When the expressway crosses the goafs inevitably,the design is generally to build the road on coal pillars as much as possible.However,the existing coal pillars are often unable to meet relevant requirements of highwa...When the expressway crosses the goafs inevitably,the design is generally to build the road on coal pillars as much as possible.However,the existing coal pillars are often unable to meet relevant requirements of highway construction.Combining three-dimensional physical model tests,numerical simulations and field monitoring,with the Urumqi East Second Ring Road passing through acute inclined goafs as a background,the deformation and failure mechanism of the overlying rock and coal pillars in acute inclined goafs under expressway load were studied.And in accordance with construction requirements of subgrade,comprehensive consideration of the deformation and instability mechanism of acute inclined goafs,the treatment measures and suggestions for this type of geological disasters were put forward.The research results confirmed the rationality of coal pillars in acute inclined goafs under the expressway through grouting.According to the ratio of diff erent overlying rock thickness to coal pillar height,the change trend and value of the required grouting range were summarized,which can provide reference for similar projects.展开更多
Carbon Carbon(C/C)composites in thermal-protection system are exposed to severe thermochemical ablation and mechanical erosion,and their thermal-protection performance is of vital importance to the structural safety a...Carbon Carbon(C/C)composites in thermal-protection system are exposed to severe thermochemical ablation and mechanical erosion,and their thermal-protection performance is of vital importance to the structural safety and flight status of hypersonic vehicles.We numerically analyzes the mesoscopic ablation-erosion of C/C Composites with Inclined Fibers(CCIF).First,a thermochemical ablation model describing the reaction-diffusion coupled problem of C/C composites on mesoscale is employed to analyze ablative process,and the corresponding surface ablation morphology is obtained.Then,the ablation morphology of CCIF is taken as the geometrical model for mechanical erosion analysis,and their damage and failure behavior under high-speed airflow shear is analyzed by using progressive damage method.Moreover,the effects of fiber inclined angle and airflow direction on the mechanical erosion of CCIF are investigated,and the ablationerosion behavior is analyzed and discussed.The results show that the failure modes of mechanical erosion in inner and edge regions are obviously different,showing granular and block erosion phenomena respectively.The mechanical erosion of CCIF in the direction of reverse flow is easier than that in the direction of forward flow.These results can provide a theoretical basis for the design and optimization of thermal protection system materials.展开更多
Oil tanks are essential components of the oil industry, facilitating the safe storage and transportation of crude oil. Safely managing oil tanks is a crucial aspect of environmental protection. Oil tanks are often use...Oil tanks are essential components of the oil industry, facilitating the safe storage and transportation of crude oil. Safely managing oil tanks is a crucial aspect of environmental protection. Oil tanks are often used under extreme operational conditions, including dynamic loads, temperature variations, etc., which may result in unpredictable deformations that can cause severe damage or tank collapses. Therefore, it is essential to establish a monitoring system to prevent and predict potential deformations. Terrestrial laser scanning (TLS) has played a significant role in oil tank monitoring over the past decades. However, the full extent of TLS capabilities for oil tank monitoring has not yet been thoroughly investigated. This study aims to evaluate TLS’s abilities in detecting deformations of oil tanks under various operating conditions. The paper has two objectives: first, to examine the deformations of two vertical oil tanks over six years, and second, to investigate potential deformations of the tanks’ surfaces during filling. Each tank was scanned three times—in the years 2015, 2016, and 2021. Mathematical models and appropriate software were developed to determine the achievable accuracy of TLS monitoring. The anticipated monitoring accuracy was simulated based on the design parameters of the oil tanks. This accuracy was subsequently used to differentiate between deformations and measurement errors. The tank surface was approximated utilizing the cylinder equation for each monitoring epoch. Additionally, deformations were analyzed at different cross-sections with the appropriate circular approximations. The results indicated that both tanks exhibited no significant deformations within a range of less than 20 mm. For the empty tanks, the average radius decreased by 4 mm, without any changes in shape. The total spatial inclination of the oil tanks was calculated using cylinder equations at different monitoring epochs. In the final stage, the observed deformations were employed to simulate the strain-stress conditions of the oil tanks. Thus, this paper presents a complex technology and the results of oil tank monitoring by TLS under various operating conditions.展开更多
The adaptation of existing natural gas pipelines for hydrogen transportation has attracted increasing attention in recent years.Yet,whether hydrogen and natural gas stratify under static conditions remains a subject o...The adaptation of existing natural gas pipelines for hydrogen transportation has attracted increasing attention in recent years.Yet,whether hydrogen and natural gas stratify under static conditions remains a subject of debate,and experimental evidence is still limited.This study presents an experimental investigation of the concentration distribution of hydrogen–natural gas mixtures under static conditions.Hydrogen concentration was measured using a KTL-2000M-H hydrogen analyzer,with a measurement range of 0–30%(by volume),an accuracy of 1%full scale(FS),and a resolution of 0.01%.Experiments were conducted in a 300 cm riser,filled with uniformly mixed hydrogen–methane standard gas,under various static conditions,including different hydrogen blending ratios(5.03%,10.03%,and 19.79%),pressures(0.5 MPa,2 MPa,and 4 MPa),and inclination angles(0◦,45◦,and 90◦).Results show that,at identical pressures and an inclination angle of 90◦,the presence of hydrogen at both ends of the riser remain nearly the same,indicating that the blending ratio exerts no significant influence on stratification.Moreover,across different pressures,the composition of the mixture remains highly uniform,with the maximum difference between the top and bottom of the riser limited to approximately 0.02%,well within the instrument’s margin of error—demonstrating that pressure has a negligible effect on hydrogen stratification.Similarly,variations in inclination angle exert minimal influence on hydrogen distribution.At 4 MPa,the concentration difference between the top and bottom ranges from 0.01%to 0.02%,confirming the absence of measurable stratification within experimental accuracy.展开更多
