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Single-column bridges are widely used for urban overpasses and highway bridges. Rising overturning incidents have exposed the vulnerability of this type of bridge, which is inherently susceptible to overturning collapse. A typical solution is to provide vertical restrainers at the beam ends. However, the current antioverturning calculation method was incapable of coordinating deformations between bridge components, which may have severe consequences in engineering practice. For example, the Huahu Viaduct, located in Hubei, China, experienced overturning failure even after applying vertical restrainers, which was not anticipated according to the current engineering experience. In this work, we proposed a modified calculation method regarding deformation coordination to predict the ultimate overturning capacity, verified through forensic investigation and numerical analysis, of the Huahu Viaduct. Compared with bridges without restrainers, overturning failures start with the failure of restrainers. Failure mechanisms are analyzed, including critical states and overturning features. Further comparison indicates that the practical method overestimates the ultimate overturning capacity by up to 38%, while the proposed method provides a more effective reference to this problem in engineering practice. [ABSTRACT FROM AUTHOR]

This article focuses on the optimal control problems governed by fourth‐order linear elliptic equations with clamped boundary conditions in the framework of the Hessian discretization method (HDM). The HDM is an abstract framework that enables the convergence analysis of several numerical methods such as the conforming finite element methods, the Adini and Morley nonconforming finite element methods (ncFEMs), the method based on gradient recovery (GR) operators, and the finite volume methods (FVMs). Basic error estimates and superconvergence results are established for the state, adjoint, and control variables. A companion operator for the GR method with specific property is designed. The article concludes with numerical results that illustrate the theoretical convergence rates for GR method, Adini ncFEM, and FVM. [ABSTRACT FROM AUTHOR]

To overcome the deficiencies of large particle radius, strict vibration conditions, and low kinetic energy exchange rate of traditional particle dampers, it is proposed to organically combine the rack and pinion inerter device with a stacked single particle damper (SSPD) to form a novel stacked single particle‐inerter damping system (SSPIS). Based on a detailed analysis of the force state of particles at various stages, the vibration damping mechanism of SSPIS is analyzed, and a mechanical model of a single‐degree‐of‐freedom (SDOF) structure equipped with an SSPIS is established. The numerical simulation and analysis process of SSPIS is provided, and a parametric design method of inerter device based on the structural performance requirements is proposed. The accuracy of the theoretical mechanical model and numerical simulation analysis process of SSPIS is verified through shaking table tests of a single‐story steel frame, and the actual damping control effect of SSPIS on the controlled structure is investigated. Both test and theoretical results show that the numerical simulation analysis process of SSPIS is clear and accurate, and the mechanical model of the SSPIS‐SDOF structural system is highly accurate. The inerter device in SSPIS can significantly improve the momentum exchange efficiency between particles and structures, and SSPIS could adaptively adjust the particle radius size on demand compared with the traditional particle dampers, with a high damping frequency band, and can realize good damping control effect under the earthquake with various types of sites, which has expansive engineering application scenarios. [ABSTRACT FROM AUTHOR]

The assessment of human losses and injuries due to earthquakes is critical for the development of risk reduction measures. Yet, most vulnerability studies have focused on the derivation of fragility functions for structural damage, neglecting the evaluation of the human impact. In this study, we implemented a fatality vulnerability assessment procedure based on advanced structural modelling, with an application to typical limestone and granite masonry buildings in Portugal. We performed nonlinear time‐history analysis on 3D numerical models whose characteristics were sampled from statistical models representing the geometric and mechanical properties of this type of construction. Engineering demand parameters, such as volume of loss and volume of survivable space, were estimated and converted into a fatality rate based on observations from past fatal earthquakes. We compared these vulnerability functions with other proposals from the literature in which conventional fragility functions are directly combined with collapse and fatality rates. Finally, the resulting vulnerability functions were tested for two earthquake scenarios for Portugal. The results from this study indicate that the conventional approach for fatality modelling tends to underestimate human losses for strong ground shaking due to the inability to account for catastrophic structural collapses. The fatality vulnerability functions developed in this work can be directly used in probabilistic seismic risk analysis or the assessment of earthquake scenarios. [ABSTRACT FROM AUTHOR]

Most traditional passive friction dampers are limited to the design of single activated energy dissipation mechanism; therefore, when the seismic intensity is not strong enough to activate the mechanism, traditional friction dampers can only increase stiffness of the structure just like braces; only when the mechanism is activated will the energy dissipation elements perform energy absorption and assist the structure to absorb received seismic energy. The objective of this study is to improve this defect of traditional friction dampers, developing a Multi–Level Friction Damper (MFD) with a two‐stage energy dissipation mechanism, helping building structures (e.g., hospitals, high‐tech plants) reduce the acceleration responses of the superstructure. MFDs are proven to provide more comprehensive protection and have higher energy dissipation benefits than traditional friction dampers by the validation of numerical analysis and shaking table test. The study in turn performed parameter fitting with the results of the numerical simulation analysis and shaking table test, and the experimental results turned out to be satisfactory, validating the accuracy of the theoretical formulas. [ABSTRACT FROM AUTHOR]

This paper investigates a steel moment resisting frame (MRF) with a novel type of self‐centering (SC) base isolators, wherein superelastic shape memory alloy (SMA) U‐shaped dampers (SMAUDs) work as core components. A two‐story steel MRF model equipped with two SMAUD‐based isolators was designed and built in the laboratory, and a series of shake table tests were conducted to examine the dynamic behavior and seismic performance of the frame. Throughout all the tests, no interventions, such as repair or replacement of frame or isolator members, were done. Shake table test results demonstrated that the SMAUD‐based isolators could withstand multiple strong earthquakes with stable SC behavior. The utilization of SMAUD‐based isolators provided effective protection for the frame, enabling it to restore its original position with minimal structural damage. A numerical model of the tested steel MRF with SMAUD‐based isolators was also built. The results obtained from the numerical analyses agreed with those of the shake table tests satisfactorily. A comparative study of the seismic performance between the MRF with SMAUD‐based isolators and the MRF with traditional steel U‐shaped damper‐based isolators was also conducted in the shake table tests. The results showed that SMAUD‐based isolators not only inherit the isolation function of conventional isolators to protect the frame but also possess an SC ability to eliminate residual isolator deformation effectively. Moreover, SMAUD‐based isolators demonstrate remarkable resilience to withstand multiple strong seismic events without any need for repair or replacement. [ABSTRACT FROM AUTHOR]

