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The erosive wear encountered in some industrial processes results in economic loss and even disastrous consequences. Hitherto, the mechanism of the erosive wear is not clear, especially when the erosive wear is caused by large particles (>3.0 mm) carried by a flowing liquid. Current approaches of predicting erosive wear need improvement, and the optimization of relevant equipment and systems lacks a sound guidance. It is of significance to further explore such a subject based on the relevant literature. The present review commences with a theoretical analysis of the dynamics of large particles and the fundamental mechanism of erosion. Then the characteristics of the erosion of various equipment are explicated. Effects of influential factors such as particle size and properties of the target material are analyzed. Subsequently, commonly used erosion models, measurement techniques, and numerical methods are described and discussed. Based on established knowledge and the studies reported, some expectations for future work are proposed. [ABSTRACT FROM AUTHOR]

This paper studies the effect of flow rate control modes on VRB performance based on a validated numerical model. Four modes were put forward, i.e., constant flow rate, variable flow rate with equal anolyte and catholyte (Variable modes I and III) and variable flow rate with unequal anolyte and catholyte (Variable mode II). Under the optimal condition (80 mA/cm2 current and 85% state of charge, SOC), the charging efficiency under the Variable mode II is 0.59% higher than that under the constant flow, while 0.45% and 0.85% higher than those under Variable modes I and III, respectively. The charging efficiency improvement could be largely ascribed to anolyte and catholyte flow adjustment independently, which balances the pump power needed and concentration overpotential loss, benefitting the reduction of total power loss. Moreover, when the charging current is 120 mA/cm2, the maximum SOC of tank under Variable modes I, II, and III increase by 7.63%, 6.41%, and 13%, respectively, in comparison with that under the constant flow rate. The significant increase under Variable mode III is due to an introduction of new objective function (pseudo power loss function), which limits the concentration overpotential difference between anolyte and catholyte, extending time to reach cut-off voltage. [ABSTRACT FROM AUTHOR]

The deep transboundary aquifer of regional scale along the Czech Republic–Austria border in Central Europe serves as a thermal-mineral water resource for balneotherapy and plays an important role in the region's development. The aquifer is composed mostly of Jurassic carbonates at depths from 160 to − 3000 masl. Despite more than two decades of exploitation, no complex analysis of groundwater flow directions and groundwater fluxes ever took place. Now, cross-border cooperation enabled the research team to gather crucial information on the Jurassic aquifer. For a better understanding of the groundwater flow system, a numerical model was developed. To simulate the effect of variable density and viscosity occurring in such a deep aquifer, the SEAWAT numerical model was used. The simulation shows that there is an inflow of low mineralised groundwater from the crystalline outcrops in the northwest and inflow of saline groundwater from southeast. Aquifer discharge was identified along the zone partly corresponding to the course of the Dyje River. To check the model's accuracy, the river water was sampled together with streamflow measurements. Detected sections of increasing chloride concentration indicate zones of the Jurassic aquifer discharge into the Dyje River. The discharge rate of 85 L/s derived from streamflow and chloride concentrations matches the value computed by the model. The relatively high discharge of the Jurassic aquifer contributes significantly to the high chloride loading observed in the Dyje River. [ABSTRACT FROM AUTHOR]

This research proposes a novel nature-based design of a new concrete armour unit for the cover layer of a rubble-mound breakwater. Armour units are versatile with respect to shape, orientation, surface condition details, and porosity. Therefore, a detailed analysis is required to investigate the exact state of their hydraulic interactions and structural responses. In this regard, the performance results of several traditional armour units, including the Antifer cube, Tetrapod, X-block and natural stone, are considered for the first step of this study. Then, the related observed results are compared with those obtained for a newly designed (artificial coral) armour unit. The research methodology utilizes the common wave flume test procedure. Furthermore, several verified numerical models in OpenFOAM code are used to gain the extra required data. The proposed armour is configured to provide an effective shore protection as an environmental-friendly coastal structure. Thus it is designed with a main trunk including deep grooves to imitate the typical geometry of a coral type configuration, so as to attain desirable performance. The observed results and an analytic hierarchy process (AHP) concept are used to compare the hydraulic performance of the studied traditional and newly proposed (artificial coral) armour units. The results indicate that the artificial coral armour unit demonstrates acceptable performance. The widely used traditional armour units might be replaced by newer designs for better wave energy dissipation, and more importantly, for fewer adverse effects on the marine environment. [ABSTRACT FROM AUTHOR]

This paper aims to propose a design method for energy piles using the results of in situ pressuremeter tests. The method is based on the incorporation of thermal effects through a numerical model of cylindrical cavity expansion. Pressuremeter profiles are generated by the numerical model, which represent the limit pressure at different temperature variations. The pile's bearing capacity is, subsequently, determined by following the standard procedure outlined in Eurocode 7 for the pile design, which is based on pressuremeter tests. Thus, relying on pressuremeter curves, the proposed method is enabled to provide the mobilized base resistance, shaft friction and the bearing capacity of an energy pile. In a second phase, a case study of an energy pile located in a clay soil is conducted in order to explain the different steps of the proposed method and to examine the impact of thermal effects on the bearing capacity. The study reveals an increase of the bearing capacity when heating which reaches 3% at Δθ = 40 °C and a decrease of 4% at Δθ = − 40 °C when cooling. This variation is non-linear and asymmetric because the decrease caused by cooling is not fully recovered during heating: A loss of 1% of the bearing capacity is observed. As a result, it is crucial to consider thermal effects in the design of geothermal piles. On the other hand, the proposed method could be a practical approach for engineers to design energy piles. [ABSTRACT FROM AUTHOR]

In this paper, a novel numerical model for characterizing the seepage and dissolution coupling effect on the durability of anti-seepage walls of earth-rock dams is proposed. The model considers the influence of hydraulic gradient-driven seepage on the non-equilibrium decomposition of the calcium dissolution in concrete, as well as the effects of seepage dissolution on pore structure, permeability, and diffusivity. The reasonableness of the model is validated by experimental and literature data, which is then applied to analyze the deterioration and failure processes of a concrete cutoff wall of an earth-rock dam in Zhejiang Province, China. On this basis, the seepage dissolution durability control indices of anti-seepage walls are identified. The findings demonstrate that the suggested method accurately explains the calcium leaching process in concrete. Under the seepage and dissolution coupling effect, calcium in the wall continuously decomposes and precipitates, leading to varying degrees of increases in structural performance parameters, which weaken the seepage control performance of the walls and consequently result in an increase in seepage discharge and hydraulic gradient. By proposing the critical hydraulic gradient as a criterion, the service life of the wall is projected to be 42.8 years. Additionally, the upstream hydraulic head, the initial permeability coefficient, and the calcium hydroxide (CH) content are three crucial indices affecting the durability of walls, and these indices should be reasonably controlled during the engineering design, construction, and operational phases. [ABSTRACT FROM AUTHOR]

The aim of this study is to predict the distribution of temperature at various positions on silver-coated firefighter protective clothing when subjected to external radiant heat flux. This will be helpful in the determination of thermal protective performance. Firefighter clothing consists of three layers, i.e., the outer shell, moisture barrier and thermal liner. The outer shell is the exposed surface, which was coated with silver particles through a physical vapor deposition process called magnetron sputtering. Afterwards, these uncoated and silver-coated samples were exposed to radiant heat transmission equipment at 10 kW/m2 as per the ISO 6942 standard. Silver-coated samples displayed better thermal protective performance as the rate of temperature rise in silver-coated samples slowed. Later, a numerical approach was employed, contemplating the impact of metallic coating on the exterior shell. The finite difference method was utilized for solving partial differential equations and the implicit method was employed to discretize the partial differential equations. The numerical model displayed a good prediction of the distribution of temperature at different nodes with respect to time. The comparison of time vs. temperature graphs at different nodes for uncoated and silver-coated samples acquired from numerical solutions showed similar patterns, as witnessed in the experimental results. [ABSTRACT FROM AUTHOR]

