This paper purports to expound a special(technical)notion of paths.A neglected fundamental fact(especially under indeterminism)is that the path-dependent direction of any diachronic outcome is backward,i.e.,later step...This paper purports to expound a special(technical)notion of paths.A neglected fundamental fact(especially under indeterminism)is that the path-dependent direction of any diachronic outcome is backward,i.e.,later steps depend on earlier ones successively,despite the ineradicable chance in their respective formation.In this paper,a token-oriented retrospective approach is proposed to overcome the limitation of the type-oriented approach in explaining path-related phenomena.My argument for the validity and utility of this approach is largely based on the elements of(PD),a definitional schema for diachronic sequences subject to a recursive counterfactual formula.I explore certain aspects of path individuation that have so far not been discussed,despite(PD)’s formal congeniality with Lewis’s‘causal chain’.Two basic patterns of path generation are examined:the first is for distinguishing actual vs possible branching paths,while the second introduces a metaphysical theme regarding the retrospective grounding of the causal status of an upstream event by its downstream(joint)effect.A central example of the paper,viz.,the Gobang game,is used to illustrate how the token-oriented approach works for path individuation.展开更多
This work presents a grounding protection system of the central solenoid model coil(CSMC)of the Comprehensive Research Facility for Fusion Technology(CRAFT).The scheme of neutral point voltage detections has been adop...This work presents a grounding protection system of the central solenoid model coil(CSMC)of the Comprehensive Research Facility for Fusion Technology(CRAFT).The scheme of neutral point voltage detections has been adopted in grounding protection system.Compared with the usual current acquisition,the measurement data is accurate,there is no redundant loop,and the economic benefit is high.In this study,the single-end and double-end grounding fault protections of superconducting magnet coil are analyzed,and the fault voltage and current under different fault conditions are calculated.The simulation model of CSMC magnet grounding fault is established,and the simulation results of the model are basically consistent with the theoretical calculation.Finally,a small capacity experiment platform is used to verify the function of the grounding protection system.The experimental results show that by comparing the neutral fault sampling voltage with the theoretical grounding protection threshold,the grounding protection system can effectively detect different types of grounding faults and transmit signals to the control system to protect the coils of superconducting magnets.展开更多
A three-dimensional coupled sea ice-ice shelf-ocean numerical model is developed for the Prydz Bay,Antarctica,using the Regional Ocean Modeling System with a grid resolution of approximately 2 km.The influence of the ...A three-dimensional coupled sea ice-ice shelf-ocean numerical model is developed for the Prydz Bay,Antarctica,using the Regional Ocean Modeling System with a grid resolution of approximately 2 km.The influence of the grounding giant iceberg D15 on the distribution of sea ice and polynyas in the Prydz Bay is analyzed through two numerical experiments.Iceberg D15,grounded off the western edge of the West Ice Shelf(WIS),obstructs the southwestward transport of sea ice along the east coast of Prydz Bay,causing sea ice to accumulate to the east of the iceberg and form multi-year fast ice.Grounding of Iceberg D15 also decreases sea ice coverage off its south edge and creates ice-free openings in spring near Davis Station and Zhongshan Station,facilitating the accessibility of vessels to the research stations.These simulated sea ice patterns closely match current satellite observations.When Iceberg D15 is removed,the previously blocked sea ice north of the iceberg,which moved westward,shifts southwesterly along the coastline,leading to a reduction in sea ice thickness during winter and spring,as well as lower sea ice concentrations in spring across large areas north and west of the iceberg.In contrast,the sea ice thickness increases considerably southwest of the WIS,extending to the front of the Amery Ice Shelf during seasons covered by sea ice.The increase in sea ice concentration can also extend to as far as 75°E in spring.Without Iceberg D15,which previously contributed to the ice barrier of Barrier Polynya(BP),the shape of BP changes,the area of BP and Davis Polynya(DP)decreases,and the polynya off the northwest edge of the WIS near 83°E expands.These polynya patterns are much similar to the satellite remote sensing observations before Iceberg D15 was grounded.From April to October,the total area of BP and DP decreases by 2.83×10^(4)km^(2)(60%)and 2.20×10^(3)km^(2)(20%),respectively,while the total sea ice production decreases by 4.11×10^(10)m^(3)(66%)and 1.52×10^(10)m^(3)(52%)compared to the experiment with iceberg.These results indicate the substantial effects of grounding giant icebergs on the spatio-temporal distribution of sea ice,the area of polynyas,and sea ice production.High-resolution Antarctic coastal numerical models,typically with grid scales of kilometers,are sufficient to represent large icebergs,and adding the grounding giant icebergs is crucial for producing realistic simulations of sea ice and polynyas.展开更多
Open-set object detectors,as exemplified by Grounding DINO,have attracted significant attention due to their remarkable perfor⁃mance on in-domain datasets like Common Objects in Context(COCO)after only few-shot fine-t...Open-set object detectors,as exemplified by Grounding DINO,have attracted significant attention due to their remarkable perfor⁃mance on in-domain datasets like Common Objects in Context(COCO)after only few-shot fine-tuning.However,their generalization capabili⁃ties in cross-domain scenarios remain substantially inferior to their in-domain few-shot performance.Prior work on fine-tuning Grounding DINO for cross-domain few-shot object detection has primarily focused on data augmentation,leaving broader systemic optimizations unex⁃plored.To bridge this gap,we propose a comprehensive end-to-end fine-tuning framework specifically designed to optimize Grounding DINO for cross-domain few-shot scenarios.In addition,we propose Mixture-of-Experts(MoE)-Grounding DINO,a novel architecture that integrates the MoE architecture to enhance adaptability in cross-domain settings.Our approach demonstrates a significant 15.4 Mean Average Precision(mAP)improvement over the Grounding DINO baseline on the Roboflow20-VL benchmark,establishing a new state of the art for crossdomain few-shot object detection(CD-FSOD).The source code and models will be made available upon publication.展开更多