This paper examines the mechanical behavior of fiber reinforced polymer (FRP)-confined concrete under cyclic compression using the 3D cohesive zone model (CZM). A numerical modeling method was developed, employing zero-thickness cohesive elements to represent the stress-displacement relationship of concrete potential fracture surfaces and FRP-concrete interfaces. Additionally, mixed-mode damage plastic constitutive models were proposed for the concrete potential fracture surfaces and FRP-concrete interface, considering interfacial friction. Furthermore, an anisotropic plastic constitutive model was developed for the FRP composite jacket. The CZM model proposed in this study was validated using experimental data from plain concrete and large rupture strain (LRS) FRP-confined concrete subjected to cyclic compression. The simulation results demonstrate that the proposed model accurately predicts the mechanical response of both concrete and FRP-confined concrete under cyclic compression. Lastly, various parametric studies were conducted to investigate the internal failure mechanism of FRP-confined concrete under cyclic loading to analyze the influence of the inner friction plasticity of different components. [ABSTRACT FROM AUTHOR]

The risk of coal spontaneous combustion in goaf is one of the disasters in coal mining, ventilation and extraction often aggravate air leakage from the goaf. Due to the unclear rule of expansion law and air leakage, the risk space for coal spontaneous combustion continues to occur. To investigate the influence of ventilation and extraction on the evolution of the risk space of coal spontaneous combustion (CSC) in goaf, further reveal the characteristics of air leakage and extraction in goaf and obtain the expansion law of CSC risk space. A three-dimensional model of goaf under surface drilling and gas extraction was developed. Using FLUENT numerical simulation software, taking a coal mine in Anhui Province, this study analyzes the influence factors, evolution law, and influence characteristics of CSC through field observations and numerical simulation. The research indicates that ventilation keeps the risk space of CSC expanding. The extraction of single drilling showed a local space expansion, while the extraction of double drilling shows the overall space expansion of the goaf. The air leakage flow path in goaf, air flow velocity vector in working face, gas concentration loss, and gas extraction characteristic parameters are determined. The loss of air leakage along the working surface meets four-stage: "strong in – flow - mixed flow – steady inflow – sudden outflow." It can be determined that the extraction intensity of single drilling should be greater than 34.8 m3/min, and the double drilling should be greater than 18.7 m3/min. The relationship between the coupling influence of ventilation and extraction and the expansion law of CSC risk space is determined, and the maximum risk space width of CSC can be predicted. The research results are of guiding significance for CSC prevention and gas efficient extraction. [ABSTRACT FROM AUTHOR]

Online shopping and e‐commerce have contributed significantly to the environmental pollution caused by the generation of packaging waste. In response to this issue, reusable express packaging has emerged as a promising solution. However, the widespread adoption of reusable express packaging faces significant challenges, namely, the initial investment burden and the complexities associated with recycling. To address these challenges and enhance resource utilization efficiency while minimizing supply–demand discrepancies, inventory sharing has emerged as an effective measure. We first establish an inventory model for reusable express packaging, which takes into account stochastic loss rates and customer service level. We further extend our research to scenarios involving both inventory sharing and competition. We substantiate the value of inventory sharing and the impact of competition through comprehensive numerical analyses. Our findings demonstrate that inventory sharing contributes to enhancing the profits of express delivery companies, especially with a more pronounced effect in companies where competition exists. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to analyze the solvability of a class of stochastic functional integral equations by utilizing the measure of non-compactness with Petryshyn’s fixed point theorem in a Banach space. The results obtained in this paper cover numerous existing results concluded under some weaker conditions by many authors. An example is given to support our main theorem. [ABSTRACT FROM AUTHOR]

Fractional derivatives are suitable for describing several physical phenomena. The construction of efficient analytical and numerical methods for the solutions of ordinary and partial fractional differential equations is an active research area and it is of great interest to the researchers. The Caputo fractional derivative is of great use in the modelling and simulation of phenomena where consideration is given to the interactions within the past and problems with nonlocal properties. This study considers the use of a hybrid of the Sumudu Transform method for constructing the solution of nonlinear equations that describe the processes in the functional and structural materials. This study considers the models that are given by the integer-order derivatives, Caputo derivatives of fractional variable orders and Caputo derivatives of fractional variable orders that are associated with delays. The study applies a hybrid of Sumudu Transform to present solutions for each considered model and makes use of graphs to show the correlation among the models. The study is of great importance in the numerical and experimental characterization of the decay properties of functional and structural materials. [ABSTRACT FROM AUTHOR]

In the present paper, the influence of liquid flow above the needle on a periodic or chaotic nature of the bubble departures process was numerically investigated. During the numerical simulations bubbles departing from the needle was considered. The perturbations of liquid flow were simulated based on the results of experimental investigations described in the paper [1]. The numerical model contains a bubble growth process and a liquid penetration into a needle process. In order to identify the influence of liquid flow above the needle on a periodic or chaotic nature of bubble departures process, the methods data analysis: wavelet decomposition and FFT were used. It can be inferred that the bubble departure process can be regulated by altering the hydrodynamic conditions above the needle, as variations in the liquid velocity in this area affect the gas supply system's conditions. Moreover, the results of numerical investigations were compared with the results of experimental investigation which are described in the paper [2]. It can be considered that, described in this paper, the numerical model can be used to study the interaction between the bubbles and the needle system for supplying gas during the bubble departures from two needles, because the interaction between the bubbles is related to disturbances in the liquid flow above the needle. [ABSTRACT FROM AUTHOR]

The intricacies of relay-aided device-to-device (D2D) communication within the novel fluctuating two-ray (FTR) model is inspected in this study. Two cases with respect to co-channel interference are considered here, in case A, co-channel interferences due to unmanned aerial vehicles affect the relay while at the D2D receiver, the co-channel interferences follow the FTR model. In case B, interferences due to unmanned aerial vehicles affect the D2D receiver and the relay now experiences interferences over the FTR channels. The channel of a co-channel interference due to unmanned aerial vehicle is assumed to be a recently proposed single-shadowing based composite fading model. Further enhancing operational efficiency, the D2D receiver incorporates a power splitting mechanism for power harvesting. In this analysis a characteristic function-based approach is applied, which serves as the foundational cornerstone for deriving expressions that govern the outage and success probabilities. These intricate expressions are connected with critical factors, such as the dynamics of path-loss phenomena, the spatial separation between the interferers and the relay, the varying distances between the interferers and the D2D receiver, and the physical gap bridging the relay and the D2D receiver. Building upon the derived expressions, an extensive numerical analysis unfurls them for both interference cases. [ABSTRACT FROM AUTHOR]