A dynamic analysis of the Makhool dam using Geo-studio software is presented in this paper for the purpose of investigating the seismic behavior of earth dams. With emphasis on the dam's height, soil characteristics, and input motion, this study examines the effect of earthquake excitation on the dam's behavior. With input from the SEEP/W program, the analysis was conducted using the QUAKE/W program. In this study, the horizontal component of motion was taken at three different values: 0.04g, 0.06g, and 0.08g. In addition to total stress in x-direction and y-direction, pore water pressure, and x-displacement, the results were presented in figures. Study findings showed that the horizontal displacement and shear strain of the dam increased with dam height, with the maximum displacement of the dam equal to 94 cm at the end of the earthquake. Besides the type of dam soil, the acceleration of the dam was also affected by the strength of the soil, since weaker soil reduced the acceleration of the dam. The pore-water pressure at the dam's base was the highest, with the horizontal movement increasing with depth. In earthquake zones, seismic evaluation is vital for dam construction, and the research provides valuable advice for designing and building earth dams. [ABSTRACT FROM AUTHOR]

• Oil retention models in various types of pipelines are established. • Hierarchical iterative algorithm based on graph theory is developed. • Oil retention in various pipelines is measured for model validation. • Mass flow rate or evaporation temperature increase may reduce oil retention. A multi-split air conditioning system may suffer damage caused by oil starvation in its compressor when the lubricating oil largely retains in long pipelines, and thus a reasonable oil charge based on accurate prediction of the oil retention in pipelines is important. The purpose of this study is to present an oil retention model for pipelines and to experimentally validate this model. The structure of pipelines connecting the outdoor unit and the indoor units with arbitrary numbers installed on separated floors is described as a combination of straight pipe types, joint types, and bend types. In modeling the oil retention, all the components of straight pipes, joints, and bends are numbered to conveniently distinguish each component which is further divided into several control volumes with equal lengths along the flow direction, and the equations of oil retention, pressure drop and enthalpy difference for the control volumes are established to describe the refrigerant-oil flow behavior. A hierarchical iterative algorithm based on the graph theory is developed in order to solve the models quickly. An experimental rig is built to measure the oil retention in four types of straight pipes, and the validation results show that the predicted oil retention in straight pipes agrees with at least 74.0 % of the experimental data within a deviation of ±20 %, and the mean deviation is lower than 15.4 %. Based on the model, the effects of oil retention reduction by increasing the total mass flow rate or the evaporation temperature of refrigerant are quantitatively analyzed. [ABSTRACT FROM AUTHOR]

In the field of lightweight structures, foldcore sandwich structure is regarded as a promising replacement for conventional honeycomb sandwich structure. In this study, a new M-type glass fiber foldcore structure was fabricated by hot-pressing molding technology, and the effects of various factors on the low-velocity impact characteristics were investigated. In addition, a 3 D progressive damage numerical model matching the experimental results was established. The results showed that the impact energy exerted a certain influence on the response characteristics of the sandwich structure, but did not change the development trend of the load curve. The sandwich panel was able to achieve the overall load-carrying potential for the impactor whose size was longer than the foldcore span (25 mm). In addition, as the sharpness of the impactor increased, the damage range of the sandwich panel became concentrated and the load-bearing capacity gradually decreased. As revealed by the findings, the maximum load and specific energy absorption of laminated sandwich panels were improved by 150 and 40% respectively compared to single sandwich panel at base position. Therefore, it is beneficial to appropriately reduce the core span and increase the number of laminations to improve impact resistance of foldcore sandwich in practical applications. [ABSTRACT FROM AUTHOR]

Photovoltaic modules are impacted by overheating, which degrades their conversion efficiency and shortens their lifespan. This work attempts to study the cooling potential for a hybrid photovoltaic/thermal (PV/T) system by employing CuO and Fe 2 O 3 nanofluids with 0.2% and 0.3% volume fractions (φ), circulated in a heat exchanger attached at the rear side of the PV module to lower the temperature of the PV cells and improve its energy and exergy efficiencies. Consequently, a 2D numerical model was analysed given the energy balance across the PV/T system layers, which is evaluated in line with measured experimental data. The results indicate that the successfully synthesised nanomaterials could improve the performance of the nanofluids and increase the heat exchange between PV/T system layers, reducing the PV cells' temperature by 23.49% and 34.58% when cooling by CuO and Fe 2 O 3 nanofluids at φ=0.3%. Compared to the uncooled PV module, the electrical efficiency has increased by 9.21% and 10.30%, while thermal efficiency increased by 38.9% and 43.3% under cooling with CuO and Fe 2 O 3 nanofluids, respectively. Thereby, the exergy destruction (exergy losses) and entropy generation have decreased by about 26% and 68% when cooling with Fe 2 O 3 nanofluid, which improved the exergy efficiency by 13% more than CuO nanofluid. [Display omitted] [ABSTRACT FROM AUTHOR]

There exist various methods for computing reactions in reinforced concrete slabs in buildings, but the most precise approaches involve solving differential equations that are challenging to apply, rendering their practical application infeasible. Consequently, practical methods adopt simplifications in the equations to ensure their practicality. The use of rigid supports is one of the commonly adopted simplifications in calculating displacements and support reactions. The grid theory assumes that the supports are rigid, which does not accurately represent reality in design practice since the beams supporting the slab deform, often causing considerable displacements in the calculation. In this study, a new extension to the grid theory is proposed, which considers the flexibility of slab supports in calculating displacements and support reactions. An analysis of bending moments and displacements of slabs was carried out on 20 numerical models with support flexibility and different boundary conditions. The analyzed loading was static and uniformly distributed, and the boundary conditions adopted in the analytical model included both simply supported and fixed slabs. The numerical analysis showed that the proposed model, which considers the flexibility of slab supports, produced results that were in good agreement with the numerical analysis. [ABSTRACT FROM AUTHOR]

Interlocking Inter-Module Connections (IMCs) in Modular Steel Buildings (MSBs) have garnered significant interest from researchers. Despite this, the optimisation of plate thicknesses in such structures has yet to be extensively explored in the existing literature. Therefore, this paper focuses on optimising the thickness of interlocking IMCs in MSBs by leveraging established experimental and numerical simulation methodologies. The study developed various numerical models for IMCs with plate thicknesses of 4 mm, 6 mm, 10 mm, and 12 mm, all subjected to compression loading conditions. The novelty of this study lies in its comprehensive parametric analysis, which evaluates the slip prediction model. A random forest regression model, trained using the 'TreeBagger' function, was also implemented to predict slip values based on applied force. Sensitivity analysis and comparisons with alternative methods underscored the reliability and applicability of the findings. The results indicate that a plate thickness of 11.03 mm is optimal for interlocking IMCs in MSBs, achieving up to 8.08% in material cost reductions while increasing deformation resistance by up to 50.75%. The 'TreeBagger' random forest regression significantly enhanced slip prediction accuracy by up to 7% at higher force levels. [ABSTRACT FROM AUTHOR]

