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This paper employs a numerical approach to investigate the impact of liquidity shocks on European options in modeling markets. To accurately capture the behavior of European options under liquidity shocks, a coupled system of differential equations is employed, consisting of a degenerate parabolic equation and a diffusion-free equation. The primary focus is on developing and analyzing implicit-explicit methods for numerically simulating European option pricing, specifically considering the presence of liquidity shocks while ensuring the positivity of the solution. The paper also includes convergence analysis and establishes the discrete comparison principle for the developed methods. Numerical experiments are conducted using both uniform and nonuniform meshes to validate the theoretical findings, demonstrating the efficiency and accuracy of the proposed methods. [ABSTRACT FROM AUTHOR]

Micro-mixers and piezoelectric pumps have been studied as independent parts, which achieves only single mixing or pumping functions. A new valveless piezoelectric mixing pump (VPMP) driven by a sinusoidal signal is proposed in this paper to achieve a structure with both pumping and mixing functions. It accomplishes this by placing obstacles in the pump chamber and in the flow channel then adding active mixing. Because it is small in size, has a simple structure and is easy to control, it can be used in micro mixing applications. In this study, numerical simulation analysis using the Fluent software tests if the new VPMP has good mixing and pumping performance, and analyzes the effect of the obstacles. Simultaneously, the results of numerical simulation are verified with experiments. It was proven that the flow rate of the VPMP can reach 12.26 mL/min, and that the liquid can achieve uniform mixing. Moreover, the obstacle placed in the pump chamber has a more obvious impact on the mixing capability, and the obstacle placed in the channel has a more obvious impact on the flow rate. In addition, with the increase of the amplitude of driving signal, the flow rate of the VPMP increased correspondingly. With the increase of the frequency, the flow rate first increased and then decreased. The capability of mixing increased with an increase of working frequency. The experimental results showed that the VPMP can achieve good pumping and mixing performance, and that one structure can possess both mixing and pumping functions. [ABSTRACT FROM AUTHOR]

This paper presents the development of a framework for the parametric design of tunnels using geographic information system (GIS) mapping and building information modelling (BIM). According to the framework, a parametric representation of each system component (e.g., layers of rock mass, size of excavation, topography, fault geometry, primary lining, secondary lining, rock bolts, etc.) can be incorporated in the GIS model with high levels of detail and used for the automatic generation of numerical models for the design of tunnel construction. This parametric evaluation allows the designer to consider several levels of detail for each component, for the efficient design and process optimization in conventional tunneling. Information between parametric analysis and numerical simulations can be freely exchanged with significantly reduced computational effort while results can be exported into BIM. It is anticipated that the proposed framework could lead to a comprehensive, yet efficient analysis of complex conventional tunneling project using parametric evaluations at the early design stages. [ABSTRACT FROM AUTHOR]

As a basic parameter of rock, the rock bridge angle plays an important role in maintaining the stability of rock masses. To study the size effect of rock bridge angle on the uniaxial compressive strength of rocks, this paper adopts the principle of regression analysis and combines numerical simulation to carry out relevant research. The research results indicate that: (1) the uniaxial compressive strength decreases with the increase of the rock bridge angle, showing a power function relationship; (2) The uniaxial compressive strength decreases with the increase of rock size and tends to stabilize when the rock size is greater than 350 mm, showing a significant size effect. (3) The fluctuation coefficient of compressive strength increases with the increase of rock bridge angle and decreases with the increase of rock size; When the rock size is 350 mm, the fluctuation coefficient is less than 5%; (4) The characteristic compressive strength and characteristic size both increase with the increase of the rock bridge angle. [ABSTRACT FROM AUTHOR]