The paper presents selected results of numerical analysis and experimental verification. The subject is the analysis of cold forging of a thin-walled hollow ball. The process of making a ball out of aluminum alloy and steel was considered. A distinctive feature of this process is the use of a special deformable insert assembly. It consists of two shaped expanding tubes, a distance ring and a centering tube. Each of these elements has a specific function, which was characterized in this article. Finite element analysis (FEA) simulation allowed proving the functionality of the insert assembly and comparing the cold forging of a steel and aluminum part, using the same inserts. Attention was also focused on the impact of the accuracy of the positioning of the insert assembly. Experimental verification confirmed the correctness of the modeling and complemented the results from FEA analysis. [ABSTRACT FROM AUTHOR]

In this work, we propose a piecewise Jacobi–Gauss spectral collocation (JGSC) method for simulating a multi-particle system involving processing delay. Through the use of Jacobi orthogonal approximation and simple Picard iteration, the method obtains the Jacobi series solution of the multi-particle model, allowing us to derive the numerical solution of the processing delay directly. The matrix–vector form of the method helps to obtain the solution parallelly and improves the efficiency significantly. Additionally, the eigenvalues of the iteration's coefficient matrix are evaluated in order to analyze the convergence of the JGSC method numerically. Numerical experiments illustrate that the JGSC method can keep the high accuracy and efficiency. Furthermore, simulation results of the model indicate that the flocking behavior can only achieved with small enough processing time delays and large enough sizes of the neighborhood. [ABSTRACT FROM AUTHOR]

The piezoelectric micropump can be a prominent component of drug delivery systems due to its high performance, low cost, and faster response. However, backpressure remains to be the most common problem in micropump technology. Thus, microvalves or the passive check valve based piezoelectric micropump can be used to prevent the backpressure. However, the complex structure of the passive check valve based micropump limits the investigations of Fluid-Structure Interaction (FSI) due to the intricate Multiphysics involved. This paper presents the investigations on the flow behaviour and performance of a passive check valve based piezoelectric micropump using numerical analysis. The simulation study comprising FSI depicts the performance of a piezoelectric micropump using a fluid-structure coupling, fluid selection, structural modelling, and piezoelectric equations. The simulation results illustrate the micropump performance characteristics such as piezoelectric actuator displacement, micropump flow rate, backpressure, and Von Mises stress. Experiments are conducted to validate simulation results by studying the effect of voltage and frequency on the micropump flow and pressure characteristics. The experimental study demonstrated that the passive check valve based piezoelectric micropump delivers a maximum flow rate of 32 ml/min at zero backpressure. The micropump can pump the fluid against maximum backpressure up to 35 kPa. [ABSTRACT FROM AUTHOR]

In numerical analysis, the quadrature formulas serve as a pivotal tool for approximating definite integrals. In this paper, we introduce a family of quadrature formulas and analyze their associated error bounds for convex functions. The main advantage of these new error bounds is that from these error bounds, we can find the error bounds of different quadrature formulas. This work extends the traditional quadrature formulas such as the midpoint formula, trapezoidal formula, Simpson's formula, and Boole's formula. We also use the power mean and Hölder's integral inequalities to find more general and sharp bounds. Furthermore, we give numerical example and applications to quadrature formulas of the newly established inequalities. [ABSTRACT FROM AUTHOR]

This research surveys the impact of the flavor number parameter on a four-dimensional Black Hole (BH) solution in Einstein’s nonlinear sigma model-SU(N) (NLSM) in accordance with the shadow, energy emission rate, sparsity, massless scalar, and electromagnetic quasinormal mode spectra. Related investigations are being carried out to explore the influence of the flavor number parameter. In particular, the findings show that shadow behavior and energy emission rate are antinomic processes in view of the flavor number parameter. On the other hand, the SU(N)-NLSM BH’s quasinormal modes are computed by first calculating the effective potential generated by the perturbation of scalar and electromagnetic fields, followed by a numerical analysis based on the sixth-order WKB approach. Our results show that the QNMs of the SU(N)-NLSM BH damp more slowly as flavor number N increases. [ABSTRACT FROM AUTHOR]

Effective disease control measures to manage the spread of Monkeypox (Mpox) virus are crucial, especially given the serious public health risks posed by the ongoing global epidemic in regions where the virus is both prevalent and not. This study introduces a precise model, based on the Caputo fractional derivative, which takes into account both human and non-human populations as well as public transportation, to delve into the transmission characteristics of Mpox outbreaks. By employing the fixed point theorem, we have precisely determined the solutions regarding existence and uniqueness. We have analyzed the stability of various equilibrium states within the model to assess Mpox’s transmission capabilities. Additionally, through detailed numerical simulations, we have gauged the impact of critical model parameters that contribute to enhancing Mpox prevention and management strategies. The insights gained from our research significantly enrich epidemiological understanding and lay the foundation for improved disease containment approaches. [ABSTRACT FROM AUTHOR]

Experimental and numerical studies were conducted to assess the stability of the breakwater of Fujairah Port on the east coast of the United Arab Emirates against tsunamis. Experiments were conducted on a 1:50 scale and numerical analysis was done with the formulas of tsunami-breakwater interaction. The experimental observations corroborated the numerical results. The breakwater was safe up to 3m of tsunami height, but when the tsunami height increased from 3m to 6m, the percentage damage to the leeside (portside) of the breakwater increased compared to the seaside. The leeside of the breakwater was deformed by tsunami overtopping and seepage — the breakwater cross-section reshaped from trapezoidal to quasi-triangular at 6m tsunami impact, however, the breakwater was not breached. Rubbles of the breakwater were transported due to sliding, rolling, and saltation by overtopping and seepage. For 6m tsunami height, rubbles from the seaside rolled over up with saltation and transported to the leeside. A large number of rubbles were transported landward from the leeside of the breakwater but a few were displaced offshore from the seaside. [ABSTRACT FROM AUTHOR]

Investigating novel collaboration modes is imperative for enhancing the cooperative ties between brand retailers and anchors as live streaming commerce moves progressively towards standardization. In this paper, we study a live streaming commerce supply chain system composed of a brand retailer and an Internet celebrity anchor. We also develop the pricing and live streaming service effort decision models under the equal proportion settlement mode of pit fee for the brand retailer and anchor. The research results show that under certain conditions, there is an optimal joint decision on price discount and live streaming service effort. In addition, the equal proportion settlement mode provides security for brand retailers but tends to expose the anchor's capabilities of live streaming sales. Consequently, anchors can only obtain a higher proportion of the pit fee by putting in more effort. Finally, through numerical analysis, we presented the impact of key parameters on the optimal decisions, demand, and profits of brand retailers and anchors. Based on these findings, we provided relevant managerial insights, offering valuable guidance and reference for the live streaming commerce industry. [ABSTRACT FROM AUTHOR]