The ethylene and vinyl acetate (VA) mixture must be compressed to a high pressure of over 100 MPa in a hyper-compressor system to initiate the polymerization. This paper presents a numerical and experimental investigation into the effects of VA concentration on the performance of a hyper-compressor. To this end, an equation of state in the form of Helmholtz free energy was developed to calculate the real thermodynamic properties of VA–ethylene mixture. The average absolute deviations of density and compressibility factor for VA-ethylene compared with experimental values were 1.82% and 1.46%, respectively. Additionally, a three-dimensional (3D) computational fluid dynamics (CFD) model was constructed considering real-fluid thermodynamics, incorporating the motion of the central valve and upstream and downstream pressure pulsations. The predicted p − V diagram and pressure pulsation were compared with experimental data to validate the accuracy of the 3D-CFD model. The results demonstrated that a higher VA weight fraction results in a shorter expansion and compression phase; higher indicated power, suction, and discharge losses; and greater pressure fluctuation. The increment of power loss during the discharge process accounted for 73.27% of the indicated power growth 35.96 kW as the VA weight fraction increased from 0% to 40%. The increment of pressure pulsation in the suction and discharge pipe were mainly attributed to high-frequency pulsations above 10 orders and low-frequency pulsations below 10 orders, respectively. [ABSTRACT FROM AUTHOR]

The vapor intrusion (VI) of volatile organic compounds (VOCs) is a major concern due to their acute and chronic toxicities to indoor human. VI could be more problematic by pressure-driven advection and this could be particularly notable in residential areas. This study introduces a numerical model designed to simulate the transport of VOCs by diffusion as well as advection in unsaturated zone. The model is validated with analytical models suggesting its ability to simulate complex VI scenarios with high fidelity. Using the developed model, several VI scenarios are investigated by considering the episodic changes of atmospheric pressure as well as ventilation system induced indoor pressure changes in an TCE contaminated site. The model simulation shows that relatively lower atmospheric pressures compare to those in indoor environment facilitate TCE migration to the atmosphere leading to less TCE intrusion into indoor environment. This is the case when the indoor pressure is greater than those in atmosphere. On the other hand, when the indoor pressure in building is lower than those in atmosphere and when the pressure in atmosphere is higher than those in indoor, more TCE is intruded inside the indoor of building through the subsurface building cracks leading to the increased TCE levels and human exposure risks. This work not only advances our understanding of VI dynamics but also provides a robust tool for predicting indoor VOC concentrations under varying environmental conditions, especially when pressure driven advection becomes an important transport process in unsaturated zone. [ABSTRACT FROM AUTHOR]

The small-scale roadway model is often used in the fine simulation of mining engineering. The determination of the structure and load conditions of the model has an important influence on the accuracy of the simulation. In this paper, a large-scale stratum model and a small-scale roadway model are established by using finite element method. The optimal loading mode of the roadway model and its applicability under different roof-sidewall stiffness ratios are studied. The simulation accuracy of the roadway model is quantitatively evaluated by comparing the distribution laws of stress field and strain field with those of the stratum models. Under the same roof-sidewall stiffness ratio, the similarity between the simulation results of the roadway model and the stratum model under displacement load is much higher than that under stress load. Under the same load mode, the stress and strain similarity between the stratum model and roadway model increases with the increase of the roof-sidewall stiffness ratio. Furtherly, the simulation application of the roadway drilling pressure relief is carried out. Compared with the large-scale stratum model with small-size elements, the small-scale roadway model under displacement load also shows obvious stress transfer after drilling pressure relief, while it has faster computational efficiency. Finally, a small-scale roadway model simulation method suitable for surrounding rock disaster occurrence mechanism and control is proposed. [ABSTRACT FROM AUTHOR]

This study presented a numerical methodology to elucidate the local mechanical response of the surface layer during and after an EDM electrical discharge, aiming to refine the numerical prediction of the residual stress and strain hardening induced by this process. Advances in models, loads, and boundary conditions were proposed and simulated using the ABAQUS/Explicit computational software. A coherent thermomechanical model was formulated, incorporating Grüneisen's hydrodynamic behavior coupled with the Johnson-Cook plasticity model. Numerical findings highlighted the efficiency of the uniform heat flux distribution model in predicting residual stresses accurately. [ABSTRACT FROM AUTHOR]

A spillway is a significant structure that releases the exceeded water during extreme flood events. It is considered as a safety valve during dams operating. Spillway location at dam body is one of the most important requirements of dam design. Different locations may influence the flow patterns which lead to change in the hydraulic performance of the spillway. In this paper, a numerical model was presented utilizing the Ansys fluent software using the realizable k-ɛ turbulence model to investigate the flow patterns of Mandali Dam's spillway at different locations. The interaction between air and water phases was simulated by using volume of fluid (VOF) model. Moreover, cavitation damage was studied for different flow discharges values. the validation of the numerical model was executed in compression with the measurement of the physical model. A discharge of 1800 m3/s was utilized for validation, while five different discharges; 1800, 1300, 1040, 440, and 67 m3/s were employed to investigate the hydraulic properties. The results show an agreement between numerical model and the physical model. According to the hydraulic properties, the spillway location at the center of the dam is better than its location at the edge of the dam. The discharge coefficient value in scenario one was found to be closer to the physical model value compared to the second scenario. At discharge 1800 and 1300, the discharge coefficient was 2.02 and 1.72, while in scenario two it was 1.46 and 1.21 in comparison with physical model which was 2.06 and 1.99. For cavitation investigations, the numerical model shows that the spillway is safe with no cavitation effects for the whole applied discharge values. [ABSTRACT FROM AUTHOR]

This article presents an analytical solution for the evaluation of the thermal performance of packed bed sensible heat storage. The numerical model developed was tested for four different solid storage mediums. The thermal energy equation is solved numerically by deploying the finite difference method. The presented analytical solution is based on a novel mathematical approach. The numerical model was validated using the computer simulation package Comsol Multiphysics v5.3. Our numerical model results are in good agreement with the published experimental data, with an overall difference of ~10%. Hence, the numerical model is an efficient way of evaluating the thermal performance of packed bed thermal energy storage systems compared to other numerical strategies or computer simulation techniques. This proves that the novel analytical model has shown to be a reliable and broadly accurate approach to acquire the thermal performance of sensible heat storage. [ABSTRACT FROM AUTHOR]

In this paper, we develop a finite-difference time-domain (FDTD) model in which the time-evolving electrical conductivity of the air ionization plasma in DC voltage needed-plate setup is represented. Maxwell's equations are solved using the FDTD method, and the associated currents and discharge fields are computed over time and in three-dimensional space. The proposed model for the electrical conductivity is dependent on time, the applied DC voltage, and the gap length. The necessary data for developing the proposed model is obtained experimentally using a standard discharge needle, with its spherical tip measuring approximately 40 μ m in diameter. Once high voltage is applied, a steady state is achieved. The electrical conductivity σ (t) and its associated parameters are then calculated using nonlinear equations proposed to reproduce the experimentally obtained plasma behavior in the full-wave FDTD model. Voltage ranges from 4 kV to 9 kV, and gap distances are between 4 mm and 8 mm. [ABSTRACT FROM AUTHOR]