Magnetohydrodynamic(MHD)radiative chemically reactive mixed convection flow of a hybrid nanofluid(Al_(2)O_(3)–Cu/H_(2)O)across an inclined,porous,and stretched sheet is examined in this study,along with its unsteady ...Magnetohydrodynamic(MHD)radiative chemically reactive mixed convection flow of a hybrid nanofluid(Al_(2)O_(3)–Cu/H_(2)O)across an inclined,porous,and stretched sheet is examined in this study,along with its unsteady heat and mass transport properties.The hybrid nanofluid’s enhanced heat transfer efficiency is a major benefit in high-performance engineering applications.It is composed of two separate nanoparticles suspended in a base fluid and is chosen for its improved thermal properties.Thermal radiation,chemical reactions,a transverse magnetic field,surface stretching with time,injection or suction through the porous medium,and the effect of inclination,which introduces gravity-induced buoyancy forces,are all important physical phenomena that are taken into account in the analysis.A system of nonlinear ordinary differential equations(ODEs)is derived from the governing partial differential equations for mass,momentum,and energy by applying suitable similarity transformations.This simplifies the modeling procedure.The bvp4c solver in MATLAB is then used to numerically solve these equations.Different governing parameters modify temperature,concentration,and velocity profiles in graphs and tables.These factors include radiation intensity,chemical reaction rate,magnetic field strength,unsteadiness,suction/injection velocity,inclination angle,and nanoparticle concentration.A complex relationship between buoyancy and magnetic factors makes hybrid nanofluids better at heat transmission than regular ones.Thermal systems including cooling technologies,thermal coatings,and electronic heat management benefit from these findings.展开更多
The pantograph area is a critical source of aerodynamic noise in high-speed trains,generating noise both directly and through its cavity,a factor that warrants considerable attention.One effective method for reducing ...The pantograph area is a critical source of aerodynamic noise in high-speed trains,generating noise both directly and through its cavity,a factor that warrants considerable attention.One effective method for reducing aerodynamic noise within the pantograph cavity involves the introduction of a jet at the leading edge of the cavity.This study investigates the mechanisms driving cavity aerodynamic noise under varying jet velocities,using Improved Delayed Detached Eddy Simulation(IDDES)and Ffowcs Williams-Hawkings(FW-H)equations.The numerical simulations reveal that an increase in jet velocity results in a higher elevation of the shear layer above the cavity.This elevation,in turn,diminishes the interaction area between the vortices produced by jet shedding and the trailing edge of the cavity wall.Consequently,the amplitude of pressure pulsations on the cavity surface is reduced,leading to a decrease in radiated far-field noise.Specifically,simulations conducted with a jet velocity of 111.11 m/s indicate a remarkable noise reduction of approximately 4 dB attributable to this mechanism.To further enhance noise mitigation,alterations to the inclination angles of the cavity’s front and rear walls are also explored.The findings demonstrate that,at a constant jet velocity,such modifications significantly diminish pressure pulsations at the intersection of the rear wall and cavity floor,optimizing overall noise reduction and achieving a maximum reduction of approximately 6 dB.展开更多
This study introduces the lattice spring model(LSM)to investigate the incline angle of a non-uniform three-segment towed array under steady-state conditions.A numerical model was established,and parametric analysis wa...This study introduces the lattice spring model(LSM)to investigate the incline angle of a non-uniform three-segment towed array under steady-state conditions.A numerical model was established,and parametric analysis was conducted to examine the effects of towing speed and cable density on the incline angle.The numerical simulations demonstrate that for a conventional three-segment towed array with heavy vibration-isolation cable and density exceeding that of seawater,the towing speed must exceed 4 kn to maintain the acoustic cable's average incline angle below 10°.To validate the proposed LSM,a 100-meter-long towed array with variable densities was fabricated and tested through lake trials.The experimental results align closely with simulations,confirming LSM as a reliable model for predicting towed array position and posture.The study concludes by analyzing the parallel computing capabilities of LSM and its application in Fluid-Structure Interaction(FSI)problems.The model's precision and parallel computing capabilities make LSM an efficient,reliable tool for analyzing the steady-state behavior of towed systems.展开更多
This research explores the characteristics of boiling in inclined pipes,a domain of great importance in engineering.Employing an experimental visualization technique,the boiling dynamics of deionizedwater are examined...This research explores the characteristics of boiling in inclined pipes,a domain of great importance in engineering.Employing an experimental visualization technique,the boiling dynamics of deionizedwater are examined at varying inclination angles,paying special attention to the emerging flow patterns.The findings demonstrate that the inclination angle significantly impacts flow pattern transitions within the 0°to 90°range.As the heat flux rises,bubbles form in the liquid.The liquid’s inertia extends the bubble-wall contact time,thereby delaying the onset of bulk bubble flow.Beyond a 90°inclination,however,the patterning behavior is more influenced by the fluid velocity.At low speeds,incomplete pipe filling results in a large liquid plug hindering flow,while high speeds lead to full pipe filling.In general,gravity,inertia,buoyancy forces,and capillary forces are themain influential factors in the considered problem.However,an analysis of the heat transfer coefficient and boiling curve for different inclination angles reveals that the observed variations are essentially due to corresponding changes in the flow pattern.Finally,an optimal mass flux and inclination angle,able to minimize total entropy generation and improve heat transfer efficiency,are determined by means of an entropy generation analysis.展开更多
A sealed portal could significantly alter the flame shape and smoke flow characteristics in inclined tunnel fires.In inclined tunnels,two typical sealing conditions could be defined,namely the upper portal sealed and ...A sealed portal could significantly alter the flame shape and smoke flow characteristics in inclined tunnel fires.In inclined tunnels,two typical sealing conditions could be defined,namely the upper portal sealed and the lower portal sealed.In this study,the effects of tunnel slope on flame shape,flame length,along with smoke mass flow rate and induced velocity at the tunnel portal,are numerically investigated.The results show that,in all scenarios,flames initially rise vertically but tilt toward the sealed portal during the quasi-steady stage,with the largest tilt angle observed in tunnels sealed at the lower portal.The slope significantly affects the flame tilt angle.The flame tilt angle in tunnels with the lower portal sealed varies irregularly with the slope,while it decreases as the slope increases in tunnels with the upper portal sealed.Subsequently,the smoke mass flow rate and induced velocity at the tunnel portal are analyzed in detail.Drawing on the obtained data,the flame length prediction models for impinging flames and non-impinging flames under different sealing conditions are developed,along with dimensionless models for smoke mass flow rate and induced wind velocity.These findings provide a theoretical foundation for the formulation of fire rescue strategies and emergency evacuation plans in inclined tunnels with one portal sealed.展开更多
The“upper coal and lower bauxite”resource distribution pattern is widespread in China,where mining of the overlying coal seam significantly alters the stress environment of the underlying bauxite layer.This study in...The“upper coal and lower bauxite”resource distribution pattern is widespread in China,where mining of the overlying coal seam significantly alters the stress environment of the underlying bauxite layer.This study investigates the stability of inclined bauxite pillars under the influence of stress redistribution caused by coal seam extraction.A theoretical model is developed to calculate the direction and magnitude of principal stresses in the inclined floor strata,and a pillar stability analysis model is established that considers the effect of principal stress rotation.The research employs a combination of theoretical analysis,physical modeling,numerical simulation,and field observation.Findings indicate that stress rotation is most pronounced at both ends of the coal seam goaf,with the maximum clockwise and counterclockwise rotation angles of 19°and-40°,respectively,observed in the bauxite layer.Inclined bauxite pillars are subjected to combined compressive and shear loading.Under such conditions,clockwise rotation of principal stress increases the shear-to-normal stress ratio,thereby reducing pillar stability.Pillars located beneath the coal wall are the first to fail due to stress concentration and principal stress rotation,which can trigger a cascade of instability among the adjacent pillars.The findings provide a theoretical basis and practical guidance for ensuring the safe co-mining of coal seams and bauxite resources.展开更多