AbstractIn case of strong seismic-induced vibration, some metallic support and anchorage systems may exhibit elastoplastic deformation. To consider this elastoplastic deformation in the seismic design of equipment, standards such as CEN/TS 2004 recommend a very simplified behavior coefficient which is constant. Neither post-elastic characteristics such as the hardening coefficient, the ductility capacity, nor the dynamic content of the equipment are considered so far in this approach. In this paper, the influence of the elastoplastic deformation in supports on equipment responses is examined by means of a systematic numerical analysis. As highlights, the effect of elastoplastic supports strongly depends on the frequency of the equipment and the post-elastic characteristics. In certain cases, the effect of elastoplastic deformation in supports can be ‘unfavorable’ with respect to the assumption of elastic supports. This is the case for support-equipment systems of high frequency for which it is recommended to limit elastoplastic deformation. Conversely, for flexible support-equipment systems, it is beneficial to explore the ductility capacity of metallic supports. Finally, for engineering applications, behavior coefficients to consider the elastoplastic deformation in supports are proposed in the format of an abacus as a function of ductile capacity, hardening coefficients, and dimensionless frequencies of the equipment. [ABSTRACT FROM AUTHOR]

Highlights Permeability quantifies the flow conductivity of fabric reinforcements and is key to predicting mold filling times and resin flow in liquid composite molding (LCM). Flow depends on the micron‐level channels within the tows and the millimeter‐level channels between them. This study presents a general multi‐scale permeability prediction framework for fabrics considering realistic inter‐ and intra‐tow geometry. A misaligned fiber representative volume element model was constructed by a random perturbation method at the micro‐scale with orientation parameters identified from microscopic images of the cross‐section. At the meso‐scale, a tow cross‐section wrapping algorithm and an interference elimination algorithm were proposed to construct continuous as‐woven tows from the virtual fiber compression simulation. The governing fluid dynamics equations were solved to obtain the flow field within the multi‐scale gaps and compute the permeability. The simplified model's permeability predictions differed from experimental results by 12.7% to 16%. This work provides valuable insights for further research and development in LCM. Fabric permeability framework considers realistic tow geometry for prediction. Microscale misaligned fiber SVE model predicts tow permeability. Adaptive winding & interference algorithms aid tow description transition. A simplified model predicts permeability reasonably without 3D measurements. [ABSTRACT FROM AUTHOR]

Highlights This paper presents the experimental, analytical, and numerical extensive investigation into the flexural creep performance of pultruded glass fiber reinforced polymer (pGFRP) composites at elevated service temperatures. The experimental phase involved a physical testing program on pGFRP coupons in a four‐point bending setup covering a wide range of loads (12%, 24%, and 37% stress levels) and temperature conditions (20, 40, and 60°C) over a long test duration of 720 h. The analytical Burgers model was employed to provide theoretical insights into the time‐dependent deformation behaviors, while the finite element analysis (FEA) simulations using derived reduction factor validated the accuracy of the proposed procedure. Burgers model was able to capture the experimental data very well and reached the ultimate strain failure limit within about 1.4–50 years depending on the case. The proposed simple FEA procedure yielded a pattern closely resembling the one observed from Burgers model in which they resulted in estimated endurance times with a roughly 15% difference between them. The higher stress and/or temperature, the longer the primary creep stage is. Burgers model is able to capture the experimental data very well in all conditions. Burgers general equation is able to predict failure within about 1.4–50 years. A proposed reduction factor based on Burgers model is utilized in FEA The FEA procedure shows a roughly 15% difference compared to Burgers model. [ABSTRACT FROM AUTHOR]

The regulation of energy associated with heat transfer is the most important problem in the food processing, chemical and biomedical engineering industries. Therefore, this investigation explores the heat transfer qualities of micropolar hybrid-nanofluid also considering entropy generation which has recently become central focus of research in the field of heat transfer processes. The purpose of this analysis is to explore the influence of magnetohydrodynamics (MHD), viscous dissipation, and heat radiation on the flow of hybrid-nanofluid with micropolar properties above an exponentially shrinking/stretching sheet. A mathematical model is constructed and the solution is acquired by utilizing numerical technique bvp-4c in MATLAB. The befitting usage of the second law of thermal physics helped in conducting the entropy production analysis. The study obtains numerical results for the governing equations, which reveal dual solutions when analyzing a shrinking sheet, contrary to a stretching sheet. The paper presents graphical depictions of the influence of different attributes upon micro-rotation, velocity, surface-friction, temperature, Nusselt number and also the entropy generation plus the Bejan number. Moreover, a comparison of heat transfer rates between conventional nanomaterial and hybrid-nanofluid is provided. The study concludes that dual solutions appear and the wall shear stress coefficient decreases as the values of micropolar parameter R 1 increase with critical values of λ being λ c = − 1. 2 8 , − 1. 3 4 and − 1. 3 7. Also thermal irreversibility, which results from fluid friction near the sheet rather than far from it, is more dominant than total entropy generation. [ABSTRACT FROM AUTHOR]

Numerous studies have indicated that turbulence typically initiates along the boundary layer of the stationary disk within a rotor–stator cavity. To describe the transition process to turbulence on the stationary side of a closed rotor–stator cavity, a comprehensive approach combining global linear stability analysis with direct numerical simulation was adopted in the present study. The proposed model aligns with that of Yim et al. (J. Fluid Mech. , vol. 848, 2018, pp. 631–647), who investigated the stability characteristics of the rotating-disk boundary layer in a rotor–stator cavity. In order to achieve a stable inflow for the stationary-disk boundary layer, we rotate the shroud together with the rotating disk. Through careful global stability analysis, the predominant spiral mode exhibiting the highest instability in the boundary layer of the stationary disk was discerned, corroborating observations from simulations. Initially, the spiral mode undergoes linear amplification, reaches a state of linear saturation and enters the nonlinear regime. Following nonlinear saturation in the flow field, a circular wave mode arises due to the influence of mean flow distortion. As the Reynolds number attained a sufficiently high level, the interplay between the downstream-propagating circular mode and spiral mode amplified disturbances in the boundary layer of the stationary disk, ultimately leading to the development of localised turbulence at the mid-radius of the rotor–stator cavity. Notably, the present study is the first to elucidate the coexistence of laminar–transitional–turbulent flow states in the stationary-disk boundary layer through direct numerical simulations. [ABSTRACT FROM AUTHOR]

Summary In this paper, computational analysis of a Caputo fractional variable‐order system with inductor‐capacitor (LC) and resistor‐capacitor (RC) electrical circuit models is presented. The existence and uniqueness of solutions to the given problem are determined using Schaefer's fixed point theorem and the Banach contraction principle, respectively. The proposed problem's computational consequences are addressed and analyzed using modified Euler and Runge–Kutta fourth‐order techniques. Furthermore, the suggested model compares several orders, including integer, fractional, and variable orders. To demonstrate the utility of the proposed approach, computational simulations are carried out on LC and RC circuit models of various orders. Furthermore, a comparative analysis with previous investigations has been carried. For the given problem, the numerical solution results in high‐precision approximations. [ABSTRACT FROM AUTHOR]