In this paper, a novel numerical model of direct methanol fuel cells (DMFC) is proposed aiming to quantitatively analyze the effect of methanol, water, and oxygen mass transfer on the performance and to further improve power and reduce energy losses. The model was validated against experimental data. The model predicts the values of variation of reactant concentrations in each layer and the effect of parameters is analyzed. The results show that overall performance is better at low methanol concentration (1–2 mol/dm3). A rise in a certain temperature (65 K) increases maximum power density by 13.6%, ECOP by 43.9%, voltage efficiency by 13.6%, thermal efficiency by 14.2% and real efficiency by 19.1%, while reducing entropy yield by 19.3%. Moreover, the average of optimization results based on multi-objective particle swarm algorithm (MOPSO) indicated that maximum power density and its corresponding ECOP , and thermal efficiency were increased by 13.47%, 0.03%, and 6.21%, respectively. [Display omitted] • A novel numerical model of DMFC considering mass transfer is proposed. • The entropy production into overpotential losses and methanol crossover loss is investigated. • The model was validated against experimental data. • The model predicts the values of variation of reactant concentrations in each layer and the leakage current density. • The MOPSO algorithm and TOPSIS method are utilized to optimize the power density, ECOP, and thermal efficiency. [ABSTRACT FROM AUTHOR]

Sediment has the potential to influence the landscape, economy and way of life. If the estimation is accurate and the distribution characteristics are known, sediment can be used as a resource. In this brief review, we evaluated recent advances in suspended sediment estimation techniques between 2011 and 2022. The three most popular techniques are Sediment Rating Curves, Machine Learning Models and Physical and/or Numerical Models. Their potential and limitations are briefly explored. Our findings indicate that Machine Learning Models perform better, whereas Sediment Rating Curves offer flexibility in field applications. On the other hand, the paucity of necessary highresolution data for model calibration and validation hinders the performance of Physical and/or Numerical Models. The sampling frequency of input sediment data emerges as a pivotal factor influencing the performance of all methods. To overcome this issue, a semi-automatic surrogate method might be useful. Also, particle size could be included in the rating curves to obtain additional information. This is especially valuable for understanding sediment dynamics and the process of delta formation. [ABSTRACT FROM AUTHOR]

• Develop the 3-D numerical model of sub-Kelvin porous media heat exchanger. • Obtain the optimal structure parameters of porous media for the best performance. • Propose the partial-width liquid gap that shows better performance than the conventional full-width one. A dilution refrigerator is an essential apparatus for achieving sub-Kelvin temperatures. Porous-media heat exchangers used inside dilution refrigerators at temperatures below 100 mK are crucial components that determine their optimal performance. In this study, a numerical model of a porous-media heat exchanger is developed. The local thermal non-equilibrium heat transfer model captures the Kapitza heat transfer between solid and fluid components, whereas the coupled Brinkman-Forchheimer and Navier-Stokes equations describe fluid flows in porous media. Results indicate that a liquid gap can enhance the thermal conduction between the flow channel and porous media, thus improving the heat-exchange efficiency of the porous media. For a constant-volume and -thickness porous media, the most suitable length-to-width ratio is 5. The concentrated phase exhibits a lower outlet temperature, whereas the dilute phase exhibits an appropriate pressure drop. For a constant-volume and -length porous media, the optimal width-to-thickness ratio is 10, which provides the best thermal and hydrodynamic performances. For a full-width liquid gap, increasing its thickness enhances both the thermal and hydrodynamic performances but also increases the usage of 3He. Under a constant volume of liquid gap, a partial-width liquid gap can improve the heat-exchange efficiency, thus achieving better thermal and hydrodynamic performances than the conventional full-width one. [ABSTRACT FROM AUTHOR]

We examine the role of aerosol hygroscopicity (κ) on the formation of clouds and precipitation over the Western Ghats (WG) in India using various numerical model simulations (i.e., particle‐by‐particle‐based small‐scale, high‐resolution mesoscale model). For the diffusional growth of cloud droplets, the size‐dependent hygroscopicity is used in the κ‐Köhler equation of direct numerical simulation. The results of the small‐scale model reveal that the distribution of cloud drop size varies from the initial mixing state to the well‐mixed state due to variation in κ. The value of κ is obtained from Humidified Tandem Differential Mobility Analyzer (HTDMA) instruments at the High Altitude Cloud Physics Laboratory, India. The idealized and real simulations using the Weather and Research Forecasting (WRF) model with the aerosol‐aware Thompson microphysics scheme are conducted by changing κ values. Depending on the type of clouds (shallow or deep), different κ values determine the mass and number of cloud and rain droplets. Low hygroscopicity (organics) simulates more and smaller drops, as well as uplifts below freezing level, resulting in more ice‐phase hydrometeors. Organic aerosols have a significant impact on the formation of more snow and graupel hydrometeors. As compared to high κ, low hygroscopicity weakens updrafts at the intermediate level and strengthens them at the upper level in the deep cloud region. The intensity of precipitation varies due to low and high κ. The findings indicate that aerosol composition has a significant impact on the activation of cloud condensation nuclei. This study suggests that aerosol hygroscopicity is essential in weather prediction models to integrate aerosol chemical compositions. [ABSTRACT FROM AUTHOR]

Dewatering of alkali metal halide salts in conventional co-current or counter-current spray driers to obtain low moisture content and agglomeration in resultant dried powders is difficult owing to their hygroscopic nature. Co-current spray driers offer the advantage of good heat transport characteristics in spray zone while counter-current spray driers offer better thermal utilization throughout the drying chamber. In the present work, modified prototype of a conventional counter-current spray drier is developed to obtain both these advantages in the drying chamber by employing induction heating and mechanical pulsation techniques. After carrying out several experiments in this prototype viz. Induction heating-based pulsed spray drier (IH-PSD), the optimal process parameters are obtained which maximize thermal utilization throughout the drying chamber and minimize both moisture content and agglomeration in resultant dried powders of sodium and potassium halide salts. The initial droplet and final particle size distributions are obtained using laser diffraction analyzer and sieve shaker experiments respectively. An experimentally validated numerical model implemented using open-source computational solvers is utilized to obtain average drying rates in IH-PSD. It is observed that the average drying rate lies between 0.03 and 0.18 mg/s and 0.04 and 0.14 mg/s for sodium and potassium metal halide salts respectively. Spray drying prototype coupled with Induction heating and mechanical pulsation. Dewatering of sodium and potassium metal halide salts using the spray drying prototype. Numerical-neural network model implemented by open source computational solvers. Utilization of Laser diffraction analyser for measurement of initial droplet size. Model calculates the average drying rate with an accuracy around 83%. [ABSTRACT FROM AUTHOR]

The stability of earth-rock dams is a critical factor in hydraulic engineering, directly impacting the safety of reservoirs and downstream regions. Seepage and thermal conduction, key physical processes influencing dam stability, are typically studied independently. However, as environmental changes become increasingly significant, the interaction between these processes--the coupling effect--cannot be overlooked. This paper delves into the coupled effects of seepage and thermal conduction in earth-rock dams, initially establishing a coupled control equation for the seepage and temperature fields. Subsequently, a numerical model for the seepage process under thermal conduction coupling effects is developed. Through precise simulation, this study aims to enhance the predictive capability of dam behavior under various environmental conditions, thereby providing a scientific basis for dam design and maintenance. The research identifies that existing models often neglect the impact of temperature on seepage characteristics and exhibit biases in parameter selection and boundary condition settings, leading to inaccurate simulations of dam behavior in complex environments. Therefore, the numerical model in this study, considering key parameters such as convective heat transfer coefficients, offers a more comprehensive assessment of the stability and functionality of earth-rock dams in real-world conditions. [ABSTRACT FROM AUTHOR]