The safety of the initial support during the construction of inclined shafts in tunnels traversing through high-hydraulic-pressure surrounding rocks is paramount.This study examines a high-hydraulic-pressure inclined ...The safety of the initial support during the construction of inclined shafts in tunnels traversing through high-hydraulic-pressure surrounding rocks is paramount.This study examines a high-hydraulic-pressure inclined shaft of a tunnel in Western Sichuan Province to analyze the damage characteristics of the initial support and propose a radial drainage and decompression treatment method.Field monitoring was conducted to assess the load and deformation of the initial support structure,and on-site investigations identified the distribution of cracked areas.In addition,numerical simulations were performed to evaluate the force and deformation characteristics of the initial support structure,which were then compared with field observations for validation.The variations in the lateral pressure coefficient and water pressure were evaluated.The results revealed that damage was primarily concentrated in the shoulder,spring line,and knee areas,with the bending moment at the knee increasing by up to 66.9%.The application of the radial drainage and decompression treatment method effectively reduced water pressure loads on the initial support.Post-treatment analysis indicated significant reductions in axial force and bending moment,enhancing structural stability.These findings provide valuable insights for improving the safety and durability of initial support systems in inclined shafts of high-hydraulicpressure railroad tunnels.展开更多
Because of actual requirement,shield machine always excavates with an inclined angle in longitudinal direction.Since many previous studies mainly focus on the face stability of the horizontal shield tunnel,the effects...Because of actual requirement,shield machine always excavates with an inclined angle in longitudinal direction.Since many previous studies mainly focus on the face stability of the horizontal shield tunnel,the effects of tensile strength cut-off and pore water pressure on the face stability of the longitudinally inclined shield tunnel are not well investigated.A failure mechanism of a longitudinally inclined shield tunnel face is constructed based on the spatial discretization technique and the tensile strength cut-off criterion is introduced to modify the constructed failure mechanism.The pore water pressure is introduced as an external force into the equation of virtual work and the objective function of the chamber pressure of the shield machine is obtained.Moreover,the critical chamber pressure of the longitudinally inclined shield tunnel is computed by optimal calculation.Parametric analysis indicates that both tensile strength cut-off and pore water pressure have a significant impact on the chamber pressure and the range of the collapse block.Finally,the theoretical results are compared with the numerical results calculated by FLAC3D software which proves that the proposed approach is effective.展开更多
Coal mine underground reservoir(CMUR) technology mitigates water scarcity in China's coal-rich western regions but lacks tailored solutions for steeply inclined coal seams.This study develops a novel framework of ...Coal mine underground reservoir(CMUR) technology mitigates water scarcity in China's coal-rich western regions but lacks tailored solutions for steeply inclined coal seams.This study develops a novel framework of steeply inclined coal mine underground reservoirs(SICMUR),which is a paradigm shift from conventional CMUR that the coal seam itself serves as the reservoir floor,challenging conventional designs due to depth-dependent permeability and mechanical constraints.Triaxial mechanical-seepage tests on Xinjiang Wudong coal samples(100,200,300 m depths) revealed a 3.5 MPa triaxial strength increase per 100 m depth and a 58-fold post-peak permeability surge at 300 versus 100 m.Similar model simulations revealed mining-induced stress redistribution and significant deformation effects,particularly subsidence and water-conducting fractures during lower coal seam mining.Results indicate a minimum 40 m safety distance between reservoirs and lower coal seams.Critical construction parameters were investigated for Wudong mine SICMUR as collapse zone heights(9.9–12.31 m) and waterconducting fracture zone heights(31.96–37.40 m).This work systematically bridges SICMUR concepts to field implementation,offering a framework for water preservation in steeply inclined mining while addressing safety concerns,providing a new approach for water reservation in steeply inclined coal mining.展开更多
Ensuring the stability of the surrounding rock mass is of great importance during the construction of a large underground powerhouse.The presence of unfavorable structural planes within the rock mass,such as faults,ca...Ensuring the stability of the surrounding rock mass is of great importance during the construction of a large underground powerhouse.The presence of unfavorable structural planes within the rock mass,such as faults,can lead to substantial deformation and subsequent collapse.A series of in situ experiments and discrete element numerical simulations have been conducted to gain insight into the progressive failure behavior and deformation response of rocks in relation to controlled collapse scenarios involving gently inclined faults.First,the unloading damage evolution process of the surrounding rock mass is characterized by microscopic analysis using microseismic(MS)data.Second,the moment tensor inversion method is used to elucidate the temporal distribution of MS event fracture types in the surrounding rock mass.During the development stage of the collapse,numerous tensile fracture events occur,while a few shear fractures corresponding to structural plane dislocation precede their occurrence.The use of the digital panoramic borehole camera,acoustic wave test,and numerical simulation revealed that gently inclined faults and deep cracks at a certain depth from the cavern periphery are the primary factors contributing to rock collapse.These results provide a valuable case study that can help anticipate and mitigate fault-slip collapse incidents while providing practical insights for underground cave excavation.展开更多