Induction heating is a clear, cheap, and highly effective technology used for many industrial and commercial applications. Generally, a time-varying magnetic field produces the required heat in the workpiece with a specially designed coil. The efficiency of the heating process depends highly on the coil design and the geometrical arrangement. A detailed and accurate finite element analysis of the induction heating process usually needs to resolve a coupled thermoelastic–magnetic problem, whose parameters values depend on the solution of another field. The paper deals with a shrink-fitting process design problem: a gear should be assembled with an axe. The interesting part of this case study is given the prescribed low limits for critical stress, the temperature of the gear material, and the heat-treated wearing surfaces. A coupled finite-element-based model and a genetic algorithm-based parameter determination methodology were presented. A thermal imaging-based measurement validated the presented numerical model and parameter determination task. The results show that the proposed methodology can be used to calibrate and validate the numerical model and optimize an induction heating process. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) microgrids comprise a multitude of small PV power stations distributed across a specific geographical area in a decentralized manner. Computational services for forecasting the output power of power stations are crucial for optimizing resource deployment. This paper proposes a deep-learning-based architecture for short-term prediction of PV power. Firstly, in order to make full use of the spatial information between different power stations, a spatio–temporal feature fusion method is proposed. This method is capable of exploiting both the power information of neighboring power stations with strong correlations and meteorological information with the PV feature data of the target power station. By using a multiscale convolutional neural network–long short-term memory (CNN-LSTM) network model, it is capable of generating a PV feature dataset containing spatio–temporal attributes that expand the data source and enhance the feature constraints. It is capable of predicting the output power sequences of power stations in PV microgrids with high model generalization and responsiveness. To validate the effectiveness of the proposed framework, an extensive numerical analysis is also conducted based on a real-world PV dataset. [ABSTRACT FROM AUTHOR]

For the purpose of improving performance and reducing the fabrication difficulty of terahertz traveling wave tubes (TWTs), this paper proposes a novel single-section high-gain slow wave structure (SWS), which is named the symmetrical quasi-synchronous step-transition (SQSST) folded waveguide (FW). The SQSST-FW SWS has an artificially designed quasi-synchronous region (QSR) to suppress self-oscillations for sustaining a high gain in an untruncated circuit. Simultaneously, a symmetrical design can improve the efficiency performance to some extent. A prototype of the SQSST-FW SWS for 650 GHz TWTs is designed based on small-signal analysis and numerical simulation. The simulation results indicate that the maximum saturation gain of the designed 650 GHz SQSST-FW TWT is 39.1 dB in a 34.3 mm slow wave circuit, occurring at the 645 GHz point when a 25.4 kV 15 mA electron beam and a 0.43 mW sinusoidal input signal are applied. In addition, a maximum output power exceeding 4 W is observed at the 648 GHz point using the same beam with an increased input power of around 2.8 mW. [ABSTRACT FROM AUTHOR]

Fractured crystalline rocks have been chosen or are under consideration by several countries as host rock formations for deep geological repositories for spent nuclear fuel. In such geological formations, flow and solute transport are mostly controlled by a network of connected natural fractures, each of them being characterised by internal heterogeneity, also denoted as roughness. Fractures are, in turn, subject to variable load caused by various factors, such as the presence of thick ice sheets formed during glaciation periods. Understanding how coupled hydro-mechanical (HM) processes affect flow and transport at the scale of a single natural fracture is crucial for a robust parameterisation of large-scale discrete fracture network models, which are not only used for nuclear waste disposal applications but are also of interest to problems related to geothermics, oil and gas production or groundwater remediation. In this work, we analyse and model an HM experiment carried out in a single natural fracture and use the results of both, the experimental and the modelling work, to get insights into fundamental questions such as the applicability of local cubic law or the effect of normal load on channeling. The initial fracture aperture was obtained from laser scanning of the two fracture surfaces and an equivalent initial aperture was then defined by moving the two fracture surfaces together and comparing the results obtained using a Navier–Stokes based computational fluid dynamics (CFD) model with the experimental flowrate obtained for unloaded conditions. The mechanical effect of the different loading stages was simulated using a high-resolution contact model. The different computed fracture apertures were then used to run groundwater flow simulations using a modified Reynolds equation. The results show that, without correction, local cubic law largely overestimates flowrates. Instead, we show that by explicitly acknowledging the difference between the mechanical aperture and the hydraulic aperture and setting the latter equal to 1/5 of the former, cubic law provides a very reasonable approximation of the experimental flowrates over the entire loading cycle. A positive correlation between fluid flow channeling and normal load is also found. [ABSTRACT FROM AUTHOR]

A dual-phase lattice structure composed of mixed units with hard and soft phase characteristics is proposed in this work. The proposed lattice structure has high specific energy absorption and high compressive strength. The load response and energy absorption characteristics under bending loads were studied through three-point bending tests and numerical analysis methods. The research results indicate that although the deformation modes of the given lattice structure are the same, the dual-phase design strategy significantly improves the bending performance of the lattice structure: the bending modulus is increased by 744.7%, and the specific energy absorption is increased by 243.5%. [ABSTRACT FROM AUTHOR]

In this study, a numerical dynamic analysis of ceiling raster panels was performed. The analysis was conducted on panels designed with inspiration from bionics. The purpose of the analysis was to enable optimisation of the location of the holes in the designed slabs in order to achieve the preferred dynamic properties, including the natural frequencies of the slabs and an appropriate airflow to avoid the occurrence of resonance. Three different types of panels were used and a total of fifteen panels were designed in terms of their geometry, with circular, elliptical, and hexagonal perforations, made of different materials: polypropylene PP, wood, and aluminium. Then, using the finite element method and ANSYS 2023 R1 software, the airflow over the ceiling panels and their natural frequencies and vibration modes were analysed. The analysis took into account not only the shape of the openings, but also their percentage area relative to the total panel area and different airflow velocities. In addition, the results were compared in an analytical way with those obtained for a solid slab. The results obtained include findings on the mode shapes and values of the vibration frequencies of the plates, air pressure maps, histograms, and plots of the pressure dependence on the surface area of the plate openings. [ABSTRACT FROM AUTHOR]