Scattering-type scanning near-field optical microscopy (s-SNOM) is becoming a premier method for the nanoscale optical investigation of materials well beyond the diffraction limit. A number of popular numerical methods exist to predict the near-field contrast for axisymmetric configurations of scatterers on a surface in the quasi-electrostatic approximation. Here, a fully electrodynamic approach is given for the calculation of near-field contrast of several scatterers in arbitrary configuration, based on the generalized Mie scattering method. Examples for the potential of this new approach are given by showing the coupling of hyperbolic phonon polaritons in hexagonal boron nitride (hBN) layers and showing enhanced scattering in core-shell systems. In general, this method enables the numerical calculation of the near-field contrast in a variety of strongly resonant scatterers and is able to accurately recreate spatial near-field maps. [ABSTRACT FROM AUTHOR]

Liquid sodium hybrid bearing is mechanical pump shaft bottom key support components, that play a balanced radial force of the impeller by fluid effect, in order to improve the bearing performance, based on the calculation model, simulation analysis, structure improvement and other aspects of analysis, this paper based on the theory of fluid mechanics of bearing finite element model for numerical calculation and analysis of flow field. Under different eccentricities and vibration velocities, the influence of structure improvement on bearing capacity is analysed. The results show that the bearing capacity of the liquid sodium hybrid bearing is mainly the hydrostatic bearing capacity, and the hydrodynamic pressure only plays an auxiliary role. After the improvement of the load‐bearing structure, the load‐bearing capacity is increased by 4%–7.3%. And the leakage is reduced by 27%–38% when the depth of the annular groove is 0.6 mm. [ABSTRACT FROM AUTHOR]

This scientific paper delves into the numerical studies of the process of filling the barrel with water and the subsequent breakup of the water jet and water atomization in the barrel of the fire extinguishing installation. The numerical model of the process of water injection into the barrel with the subsequent breakup of water by a shock wave was substantiated. To simulate these processes, the ANSYS software was used. VOF (volume of fluid) method-based model was applied where it is assumed that there is no penetration of one medium into another. The solution is based on the surface tracking method applied to a fixed Eulerian grid. According to the results of the numerical study, it was established that the water injection time significantly exceeds the duration of the gas detonation cycle in the fire extinguishing installation. In particular, we found out that it takes 8 ms just to spread the water jet from one side of the barrel to the other. It was observed that a high quality of water atomization under the action of a high-speed gas flow including the water located along the barrel wall. We stated that it is unreasonable to use the pulse injection of water into the barrel in the designed fire extinguishing installation due to a high fregiency of the shock wave generation exceeding 23 Hz. [ABSTRACT FROM AUTHOR]

The paper is dedicated to the numerical study of the dependence of plasma antenna resonance wavelengths on pressure. The study was carried out by simulating a RF capacitively coupled plasma with the Comsol Multiphysics software in one- dimensional formulation. Based on the calculated electric current in the plasma, the directional pattern and axial distribution of the electromagnetic field were found by solving Maxwell's equations in a 2D formulation. The results showed that one of the advantages of plasma antennas is the transmission of waves at significantly longer wavelengths compared to metal antennas of similar geometry. [ABSTRACT FROM AUTHOR]

A paramount determinant in the selection of irrigation canal overflow configurations resides in their flow conveyance capacity. This overflow capacity is contingent upon the effective length and geometric characteristics of the weir. In the present investigation, the hydraulic performance and discharge coefficient (Cd) of circular-crested weir were scrutinized through the utilization of FLUENT software. Specifically, the study delved into the impact of geometric parameters, namely the radius and height of the crest, on these hydraulic aspects. Following the execution of calibration and validation procedures using FLUENT in conjunction with laboratory-derived data, the outcomes of the simulation revealed that augmenting the radius of the crest led to a corresponding escalation of 144.28% in the maximum pressure exerted on the crest and a 6.84% increase in flow depth. Conversely, the maximum velocity and Cd experienced reductions of 6.84% and 7.82%, respectively. The elevation of the weir height exhibited negligible influence on the maximum pressure magnitude at the crest. Contrastingly, a reduction in weir height constricted the range of pressure variations on the crest, indicating a more limited domain of pressure changes. Elevating the weir height induces a notable augmentation in the maximum flow velocity at the crest by 44.36%, concomitant with a reduction in both the depth and Cd by 52.66% and 68.96%, respectively. [ABSTRACT FROM AUTHOR]

The shear strength parameter of an anchoring interface is one of the key parameters affecting the design of bolt support. To better realize the design of bolt support, the pullout model of fully grouted bolts was established by FLAC3D numerical software. The commonly used tri-linear bond-slip model of the anchoring interface was selected. The variable controlling method was used to investigate the effects of the shear strength parameters of the anchoring interface on the bearing performance of fully grouted bolts. The results show that, with the increase in the displacement at the peak shear stress, the bearing capacity and the energy absorption of fully grouted bolts decrease and the ability of the fully grouted anchoring system to resist external loads weakens. Meanwhile, the deformation capacity of fully grouted bolts increases, and the durability of the fully grouted anchoring system is enhanced. With the increase in the residual shear stress and the displacement at the residual shear stress, the bearing capacity and deformation capacity of fully grouted bolts both increase, and the energy absorption also increases. Increasing the post-peak bearing properties of the anchoring interface can help improve the bearing performance of fully grouted bolts and enhance the ability of the fully grouted bolts to resist failure. The results may provide guidance for support design and performance enhancement of fully grouted bolts. [ABSTRACT FROM AUTHOR]

The Holocene Storegga tsunami, 8120–8175 cal a bp, resulted in run‐up heights of up to 3–6 m around mainland UK and coincided with a suggested large population decline in the coastally focused Mesolithic population in Northern Britain. At Howick, Northumberland, the site of a Mesolithic settlement, a nearby sediment deposit may be of tsunamigenic origin, but this is uncertain. Here, a numerical model was used to simulate the Storegga tsunami in Northumberland. Two scenarios of relative sea‐level change, and a third incorporating high tide, were simulated with mortality estimated within the intertidal zone for the Mesolithic sites in the region. The results showed that only with the addition of high tide could the sediment deposit site have been inundated by the tsunami. At Howick, mortality estimates varied but were up to 100% within the resource‐rich intertidal zone. The tsunami inundated a large area and would have led to the loss of key resources such as hazelnuts prior to the winter months. These combined effects would have probably been replicated throughout coastal settlements in Northern Britain, possibly leading to the contemporary population decline estimated to have occurred at this time. [ABSTRACT FROM AUTHOR]

