by horizontal soil movements. In many cases, the lateral pressure acting on piles due to horizontal soil movements is calculated with empirically or analytically based approaches, respectively. However, most of these design approaches do not consider possible influences on the resulting pile loads. This paper presents the results of model tests and numerical simulations on single piles and pile groups in cohesive soil subjected to lateral loads which were carried out to overcome limitations of available design approaches. Based on extensive small-scale 1 × g-model tests and numerical investigations with the finite element method, influencing factors on the lateral pressure, such as the roughness of the pile–soil interface, the pile size, the pile shape and the pile spacing were identified. A parametric study with the numerical model quantified the most relevant factors influencing the development of lateral pressure on piles due to adjacent surface loads and lead to the development of a simplified analysis approach. [ABSTRACT FROM AUTHOR]

Understanding the amount of bentonite intrusion into rock cracks is necessary to evaluate the performance of natural barrier materials for geological disposal. In this study, assuming a possible chemical action in geological disposals, bentonite was immersed in various solutions to accelerate the chemical action, and a half-year swelling and intrusion experiment was conducted. The experimental results showed that the swelling pressure and intrusion distance of bentonite in a solution environment differed depending on the solution type and that both were smaller than those in a purified water environment. The swelling pressure of bentonite in the environments of the KOH, NaOH, MgCl2, and NaCl solutions decreased significantly, and it did not significantly enter into the gaps in these systems. This is undesired in situations where gaps such as the cracks of rock must be filled. Furthermore, a numerical analysis model was constructed that can simply represent the complex intrusion behavior of bentonite in cracks considering the balance of three forces acting on bentonite. The analysis results confirmed that under conditions where the external swelling pressure fluctuates over time, the intruding fluid fills the cracks more slowly than under conditions where the external swelling pressure is constant. It was also confirmed that under conditions where the viscosity of the intruding fluid decreases over time, the intruding fluid fills the cracks faster than under conditions where the upper limit viscosity is constant. The numerical results clarified that the governing equation for bentonite intrusion into closed cracks may express the long-term intrusive behavior of bentonite into cracks during geological disposal. [ABSTRACT FROM AUTHOR]

A dual jet system, comprising a wall jet flowing tangential to a solid wall and a parallel offset jet, possesses a unique flow field that has proven advantageous in many industrial applications. Despite this, investigations of dual jets are severely underrepresented in the published literature, meaning their flow and heat transfer characteristics are yet to be fully understood. Many published studies dedicated to the characterization of dual jet flows are entirely numerical in nature, and significant discrepancies exist among the reported findings. This can be attributed to the distinct lack of experimental data related to dual jet flows, which has to date prohibited the full validation of any existing dual jet numerical model. The purpose of this report is to perform a comprehensive review of the available dual-jet literature to ascertain the present understanding of dual jet flow behavior and related heat transfer characteristics. An in-depth overview of dual jet flow theory is provided, and the reported effects of varying the major dual jets' parameters are discussed, e.g., jet Reynolds number, jet offset ratio, and jet velocity ratio. In doing so, the major discrepancies among the relevant dual-jet studies are highlighted and a clear gap in the literature is identified. Recommendations for future studies on dual jets are provided. [ABSTRACT FROM AUTHOR]

The Polymer Electrolyte Membrane Water Electrolyser (PEMWE) has gained significant interest among various electrolysis methods due to its ability to produce highly purified, compressed hydrogen. The spatial configuration of bipolar plates and their flow channel patterns play a critical role in the efficiency and longevity of the PEM water electrolyser. Optimally designed flow channels ensure uniform pressure and velocity distribution across the stack, enabling high-pressure operation and facilitating high current densities. This study uses flow channel geometry inspired by authentic vine leaf patterns found in biomass, based on various plant leaves, including Soybean, Victoria Amazonica, Water Lily, Nelumbo Nucifera, Kiwi, and Acalypha Hispida leaves, as a novel channel pattern to design a PEM bipolar plate with a circular cross-section area of 13.85 c m 2 . The proposed bipolar design is further analysed with COMSOL Multiphysics to integrate the conservation of mass and momentum, molecular diffusion (Maxwell–Stefan), charge transfer equations, and other fabrication factors into a cohesive single-domain model. The simulation results showed that the novel designs have the most uniform velocity profile, lower pressure drop, superior pressure distribution, and heightened mixture homogeneity compared to the traditional serpentine models. [ABSTRACT FROM AUTHOR]

High thin-walled cold-formed steel purlins of the Z cross section are important elements of large-span steel structures in the construction industry. The present numerical study uses the finite element method to analyse the 300 mm and 350 mm high Z cross sections in-depth. The prepared numerical models are verified and validated at several levels with experiments that have been previously published. Significant agreement between the numerical models and the experimental results regarding Mises stress, proportional strain, failure mode, and force-deformation diagram have been obtained. With the verification, the presented procedure and partial findings can be applied to other similar problems. The results can be used to help research and corporate groups optimise the structural design of cold-formed thin-walled steel structures. [ABSTRACT FROM AUTHOR]