Multi-material additive manufacturing using heterogeneous powders as raw materials is one of the important development directions of metal additive manufacturing technology. The evaporation behavior of heterogeneous powders in the selective laser melting (SLM) process has a significant influence on the accuracy of chemical composition control and the quality of the final product. In this paper, the fusion process of Fe20Mn (80 wt.% Fe and 20 wt.% Mn) heterogeneous powder, Fe and Mn elemental powders, and Fe20Mn pre-alloyed powder is numerically simulated using FLOW-3D® software and partially validated through SLM experimental results. The morphology and the characteristics of the flow field and temperature field in the melt pool for four kinds of powder materials are analyzed. The influence of the elemental evaporation behavior of different powders on the mass loss of the Mn element is discussed. The results show that the excessive accumulation of heat increases the maximum temperature of the melt pool, thus increasing mass loss. The Fe20Mn heterogeneous powder has a wider heat-affected zone and a higher peak value of temperature, nearly 400 K higher than that of the Fe20Mn pre-alloyed powders, which exhibits an intensive evaporation behavior. The mass loss of the Mn element obtained from the SLM experiment for Fe20Mn heterogeneous powders forming parts is more than the Fe20Mn pre-alloyed powders' forming parts for different laser powers, up to 17 wt.% at P = 120 W. This tendency is consistent with the numerical analysis of the effect of evaporation behavior of Fe–Mn heterogeneous powder during the SLM process. This study provides the necessary theoretical reference and process guidance for realizing the precise control of the SLM composition of a heterogeneous powder in multi-material additive manufacturing caused by evaporation behavior. [ABSTRACT FROM AUTHOR]

The present paper provides a brief overview of the existing methods for energy separation and an analysis of the possibility of the practical application of the Hartmann–Sprenger effect to provide quasi-isothermal pressure reduction of natural gas at the facilities within a gas transmission system. The recommendations of external authors are analyzed. A variant of a quasi-isothermal pressure regulator is proposed, which assumes the mixing of flows after energy separation. Using a numerical simulation of gas dynamics, it is demonstrated that the position of the resonators can be determined on the basis of calculations of the structure of the underexpanded jet without taking into account the resonator and, accordingly, without the need for time-consuming calculations of the dynamics of the processes. Based on the results of simulating the gas dynamics of two nozzle–resonator pairs installed in a single flow housing, it is shown that, in order to optimize the regulator length, the width of the passage between the two nearest resonators should be greater than or equal to the sum of diameters of the critical sections of the nozzles. Numerical vibroacoustic analysis demonstrated that the most dangerous part of the resonator is the frequency of its natural oscillations. [ABSTRACT FROM AUTHOR]

The urban underlying surface may affect the thunderstorm process. However, current research on this phenomenon is still in its infancy. This paper aimed to analyze the influence of the urban underlying surface on the evolution of thunderstorm organization through ground observation and numerical simulation. The results indicated that when the thunderstorm system with strong synoptic conditions passed through the built-up area of Beijing, it exhibited obvious bifurcation and detour. The dynamic field of near-surface cold pools could serve as diagnostic indicators for understanding how the urban underlying surface affects the thunderstorm process. The large-scale compact-rise clusters in the city center could alter the movement direction and path of the cold pool outflow, thereby influencing the thunderstorm organization process. In addition to the spatial configuration of the building complex, the city size might also be an important factor influencing the thunderstorm process. This study might provide a fundamental foundation and technical support for predicting and assessing urban thunderstorm disasters. [ABSTRACT FROM AUTHOR]

For all humanity, the sudden outbreak of Corona Virus Disease 2019 has been an important problem. Timely and effective media coverage is considered to be one of the effective approaches to control the spread of epidemic in early stage. In this paper, a Sentiment‐enabled Susceptible‐Exposed‐Infected‐Recovered (SEIR) model is established to reveal the relationship between the propagation of the epidemic and media coverage. The authors take the positive and negative media coverage into consideration when implementing the Sentiment‐enabled SEIR model. This model is constructed by parameterizing the number of current confirmed cases, cumulative cured cases, cumulative deaths, and media coverage. The numerical simulation and sensitivity analysis are conducted based on the Sentiment‐enabled SEIR model. The numerical analysis confirms the rationality of the Sentiment‐enabled SEIR model. The sensitivity analysis shows that positive media coverage acts a pivotal part in reducing the figure for confirmed cases. Negative media coverage has an effect on the figure for confirmed cases is not as significant as that of positive media coverage, but it is not negligible. [ABSTRACT FROM AUTHOR]