The Diffusion Peterlin Viscoelastic Fluid (DPVF) model describes the movement of specific incompressible polymeric fluids. In this paper, we introduce and evaluate a new low-complexity linear-time filter finite element (FE) method for the DPVF model. In order to avoid the value at time t = − Δ t , the proposed time filter method consists of three steps, including a post-processing step. Firstly, a first-order Euler backward nonlinear fully discrete mixed FE scheme is employed to compute the numerical solutions at time t 1 = Δ t. For n ≥ 1 , we obtain the intermediate values ( u ˜ h n + 1 , p ˜ h n + 1 , d ˜ h n + 1) in Step II using a fully implicit backward Euler scheme. At the same time level, we proceed with these intermediate values ( u ˜ h n + 1 , p ˜ h n + 1 , d ˜ h n + 1) using the linear time filters. The linear time filters step does not significantly increase computational complexity. However, it can enhance temporal convergence accuracy from first order to second order for backward Euler time filter (BE time filter), and from second order to three order for BDF2 time filter. We demonstrate the almost unconditional stability of the scheme. Error estimates for the time filter method are derived and presented. Several numerical experiments are conducted to validate the theoretical findings and showcase the efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

We propose a novel and simple spectral method based on the semi-discrete Fourier transforms to discretize the fractional Laplacian (− Δ) α 2 . Numerical analysis and experiments are provided to study its performance. Our method has the same symbol | ξ | α as the fractional Laplacian (− Δ) α 2 at the discrete level, and thus it can be viewed as the exact discrete analogue of the fractional Laplacian. This unique feature distinguishes our method from other existing methods for the fractional Laplacian. Note that our method is different from the Fourier pseudospectral methods in the literature which are usually limited to periodic boundary conditions (see Remark 1.1). Numerical analysis shows that our method can achieve a spectral accuracy. The stability and convergence of our method in solving the fractional Poisson equations were analyzed. Our scheme yields a multilevel Toeplitz stiffness matrix, and thus fast algorithms can be developed for efficient matrix-vector multiplications. The computational complexity is O (2 N log ⁡ (2 N)) , and the memory storage is O (N) with N the total number of points. Extensive numerical experiments verify our analytical results and demonstrate the effectiveness of our method in solving various problems. [ABSTRACT FROM AUTHOR]

Standard Galerkin methods often perform poorly for problems with low diffusion. In particular for purely convective transport, least-squares (LS) formulations provide a good alternative. While spatial stability is relatively straightforward in a least-squares finite element framework, estimates in time are restricted, in most cases, to one dimension. This article presents temporal stability proofs for the LS formulation of θ -schemes, including unconditional stability for the backward Euler and Crank-Nicolson methods in two or three dimensions. The theory includes also the linear advection-reaction equation. A series of numerical experiments confirm that the new stability estimates are sharp. [ABSTRACT FROM AUTHOR]

Elastomeric materials are widely used in different industries due to their excellent capability to withstand different loading types. There are significant challenges to the efficient design of elastomeric structures because of the rate-dependent and highly nonlinear behavior of this type of material. In this study, a damage zone model was employed to simulate the material behavior and damage evolution in polyurethane (PU) elastomers with different shore hardness. This model consists of three sections, hyper viscoelastic constitutive model, damage initiation, and damage evolution using a hyper viscoelastic traction-separation law. To simulate the nonlinear behavior of PU, a dynamic increase factor (DIF) implemented into the Mooney–Rivlin strain density function with 9 parameters. The material characteristics are specified by performing the experimental tests for three different shore hardness. In this study, a user-defined subroutine (VUMAT) was developed to predict the damage evolution in the pure shear tearing specimen of PU elastomers. The results verification proves a good agreement between the FEA simulation and experimental data. Therefore, the developed numerical analysis procedure can be used to investigate the damage initiation and evolution in elastomeric materials. [ABSTRACT FROM AUTHOR]

This paper examined the mechanical properties of wrist–hand orthoses made from polylactic acid (PLA) and polyethylene terephthalate glycol (PETG), produced through material extrusion with infill densities of 55% and 80%. These orthoses, commonly prescribed for wrist injuries, were 3D-printed flat and subsequently thermoformed to fit the user's hand. Experimental and numerical analyses assessed their mechanical resistance to flexion after typical wear conditions, including moisture and long-term aging, as well as their moldability. Digital Imaging Correlation investigations were performed on PLA and PETG specimens for determining the characteristics required for running numerical analysis of the mechanical behavior of the orthoses. The results indicated that even the orthoses with the lower infill density maintained suitable rigidity for wrist immobilization, despite a decrease in their mechanical properties after over one year of shelf life. PLA orthoses with 55% infill density failed at a mean load of 336 N (before aging) and 215 N (after aging), while PETG orthoses did not break during tests. Interestingly, PLA and PETG orthoses with 55% infill density were less influenced by aging compared to their 80% density counterparts. Additionally, moisture and aging affected the PLA orthoses more, with thermoforming, ongoing curing, and stress relaxation as possible explanations related to PETG behavior. Both materials proved viable for daily use, with PETG offering better flexural resistance but posing greater thermoforming challenges. [ABSTRACT FROM AUTHOR]

In this article, we study a time splitting Fourier pseudo‐spectral (TSFP) method for the nonlinear Schrödinger equation with wave operator (NLSW). The nonlinear strength of the NLSW is characterized by ε∈(0,1]$$ \varepsilon \in \left(0,1\right] $$. Specifically, we propose a coupled system which is equivalent to the NLSW and then apply the TSFP method to this system. As a geometric advantage, the TSFP method has time symmetry and conserves the discrete mass. Rigorous convergence analysis is provided to establish improved error bounds at O(hm+ε2pτ2)$$ O\left({h}^m+{\varepsilon}^{2p}{\tau}^2\right) $$ up to the long‐time at O(1/ε2p)$$ O\left(1/{\varepsilon}^{2p}\right) $$ where m$$ m $$ depends on the smoothness of the solution. Compared with the error bounds O(hm+τ2)$$ O\left({h}^m+{\tau}^2\right) $$ obtained by traditional analysis, our error bounds are greatly improved, especially when the problem presents weak nonlinearity, i.e. 0<ε≪1$$ 0<\varepsilon \ll 1 $$. In error analysis, combining with classical numerical analysis tools, we adopt the regularity compensation oscillation (RCO) technique to study the error accumulation process in detail and then establish the improved error bounds. The numerical experiments support our theoretical analysis. In addition, the numerical results show the long‐term stability of discrete energy. [ABSTRACT FROM AUTHOR]