Current developments in magnetohydrodynamic(MHD)convection and nanofluid engineering technology have have greatly enhanced heat transfer performance in process systems,particularly through the use of carbon nanotube(C...Current developments in magnetohydrodynamic(MHD)convection and nanofluid engineering technology have have greatly enhanced heat transfer performance in process systems,particularly through the use of carbon nanotube(CNT)–based fluids that offer exceptional thermal conductivity.Despite extensive research on MHD natural convection in enclosures,the combined effects of complex obstacle geometries,magnetic fields,and CNT nanofluids in three-dimensional configurations remain insufficiently explored.This research investigates MHD natural convection of carbon nanotube(CNT)-water nanofluid within a three-dimensional cavity.The study considers an inclined cross-shaped hot obstacle,a configuration not extensively explored in previous works.The work aims to elucidate the combined effects of CNT nanofluid concentration,magnetic field strength,and obstacle inclination on fluid flow patterns and heat transfer characteristics.Numerical simulations are performed using the finite element method(FEM)based on the Galerkin Weighted Residual approach.The analysis systematically considers variations in Rayleigh number(Ra),Hartmann number(Ha),nanoparticle volume fraction(Φ),and obstacle inclination angle(θ).Results show that increasing Ra from 103 to 106 enhances convective heat transfer by up to 228%,while raising the CNT volume fraction to 4.5%improves heat transfer by about 64%.In contrast,strengthening the magnetic field from Ha=0 to Ha=100 suppresses fluid motion and reduces heat transfer by nearly 67%,whereas varying the obstacle inclination from 0○to 45○leads to a 4.6%decrease in efficiency.The addition of nanoparticles slightly increases viscosity,reducing flow intensity by 8.3%when Ha=0.Furthermore,a novel multiparametric correlation is proposed,accurately predicting the average Nusselt number as a function of Ra,Ha,ϕ,andθ,with an R2 of 0.98.These findings provide new insights into the role of geometry,magnetic effects,and nanofluids in heat transfer enhancement,offering practical guidance for the design and optimization of advanced thermal systems.展开更多
In this paper,the authors examine various slip effects on themagnetic field and thermal radiative impacts on the flow,mass and heat transfer of a Jeffrey nanofluid over a 2-dimensional inclined stretching sheet by a p...In this paper,the authors examine various slip effects on themagnetic field and thermal radiative impacts on the flow,mass and heat transfer of a Jeffrey nanofluid over a 2-dimensional inclined stretching sheet by a porous media.The offered work is modelled to be in the form of a combination of coupled highly nonlinear partial differential equations in dimensional contexts.Governing equations were obtained,dimensionless parameters were defined in terms of similarity parameters,and the solutionswere obtained by the Homotopy Analysis Method(HAM).The analysis is significant as the effects of viscosity are identified and the important parameters are to be determined that could eventually control a type of flowbehaviour,especially in promoting the flowand inhibiting flowof velocity,temperature,and concentrations.The findings show that such an increase in themagnetic parameter decreases the velocity profile by approximately 15%due to more Lorentz forces,and thermal radiation increases the temperature profile by up to 25%,therefore,enhancing the rate of heat transfer.The process of Brownian motion and thermophoresis increases the depth of the thermal boundary layer by 10–20 percent and reduces in concentration profiles by 12 percent when the Brownian motion parameter increases.A velocity slip parameter lowers the velocity field by about 18 percent,and a parameter of permeability lowers the momentum of flow by another 10 percent.The HAM solutions show very high accuracy levels,having an order of convergence at level 15 and errormargins are well below 0.01 percent compared to the earlier studies.All these findings can provide profound knowledge in improving heat transmission in non-Newtonian fluid systems and can be used in biomedical engineering,thermal insulation,and industrial processes such as polymer extrusion and cooling technology.Principles of heat and mass transfer give us the crucial foundation on which to study the behavior of heat andmaterial flows in other engineering and scientific disciplines.Such principles apply to various fields of study,including the following engineering fields:mechanical,chemical,aerospace,civil,and environmental.展开更多
This study focuses on steeply inclined and extremely thick coal seams(SIETCS)characterized by immense thickness,a steep inclination of coal seams(87°),and high horizontal stress.The geological conditions and mini...This study focuses on steeply inclined and extremely thick coal seams(SIETCS)characterized by immense thickness,a steep inclination of coal seams(87°),and high horizontal stress.The geological conditions and mining technology associated with SIETCS differ significantly from those of generally inclined coal seams,resulting in notable variations in roadway stress distributions.On SIETCS have predominantly examined the impact of rock layers flanking coal seams on rock bursts,with limited emphasis on SIETCS roadways.This study employs comprehensive methods,integrating numerical simulations,theoretical analyses,and field detections to investigate the stress distribution of SIETCS and the mechanisms of rock burst-induced vertical damage,subsequently validated in situ.The vertical stress in SIETCS is minimal,while horizontal stress is concentrated,leading to the formation of layered crack structures(LCS)that distribute above and below the roadways.Additionally,elastic energy significantly concentrates within the LCS.Axial dynamic compressive stress and vertical dynamic tensile stress along the LCS diminish its stability,readily triggering failure.During the LCS failure process,the stored energy is released,converting into kinetic energy required for coal body ejection after reaching the minimum energy for failure and dissipative energy,ultimately leading to rock burst-induced vertical damage in roadways.On-site detection and analysis within SIETCS,along with historical rock burst data,confirm the existence of LCS and its role in inducing vertical rock burst damage.This research establishes essential foundations for preventing rock bursts within SIETCS.展开更多
This paper investigates the configuration design associated with boundary-constrained swarm flying.An analytic swarm configuration is identified to ensure the passive safety between each pair of spacecraft in the radi...This paper investigates the configuration design associated with boundary-constrained swarm flying.An analytic swarm configuration is identified to ensure the passive safety between each pair of spacecraft in the radial-cross-track plane.For the first time,this work derives the explicit configurable spacecraft amount to clarify the configuration's accommodation capacity while considering the maximum inter-spacecraft separation constraint.For larger-scale design problem that involves hundreds of spacecraft,this paper proposes an optimization framework that integrates a Relative Orbit Element(ROE)affine transformation operation and successional convex optimization.The framework establishes a multi-subcluster swarm structure,allowing decoupling the maintenance issues of each subcluster.Compared with previous design methods,it ensures that the computational cost for constraints verification only scales linearly with the swarm size,while also preserving the configuration optimization capacities.Numerical simulations demonstrate that the proposed analytic configuration strictly meets the design constraints.It is also shown that the proposed framework reduces the handled constraint amount by two orders compared with direct optimization,while achieving a remarkable swarm safety enhancement based on the existing analytic configuration.展开更多
Nathaniel Hawthorne not only strongly condemns the belief that men are more evil than good, but also conveys the inclination towards good through the Scarlet Letter. The characters like Hester Prynne, Dimmesdale, ...Nathaniel Hawthorne not only strongly condemns the belief that men are more evil than good, but also conveys the inclination towards good through the Scarlet Letter. The characters like Hester Prynne, Dimmesdale, Chillingworth and even the community are the specific examples. Despite the fact that good and evil coexist in human nature, human beings are liable to be strongly affected and controlled by the striving towards good.展开更多
基金Science and Technology Major Project of Xinjiang Uygur Autonomous Region(2020A03003-7)Fundamental Research on Natural Science Program of Shaanxi Province(2021JM-180)+2 种基金Fundamental Research Funds for the Central Universities,CHD(Project for Leading Talents)(300102211302)Tianshan Cedar Plan of Science and Technology Department of Xinjiang Uygur Autonomous Region(2017XS13)Shaanxi Province Young Talent Lifting Program(CLGC202219).