In contemporary medium-voltage distribution networks heavily penetrated by distributed energy resources(DERs),the harmonic components injected by power-electronic interfacing converters,together with the inherently in...In contemporary medium-voltage distribution networks heavily penetrated by distributed energy resources(DERs),the harmonic components injected by power-electronic interfacing converters,together with the inherently intermittent output of renewable generation,distort the zero-sequence current and continuously reshape its frequency spectrum.As a result,single-line-to-ground(SLG)faults exhibit a pronounced,strongly non-stationary behaviour that varies with operating point,load mix and DER dispatch.Under such circumstances the performance of traditional rule-based algorithms—or methods that rely solely on steady-state frequency-domain indicators—degrades sharply,and they no longer satisfy the accuracy and universality required by practical protection systems.To overcome these shortcomings,the present study develops an SLG-fault identification scheme that transforms the zero-sequence currentwaveforminto two-dimensional image representations and processes themwith a convolutional neural network(CNN).First,the causes of sample-distribution imbalance are analysed in detail by considering different neutralgrounding configurations,fault-inception mechanisms and the statistical probability of fault occurrence on each phase.Building on these insights,a discriminator network incorporating a Convolutional Block Attention Module(CBAM)is designed to autonomously extract multi-layer spatial-spectral features,while Gradient-weighted Class Activation Mapping(Grad-CAM)is employed to visualise the contribution of every salient image region,thereby enhancing interpretability.A comprehensive simulation platform is subsequently established for a DER-rich distribution system encompassing several representative topologies,feeder lengths and DER penetration levels.Large numbers of realistic SLG-fault scenarios are generated—including noise and measurement uncertainty—and are used to train,validate and test the proposed model.Extensive simulation campaigns,corroborated by field measurements from an actual utility network,demonstrate that the proposed approach attains an SLG-fault identification accuracy approaching 100 percent and maintains robust performance under severe noise conditions,confirming its suitability for real-world engineering applications.展开更多
In this study, the ground potential rise(GPR) phenomenon caused by a lightning current injected into a field-shaped artificial grounding grid, as well as the potential difference between two different nodes at the edg...In this study, the ground potential rise(GPR) phenomenon caused by a lightning current injected into a field-shaped artificial grounding grid, as well as the potential difference between two different nodes at the edge of the grounding grid, was observed and analyzed under artificially triggered lightning conditions. Based on circuit theory and measured current data, a π-equivalent circuit was established to simulate the transient response of the grounding grid.Nineteen return strokes from three artificially triggered lightning events were analyzed. The peak currents of the 19 return strokes range from -6.7 to -25.1 kA, and the mean value was -14.3 kA. The GPR decreased rapidly and formed a subpeak after reaching the initial peak, with the mean value of the initial peak being -148.65 kV and the mean value of the subpeak being -92.87 kV. The GPR induced by the triggered lightning currents exhibited a subpeak phenomenon. Simulation results indicate that the subpeak phenomenon is related to localized corrosion of the vertical grounding electrode. The potential difference at the grounding grid edge exhibited a multi-pulse waveform with alternating polarity, dominated by positive pulses. The peak values of both the positive and negative polarity pulses gradually decreased, with the first positive pulse displaying a significantly higher intensity than that of subsequent pulses.展开更多
The Beijing Plain,characterized by a sand-clay interlayer structure,is highly susceptible to ground fissure disasters,which threaten urban construction and residents’lives.However,the characteristics of crack propaga...The Beijing Plain,characterized by a sand-clay interlayer structure,is highly susceptible to ground fissure disasters,which threaten urban construction and residents’lives.However,the characteristics of crack propagation and the influence zone of ground fissures in the sand-clay interlayer remains inadequately understood.Therefore,based on the excavation of large-scale trenches,physical simulation experiments were conducted to investigate the crack propagation of buried ground fissures within sand-clay interlayers.The results showed that two crack patterns,V-shaped anti-dip and dip cracks,occurred during the subsidence of the hanging wall.A total of 33 cracks occurred across the entire profile,with 9 in the sand layer,31 in the clay layer,and 7 in both types of soil.The number of cracks was significantly higher in the clay layer than in the sand layer.Sudden changes occurred as the cracks propagated to the sand-clay interface,weakening or disrupting the surface.Tensile cracking and differential settlement were observed on the surface,and the influence range of the hanging wall was 1.03 to 2.65 times that of the footwall.Additionally,FLAC3D numerical simulations were used to examine the critical displacement values required to induce cracking in the overburden soil layer due to fault movement in the bedrock.A significant positive correlation between the critical displacement(Sv,cr)and overburden thickness(H)was observed,with a correlation coefficient of 0.996.Sv,cr exhibited four stages:Increase,Stable,Increase,and Disappear.This study provides a comprehensive understanding of crack propagation in ground fissures at sand-clay interlayers,offering a scientific basis for the prevention and control of such disasters and optimizing land use in the region.展开更多
Backfill is routinely adopted as a ground support measure for underground mines.However,ground stability enhancement by backfill has received limited research attention.This is likely to be because of the conventional...Backfill is routinely adopted as a ground support measure for underground mines.However,ground stability enhancement by backfill has received limited research attention.This is likely to be because of the conventional assumption that the fill material exhibits a significantly lower stiffness than the host rocks.Significantly,a recent pioneering work revealed the time-dependent ground stability around a backfilled stope with vertical walls through numerical modeling.In practice,underground stopes typically exhibit a higher or lower degree of inclination.This alters the stress state in peripheral rocks and may induce severe instability and dilution,particularly in stope-hanging walls.Hence,it is imperative to analyze the time-dependent ground stability of inclined backfilled stopes for backfill structure design.Therefore,comprehensive numerical simulations were performed using FLAC3D to address this knowledge deficiency by incorporating a coupled analysis of the backfill consolidation behavior and long-term creep deformation in surrounding rocks.The ground stability was evaluated based on the confinement effectiveness,strength-stress ratio,stress path relative to the yield surface,and time-dependent stress redistribution in the rocks.A parametric study revealed that the inclination angle of the backfilled stope reduced the confinement effectiveness in the host rocks when the wall creep was minor.This exacerbated the rock mass sloughing potential.However,a backfilled stope with a shallower dip angle achieved superior ground stability enhancement when the creep deformation was substantial,by applying a more significant compression on the backfill and effectively mobilizing its passive support performance during consolidation.Additional simulations were conducted to analyze the effects of stope height and width,mine depth,mechanical properties of rocks,backfill compressibility,and filling gap on the time-dependent stress redistribution and stability around the inclined backfilled stope.展开更多