Accurately simulating the deployment process of coupled systems in deep-sea environments remains a significant challenge. This study employs the Absolute Nodal Coordinate Formulation (ANCF) to dynamically model and analyze multi-body systems based on the Pendant Installation Method (PIM). Utilizing the principle of energy conversion, this study calculates the stiffness, generalized elastic forces, mass matrices, and Morison equation, formulating a motion equation for the dynamic coupling of nonlinear time-domain forces in cables during pendulum deployment, which is numerically solved using the implicit generalized-α method. By comparing the simulation results of this model with those from the catenary theory model, the advanced modeling capabilities of this model are validated. Lastly, the sensitivity of the multi-body system under various boundary conditions is analyzed. The results indicate that deployment operations are more effective in environments with strong ocean currents. Furthermore, upon comparing the impacts of structural mass and deployment depth on the system, it was found that deployment depth has a more significant effect. Consequently, the findings of this study provide a scientific basis for formulating subsequent optimization strategies. [ABSTRACT FROM AUTHOR]

Featured Application: The work reported in this paper contributes to the further improvement of the reverse-time migration imaging accuracy of VSP data, which has broad application prospects for oil and gas exploration of unconventional reservoirs. Vertical seismic profiling has garnered widespread attention in the industry as a supplement to seismic exploration due to its higher data quality compared to surface seismic data. However, its unique observation system in which geophones are only distributed within observation wells results in uneven coverage of subsurface structures. This can lead to significant noise when directly applying conventional reverse-time migration techniques used in surface seismic imaging. This study addresses the issue of noise suppression in reverse-time migration imaging associated with walk-away vertical seismic profiling and presents two main innovations. First, a common-receiver reverse-time migration imaging method is proposed, which uses the observation signals as excitation signals for the corresponding shots after reverse-time processing. Second, an excitation-time-constrained cross-correlation imaging condition is introduced to eliminate non-contributing portions of the wavefield, thereby modifying the traditional cross-correlation imaging condition to include an excitation time constraint. The combination of these methods enhances imaging quality by effectively suppressing noise, as demonstrated through theoretical analysis and numerical simulations with synthetic models. [ABSTRACT FROM AUTHOR]

The flow rate is a significant factor in the operation of centrifugal pumps. The characteristic curve of the pump head is frequently employed in the calculation of the flow rate. Nevertheless, this may be subject to alteration because of prewhirl on the suction side of the pump. Calculating the changes in the head's characteristic curve reveals a change in hydraulic losses. The impact of prewhirl on hydraulic losses is investigated by experimental and numerical analysis of two radial centrifugal pumps. It is demonstrated that the primary changes occur in the pump impeller losses. Relative velocity is a significant factor in this context. Alterations in the pumps' configurations result in a range of secondary flows and shock losses at the leading edge of the blades. A physical model, derived on the basis of the relative velocity, is used to predict the characteristic curves of radial centrifugal pumps with prewhirl with a high degree of accuracy. The results demonstrate a notable enhancement in comparison to modelling techniques that do not incorporate the fluctuating hydraulic losses. [ABSTRACT FROM AUTHOR]

This study investigates the effectiveness of positive position feedback (PPF) in reducing vibration amplitudes in an electric vehicle generator, specifically at super harmonic resonance (SHR) with 1:1 Internal Resonance (IR). Here is a breakdown. Simplified Model: The study uses a simplified nonlinear dynamic model (one degree of freedom, up to fifth-order nonlinear components) with external force, analyzed using the Multiple Time Scales Method (MTSM) with a first-order approximation. Focus on Resonance: The primary focus is on understanding the system's behavior at SHR with 1:1 IR and how PPF can mitigate vibrations in this specific scenario. Frequency Response and Controller Influence: Frequency response functions are used to analyze the system's stability with PPF, examining how different controller parameters affect the main system's dynamics. Validation: Numerical solutions, obtained using the fourth-order Runge–Kutta method ('RK-4'), are used to demonstrate and evaluate the system's amplitude with and without PPF. The analytical and numerical results show strong agreement, validating the model's accuracy. In essence, the research explores using PPF as a vibration control strategy in a specific resonance condition within an electric vehicle generator, using a combination of analytical and numerical methods for analysis and validation. [ABSTRACT FROM AUTHOR]

Prestressed spun high-strength concrete (PHC) piles are commonly used in various types of structures, including bridges, buildings and marine infrastructures. However, piles installed in aggressive environments are vulnerable to corrosion of the steel, which can lead to rapid degradation of the piles. As a corrosion-resistant material, carbon fiber-reinforced polymer (CFRP) is considered an alternative to steel tendons for durability enhancement. In this study, a new pile system with CFRP was proposed. Experimental tests of three full-scale piles and a numerical analysis of eight piles with various parameters were performed to investigate the flexural performance of CFRP prestressed spun high-strength concrete pile. The proposed piles were loaded under four-point bending after prestressing. The experimental and numerical results verified the feasibility of the proposed system, and the CFRP pile exhibited twice of flexural capacity of that of steel-reinforced piles. The flexural performance of the CFRP PHC pile was significantly affected by the reinforcement ratio, prestressing level and modulus of the CFRP. An analytical approach predicting the flexural capacity of the CFRP PHC pile was proposed based on the parametric study. Ninety percent accuracy was achieved for the proposed analytical approach. The presented study can significantly promote the application of CFRP in pile foundations and improve the durability of PHC piles. [ABSTRACT FROM AUTHOR]

Transonic buffet flow is a classical complex and unstable flow that has a negative effect on aircraft fly safety. Therefore, it is crucial to study the unsteady characteristics of buffet flow. The numerical analysis method is very useful in achieving the aforementioned goal. In this paper, focused on the typical supercritical airfoil OAT15A in fixed and pitching conditions, unsteady Reynolds averaged Navier–Stokes (URANS) closed with the sst-kω turbulence mode, coupled with the structure dynamical equation, is utilized to investigate the transonic buffet flow. Firstly, from the perspective of coherent flow structure, flow velocity divergence snapshots constructed from unsteady flow solutions are used to analyze the feature of transonic buffets in the two cases mentioned. Then, DMD modes are extracted by the dynamic mode decomposition technique from the velocity snapshots and adopted to analyze the flow modes of the two distinct flow fields. The numerical simulation results show that, in the fixed case, the regular motion feature of the buffet is present, the shock oscillation is closely related to the vortex structure, and the durations of rearward and forward movements of the shock are both equal to half of the buffet period. In the pitching case, the duration of the rearward motion of the primary shock is approximately five eighths of one buffet period, and the secondary shock appears with the primary one moving downstream, and they interact with each other. The region of the shock movement is larger than that of the fixed case, and there is chaotic flow rather than periodic flow in its wake. Structural elastic oscillation changes the characteristics of the aerodynamic response, which is solely affected by the frequency of the pitching oscillation. [ABSTRACT FROM AUTHOR]