文摘When the expressway crosses the goafs inevitably,the design is generally to build the road on coal pillars as much as possible.However,the existing coal pillars are often unable to meet relevant requirements of highway construction.Combining three-dimensional physical model tests,numerical simulations and field monitoring,with the Urumqi East Second Ring Road passing through acute inclined goafs as a background,the deformation and failure mechanism of the overlying rock and coal pillars in acute inclined goafs under expressway load were studied.And in accordance with construction requirements of subgrade,comprehensive consideration of the deformation and instability mechanism of acute inclined goafs,the treatment measures and suggestions for this type of geological disasters were put forward.The research results confirmed the rationality of coal pillars in acute inclined goafs under the expressway through grouting.According to the ratio of diff erent overlying rock thickness to coal pillar height,the change trend and value of the required grouting range were summarized,which can provide reference for similar projects.
基金supported by the National Natural Science Foundation of China(Nos.U2241240,12172045 and 12221002)the Opening Fund of State Key Laboratory of Explosion Science and Technology of Beijing Institute of Technology,China(No.ZDKT23-02)。
文摘Carbon Carbon(C/C)composites in thermal-protection system are exposed to severe thermochemical ablation and mechanical erosion,and their thermal-protection performance is of vital importance to the structural safety and flight status of hypersonic vehicles.We numerically analyzes the mesoscopic ablation-erosion of C/C Composites with Inclined Fibers(CCIF).First,a thermochemical ablation model describing the reaction-diffusion coupled problem of C/C composites on mesoscale is employed to analyze ablative process,and the corresponding surface ablation morphology is obtained.Then,the ablation morphology of CCIF is taken as the geometrical model for mechanical erosion analysis,and their damage and failure behavior under high-speed airflow shear is analyzed by using progressive damage method.Moreover,the effects of fiber inclined angle and airflow direction on the mechanical erosion of CCIF are investigated,and the ablationerosion behavior is analyzed and discussed.The results show that the failure modes of mechanical erosion in inner and edge regions are obviously different,showing granular and block erosion phenomena respectively.The mechanical erosion of CCIF in the direction of reverse flow is easier than that in the direction of forward flow.These results can provide a theoretical basis for the design and optimization of thermal protection system materials.
文摘Oil tanks are essential components of the oil industry, facilitating the safe storage and transportation of crude oil. Safely managing oil tanks is a crucial aspect of environmental protection. Oil tanks are often used under extreme operational conditions, including dynamic loads, temperature variations, etc., which may result in unpredictable deformations that can cause severe damage or tank collapses. Therefore, it is essential to establish a monitoring system to prevent and predict potential deformations. Terrestrial laser scanning (TLS) has played a significant role in oil tank monitoring over the past decades. However, the full extent of TLS capabilities for oil tank monitoring has not yet been thoroughly investigated. This study aims to evaluate TLS’s abilities in detecting deformations of oil tanks under various operating conditions. The paper has two objectives: first, to examine the deformations of two vertical oil tanks over six years, and second, to investigate potential deformations of the tanks’ surfaces during filling. Each tank was scanned three times—in the years 2015, 2016, and 2021. Mathematical models and appropriate software were developed to determine the achievable accuracy of TLS monitoring. The anticipated monitoring accuracy was simulated based on the design parameters of the oil tanks. This accuracy was subsequently used to differentiate between deformations and measurement errors. The tank surface was approximated utilizing the cylinder equation for each monitoring epoch. Additionally, deformations were analyzed at different cross-sections with the appropriate circular approximations. The results indicated that both tanks exhibited no significant deformations within a range of less than 20 mm. For the empty tanks, the average radius decreased by 4 mm, without any changes in shape. The total spatial inclination of the oil tanks was calculated using cylinder equations at different monitoring epochs. In the final stage, the observed deformations were employed to simulate the strain-stress conditions of the oil tanks. Thus, this paper presents a complex technology and the results of oil tank monitoring by TLS under various operating conditions.
基金supported by the“Open Bidding for Selecting the Best Candidates”Project of Fujian Province(No.2023H0054)the National Natural Science Foundation of China(No.52372311)the Research and Application of Key Technologies for Clean Energy Supply(No.2023ZZ31YJ04).
文摘The adaptation of existing natural gas pipelines for hydrogen transportation has attracted increasing attention in recent years.Yet,whether hydrogen and natural gas stratify under static conditions remains a subject of debate,and experimental evidence is still limited.This study presents an experimental investigation of the concentration distribution of hydrogen–natural gas mixtures under static conditions.Hydrogen concentration was measured using a KTL-2000M-H hydrogen analyzer,with a measurement range of 0–30%(by volume),an accuracy of 1%full scale(FS),and a resolution of 0.01%.Experiments were conducted in a 300 cm riser,filled with uniformly mixed hydrogen–methane standard gas,under various static conditions,including different hydrogen blending ratios(5.03%,10.03%,and 19.79%),pressures(0.5 MPa,2 MPa,and 4 MPa),and inclination angles(0◦,45◦,and 90◦).Results show that,at identical pressures and an inclination angle of 90◦,the presence of hydrogen at both ends of the riser remain nearly the same,indicating that the blending ratio exerts no significant influence on stratification.Moreover,across different pressures,the composition of the mixture remains highly uniform,with the maximum difference between the top and bottom of the riser limited to approximately 0.02%,well within the instrument’s margin of error—demonstrating that pressure has a negligible effect on hydrogen stratification.Similarly,variations in inclination angle exert minimal influence on hydrogen distribution.At 4 MPa,the concentration difference between the top and bottom ranges from 0.01%to 0.02%,confirming the absence of measurable stratification within experimental accuracy.