Upper protective layer (UPL) mining is extensively utilised as a pressure relief strategy to prevent outbursts and coal bursts. However, when the excavation height of the protected layer is substantial, the depressurisation efficacy of the protective layer may be diminished. This paper takes the Haishiwan coal mine in China as a case study and explores the stress evolution and influencing factors in the mining of extra-thick coal seam beneath the protective layer through theoretical analysis, numerical simulation, and field observation. The results indicate that increasing the excavation height of the coal seam will lead to the upward development of the collapse zone in the overburden of the goaf, with the "masonry beam" structure formed at a higher position by key strata blocks. The overburden above the masonry beam will be supported by the coal rock masse on both sides of the structure, leading to increased stress on the coal seam near the goaf and eliminating the depressurisation effect of the protective layer. Numerical simulation shows that factors such as faults, protective layers, interlayer spacing, and the height of coal seam excavation significantly affect the stress distribution in the protected layer. With the increase in interlayer spacing and the thickness of coal seam extraction, the stress reduction phenomenon of the UPL gradually decreases, especially with an abnormal stress concentration of the gob-side coal seam. Observations of Surface subsidence and the distribution of mining-induced seismic events corroborate the conclusions of theoretical analysis and numerical simulations. The results offer valuable guidance for the mining of extra-thick coal seams and the selection of the UPL. [ABSTRACT FROM AUTHOR]

In order to understand and master the diffusion mechanism and spatial concentration distribution of hydrogen leakage in the engine room, this paper studies the diffusion behavior and concentration distribution of hydrogen under the coupling effect of multiple factors, and further explores the optimal installation location of the sensors. The results indicate that when the ventilation rate increases by 1, 2, and 3 times, the diffusion volume of hydrogen decreases by about 0.4, 0.5, and 0.6 times. The harm of the increase in leakage diameter is greater than the leakage pressure. And the temperature has a greater impact on the hydrogen volume fraction in areas below 4 % and a smaller impact on areas above 4 %. In this environment, the sensors should be installed at or above 5.5 m in the rear of the engine room and above the axis of the hydrogen transport pipeline interface, valves and other places prone to leakage. • Taking a ship engine room as the research object. • The influence of various factors on hydrogen distribution is compared. • The spatial concentration distribution of hydrogen leakage is analyzed. • Explored the installation position of the sensors. [ABSTRACT FROM AUTHOR]

The aim of this paper is to establish a precise illustration for the structure of the nonconstant steady states for a Beddington–DeAngelis and Tanner predator–prey reaction–diffusion system with prey‐taxis. We treat the nonlinear prey‐taxis as a bifurcation parameter to analyze the bifurcation structure of the system. Furthermore, the exported global bifurcation theorem, under a rather natural condition, offers the existence of nonconstant steady states. In the proof, a priori estimates of steady states will play an important role. The local stability analysis with a numerical simulation and bifurcation analysis are given. Finally, some conclusions including biological meanings are performed to summarize our main analytic results and future investigations. [ABSTRACT FROM AUTHOR]