Pile group-supported bridges in liquefied sloping ground with crust are prone to severe damage.However,there remains a limited comprehension of the intricate interactions among pile group,soil,and superstructures,as w...Pile group-supported bridges in liquefied sloping ground with crust are prone to severe damage.However,there remains a limited comprehension of the intricate interactions among pile group,soil,and superstructures,as well as the associated failure mechanisms.To address this issue,this paper presents large-scale shaking table tests conducted on pile group-supported bridges in sloping liquefiable ground with crust to uncover the intricate interaction mechanisms.Firstly,the dynamic characteristics and interaction of the pile-soil-superstructure system were explored.Then,the lateral displacement and acceleration of the superstructure and pile were presented.Next,the curvature and damage characteristics of the pile group-supported bridge were discussed.Finally,through cross-correlation analysis,the study revealed the inertia and kinematic effects,focusing on how the effects influenced the seismic demands.Results indicate that significant differences are observed in pile-soil interactions during strong seismic events depending on the depth and liquefaction stage.As earthquake intensity increases,peak displacement in the superstructure rises linearly while residual displacement grows exponentially.Moreover,the pile group effect becomes more pronounced,especially at the pile head,with the trailing piles showing greater curvature than the leading ones.Due to significant soil lateral spreading and the shadowing effect within the pile group,the leading piles experience prominent kinematic effects from the surface down to the intermediate layer of saturated sand compared to the trailing piles.These findings contribute valuable insights for improving the seismic design approach for bridges with pile groups in sloping liquefied soils.展开更多
Rapidly-exploring Random Tree(RRT)and its variants have become foundational in path-planning research,yet in complex three-dimensional off-road environments their uniform blind sampling and limited safety guarantees l...Rapidly-exploring Random Tree(RRT)and its variants have become foundational in path-planning research,yet in complex three-dimensional off-road environments their uniform blind sampling and limited safety guarantees lead to slow convergence and force an unfavorable trade-off between path quality and traversal safety.To address these challenges,we introduce HS-APF-RRT*,a novel algorithm that fuses layered sampling,an enhanced Artificial Potential Field(APF),and a dynamic neighborhood-expansion mechanism.First,the workspace is hierarchically partitioned into macro,meso,and micro sampling layers,progressively biasing random samples toward safer,lower-energy regions.Second,we augment the traditional APF by incorporating a slope-dependent repulsive term,enabling stronger avoidance of steep obstacles.Third,a dynamic expansion strategy adaptively switches between 8 and 16 connected neighborhoods based on local obstacle density,striking an effective balance between search efficiency and collision-avoidance precision.In simulated off-road scenarios,HS-APF-RRT*is benchmarked against RRT*,GoalBiased RRT*,and APF-RRT*,and demonstrates significantly faster convergence,lower path-energy consumption,and enhanced safety margins.展开更多
This study focuses on permanent surface dislocations caused by a strike-slip fault in an alluvial valley.A twodimensional mathematical model is utilized,considering the valley to have a half-cylindrical shape.The vall...This study focuses on permanent surface dislocations caused by a strike-slip fault in an alluvial valley.A twodimensional mathematical model is utilized,considering the valley to have a half-cylindrical shape.The valley medium is assumed to be isotropic,linear elastic and nonhomogeneous,such that the shear modulus of the valley has spatial dependency.The valley is surrounded by an isotropic,linear elastic and homogeneous half-space.A strike-slip fault is located at the intersection between the valley and the half-space.The problem is solved analytically by using finite Fourier transform.Displacement functions are obtained in closed-form,in terms of power series and hypergeometric function series.Unknown coefficients of these series are determined from the boundary conditions,leading to an analytical exact solution.Numerical results indicate that the nonhomogeneity of the alluvial valley material has a limited impact on permanent surface dislocations unless there is a significant variation in the material properties within the functionally graded zone.In many cases,approximating the nonhomogeneous alluvial valley as a homogeneous medium is suitable.展开更多
The failure and collapse of coal pillar ribs represent a significant hazard in the mining industry,with the associated risk of fatalities and injuries anticipated to rise as mining operations advance to greater depths...The failure and collapse of coal pillar ribs represent a significant hazard in the mining industry,with the associated risk of fatalities and injuries anticipated to rise as mining operations advance to greater depths.The development of support guidelines through an enhanced understanding of pillar damage and rock–support interaction mechanisms is crucial to resolving this issue.Bonded block models(BBMs)represent a convenient tool for this purpose,as they can reasonably reproduce the rock fracturing process;however,it is not known to what extent this modeling technique can be applied to simulate pillar failure mechanisms and support interaction in anisotropic rock masses,such as coal.To bridge this gap in research,hypothetical coal pillar BBMs of different width-to-height ratios were developed and calibrated to match Mark–Bieniawski's pillar strength equation,along with a few other attributes from the literature(stress levels at the edge of pillars and the transition from brittle to strain-hardening behavior with increasing width-to-height ratio).Elongated blocks were employed to capture the anisotropic behavior of coal mass.With the reliability of the model established,a few different support patterns were evaluated to ensure that the outputs are broadly consistent with expectations.Finally,simulations of roadway development and additional mining activities were completed considering geo-mining conditions representative of underground coal mines in the USA.The good consistency between model response and expected behaviors per field observation demonstrates the potential of BBMs to be used as a support design tool.展开更多
Honeycombing Lung(HCL)is a chronic lung condition marked by advanced fibrosis,resulting in enlarged air spaces with thick fibrotic walls,which are visible on Computed Tomography(CT)scans.Differentiating between normal...Honeycombing Lung(HCL)is a chronic lung condition marked by advanced fibrosis,resulting in enlarged air spaces with thick fibrotic walls,which are visible on Computed Tomography(CT)scans.Differentiating between normal lung tissue,honeycombing lungs,and Ground Glass Opacity(GGO)in CT images is often challenging for radiologists and may lead to misinterpretations.Although earlier studies have proposed models to detect and classify HCL,many faced limitations such as high computational demands,lower accuracy,and difficulty distinguishing between HCL and GGO.CT images are highly effective for lung classification due to their high resolution,3D visualization,and sensitivity to tissue density variations.This study introduces Honeycombing Lungs Network(HCL Net),a novel classification algorithm inspired by ResNet50V2 and enhanced to overcome the shortcomings of previous approaches.HCL Net incorporates additional residual blocks,refined preprocessing techniques,and selective parameter tuning to improve classification performance.The dataset,sourced from the University Malaya Medical Centre(UMMC)and verified by expert radiologists,consists of CT images of normal,honeycombing,and GGO lungs.Experimental evaluations across five assessments demonstrated that HCL Net achieved an outstanding classification accuracy of approximately 99.97%.It also recorded strong performance in other metrics,achieving 93%precision,100%sensitivity,89%specificity,and an AUC-ROC score of 97%.Comparative analysis with baseline feature engineering methods confirmed the superior efficacy of HCL Net.The model significantly reduces misclassification,particularly between honeycombing and GGO lungs,enhancing diagnostic precision and reliability in lung image analysis.展开更多