文摘Magnetohydrodynamic(MHD)radiative chemically reactive mixed convection flow of a hybrid nanofluid(Al_(2)O_(3)–Cu/H_(2)O)across an inclined,porous,and stretched sheet is examined in this study,along with its unsteady heat and mass transport properties.The hybrid nanofluid’s enhanced heat transfer efficiency is a major benefit in high-performance engineering applications.It is composed of two separate nanoparticles suspended in a base fluid and is chosen for its improved thermal properties.Thermal radiation,chemical reactions,a transverse magnetic field,surface stretching with time,injection or suction through the porous medium,and the effect of inclination,which introduces gravity-induced buoyancy forces,are all important physical phenomena that are taken into account in the analysis.A system of nonlinear ordinary differential equations(ODEs)is derived from the governing partial differential equations for mass,momentum,and energy by applying suitable similarity transformations.This simplifies the modeling procedure.The bvp4c solver in MATLAB is then used to numerically solve these equations.Different governing parameters modify temperature,concentration,and velocity profiles in graphs and tables.These factors include radiation intensity,chemical reaction rate,magnetic field strength,unsteadiness,suction/injection velocity,inclination angle,and nanoparticle concentration.A complex relationship between buoyancy and magnetic factors makes hybrid nanofluids better at heat transmission than regular ones.Thermal systems including cooling technologies,thermal coatings,and electronic heat management benefit from these findings.
基金supported by National Natural Science Foundation of China(12172308).
文摘The pantograph area is a critical source of aerodynamic noise in high-speed trains,generating noise both directly and through its cavity,a factor that warrants considerable attention.One effective method for reducing aerodynamic noise within the pantograph cavity involves the introduction of a jet at the leading edge of the cavity.This study investigates the mechanisms driving cavity aerodynamic noise under varying jet velocities,using Improved Delayed Detached Eddy Simulation(IDDES)and Ffowcs Williams-Hawkings(FW-H)equations.The numerical simulations reveal that an increase in jet velocity results in a higher elevation of the shear layer above the cavity.This elevation,in turn,diminishes the interaction area between the vortices produced by jet shedding and the trailing edge of the cavity wall.Consequently,the amplitude of pressure pulsations on the cavity surface is reduced,leading to a decrease in radiated far-field noise.Specifically,simulations conducted with a jet velocity of 111.11 m/s indicate a remarkable noise reduction of approximately 4 dB attributable to this mechanism.To further enhance noise mitigation,alterations to the inclination angles of the cavity’s front and rear walls are also explored.The findings demonstrate that,at a constant jet velocity,such modifications significantly diminish pressure pulsations at the intersection of the rear wall and cavity floor,optimizing overall noise reduction and achieving a maximum reduction of approximately 6 dB.
基金supported by the Key Research Project of Zhejiang Lab(Grant No.K2022MEOAC01)。
文摘This study introduces the lattice spring model(LSM)to investigate the incline angle of a non-uniform three-segment towed array under steady-state conditions.A numerical model was established,and parametric analysis was conducted to examine the effects of towing speed and cable density on the incline angle.The numerical simulations demonstrate that for a conventional three-segment towed array with heavy vibration-isolation cable and density exceeding that of seawater,the towing speed must exceed 4 kn to maintain the acoustic cable's average incline angle below 10°.To validate the proposed LSM,a 100-meter-long towed array with variable densities was fabricated and tested through lake trials.The experimental results align closely with simulations,confirming LSM as a reliable model for predicting towed array position and posture.The study concludes by analyzing the parallel computing capabilities of LSM and its application in Fluid-Structure Interaction(FSI)problems.The model's precision and parallel computing capabilities make LSM an efficient,reliable tool for analyzing the steady-state behavior of towed systems.
基金supported by the National Natural Science Foundation of China(Project No.52166004)the National Key Research and Development Program of China(Project No.2022YFC3902000)the Major Science and Technology Special Project of Yunnan Province(Project Nos.202202AG050007,202202AG050002).
文摘This research explores the characteristics of boiling in inclined pipes,a domain of great importance in engineering.Employing an experimental visualization technique,the boiling dynamics of deionizedwater are examined at varying inclination angles,paying special attention to the emerging flow patterns.The findings demonstrate that the inclination angle significantly impacts flow pattern transitions within the 0°to 90°range.As the heat flux rises,bubbles form in the liquid.The liquid’s inertia extends the bubble-wall contact time,thereby delaying the onset of bulk bubble flow.Beyond a 90°inclination,however,the patterning behavior is more influenced by the fluid velocity.At low speeds,incomplete pipe filling results in a large liquid plug hindering flow,while high speeds lead to full pipe filling.In general,gravity,inertia,buoyancy forces,and capillary forces are themain influential factors in the considered problem.However,an analysis of the heat transfer coefficient and boiling curve for different inclination angles reveals that the observed variations are essentially due to corresponding changes in the flow pattern.Finally,an optimal mass flux and inclination angle,able to minimize total entropy generation and improve heat transfer efficiency,are determined by means of an entropy generation analysis.
基金financially supported by National Natural Science Foundation of China(NSFC)under Grant No.52208115Science and Technology Support Plan for Youth Innovation of Colleges and Universities of Shandong Province of Chain(No.2023KJ122)+2 种基金Leading Researcher Studio Fund of Jinan(No.202333050)Natural Science Foundation of Shandong Province(ZR2024ME027)Young Talent of Lifting engineering for Science and Technology in Shandong,China(SDAST2024QTA077).
文摘A sealed portal could significantly alter the flame shape and smoke flow characteristics in inclined tunnel fires.In inclined tunnels,two typical sealing conditions could be defined,namely the upper portal sealed and the lower portal sealed.In this study,the effects of tunnel slope on flame shape,flame length,along with smoke mass flow rate and induced velocity at the tunnel portal,are numerically investigated.The results show that,in all scenarios,flames initially rise vertically but tilt toward the sealed portal during the quasi-steady stage,with the largest tilt angle observed in tunnels sealed at the lower portal.The slope significantly affects the flame tilt angle.The flame tilt angle in tunnels with the lower portal sealed varies irregularly with the slope,while it decreases as the slope increases in tunnels with the upper portal sealed.Subsequently,the smoke mass flow rate and induced velocity at the tunnel portal are analyzed in detail.Drawing on the obtained data,the flame length prediction models for impinging flames and non-impinging flames under different sealing conditions are developed,along with dimensionless models for smoke mass flow rate and induced wind velocity.These findings provide a theoretical foundation for the formulation of fire rescue strategies and emergency evacuation plans in inclined tunnels with one portal sealed.