This paper proposes an assembled X-shaped flexural steel damper. Welding is waived for the novel damper. As the kernel element of the damper, the X-shaped flexural steel plates have the advantages of ease of installation and replacement if necessary. In the analytical part, the effective height of the flexural steel plate was suggested, and then, the yield displacement, yield load and initial stiffness of the damper were derived. The proof-of-concept cyclic loading test was conducted using one reduced-scale specimen within a four-bar linkage experimental setup. The hysteretic performance indexes, including strength, stiffness and energy dissipation, were quantified. The high-fidelity finite element (FE) models were established by ABAQUS. The parametric study was further conducted based on the verified FE model. The considered parameters were the height and thickness of the steel plates. The testing results indicate that the proposed damper has plump hysteretic curve with good energy dissipation capacity and excellent ductility, although slight slip behavior can be found due to the gap caused by the assembling process. The results obtained from analytical method and numerical model are in good agreement with the experimental data. The results of parametric analysis show that the numerical results well agree with analytical predictions, indicating the numerical model can reflect the mechanical behavior of AXSFD. A benchmark frame building was selected to demonstrate the seismic control efficacy of the damper. The nonlinear time history analysis results indicate that the damper reduced both peak and residual interstory drift ratios for the protected structure. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) is being considered for use to enhance oil recovery and resource utilization and storage, with wide technical adaptability. In this paper, a numerical simulation method is used to study the adaptability of CO2 huff and puff in shale reservoirs. A fluid model introduces the nanoconfinement effect and reflects the nanoconfinement effect using the fluid p–T phase diagram. This method uses local grid refinement and changes the permeability near the grid to characterize the reservoir reconstruction volume (SRV) fracture network while considering the CO2 diffusion effect. The results indicate that by using the incremental recovery rate and oil change rate as references, adaptive charts can be obtained for different Kf/Km and oil saturation. When Kf/Km is 1000 and the increase in the CO2 recovery rate reaches 1.5%, the lower limit of oil saturation is 0.54. When Kf/Km is 1000 and the increase in the CO2 recovery rate reaches 2%, the lower limit of oil saturation is 0.57. When the oil saturation is 0.5 and the CO2 huff and puff oil change rate reaches 0.3, the lower limit of Kf/Km is 700. Finally, when the oil saturation is 0.548 and the CO2 huff and puff oil change rate reaches 0.6, the lower limit of Kf/Km is 10. The research results are significant and can guide the design and application of on-site CO2 throughput test plans. [ABSTRACT FROM AUTHOR]

In this paper, we propose an approach for describing wave propagation in finite-size microstructured metamaterials using a reduced relaxed micromorphic model. This method introduces an additional kinematic field with respect to the classical Cauchy continua, allowing to capture the effects of the underlying microstructure with a homogeneous model. We show that the reduced relaxed micromorphic model is not only effective for studying infinite-size metamaterials, but also efficient for numerical simulations and analysis on specimens of finite size. This makes it an essential tool for designing and optimizing metamaterials structures with specific wave propagation properties. The proposed model's efficiency is assessed through numerical simulations for finite-size benchmark problems, and shows a good agreement for a wide range of frequencies. The possibility of producing the same macroscopic metamaterial with different but equivalent unit cell "cuts" is also analyzed, showing that, even close to the boundary, the reduced relaxed micromorphic model is capable of giving accurate responses for the considered loading and boundary conditions. [ABSTRACT FROM AUTHOR]

In this paper, we propose and analyse a predator-prey model with disease in prey. We assume that a portion of healthy prey takes refuge to avoid predation. We find the biologically feasible equilibrium points and their stability criteria by using linearization technique. We also perform Hopf bifurcation analysis around the co-existing equilibrium point. We use substantial numerical simulation to verify our theoretical results and to investigate rich dynamics that are not possible to achieve analytically. We illustrate rich dynamics such as Hopf bifurcation. chaos, bistability, and others using one and two parameter bifurcation diagrams. We find that disease invasion in prey can produce chaos by inducing period-doubling bifurcation. but refuge can reduce chaos by causing period-halving bifurcation. We also observe that refuge can reduce the prevalence of disease in the Prey population. [ABSTRACT FROM AUTHOR]

The treelike structure links members and transfers loads via its solitary cast steel joint with branches. Therefore, the joint's bearing capacity significantly affects the treelike structure's stability, security, and economics. This paper utilized experimental verification and numerical modeling to examine the mechanical behavior of cast-steel joints with branches in the treelike structure under various loading conditions. Then, researchers investigated the failure process and mechanism of joints, and the three most common failure modes were outlined. Furthermore, the researchers proposed the bearing capacity calculation formula based on the common failure modes. The results show that the three common failure modes of the cast-steel joints with branches under different loading conditions are the failure in the joint core area under the axial load, the failure in the main pipe compression side under eccentric load, and the failure in the compression side of the single branch pipe root when the single branch pipe is under the uneven load. The suggested empirical calculation method can serve as a reference point for similar engineering practices design. [ABSTRACT FROM AUTHOR]