In light of the limitation that passive suspension can only provide vibration isolation within a specific range, a magnetorheological suspension in extrusion mode was developed. The reliability of structural parameters was ensured through theoretical analysis and numerical simulation, building upon traditional hydraulic suspension. A model linking static stiffness to the diameter of the upper extrusion plate, as well as the heights of the upper and lower liquid chambers, was established using Simulink as an evaluation index. The static stiffness performance of the magnetorheological suspension was then optimized using this model. Results indicate that while meeting the static stiffness requirements, the optimized Magnetorheological Suspension demonstrated a 29.22% increase in static stiffness (approximately 57.71 N/mm) compared to its previous state, validating the effectiveness of stiffness optimization for this system. [ABSTRACT FROM AUTHOR]

Water inrush from separation layers is a special type of water inrush disaster that occurs during coal mining. It is characterized by the absence of precursors before the inrush, a sudden and massive influx of water, strong destructive power, and significant difficulty in prevention and control. This disaster causes substantial economic losses and casualties in mines. To study the dynamic evolution characteristics of the overlying rock strata in Guojiahe coal mine, field investigations, theoretical analysis, physical simulations, and numerical simulations were conducted. The development state of the overlying rock strata and the height of the water-conducting fractures in the 1304 working face during continuous mining were analyzed, and the spatial position of the strata where water hazards could form was determined. Through theoretical calculations, the height of the water-conducting fracture zone was found to be approximately 205 m, forming a water-storable separation space about 248 m above the coal seam roof. A physical similarity model was constructed to study the development state of overlying rock strata separation in the 1304 working face. Experimental results indicate that, as the working face advances, the rock strata gradually develop lateral separation spaces from bottom to top, and vertical fractures increase progressively in a similar manner. The spaces and fractures formed in the early stages of the working face advance gradually close and form a compaction zone. However, new fractures develop near the working face side. As mining continues, the asynchronous movement of the overlying rock promotes the development of vertical fractures, providing water-conducting channels for water inrush from the separation. Based on numerical simulation analysis of the development state of overlying rock strata separation and the height of the water-conducting fracture zone, it can be concluded that the water-storable separation space develops between the 8th layer of the formation of sandy mudstone and the 9th layer of the Yijun Formation conglomerate, which is 248 m from the coal seam roof. When excavated to 280 m, the separation space reaches its maximum, with a width of about 19 m and a height of about 1.2 m, and the water storage capacity increases to its maximum. The height of the water-conducting fracture zone eventually increases to 202 m. [ABSTRACT FROM AUTHOR]

Geologic fractures such as joints, faults, and slip surfaces govern the stability and performance of many subsurface systems in the built environment. As such, a variety of approaches have been developed for computational modeling of geologic fractures. Yet none of them lends itself to a straightforward utilization with the classical finite element method widely used in practice. Over the past decade, phase-field modeling has become a popular approach for simulating fracture, because it can be implemented simply with the standard finite element method without any surface-tracking algorithms. However, the standard phase-field formulations do not incorporate several critical features of geologic fractures, including frictional contact, pressure-dependence, quasibrittleness, mode-mixity, and their combined impacts on cracking. This article provides a brief report of a novel phase-field model that incorporates these features of geologic fractures in a well-verified and validated manner. Remarkably, the phase-field model allows one to simulate the combination of cohesive tensile fracture and frictional shear fracture without any algorithms for surface tracking and contact constraints. It is also demonstrated how phase-field modeling enables us to gain insights into geologic fractures that are challenging to investigate experimentally. [ABSTRACT FROM AUTHOR]

Introduction: Soil organic carbon (SOC) content can vary significantly across a given plot. Therefore, a representative sampling is a prerequisite to obtain meaningful results from analysis and of utter importance when SOC quantification is used to quantify (temporary) carbon dioxide removal (CDR). However, certain management practices aiming to increase SOC further increase the level of heterogeneity and may challenge representative sampling schemes. This includes concentrated root-zone application of biochar, which immediately increases SOC with the input of biochar-C and may promote the local enrichment of non-biochar SOC over time. Methods: Here, we used numerical modelling to quantify the number of single sampling points (soil cores) needed to achieve a representative sample of biochar-C and total SOC on a plot after application of biochar in rows, e.g., for growing vegetables, or in the circumference of trees in agroforestry systems. Results: After row application of 5 t ha-1 biochar in soil with rather low SOC content (26 t ha-1), 140 soil cores (per 0.25 ha plot) where necessary to achieve representative sampling of C-stocks (±5% error) in 90% of the repeated sampling simulation cases. Compared to realistic and cost-effective soil sampling scenarios in agronomic practice, we conclude that concentrated root zone application of biochar makes representative sampling for quantification of SOC in soils with low baseline C-stocks virtually impossible. Discussion: This finding calls into question the soil-sampling and SOC-analysisbased ("result-based") monitoring of SOC as a (temporary) CDR when biochar might have been applied. Considering the rapid scaling of biochar production and use in agriculture, this is a considerable challenge for SOC certification. Instead, action-based incentives, rewarding farmers for carrying out specific practices, could be applied to promote carbon farming practices. [ABSTRACT FROM AUTHOR]

Rock slope failures pose significant challenges in geotechnical engineering due to the intricate nature of rock masses, discontinuities, and various destabilizing factors during and after excavation. In mining industries, such as national cement factories, multi-benched excavation systems are commonly used for quarrying. However, cut slopes are often designed with steep angles to maximize economic benefits, inadvertently neglecting critical slope stability issues. This oversight can lead to slope instability, endangering human lives and property. This study focuses on analyzing the stability of existing quarry cut slopes, estimating their final depth, and conducting a parametric study of geometric profiles including bench height, width, face angle, and rump width. Kinematic analysis helps identify potential failure modes. The results reveal that the existing quarry cut slope is prone to toppling, wedge failure, and planar failure with probabilities of 42.68%, 19.53%, and 14.23%, respectively. Numerical modeling using the finite element method (Phase2 8.0 software) was performed under both static and dynamic loading conditions. The shear reduction factor (SRF) of the existing quarry cut slope was 1.01 under static loading and 0.86 under dynamic loading. Similarly, for the estimated depth, the SRF was 0.82 under static loading and 0.7 under dynamic loading. These values indicate that the slope stability falls significantly below the minimum acceptable SRF, rendering it unstable. The parametric study highlights the face angle of the bench as the most influential parameter in slope stability. By adjusting the bench face angle from 90° to 75°, 70°, and 65°, the SRF increased by 31.6%, 35.4%, and 37.9%, respectively. Among these, a 70° bench face angle is recommended for optimal stability with a SRF of 1.27 under static loading and 1.18 under dynamic loading. [ABSTRACT FROM AUTHOR]