The widely distributed loess deposits in the Yellow River Basin exhibit unique engineering geological characteristics.The variations in their thickness and stratigraphic structure significantly amplify ground motion p...The widely distributed loess deposits in the Yellow River Basin exhibit unique engineering geological characteristics.The variations in their thickness and stratigraphic structure significantly amplify ground motion parameters,directly influencing the regional seismic hazard risk level.This study methodically conducted on-site studies and observations of building collapses and damages resulting from seismic amplification effects,using the Wenchuan M_(S)8.0 earthquake as a case study.Comprehensive experimental and numerical simulation studies were carried out.A large-scale shaking table test was performed,and numerical models for 14 different loess sites types were established.Various types of seismic waves were incorporated into these models for systematic numerical simulation calculations.The research reveals the mechanisms by which loess deposit thickness and stratigraphic structure in the Yellow River Basin affect seismic ground motion amplification.The results indicate that as the epicentral distance increases,the peak ground motion shows a marked attenuation trend,with the horizontal component attenuating substantially faster than the vertical component.As the overlying loess layer thickness increases from 50 to 100 m,the seismic intensity may escalate by 3−4 degrees,and the peak acceleration may amplify by 1.5−2.2 times.With the augmentation of loess deposit thickness and the proliferation of soil layers,both the peak acceleration response spectrum and the characteristic period demonstrate an upward tendency,exhibiting slight fluctuations contingent upon the seismic wave type.展开更多
Shield tunneling in saturated ground poses challenges due to the potential risk of ground collapse resulting from seepage force and inadequate support pressure.This study employed a laboratory model test and a theoret...Shield tunneling in saturated ground poses challenges due to the potential risk of ground collapse resulting from seepage force and inadequate support pressure.This study employed a laboratory model test and a theoretical validation to elucidate the mechanisms of face failure and subsequent ground collapse in saturated ground during slurry pressure-balanced shield(SPBS)tunneling operations.A slurry circulation system was developed to ensure steady shield tunneling and to replicate the phenomena of ground collapse.Investigations into shield tunneling parameters and ground responses,including soil pressure,pore water pressure,and surface subsidence,were conducted to understand the mechanisms of face failure and subsequent ground collapse.The theoretical solution for the critical collapse pressure of the tunnel face,based on the rotational failure mechanism,was validated through the comparison with the experimentally determined critical collapse pressure.The results indicate that:(1)appropriate adjustments of tunneling parameters are crucial for promoting filtercake formation,maintaining chamber pressure,and minimizing ground subsidence;(2)chamber pressure,soil pressure,pore water pressure,and ground subsidence are closely correlated with shield tunneling parameters and the formation of filter cake;(3)ground collapse follows a continuous failure mode due to the destruction of filtercake and the decrease in chamber pressure;(4)the soil pressure at the cutterhead is more sensitive to disturbances from shield tunneling than chamber pressure;and(5)experimentally determined critical collapse pressures is consistent with the theoretical solution of limit analysis.展开更多
The research findings on the ground motion and liquefaction potential analyses during the 2018 Great Indonesia Earthquake(M_(w)7.5)are significant and crucial.The earthquake triggered soil-structure damage due to liqu...The research findings on the ground motion and liquefaction potential analyses during the 2018 Great Indonesia Earthquake(M_(w)7.5)are significant and crucial.The earthquake triggered soil-structure damage due to liquefaction.This study,which thoroughly investigated four sites at Palu,was conducted by performing a comprehensive ground motion parameter analysis.The ground motion characteristics were presented and justified,particularly for the most impacted direction.Ground motion predictions were analysed to define the spectral accelerations,and matching spectral accelerations were conducted to produce ground motions for each site.Non-linear seismic ground response analysis based on the hyperbolic model of pressure pressure-dependent was performed to investigate cyclic soil behaviour.The results revealed that ground motion is crucial in significant soil damage,and the earthquake energy could trigger deep liquefaction.As the most significant ground motion,the vertical ground motion is essential in determining deep liquefaction.The discussion on the impact of liquefaction based on the results of the numerical analysis is presented.Significant ground motion with a longer duration could have a substantial impact on deep liquefaction in the study area.These findings depict how the 2018 Indonesia Earthquake(M_(w)7.5)triggered a mega-liquefaction in Palu City.The results could enhance the understanding of the importance of seismic hazard assessment.It is recommended that site investigation and soil improvement should be planned to counteract liquefaction damage before construction.This study also suggests conducting seismic hazard assessments for city development to minimise the potential disaster impact in the study area.展开更多
With the continuous advancement of unmanned technology in various application domains,the development and deployment of blind-spot-free panoramic video systems have gained increasing importance.Such systems are partic...With the continuous advancement of unmanned technology in various application domains,the development and deployment of blind-spot-free panoramic video systems have gained increasing importance.Such systems are particularly critical in battlefield environments,where advanced panoramic video processing and wireless communication technologies are essential to enable remote control and autonomous operation of unmanned ground vehicles(UGVs).However,conventional video surveillance systems suffer from several limitations,including limited field of view,high processing latency,low reliability,excessive resource consumption,and significant transmission delays.These shortcomings impede the widespread adoption of UGVs in battlefield settings.To overcome these challenges,this paper proposes a novel multi-channel video capture and stitching system designed for real-time video processing.The system integrates the Speeded-Up Robust Features(SURF)algorithm and the Fast Library for Approximate Nearest Neighbors(FLANN)algorithm to execute essential operations such as feature detection,descriptor computation,image matching,homography estimation,and seamless image fusion.The fused panoramic video is then encoded and assembled to produce a seamless output devoid of stitching artifacts and shadows.Furthermore,H.264 video compression is employed to reduce the data size of the video stream without sacrificing visual quality.Using the Real-Time Streaming Protocol(RTSP),the compressed stream is transmitted efficiently,supporting real-time remote monitoring and control of UGVs in dynamic battlefield environments.Experimental results indicate that the proposed system achieves high stability,flexibility,and low latency.With a wireless link latency of 30 ms,the end-to-end video transmission latency remains around 140 ms,enabling smooth video communication.The system can tolerate packet loss rates(PLR)of up to 20%while maintaining usable video quality(with latency around 200 ms).These properties make it well-suited for mobile communication scenarios demanding high real-time video performance.