This paper reviews latest developments of substructures for offshore wind turbines focusing on investigations and applications of hybrid foundations. Model tests and numerical analyses were used to simulate the loading of hybrid piles in sand. The results of pile-soil interaction were investigated to confirm the changes in soil stiffness around the hybrid monopile head. The mechanism and factors affecting the change in lateral stiffness of the hybrid foundation were explained by analysing p-y curves for M+H loading conditions in sand. Based on this research, a new shape of p-y curves for hybrid monopiles was established and a method for determining key parameters was proposed. The effectiveness of new p-y curves was verified by comparing back-calculated results with those from numerical simulations. The conducted tests confirmed that the hybrid monopile displacement is 30-50% smaller when compared to a standard monopile with similar dimensions. The gained experiences can be useful for designers and researchers to enhance the design of foundations for offshore wind turbines. [ABSTRACT FROM AUTHOR]

What are the geometrical and mechanical properties ruling bistability of Kresling origami metamaterials? How can we tune the magnitude of their axial-torsional coupling? Complete answers to these compelling questions cannot be found in the scientific literature, as the intertwining between bistability, axial-torsional coupling and an other significant behaviour, namely transverse dilation/contraction, remains mostly uninvestigated. This contribution aims at shedding light on this intertwining, through the use of a discrete model of Kresling origami that takes into account folding resistance. The present study is mostly computational and involves both pre- and post-critical analyses. It is based on displacement controlled tests — shearing and axial shortening/lengthening. Single-storey Kresling origami's are first considered, preliminarly to multiple-storey tubes, where buckling is observed. Several parameters are taken into account such as the number of storeys, stretching and folding stiffnesses, and – for shearing tests – the prescribed displacement direction in the transversal plane. The ultimate goal of the paper is to provide evidence that can be useful in the construction of homogenised continuum models of Kresling origami metamaterials. • We present some numerical simulation concerning metamaterials based on Kresling tube pattern. • Numerical analyses of some selected tests clarifies the mechanical behaviour of metamaterials based on Kresling pattern. • Numerical simulations address the homogenised model of Kresling tubes. [ABSTRACT FROM AUTHOR]

• An in situ bitumen decomposition kinetic model is developed. • The significance of bitumen decomposition to oil recovery is discussed. • A green and economical recovery tech without steam additives injection from surface. • The tech has higher oil production, lower steam consumption and carbon emission. In the late stages of Steam Assisted Gravity Drainage (SAGD) development, the increase in steam chamber volume and greater heat losses result in elevated thermal losses, and increased CO 2 emissions, leading to reduced economic efficiency. To address this issue, this paper proposes a pioneering approach, termed the in situ solvent generation enhanced SAGD technique (ISSG-SAGD). Through a comprehensive review of Athabasca bitumen aquathermolysis, thermal cracking, and their phase behavior with solvents, a general reaction kinetic model and fluid model are established. Subsequently, the feasibility and recovery mechanism of ISSG-SAGD are elucidated by employing numerical simulation that compares SAGD with ISSG-SAGD. Results show that, in comparison to SAGD, ISSG-SAGD reduces steam consumption by 13.77 %, lowers carbon intensity by 18.12 % and increases oil production by 5.48 %. These advantages arise from the synergistic integration of recovery mechanisms characteristic of Expanding Solvent SAGD (ES-SAGD) and Steam and Gas Push (SAGP). Notably, non-condensable gas accumulation above the steam chamber diminishes heat loss while replenishing reservoir energy. Simultaneously, light hydrocarbons are strategically positioned at the drainage interface, leading to a reduction in residual oil saturation and an increment in drainage rates. Consequently, ISSG-SAGD emerges as an environmentally sustainable and economically viable trajectory for heavy oil development. [ABSTRACT FROM AUTHOR]