When evaluating the value of a particular firm or asset, to calculate the final result objectively and consider the critical variables of the market conjuncture, it is necessary to select the optimal discount rate, which will be used to assess the riskiness of cash flows. The discount rate should reflect all possible premiums impacting the financial and non-financial riskiness of the evaluated asset. In particular, for calculating the value of the loan obligation, the discount rate must reflect the default premium, which implies the risk that the borrower will not be able to repay the obligation in the predetermined volume and term stipulated by the agreement. On the other hand, when investing with equity, the discount rate should reflect the equity risk premium. Therefore, a logical question arises: how do we measure the riskiness of default and investor's equity? It is rational to share the opinion that assessing the risk from the investors' point of view and subsequently converting it into a numerical indicator is a rather complex task, especially when it comes to developing countries, where the sources of market risk, measurability, are even more obscure and require additional observation and study. Therefore, the selection of the optimal model, which is as close as possible to reality and, at the same time, can quickly reflect all the risk factors that affect the investment, is critically important. This task is complex for an investor, but based on theoretical and practical knowledge, experience, and logic, it is possible to cope with this challenge. Financial and economic representatives unanimously agree that selecting an effective numerical model for calculating the cost of equity and reflecting relevant risk factors in it is beneficial both for local and global investors and for a developing country's stable economic growth. Improving the cost of capital methodology can transmit positive results to the economy and its agents through several channels. Within the framework of the article, a comparative analysis of numerical models for measuring investment cost was carried out. In the first part of the article, the theoretical and practical numerical models in the financial and economic literature were reviewed in detail. After that, an analysis of the capital asset pricing model, arbitrage pricing model, multifactor, and alternative models was carried out, the shortcomings and advantages of each model were reviewed, as well as a discussion was made about how realistic the assumptions behind these models are and how materially damaging the existence of these assumptions can be to the numerical results, of the model as a predictor of expected returns. The next part of the article analyzed which numerical model should be used and what changes are needed so that the standard financial models for calculating the cost of equity would reflect the systemic risk environment of the developing country relevantly. The literature review shows several main directions to choose from when selecting a measurement model for expected returns. Within the article, the decision to choose a model for calculating the cost of capital in developing countries is based on theoretical and pragmatic considerations. During the selection of the methodology, further questions were asked: to what extent is it possible to obtain information about the variables required to use the numerical model, how simple and intuitive the essence of the model, and what the interpretation of the results derived from it will be for the reader, which model, as a determinant of future expected returns, is inclined to use in the empirical studies carried out in the financial field. After analyzing and evaluating the questions arising from all the factors mentioned earlier, a modified version of the capital asset pricing model was selected. Modifying the capital asset pricing model allows for a change in the standard approach and reflects all the additional risk factors that may characterize the economy of a developing country. The essence of the modification lies in including an additional premium in the numerical model, which will reflect and try to reflect local financial and non-financial riskiness in numerical indicators. Aswat Damodaran notes that the modified CAPM's main advantage is its simplicity and intuitiveness in assessing the relationship between risk and opportunities. Also, Damodaran emphasizes that more sophisticated and complex numerical models, such as arbitrage pricing, Fama and French 3-factor, and other models, despite being better explainers of historical trends, empirical research shows that they cannot offer Significantly improved forecasts of expected rates of return compared to CAPM, it is therefore not surprising that the capital asset pricing model is still the most popular and applicable to investors today. Calculating the cost of equity is a rather complex and time-consuming process, which in turn requires a reliable information resource, in-depth knowledge of the field, and a detailed analysis of the features of the potential investment proposal. When an investment decision is made in the market of a developing country, all the circumstances mentioned above are associated with additional risk factors, such as access to historical databases, reliable information resources, the existence of political risks, low level of development of the country's financial infrastructure, low transparency of the market, increased signs of corruption and others. Hence, directly selecting and transferring the numerical model that is used in developed markets to the market of a developing country could be materially damaging and not lead to optimal financial decision-making for the investor. Based on this fact, within the framework of the article, a traditional, wellknown capital asset pricing model was selected and recommended, which should be modified and include a premium relevant to a developing country's systemic risk. On the other hand, as mentioned at the beginning of the article, the numerical model for calculating the investment discount rate, which is consistent with economic and financial logic, is beneficial for the economy of a developing country in many ways, including effective allocation of resources among economic agents, support for the development of financial infrastructure, increasing the transparency of financial markets, and others. [ABSTRACT FROM AUTHOR]

Human surrogates have long been employed to simulate human behaviour, beginning in the automotive industry and now widely used throughout the safety framework to estimate human injury during and after accidents and impacts. In the specific context of blunt ballistics, various methods have been developed to investigate wound injuries, including tissue simulants such as clays or gelatine ballistic, physical dummies and numerical models. However, all of these surrogate entities must be biofidelic, meaning they must accurately represent the biological properties of the human body. This paper provides an overview of physical and numerical surrogates developed specifically for blunt ballistic impacts, including their properties, use and applications. The focus is on their ability to accurately represent the human body in the context of blunt ballistic impact. [ABSTRACT FROM AUTHOR]

Seawater intrusion (SWI) is a consequence of communication between the ocean and inland groundwater entailed by overexploitation and has been a global issue harming production, life and ecology in coastal regions. This paper established a numerical model to identify SWI features in a wider space under different pumping-well layouts based on the number of wells (N), distance between the coastline and wells (Dcw), and distance between wells (Dww) and further researched the influence of the location of the screen (Ls) and calculated S as an index inferring the SWI degree. An evaluation index (EI) was proposed considering two contradictory parameters: the corresponding total critical pumping rate (Qc) indicated the critical situation in which saltwater was almost pumped, played a good role as the resource function, and S referred the negative environmental impact. Sensitivity analysis was performed to explore the relationship between the evaluation indexes and the parameters of pumping well layouts. The results revealed how seawater intruded inland groundwater under different pumping well layouts and the anthropogenic impact factors influencing the SWI process. Sensitivity analysis verified that Dcw was the key factor in optimizing pumping well layouts to maximize the quantity of groundwater resources and minimize the environmental damage of SWI. Research on Ls revealed that a higher location of the screen of the well could effectively abate SWI. This research fully explained SWI characteristics under different pumping well layouts and proposed the key factors during coastal groundwater exploitation work, which enhanced the understanding of SWI and contributed to the arrangement of realworld water pumping activities in coastal regions. [ABSTRACT FROM AUTHOR]

Dunes are important for bedload transport in almost all large river systems and exert an important control flow resistance. Investigating dunes is fundamental for simulating discharge, sediment transport, and flood routing. However, the spatiotemporal dynamics of dunes and flow resistance remain poorly understood in large alluvial river systems mainly due to the lack of high‐resolution data. Here we analyzed in‐field observed data on annual profiles of 450 cross‐sections, river bathymetry, discharge, water levels, and sediment in the Middle Yangtze River, and found that dunes developed and flow resistance increased (+10%) in the post‐Three Gorges Dam period. We ascertain that the development of dunes plays the dominant role in augmenting flow resistance, as evidenced by roughness height change (+29%) using a modified Van Rijn method. Ultimately, dune development was incorporated into a hydrogeomorphic numerical model of the Yangtze River to improve flow resistance quantification, and thus, the water level simulation. Our findings highlight the potential increase in flow resistance in response to upstream damming in large rivers and have important implications for flood management and riverine ecology. Key Points: Random wave analysis is utilized to evaluate dune characteristics and calculate flow resistanceAn amplificated flow resistance after upstream damming, declining with downstream distanceThe development of large dunes accompanied by riverbed grain coarsening jointly increases flow resistance [ABSTRACT FROM AUTHOR]

ABSTRACT Cylindrical steel silos with flat bottoms are widely used in agriculture and industry for storing granular materials. While research has advanced our understanding of pressure on silo walls, accurate prediction, especially during the dynamic filling and discharge phases, remains a challenge. This study presents a finite element (FE) analysis of pressure distribution in a model cylindrical steel silo with a flat bottom, investigating the influence of the height-to-diameter (H/D) ratio. The numerical results were validated against experimental data from a pilot-scale test facility storing corn. Material properties were determined through laboratory experiments, with mechanical properties obtained from literature. An arbitrary Lagrangian formulation was employed for the FE calculations. The FE results showed good agreement with experimental data for static pressure distribution on the silo wall across all H/D ratios analyzed. While the patterns of dynamic pressure curves were similar, the FE-predicted magnitudes were lower than those observed experimentally. Notably, the simulations captured significant pressure fluctuations during silo discharge.