展开更多
This study presents a sustainable approach for the valorization of spent coffee grounds(CG)by converting them into carboxylated cellulose nanofibrils(CG-TCNF)via formic acid/hydrogen peroxide pretreatment followed by ...This study presents a sustainable approach for the valorization of spent coffee grounds(CG)by converting them into carboxylated cellulose nanofibrils(CG-TCNF)via formic acid/hydrogen peroxide pretreatment followed by TEMPO/NaClO/NaClO_(2)-mediated oxidation.The pretreatment efficiently removed lignin,hemicellulose,and other non-cellulosic components,yielding purified cellulose(CG-C)with high crystallinity(CrI=84%).Subsequent regioselective oxidation introduced carboxyl groups at the C6 position of cellulose chains,achieving a high carboxylate content of 1.4 mmol/g.The resulting CG-TCNF exhibited a well-dispersed nanofibrillar morphology with an average width of 3.57 nm and a high specific surface area of 265 m^(2)/g.Comprehensive characterization confirmed the successful oxidation and nanofibrillation:Fourier TransformInfaraed(FT-IR)Spectroscopy revealed the characteristic carboxylate absorption bands,X-ray Diffraction(XRD)showed preserved cellulose I structurewith a slight reduction in crystallinity(CrI=79.2%),and zeta potential measurements indicated good colloidal stability(-45.23 mV)in aqueous suspension.Thermal analysis demonstrated that the introduced carboxyl groups reduced the thermal stability of the nanofibrils compared to the precursor cellulose.This work establishes a novel route for directly transforming coffee grounds into functional nanocellulose,highlighting its potential as a sustainable feedstock for high-value nanomaterials.展开更多
This study presents an effective hybrid simulation approach for simulating broadband ground motion in complex near-fault locations.The approach utilizes a deterministic approach based on the spectral element method(SE...This study presents an effective hybrid simulation approach for simulating broadband ground motion in complex near-fault locations.The approach utilizes a deterministic approach based on the spectral element method(SEM),which is used to simulate low-frequency ground motion(f<1 Hz)by incorporating an innovative efficient discontinuous Galerkin(DG)method for grid division to accurately model basin sedimentary layers at reduced costs.It also introduces a comprehensive hybrid source model for high-frequency random scattering and a nonlinear analysis module for basin sedimentary layers.Deterministic outcomes are combined with modified three-dimensional stochastic finite fault method(3D-EXSIM)simulations of high-frequency ground motion(f>1 Hz).A fourth-order Butterworth filter with zero phase shift is employed for time-domain filtering of low-and high-frequency time series at a crossover frequency of 1 Hz,merging the low and high-frequency ground motions into a broadband time series.Taking an Ms 6.8 Luding earthquake,as an example,this hybrid method was used for a rapid and efficient simulation analysis of broadband ground motion in the region.The accuracy and efficiency of this hybrid method were verified through comparisons with actually observed station data and empirical attenuation curves.Deterministic method simulation results revealed the effects of mountainous topography,basin effects,nonlinear effects within the basin’s sedimentary layers,and a coupling interaction between the basin and the mountains.The findings are consistent with similar studies,showing that near-fault sedimentary basins significantly focus and amplify strong ground motion,and the soil’s nonlinear behavior in the basin influences ground motion to varying extents at different distances from the fault.The mountainous topography impacts the basin’s response to ground motion,leading to barrier effects.This research provides a scientific foundation for seismic zoning,urban planning,and seismic design in nearfault mountain basin regions.展开更多
文摘This paper purports to expound a special(technical)notion of paths.A neglected fundamental fact(especially under indeterminism)is that the path-dependent direction of any diachronic outcome is backward,i.e.,later steps depend on earlier ones successively,despite the ineradicable chance in their respective formation.In this paper,a token-oriented retrospective approach is proposed to overcome the limitation of the type-oriented approach in explaining path-related phenomena.My argument for the validity and utility of this approach is largely based on the elements of(PD),a definitional schema for diachronic sequences subject to a recursive counterfactual formula.I explore certain aspects of path individuation that have so far not been discussed,despite(PD)’s formal congeniality with Lewis’s‘causal chain’.Two basic patterns of path generation are examined:the first is for distinguishing actual vs possible branching paths,while the second introduces a metaphysical theme regarding the retrospective grounding of the causal status of an upstream event by its downstream(joint)effect.A central example of the paper,viz.,the Gobang game,is used to illustrate how the token-oriented approach works for path individuation.
文摘This work presents a grounding protection system of the central solenoid model coil(CSMC)of the Comprehensive Research Facility for Fusion Technology(CRAFT).The scheme of neutral point voltage detections has been adopted in grounding protection system.Compared with the usual current acquisition,the measurement data is accurate,there is no redundant loop,and the economic benefit is high.In this study,the single-end and double-end grounding fault protections of superconducting magnet coil are analyzed,and the fault voltage and current under different fault conditions are calculated.The simulation model of CSMC magnet grounding fault is established,and the simulation results of the model are basically consistent with the theoretical calculation.Finally,a small capacity experiment platform is used to verify the function of the grounding protection system.The experimental results show that by comparing the neutral fault sampling voltage with the theoretical grounding protection threshold,the grounding protection system can effectively detect different types of grounding faults and transmit signals to the control system to protect the coils of superconducting magnets.
基金The National Natural Science Foundation of China under contract Nos 41976217 and 42306249the National Key Research and Development Program of China under contract No.2018YFA0605701.