基金Project(2021YFC2902101)supported by the National Key Research and Development Program of ChinaProjects(42271139,52174135)supported by the National Natural Science Foundation of China。
文摘The“upper coal and lower bauxite”resource distribution pattern is widespread in China,where mining of the overlying coal seam significantly alters the stress environment of the underlying bauxite layer.This study investigates the stability of inclined bauxite pillars under the influence of stress redistribution caused by coal seam extraction.A theoretical model is developed to calculate the direction and magnitude of principal stresses in the inclined floor strata,and a pillar stability analysis model is established that considers the effect of principal stress rotation.The research employs a combination of theoretical analysis,physical modeling,numerical simulation,and field observation.Findings indicate that stress rotation is most pronounced at both ends of the coal seam goaf,with the maximum clockwise and counterclockwise rotation angles of 19°and-40°,respectively,observed in the bauxite layer.Inclined bauxite pillars are subjected to combined compressive and shear loading.Under such conditions,clockwise rotation of principal stress increases the shear-to-normal stress ratio,thereby reducing pillar stability.Pillars located beneath the coal wall are the first to fail due to stress concentration and principal stress rotation,which can trigger a cascade of instability among the adjacent pillars.The findings provide a theoretical basis and practical guidance for ensuring the safe co-mining of coal seams and bauxite resources.
基金supported by the National Natural Science Foundation of China(Grant Nos.42277165,41920104007)the Hubei Natural Science Foundation(Grant No.2023AFD217).
文摘The safety of the initial support during the construction of inclined shafts in tunnels traversing through high-hydraulic-pressure surrounding rocks is paramount.This study examines a high-hydraulic-pressure inclined shaft of a tunnel in Western Sichuan Province to analyze the damage characteristics of the initial support and propose a radial drainage and decompression treatment method.Field monitoring was conducted to assess the load and deformation of the initial support structure,and on-site investigations identified the distribution of cracked areas.In addition,numerical simulations were performed to evaluate the force and deformation characteristics of the initial support structure,which were then compared with field observations for validation.The variations in the lateral pressure coefficient and water pressure were evaluated.The results revealed that damage was primarily concentrated in the shoulder,spring line,and knee areas,with the bending moment at the knee increasing by up to 66.9%.The application of the radial drainage and decompression treatment method effectively reduced water pressure loads on the initial support.Post-treatment analysis indicated significant reductions in axial force and bending moment,enhancing structural stability.These findings provide valuable insights for improving the safety and durability of initial support systems in inclined shafts of high-hydraulicpressure railroad tunnels.
基金Projects(52278395,52208409) supported by the National Natural Science Foundation of ChinaProject(2022JJ40531) supported by the Natural Science Foundation of Hunan Province,China。
文摘Because of actual requirement,shield machine always excavates with an inclined angle in longitudinal direction.Since many previous studies mainly focus on the face stability of the horizontal shield tunnel,the effects of tensile strength cut-off and pore water pressure on the face stability of the longitudinally inclined shield tunnel are not well investigated.A failure mechanism of a longitudinally inclined shield tunnel face is constructed based on the spatial discretization technique and the tensile strength cut-off criterion is introduced to modify the constructed failure mechanism.The pore water pressure is introduced as an external force into the equation of virtual work and the objective function of the chamber pressure of the shield machine is obtained.Moreover,the critical chamber pressure of the longitudinally inclined shield tunnel is computed by optimal calculation.Parametric analysis indicates that both tensile strength cut-off and pore water pressure have a significant impact on the chamber pressure and the range of the collapse block.Finally,the theoretical results are compared with the numerical results calculated by FLAC3D software which proves that the proposed approach is effective.
基金supported by Beijing Natural Science Foundation (No.8254049)the National Natural Science Foundation of China (No.52374139)the Deep Earth Probe and Mineral Resources Exploration-National Science and Technology Major Project (No.2024ZD1004505)。
文摘Coal mine underground reservoir(CMUR) technology mitigates water scarcity in China's coal-rich western regions but lacks tailored solutions for steeply inclined coal seams.This study develops a novel framework of steeply inclined coal mine underground reservoirs(SICMUR),which is a paradigm shift from conventional CMUR that the coal seam itself serves as the reservoir floor,challenging conventional designs due to depth-dependent permeability and mechanical constraints.Triaxial mechanical-seepage tests on Xinjiang Wudong coal samples(100,200,300 m depths) revealed a 3.5 MPa triaxial strength increase per 100 m depth and a 58-fold post-peak permeability surge at 300 versus 100 m.Similar model simulations revealed mining-induced stress redistribution and significant deformation effects,particularly subsidence and water-conducting fractures during lower coal seam mining.Results indicate a minimum 40 m safety distance between reservoirs and lower coal seams.Critical construction parameters were investigated for Wudong mine SICMUR as collapse zone heights(9.9–12.31 m) and waterconducting fracture zone heights(31.96–37.40 m).This work systematically bridges SICMUR concepts to field implementation,offering a framework for water preservation in steeply inclined mining while addressing safety concerns,providing a new approach for water reservation in steeply inclined coal mining.
基金funding support from the National Natural Science Foundation of China(Grant Nos.U23A2060,42177143,and 42277461).
文摘Ensuring the stability of the surrounding rock mass is of great importance during the construction of a large underground powerhouse.The presence of unfavorable structural planes within the rock mass,such as faults,can lead to substantial deformation and subsequent collapse.A series of in situ experiments and discrete element numerical simulations have been conducted to gain insight into the progressive failure behavior and deformation response of rocks in relation to controlled collapse scenarios involving gently inclined faults.First,the unloading damage evolution process of the surrounding rock mass is characterized by microscopic analysis using microseismic(MS)data.Second,the moment tensor inversion method is used to elucidate the temporal distribution of MS event fracture types in the surrounding rock mass.During the development stage of the collapse,numerous tensile fracture events occur,while a few shear fractures corresponding to structural plane dislocation precede their occurrence.The use of the digital panoramic borehole camera,acoustic wave test,and numerical simulation revealed that gently inclined faults and deep cracks at a certain depth from the cavern periphery are the primary factors contributing to rock collapse.These results provide a valuable case study that can help anticipate and mitigate fault-slip collapse incidents while providing practical insights for underground cave excavation.
基金Deputyship for Research&Innovation,Ministry of Education in Saudi Arabia for funding this research work through the project number RI-44-0451.