Slab-on-pile (SOP) have been constructed widely in many highway projects in Indonesia as it is preferable in soft-soil sites. This study is aimed to determine the optimal structural configuration by adding braced frame devices to the longitudinal direction of the slab-on-pile structure. The optimization process was carried out to obtain the minimum number of pile configurations, reducing construction costs. A total of three numerical models were compared, namely SOP-A, SOP-B, and SOP-C, representing SOP with configurations of 50 piles, 35 piles, and 35 piles plus thirty braced frames, respectively. The cyclic analysis procedure and structure design were executed based on ACI 374.1 and the Indonesian standard SNI 1725:2016. The results showed that all P-M responses of the SOP-A and SOP-C structures met the cross-section capacity requirements, except for the SOP-B. The addition of braced frames in SOP-C facilitated a 38% energy dissipation improvement and caused a significant reduction of number of the spun piles.

Ventilation plays a key role in the livestock buildings since it is important to guarantee a comfortable environment and adequate indoor air quality for the animals. Naturally ventilated barns are usually characterized by high variability in the ventilation conditions. Moreover, the ventilation efficiency can be very different in different areas of a barn because of the different presence of the animals. On the other hand, appropriate ventilation is an essential requirement to ensure animal welfare and efficient and sustainable production since a proper ventilation is the most efficient way to remove undesirable air pollutants and to obtain a comfortable microclimate for the welfare of the animals. In this regard, the computational fluid dynamic (CFD) simulations represent a powerful and useful tool because they can be used to assess ventilation and microclimate conditions. In this context, the present study has the object to assess whether different CFD modelling approaches (i.e. model with animals modelled as obstacles with closed volume and model enriched with cows modelled as obstacles capable of exchanging heat with the surrounding air volume) show differences in relation to the climatic conditions inside a naturally ventilated dairy barn. The comparison of the results, set in terms of indoor air temperature and air velocity contours of the two different models, arises that if a precise definition of the microclimatic features is necessary, in order to correlate them with production parameters or assess animal welfare indexes, thermal simplification is not acceptable since can lead to completely misleading conclusions and incorrect evaluations. Then, only adopting CFD models considering the animal thermal behaviour is possible to obtain effective information both for the proper barn system management and for the creation of useful tools driving the farmers' choices.

The disaster assessment and mitigation of urban infrastructure under explosion loads is a research focus. Prefabricated tunnels are usually connected by joints, and their mechanical properties under explosion loads are of concern. To evaluate the dynamic response characteristics of prefabricated frame tunnels with steel box joints under explosive loads, an anti-explosion strategy was proposed in this study. A three-dimensional refined numerical model of the dynamic response of prefabricated frame tunnels was established, and the reliability of the modelling method was validated by full-scale explosion test results. The deformation characteristics, structural stress, damage evolution, and failure mode of these tunnels under vehicle explosion loads were explored. The influences of the thickness, stirrup spacing, and reinforcement ratio on the anti-explosion ability of the middle partition wall were evaluated. The results show that the displacement response of the tunnel partition wall changed in three stages and that the displacement increased significantly when the TNT equivalent explosive force reached 227 kg. The joint of the middle partition wall underwent the most deformation, and the degree of damage of the tunnel corner and the joint was higher than that of other parts. Under the influence of the Mach effect caused by the overpressure shock wave, cracks were generated in the middle partition wall of the tunnel, and obvious tension and compression areas formed. At Z⩽0.8, the failure mode of section S5 of the middle partition wall was mainly a seismic collapse failure and combined bending and shear failure. An increase in the thickness of the middle wall and a reduction in the stirrup spacing helped to improve the anti-explosion performance of the middle wall in this tunnel.

Chloride ion concentration is crucial for the reliability of stay cables, particularly when their protective covers are compromised. Previous studies have focused on the corrosion of single wires or cables over time, proposing estimation models that primarily consider corrosion duration while neglecting other significant factors. Addressing this gap, this paper establishes a corrosion damage model for stay cables considering time, temperature, humidity and inclination angle based on the diffusion characteristics of chloride ions. Firstly, We conducted accelerated corrosion experiments on stay cables in different environments to assess the characteristics of the spatial distribution of chloride ion concentrations within the cables and the mass loss characteristics of the wires. Secondly, a three-dimensional diffusion model for chloride ions in stay cables is proposed based on Fick's second law. A pivotal innovation of our research is the application of diverse machine learning techniques to explore how the diffusion coefficient of chloride ions is influenced by factors like time and environmental temperature, leading to the formulation of a sophisticated chloride ion diffusion model. Finally, by amalgamating this diffusion model with the established corrosion law for steel reinforcement, we devised a comprehensive corrosion damage evolution model for the steel wires of stay cables. The result demonstrates the anisotropic diffusion of chloride ions and its substantial correlation with the corrosion damage observed in steel wires. Notably, the PSO-BPNN method emerged as a highly accurate predictor for the diffusion coefficient of chloride ions. The model established in this paper considers a variety of influencing factors and accurately predicts the corrosion damage characteristics of stay cables, which makes an important contribution to improving the reliability of stay cables.

While computer modeling of annular displacement efficiency is widely applied in cementing engineering, modeling the displacement flow inside a casing or drill string for cementing operations has received less attention. Although predicting displacement efficiency inside a full-length pipe is desired by cementing engineers, the attempt of developing a model with both efficiency and accuracy faces challenges. Access to computer simulators for this purpose is limited. Compared with annular flow, the displacement flow inside pipe, although within a simpler geometry and without eccentricity effect, is not simpler in physics, modelling strategy and predictability, because a variety of flow patterns and flow instabilities can develop to create complicated fluid interfaces. In this paper, we present an integrated numerical model developed to simulate displacement flows inside a full-length pipe, which connects an existing annulus model to enable complete displacement simulations of cementing jobs. The model uses three-dimensional grid to solve fluid concentrations with degrees of mixing, and incorporates flow instability detection and flow regime determination. Applied in cementing, the model accounts for effects of pumping rate, well inclination, pipe rotation, fluid densities, rheological parameters and more. This computationally efficient model does not rely on high-resolution mesh as often required by conventional Computational Fluid Dynamics models, thus it is suitable to be implemented in a cementing software for daily use by well cementing engineers. The methodology of the model is discussed in detail in this paper. To validate the model, we examine simulation results against experimental results obtained in our laboratory tests and CFD simulations; acceptable agreement is found under different testing conditions. We also presented two case studies of real cementing jobs with cement evaluation logs compared to simulation results, showing that the model can predict consistent displacement efficiency results.

The thermal behavior of the cladding layer and the flow behavior of the molten pool significantly affect the geometry, temperature distribution and microstructure of the cladding track, thus affecting the mechanical properties of the cladding. Based on the interaction between the laser and powders, a calculation method of the cross-sectional area of the cladding track is proposed. The droplet energy method and the moving grid method are first combined to establish the surface growth model of the cladding track, to calculate the geometry of the cladding track. Then, the temperature field and flow field of the cladding track are studied. The driving forces of the molten pool flow including shear viscosity, gravity, buoyancy, surface tension at the gas-liquid boundary and pressure between liquids are considered to carry out the dynamics study of the molten pool. According to the force condition of the infinitesimal in the molten pool, the dynamic rules and boundary rules of the molten pool are established, so as to solve the flow field of the molten pool. In addition, the calculated geometry of the cladding track is compared with the experimental result to verify the accuracy of the model, and the microhardness of the cladding track is measured. The results show that the relative error between the simulation and the experiment is less than 6%, and the microhardness of the cladding layer is significantly improved. This work can provide a method for studying the morphology, temperature field, and flow field of laser cladding.