文摘A three-dimensional coupled sea ice-ice shelf-ocean numerical model is developed for the Prydz Bay,Antarctica,using the Regional Ocean Modeling System with a grid resolution of approximately 2 km.The influence of the grounding giant iceberg D15 on the distribution of sea ice and polynyas in the Prydz Bay is analyzed through two numerical experiments.Iceberg D15,grounded off the western edge of the West Ice Shelf(WIS),obstructs the southwestward transport of sea ice along the east coast of Prydz Bay,causing sea ice to accumulate to the east of the iceberg and form multi-year fast ice.Grounding of Iceberg D15 also decreases sea ice coverage off its south edge and creates ice-free openings in spring near Davis Station and Zhongshan Station,facilitating the accessibility of vessels to the research stations.These simulated sea ice patterns closely match current satellite observations.When Iceberg D15 is removed,the previously blocked sea ice north of the iceberg,which moved westward,shifts southwesterly along the coastline,leading to a reduction in sea ice thickness during winter and spring,as well as lower sea ice concentrations in spring across large areas north and west of the iceberg.In contrast,the sea ice thickness increases considerably southwest of the WIS,extending to the front of the Amery Ice Shelf during seasons covered by sea ice.The increase in sea ice concentration can also extend to as far as 75°E in spring.Without Iceberg D15,which previously contributed to the ice barrier of Barrier Polynya(BP),the shape of BP changes,the area of BP and Davis Polynya(DP)decreases,and the polynya off the northwest edge of the WIS near 83°E expands.These polynya patterns are much similar to the satellite remote sensing observations before Iceberg D15 was grounded.From April to October,the total area of BP and DP decreases by 2.83×10^(4)km^(2)(60%)and 2.20×10^(3)km^(2)(20%),respectively,while the total sea ice production decreases by 4.11×10^(10)m^(3)(66%)and 1.52×10^(10)m^(3)(52%)compared to the experiment with iceberg.These results indicate the substantial effects of grounding giant icebergs on the spatio-temporal distribution of sea ice,the area of polynyas,and sea ice production.High-resolution Antarctic coastal numerical models,typically with grid scales of kilometers,are sufficient to represent large icebergs,and adding the grounding giant icebergs is crucial for producing realistic simulations of sea ice and polynyas.
文摘Open-set object detectors,as exemplified by Grounding DINO,have attracted significant attention due to their remarkable perfor⁃mance on in-domain datasets like Common Objects in Context(COCO)after only few-shot fine-tuning.However,their generalization capabili⁃ties in cross-domain scenarios remain substantially inferior to their in-domain few-shot performance.Prior work on fine-tuning Grounding DINO for cross-domain few-shot object detection has primarily focused on data augmentation,leaving broader systemic optimizations unex⁃plored.To bridge this gap,we propose a comprehensive end-to-end fine-tuning framework specifically designed to optimize Grounding DINO for cross-domain few-shot scenarios.In addition,we propose Mixture-of-Experts(MoE)-Grounding DINO,a novel architecture that integrates the MoE architecture to enhance adaptability in cross-domain settings.Our approach demonstrates a significant 15.4 Mean Average Precision(mAP)improvement over the Grounding DINO baseline on the Roboflow20-VL benchmark,establishing a new state of the art for crossdomain few-shot object detection(CD-FSOD).The source code and models will be made available upon publication.
基金supported by the Science and Technology Program of China Southern Power Grid(031800KC23120003).
文摘In contemporary medium-voltage distribution networks heavily penetrated by distributed energy resources(DERs),the harmonic components injected by power-electronic interfacing converters,together with the inherently intermittent output of renewable generation,distort the zero-sequence current and continuously reshape its frequency spectrum.As a result,single-line-to-ground(SLG)faults exhibit a pronounced,strongly non-stationary behaviour that varies with operating point,load mix and DER dispatch.Under such circumstances the performance of traditional rule-based algorithms—or methods that rely solely on steady-state frequency-domain indicators—degrades sharply,and they no longer satisfy the accuracy and universality required by practical protection systems.To overcome these shortcomings,the present study develops an SLG-fault identification scheme that transforms the zero-sequence currentwaveforminto two-dimensional image representations and processes themwith a convolutional neural network(CNN).First,the causes of sample-distribution imbalance are analysed in detail by considering different neutralgrounding configurations,fault-inception mechanisms and the statistical probability of fault occurrence on each phase.Building on these insights,a discriminator network incorporating a Convolutional Block Attention Module(CBAM)is designed to autonomously extract multi-layer spatial-spectral features,while Gradient-weighted Class Activation Mapping(Grad-CAM)is employed to visualise the contribution of every salient image region,thereby enhancing interpretability.A comprehensive simulation platform is subsequently established for a DER-rich distribution system encompassing several representative topologies,feeder lengths and DER penetration levels.Large numbers of realistic SLG-fault scenarios are generated—including noise and measurement uncertainty—and are used to train,validate and test the proposed model.Extensive simulation campaigns,corroborated by field measurements from an actual utility network,demonstrate that the proposed approach attains an SLG-fault identification accuracy approaching 100 percent and maintains robust performance under severe noise conditions,confirming its suitability for real-world engineering applications.
基金National Natural Science Foundation of China(42575091)Marine Meteorological Science and Data Center Program (2024B1212070014)。
文摘In this study, the ground potential rise(GPR) phenomenon caused by a lightning current injected into a field-shaped artificial grounding grid, as well as the potential difference between two different nodes at the edge of the grounding grid, was observed and analyzed under artificially triggered lightning conditions. Based on circuit theory and measured current data, a π-equivalent circuit was established to simulate the transient response of the grounding grid.Nineteen return strokes from three artificially triggered lightning events were analyzed. The peak currents of the 19 return strokes range from -6.7 to -25.1 kA, and the mean value was -14.3 kA. The GPR decreased rapidly and formed a subpeak after reaching the initial peak, with the mean value of the initial peak being -148.65 kV and the mean value of the subpeak being -92.87 kV. The GPR induced by the triggered lightning currents exhibited a subpeak phenomenon. Simulation results indicate that the subpeak phenomenon is related to localized corrosion of the vertical grounding electrode. The potential difference at the grounding grid edge exhibited a multi-pulse waveform with alternating polarity, dominated by positive pulses. The peak values of both the positive and negative polarity pulses gradually decreased, with the first positive pulse displaying a significantly higher intensity than that of subsequent pulses.
基金financial support was received for the research,authorship,and/or publication of this articlesupported by National Natural Science Foundation of China(Grant No.41877250,41272284,41807243)+2 种基金the Key Laboratory of Earth Fissures Geological Disaster,Ministry of Natural Resources(Grant No.EFGD20240601)the Natural Science Foundation of Shaanxi Province-General Project(Grant No.2023-JC-YB-231)-Suitability Evaluation of Precast Prestressed Underground Comprehensive Pipe Gallery Crossing Active Ground Fissurethe Fundamental Research Funds for the Central Universities,CHD(Grant Nos.300102264909).