文摘Current developments in magnetohydrodynamic(MHD)convection and nanofluid engineering technology have have greatly enhanced heat transfer performance in process systems,particularly through the use of carbon nanotube(CNT)–based fluids that offer exceptional thermal conductivity.Despite extensive research on MHD natural convection in enclosures,the combined effects of complex obstacle geometries,magnetic fields,and CNT nanofluids in three-dimensional configurations remain insufficiently explored.This research investigates MHD natural convection of carbon nanotube(CNT)-water nanofluid within a three-dimensional cavity.The study considers an inclined cross-shaped hot obstacle,a configuration not extensively explored in previous works.The work aims to elucidate the combined effects of CNT nanofluid concentration,magnetic field strength,and obstacle inclination on fluid flow patterns and heat transfer characteristics.Numerical simulations are performed using the finite element method(FEM)based on the Galerkin Weighted Residual approach.The analysis systematically considers variations in Rayleigh number(Ra),Hartmann number(Ha),nanoparticle volume fraction(Φ),and obstacle inclination angle(θ).Results show that increasing Ra from 103 to 106 enhances convective heat transfer by up to 228%,while raising the CNT volume fraction to 4.5%improves heat transfer by about 64%.In contrast,strengthening the magnetic field from Ha=0 to Ha=100 suppresses fluid motion and reduces heat transfer by nearly 67%,whereas varying the obstacle inclination from 0○to 45○leads to a 4.6%decrease in efficiency.The addition of nanoparticles slightly increases viscosity,reducing flow intensity by 8.3%when Ha=0.Furthermore,a novel multiparametric correlation is proposed,accurately predicting the average Nusselt number as a function of Ra,Ha,ϕ,andθ,with an R2 of 0.98.These findings provide new insights into the role of geometry,magnetic effects,and nanofluids in heat transfer enhancement,offering practical guidance for the design and optimization of advanced thermal systems.
文摘In this paper,the authors examine various slip effects on themagnetic field and thermal radiative impacts on the flow,mass and heat transfer of a Jeffrey nanofluid over a 2-dimensional inclined stretching sheet by a porous media.The offered work is modelled to be in the form of a combination of coupled highly nonlinear partial differential equations in dimensional contexts.Governing equations were obtained,dimensionless parameters were defined in terms of similarity parameters,and the solutionswere obtained by the Homotopy Analysis Method(HAM).The analysis is significant as the effects of viscosity are identified and the important parameters are to be determined that could eventually control a type of flowbehaviour,especially in promoting the flowand inhibiting flowof velocity,temperature,and concentrations.The findings show that such an increase in themagnetic parameter decreases the velocity profile by approximately 15%due to more Lorentz forces,and thermal radiation increases the temperature profile by up to 25%,therefore,enhancing the rate of heat transfer.The process of Brownian motion and thermophoresis increases the depth of the thermal boundary layer by 10–20 percent and reduces in concentration profiles by 12 percent when the Brownian motion parameter increases.A velocity slip parameter lowers the velocity field by about 18 percent,and a parameter of permeability lowers the momentum of flow by another 10 percent.The HAM solutions show very high accuracy levels,having an order of convergence at level 15 and errormargins are well below 0.01 percent compared to the earlier studies.All these findings can provide profound knowledge in improving heat transmission in non-Newtonian fluid systems and can be used in biomedical engineering,thermal insulation,and industrial processes such as polymer extrusion and cooling technology.Principles of heat and mass transfer give us the crucial foundation on which to study the behavior of heat andmaterial flows in other engineering and scientific disciplines.Such principles apply to various fields of study,including the following engineering fields:mechanical,chemical,aerospace,civil,and environmental.
基金support of the National Natural Science Foundation of China(52374180,52327804).
文摘This study focuses on steeply inclined and extremely thick coal seams(SIETCS)characterized by immense thickness,a steep inclination of coal seams(87°),and high horizontal stress.The geological conditions and mining technology associated with SIETCS differ significantly from those of generally inclined coal seams,resulting in notable variations in roadway stress distributions.On SIETCS have predominantly examined the impact of rock layers flanking coal seams on rock bursts,with limited emphasis on SIETCS roadways.This study employs comprehensive methods,integrating numerical simulations,theoretical analyses,and field detections to investigate the stress distribution of SIETCS and the mechanisms of rock burst-induced vertical damage,subsequently validated in situ.The vertical stress in SIETCS is minimal,while horizontal stress is concentrated,leading to the formation of layered crack structures(LCS)that distribute above and below the roadways.Additionally,elastic energy significantly concentrates within the LCS.Axial dynamic compressive stress and vertical dynamic tensile stress along the LCS diminish its stability,readily triggering failure.During the LCS failure process,the stored energy is released,converting into kinetic energy required for coal body ejection after reaching the minimum energy for failure and dissipative energy,ultimately leading to rock burst-induced vertical damage in roadways.On-site detection and analysis within SIETCS,along with historical rock burst data,confirm the existence of LCS and its role in inducing vertical rock burst damage.This research establishes essential foundations for preventing rock bursts within SIETCS.
基金co-supported by the National Natural Science Foundation of China(Nos.52272408,U21B2008)the Guangdong Basic and Applied Basic Research Foundation,China(No.2023B1515120018)。
文摘This paper investigates the configuration design associated with boundary-constrained swarm flying.An analytic swarm configuration is identified to ensure the passive safety between each pair of spacecraft in the radial-cross-track plane.For the first time,this work derives the explicit configurable spacecraft amount to clarify the configuration's accommodation capacity while considering the maximum inter-spacecraft separation constraint.For larger-scale design problem that involves hundreds of spacecraft,this paper proposes an optimization framework that integrates a Relative Orbit Element(ROE)affine transformation operation and successional convex optimization.The framework establishes a multi-subcluster swarm structure,allowing decoupling the maintenance issues of each subcluster.Compared with previous design methods,it ensures that the computational cost for constraints verification only scales linearly with the swarm size,while also preserving the configuration optimization capacities.Numerical simulations demonstrate that the proposed analytic configuration strictly meets the design constraints.It is also shown that the proposed framework reduces the handled constraint amount by two orders compared with direct optimization,while achieving a remarkable swarm safety enhancement based on the existing analytic configuration.
文摘Nathaniel Hawthorne not only strongly condemns the belief that men are more evil than good, but also conveys the inclination towards good through the Scarlet Letter. The characters like Hester Prynne, Dimmesdale, Chillingworth and even the community are the specific examples. Despite the fact that good and evil coexist in human nature, human beings are liable to be strongly affected and controlled by the striving towards good.