Abstract The potential effects of Grand Ethiopian Renaissance Dam (GERD) failure on the downstream countries were numerically assessed. Flow discharge reaching Lake Nasser and the corresponding water levels were determined, and the inundated areas were defined as a result of GERD failure. High-resolution digital elevation model was developed with 2670-km length starting from GERD till Aswan High Dam. GERD’s reservoir, urban, and rural lands downstream of the GERD were presented using a numerical model. The modeled areas included parts of Ethiopia, Sudan, and Egypt, not to mention Toshka Spillway. The model areas were not divided into parts because of calculating the water levels at the existence of intermediate dams as model outputs. In case possible failure of GERD, Roseires and Sennar dams could collapse. Meanwhile, Merowe dam can sustain with the operation of its emergency spillway. Wave height reaches 100-m downstream of the GERD and 64-m and 31-m downstream of the Roseires and Merowe dams, respectively.

The performance of geosynthetic-reinforced embankments under traffic moving loads is always a hotspot in the geotechnical engineering field. A three-dimensional (3D) model of a geosynthetic-reinforced embankment without drainage consolidation was established using the finite element software ABAQUS. In this model, the traffic loads were simulated by two moving loads of rectangular pattern, and their amplitude, range, and moving speed were realized by a Fortran subroutine. The embankment fill was simulated by an equivalent linear viscoelastic model, which can reflect its viscoelasticity. The geogrid was simulated by the truss element, and the geocell was simulated by the membrane element. Infinite elements were utilized to weaken the boundary effect caused by the model geometry at the boundaries. Validation of the established numerical model was conducted by comparing the predicted deformations in the cross-section of the geosynthetic-reinforced embankment with those from the existing literature. On this basis, the dynamic stress and strain distribution in the pavement structure layer of the geosynthetic-reinforced embankment under a moving load was also analyzed. Finally, a parametric study was conducted to examine the influences of the different types of reinforcement, overload, and the moving load velocity on the geosynthetic-reinforced embankment.

Weirs serve as fundamental structures for channeling excess flow from behind dams to downstream areas. In this study, a numerical and laboratory investigation was conducted to explore the impact of different base nose shapes installed under the outlet keys and varying Wi/Wo ratios on discharges ranging from 5 to 80 liters/second. For numerical simulation, the optimal number of cells for meshing was determined, and a suitable turbulence model was selected. The results demonstrated that the numerical model effectively simulated the laboratory sample with a high degree of accuracy. Furthermore, the numerical model closely approximated PKW for all parameters Q, H, and Cd when compared to the laboratory sample. The findings revealed that, in laboratory models with a maximum discharge area of 80 liters per second, the weir with Wi/Wo=1.2 and a 285 mm valve exhibited the lowest value, whereas the weir with Wi/Wo=0.71 and a 305 mm valve showed the highest, owing to the higher discharge in the input-output ratio. Additionally, as the ratio of flow head to H/P weir height increased, the discharge coefficient Cd decreased. In comparing the flow conditions in weirs with different base nose shapes, it was observed that the weir with a spindle nose shape outperformed the piano key weir with a flat, semi-cylindrical, and triangular base nose. The coefficient of discharge in PKW1.2S and PKW1.2TR weirs, compared to the PKW1.20 weir, increased by 27% and 20%, respectively.

During the severe rainstorm in North China from 31 July to 1 August in 2023, CMA-GFS, CMA-EPS, EC-EPS, EC-HR, NCEP-GFS, CMA-TYM, CMA-MESO, and CMA-BJ are tested and evaluated using synoptic verification, threat score (TS), and MODE (method for object-based diagnostic evaluatin). The persistence and intensity of long-term heavy rainfall, as well as the area and intensity of short-term heavy rainfall, are tested and analyzed for their effectiveness over time. Results indicate that the cumulative precipitation predicted by EC-EPS may exceed 100 mm for 14 days in advance, but there is no prediction ability for extreme heavy precipitation above 600 mm. EC-HR forecast for the location of precipitation is generally accurate up to 8 days in advance. In the short term, the daily precipitation intensity forecast by CMA-BJ closely matches the actual situation, indicating its significance in predicting precipitation extremes. The average and maximum precipitation values of CMA-GFS, EC-HR, and NCEP-GFS in the areas with concentrated heavy precipitation are lower than actual values. CMA-GFS doesn't perform very well while EC-HR is closer to the actual situation. CMA-GFS, EC-HR, and NCEP-GFS models all provide inadequate forecasts for the persistence of heavy rainfall. However, EC-HR has a relative advantage in predicting persistent precipitation 8 days in advance. TS of CMA-BJ is highest for precipitation forecasts above 50 mm and 100 mm. EC-HR and CMA-TYM precipitation forecasts above 50 mm are relatively stable. From the daily MODE results of the precipitation concentration period from 29 July to 31 July, it is evident that EC-HR exhibits a northward predictive characteristic, while the prediction of CMA-BJ is slightly southward. The forecasting ability of CMA-GFS is insufficient, and forecasts from NCEP-GFS and CMA-MESO are not stable. The high-pressure system in North China has a significant impact on the precipitation. EC-HR model forecasts the formation and reinforcement of a 500 hPa high-pressure system 3 to 4 days earlier than CMA-GFS and NCEP-GFS models. It also surpasses both in predicting the precise location and strength of intense precipitation. Additionally, EC-HR model predicts the emergence of a 925 hPa low-pressure trough and a low-level jet 7 days in advance. However, it underestimates the intensity of the trough and jet system, with the actual location being to the west to north. CMA-GFS and NCEP-GFS underestimate the impact of the Taihang Mountains on easterly winds, leading to significantly lower precipitation forecasts. The analysis of the deviation in the 36 h precipitation forecast for 30 July also shows that EC-HR has weak predictions for low-level wind fields, trough positions, and convective precipitation, resulting in a weak intensity of heavy precipitation and a west-north precipitation area.

Simulations of rock damage and gas transport following underground explosions that omit preexisting fracture networks in the subsurface cannot fully characterize the influence of geo-structural variability on gas transport. Previous studies do not consider the impact that fracture network structure and variability have on gas seepage. In this study, we develop a sequentially coupled, axi-symmetric model to look at the damage pattern and resulting gas breakthrough curves following an underground explosion given different fracture network realizations. We simulate 0.327 and 0.164 kT chemical explosives with burial depths of 100 m for 90 stochastically generated fracture networks. Gases quickly reach the surface in 30% of the higher yield simulations and 5% of the lower yield simulations. The fast breakthrough can be attributed to the formation of connected pathways between fractures to the surface. The formation of a connected damage pathway to the surface is not clearly correlated with the fracture intensity (P32) in our simulations. Breakthrough curves with slower transport are highly variable depending on the fracture network sample. The variability in the breakthrough behavior indicates that ignoring the influence of fracture networks on rock damage, which strongly influences the hydraulic properties following an underground explosion, will likely lead to a large underestimation of the uncertainty in the gas transport to the surface. This work highlights the need for incorporation of fracture networks into models for accurately predicting gas seepage following underground explosions.