文摘The Beijing Plain,characterized by a sand-clay interlayer structure,is highly susceptible to ground fissure disasters,which threaten urban construction and residents’lives.However,the characteristics of crack propagation and the influence zone of ground fissures in the sand-clay interlayer remains inadequately understood.Therefore,based on the excavation of large-scale trenches,physical simulation experiments were conducted to investigate the crack propagation of buried ground fissures within sand-clay interlayers.The results showed that two crack patterns,V-shaped anti-dip and dip cracks,occurred during the subsidence of the hanging wall.A total of 33 cracks occurred across the entire profile,with 9 in the sand layer,31 in the clay layer,and 7 in both types of soil.The number of cracks was significantly higher in the clay layer than in the sand layer.Sudden changes occurred as the cracks propagated to the sand-clay interface,weakening or disrupting the surface.Tensile cracking and differential settlement were observed on the surface,and the influence range of the hanging wall was 1.03 to 2.65 times that of the footwall.Additionally,FLAC3D numerical simulations were used to examine the critical displacement values required to induce cracking in the overburden soil layer due to fault movement in the bedrock.A significant positive correlation between the critical displacement(Sv,cr)and overburden thickness(H)was observed,with a correlation coefficient of 0.996.Sv,cr exhibited four stages:Increase,Stable,Increase,and Disappear.This study provides a comprehensive understanding of crack propagation in ground fissures at sand-clay interlayers,offering a scientific basis for the prevention and control of such disasters and optimizing land use in the region.
基金funding support from the National Natural Science Foundation of China(Nos.52304101 and 52204153)the China Postdoctoral Science Foundation(No.2023MD734215)+2 种基金the Youth Talent Support Program of Xi’an Association for Science and Technology(No.959202413070)the Key Research and Development Program of Shaanxi(No.2023-LL-QY-07)the Key Research and Development Program of Zhejiang(No.2023C03182).
文摘Backfill is routinely adopted as a ground support measure for underground mines.However,ground stability enhancement by backfill has received limited research attention.This is likely to be because of the conventional assumption that the fill material exhibits a significantly lower stiffness than the host rocks.Significantly,a recent pioneering work revealed the time-dependent ground stability around a backfilled stope with vertical walls through numerical modeling.In practice,underground stopes typically exhibit a higher or lower degree of inclination.This alters the stress state in peripheral rocks and may induce severe instability and dilution,particularly in stope-hanging walls.Hence,it is imperative to analyze the time-dependent ground stability of inclined backfilled stopes for backfill structure design.Therefore,comprehensive numerical simulations were performed using FLAC3D to address this knowledge deficiency by incorporating a coupled analysis of the backfill consolidation behavior and long-term creep deformation in surrounding rocks.The ground stability was evaluated based on the confinement effectiveness,strength-stress ratio,stress path relative to the yield surface,and time-dependent stress redistribution in the rocks.A parametric study revealed that the inclination angle of the backfilled stope reduced the confinement effectiveness in the host rocks when the wall creep was minor.This exacerbated the rock mass sloughing potential.However,a backfilled stope with a shallower dip angle achieved superior ground stability enhancement when the creep deformation was substantial,by applying a more significant compression on the backfill and effectively mobilizing its passive support performance during consolidation.Additional simulations were conducted to analyze the effects of stope height and width,mine depth,mechanical properties of rocks,backfill compressibility,and filling gap on the time-dependent stress redistribution and stability around the inclined backfilled stope.
基金supported by the National Natural Science Foundation of China(Grant No.52408513)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(Grant No.GZB20240153)the China Postdoctoral Science Foundation(Grant No.2024M760465).
文摘Pile group-supported bridges in liquefied sloping ground with crust are prone to severe damage.However,there remains a limited comprehension of the intricate interactions among pile group,soil,and superstructures,as well as the associated failure mechanisms.To address this issue,this paper presents large-scale shaking table tests conducted on pile group-supported bridges in sloping liquefiable ground with crust to uncover the intricate interaction mechanisms.Firstly,the dynamic characteristics and interaction of the pile-soil-superstructure system were explored.Then,the lateral displacement and acceleration of the superstructure and pile were presented.Next,the curvature and damage characteristics of the pile group-supported bridge were discussed.Finally,through cross-correlation analysis,the study revealed the inertia and kinematic effects,focusing on how the effects influenced the seismic demands.Results indicate that significant differences are observed in pile-soil interactions during strong seismic events depending on the depth and liquefaction stage.As earthquake intensity increases,peak displacement in the superstructure rises linearly while residual displacement grows exponentially.Moreover,the pile group effect becomes more pronounced,especially at the pile head,with the trailing piles showing greater curvature than the leading ones.Due to significant soil lateral spreading and the shadowing effect within the pile group,the leading piles experience prominent kinematic effects from the surface down to the intermediate layer of saturated sand compared to the trailing piles.These findings contribute valuable insights for improving the seismic design approach for bridges with pile groups in sloping liquefied soils.
基金supported in part by 14th Five Year National Key R&D Program Project(Project Number:2023YFB3211001)the National Natural Science Foundation of China(62273339,U24A201397).
文摘Rapidly-exploring Random Tree(RRT)and its variants have become foundational in path-planning research,yet in complex three-dimensional off-road environments their uniform blind sampling and limited safety guarantees lead to slow convergence and force an unfavorable trade-off between path quality and traversal safety.To address these challenges,we introduce HS-APF-RRT*,a novel algorithm that fuses layered sampling,an enhanced Artificial Potential Field(APF),and a dynamic neighborhood-expansion mechanism.First,the workspace is hierarchically partitioned into macro,meso,and micro sampling layers,progressively biasing random samples toward safer,lower-energy regions.Second,we augment the traditional APF by incorporating a slope-dependent repulsive term,enabling stronger avoidance of steep obstacles.Third,a dynamic expansion strategy adaptively switches between 8 and 16 connected neighborhoods based on local obstacle density,striking an effective balance between search efficiency and collision-avoidance precision.In simulated off-road scenarios,HS-APF-RRT*is benchmarked against RRT*,GoalBiased RRT*,and APF-RRT*,and demonstrates significantly faster convergence,lower path-energy consumption,and enhanced safety margins.