• Mechanical response characteristics of beam-column substructures exposed to fire are analyzed. • Explicit calculation formulas for determining the collapse resistance are derived in detail. • Proposed theoretical calculated formulas agree well with these from numerical simulations. • Error analysis is conducted to reveal deviation reasons between theoretical model and numerical simulations. This paper provides a simplified analytical model for the restrained steel beam-column substructure under a fire-induced progressive collapse scenario, which is applied to predict the collapse resistance of substructures under fire. The simplified model is formulated for axially and rotationally restrained two-span steel beam-column substructures under column-loss scenarios and involves rigid and semi-rigid connections. The response characteristics of restrained substructures exposed to fire under column-loss scenarios in each response stage are elaborately analyzed. A "negative" catenary stage, in consideration of the unique negative axial force effects induced by the temperature thermal expansion, was first introduced in the five-stage simplified model for restrained substructures exposed to fire against progressive collapse. Subsequently, the explicit calculation formulas for determining the vertical loads and deflection of both rigid and semi-rigid joint substructures exposed to fire were derived in a quantified way, based on rigid-plastic mechanisms and restraint coefficient methods. In addition, the corresponding numerical simulation analysis on a restrained two-span steel beam-column substructure with different end constraints and fire conditions was carried out to verify the applicability and reliability of established theoretical formulas. Comparisons of vertical load-deflection relationships between the calculation formulas and corresponding numerical simulation shows good accuracy. For more accurate prediction results, the error analysis was further conducted, and several theoretical formulas were modified, which were verified to be accurate and reliable after correction. With derived resistance functions, the resistance of steel beam-column substructures in fire-induced progressive collapse scenarios can be predicted. [ABSTRACT FROM AUTHOR]

In this paper, two classes of efficient difference schemes for the simulation of the time-fractional Korteweg–de Vries equation are carried out. The temporal derivative is approximated with the help of the uniform/nonuniform L 1 formula and the uniform L 2 - 1 σ formula, respectively. The spatial derivative is done with the uniform centered difference scheme. Unique solvability, boundedness and convergence of the corresponding difference schemes are rigorously proved at length. As far as we know, the proposed schemes achieve the highest convergence order in space among all the difference methods for the time-fractional KdV equation. Several numerical examples confirm the theoretical results and demonstrate the dynamic behavior. • Numerical analysis of two classes of efficient difference schemes for the simulation of the time-fractional KdV equation. • The highest convergence in space among all the difference methods for the time-fractional KdV equation up to now. • Numerical confirmation of the accuracy of theoretical results and demonstration of the dynamic behavior of KdV equation. [ABSTRACT FROM AUTHOR]

• Proper quantification of joint rotational stiffness (JRS) of a flight intersection joint (FIJ) influences the dynamic characteristics of a flight vehicle. • JRS of an FIJ is often determined experimentally due to the lack of a right predictive model. • An analytical model is proposed to evaluate the JRS of a radial-type FIJ when subjected to an external bending moment. • Numerical analyses and experiments are performed on six different FIJ configurations. • JRS and moment-rotation behavior predicted by the proposed model are correlated with both experimental and numerical analyses. • Further, the effect of joint clearances on the behavior of FIJ is investigated through the present model. Joint rotational stiffness (JRS) of a flight intersection joint (FIJ) and its accurate quantification play an essential role in studying the dynamic modal characteristics of a flight vehicle. This JRS of a FIJ is mostly determined through elaborate experiments due to the non-availability of a reliable predictive model. Therefore, in this paper, an analytical model is proposed to evaluate JRS of a radial type FIJ when subjected to external bending moment. In this model, at first, the tensile and compressive part of the FIJ section is identified by determining the neutral axis position. The respective part's contributing stiffness is then estimated by employing a spring-mass model. Later, the JRS expression is derived from the moment equilibrium condition and expressed as a function of the stiffness of the tensile and compressive part and neutral axis position. Subsequently, finite element analysis (FEA) is conducted with different numbers of screws, followed by detailed experimental investigations. The proposed analytical model is validated with the results from FEA and experiments for different screw configurations of FIJ. Further, the proposed model is extended to account for the effect of joint clearances on the JRS and the corresponding moment-rotation characteristics of the FIJ. [Display omitted] [ABSTRACT FROM AUTHOR]