文摘This study focuses on permanent surface dislocations caused by a strike-slip fault in an alluvial valley.A twodimensional mathematical model is utilized,considering the valley to have a half-cylindrical shape.The valley medium is assumed to be isotropic,linear elastic and nonhomogeneous,such that the shear modulus of the valley has spatial dependency.The valley is surrounded by an isotropic,linear elastic and homogeneous half-space.A strike-slip fault is located at the intersection between the valley and the half-space.The problem is solved analytically by using finite Fourier transform.Displacement functions are obtained in closed-form,in terms of power series and hypergeometric function series.Unknown coefficients of these series are determined from the boundary conditions,leading to an analytical exact solution.Numerical results indicate that the nonhomogeneity of the alluvial valley material has a limited impact on permanent surface dislocations unless there is a significant variation in the material properties within the functionally graded zone.In many cases,approximating the nonhomogeneous alluvial valley as a homogeneous medium is suitable.
基金sponsored by the Alpha Foundation for the Improvement of Mine Safety and Health,Inc.(ALPHA FOUNDATION).
文摘The failure and collapse of coal pillar ribs represent a significant hazard in the mining industry,with the associated risk of fatalities and injuries anticipated to rise as mining operations advance to greater depths.The development of support guidelines through an enhanced understanding of pillar damage and rock–support interaction mechanisms is crucial to resolving this issue.Bonded block models(BBMs)represent a convenient tool for this purpose,as they can reasonably reproduce the rock fracturing process;however,it is not known to what extent this modeling technique can be applied to simulate pillar failure mechanisms and support interaction in anisotropic rock masses,such as coal.To bridge this gap in research,hypothetical coal pillar BBMs of different width-to-height ratios were developed and calibrated to match Mark–Bieniawski's pillar strength equation,along with a few other attributes from the literature(stress levels at the edge of pillars and the transition from brittle to strain-hardening behavior with increasing width-to-height ratio).Elongated blocks were employed to capture the anisotropic behavior of coal mass.With the reliability of the model established,a few different support patterns were evaluated to ensure that the outputs are broadly consistent with expectations.Finally,simulations of roadway development and additional mining activities were completed considering geo-mining conditions representative of underground coal mines in the USA.The good consistency between model response and expected behaviors per field observation demonstrates the potential of BBMs to be used as a support design tool.
文摘Honeycombing Lung(HCL)is a chronic lung condition marked by advanced fibrosis,resulting in enlarged air spaces with thick fibrotic walls,which are visible on Computed Tomography(CT)scans.Differentiating between normal lung tissue,honeycombing lungs,and Ground Glass Opacity(GGO)in CT images is often challenging for radiologists and may lead to misinterpretations.Although earlier studies have proposed models to detect and classify HCL,many faced limitations such as high computational demands,lower accuracy,and difficulty distinguishing between HCL and GGO.CT images are highly effective for lung classification due to their high resolution,3D visualization,and sensitivity to tissue density variations.This study introduces Honeycombing Lungs Network(HCL Net),a novel classification algorithm inspired by ResNet50V2 and enhanced to overcome the shortcomings of previous approaches.HCL Net incorporates additional residual blocks,refined preprocessing techniques,and selective parameter tuning to improve classification performance.The dataset,sourced from the University Malaya Medical Centre(UMMC)and verified by expert radiologists,consists of CT images of normal,honeycombing,and GGO lungs.Experimental evaluations across five assessments demonstrated that HCL Net achieved an outstanding classification accuracy of approximately 99.97%.It also recorded strong performance in other metrics,achieving 93%precision,100%sensitivity,89%specificity,and an AUC-ROC score of 97%.Comparative analysis with baseline feature engineering methods confirmed the superior efficacy of HCL Net.The model significantly reduces misclassification,particularly between honeycombing and GGO lungs,enhancing diagnostic precision and reliability in lung image analysis.
基金supported by the Earthquake Science and Technology Spark Plan Project(No.XH23041C)The Natural Science Foundation of Gansu Province(No.22JR11RA090)Gansu Lanzhou Geophysics National Observation and Research Station(No.2021Y14).
文摘The widely distributed loess deposits in the Yellow River Basin exhibit unique engineering geological characteristics.The variations in their thickness and stratigraphic structure significantly amplify ground motion parameters,directly influencing the regional seismic hazard risk level.This study methodically conducted on-site studies and observations of building collapses and damages resulting from seismic amplification effects,using the Wenchuan M_(S)8.0 earthquake as a case study.Comprehensive experimental and numerical simulation studies were carried out.A large-scale shaking table test was performed,and numerical models for 14 different loess sites types were established.Various types of seismic waves were incorporated into these models for systematic numerical simulation calculations.The research reveals the mechanisms by which loess deposit thickness and stratigraphic structure in the Yellow River Basin affect seismic ground motion amplification.The results indicate that as the epicentral distance increases,the peak ground motion shows a marked attenuation trend,with the horizontal component attenuating substantially faster than the vertical component.As the overlying loess layer thickness increases from 50 to 100 m,the seismic intensity may escalate by 3−4 degrees,and the peak acceleration may amplify by 1.5−2.2 times.With the augmentation of loess deposit thickness and the proliferation of soil layers,both the peak acceleration response spectrum and the characteristic period demonstrate an upward tendency,exhibiting slight fluctuations contingent upon the seismic wave type.
基金support of the National Natural Science Foundation of China(Grant Nos.52179116 and 51991392)the support of Key Deployment Projects of Chinese Academy of Sciences(Grant No.ZDRW-ZS-2021-3).
文摘Shield tunneling in saturated ground poses challenges due to the potential risk of ground collapse resulting from seepage force and inadequate support pressure.This study employed a laboratory model test and a theoretical validation to elucidate the mechanisms of face failure and subsequent ground collapse in saturated ground during slurry pressure-balanced shield(SPBS)tunneling operations.A slurry circulation system was developed to ensure steady shield tunneling and to replicate the phenomena of ground collapse.Investigations into shield tunneling parameters and ground responses,including soil pressure,pore water pressure,and surface subsidence,were conducted to understand the mechanisms of face failure and subsequent ground collapse.The theoretical solution for the critical collapse pressure of the tunnel face,based on the rotational failure mechanism,was validated through the comparison with the experimentally determined critical collapse pressure.The results indicate that:(1)appropriate adjustments of tunneling parameters are crucial for promoting filtercake formation,maintaining chamber pressure,and minimizing ground subsidence;(2)chamber pressure,soil pressure,pore water pressure,and ground subsidence are closely correlated with shield tunneling parameters and the formation of filter cake;(3)ground collapse follows a continuous failure mode due to the destruction of filtercake and the decrease in chamber pressure;(4)the soil pressure at the cutterhead is more sensitive to disturbances from shield tunneling than chamber pressure;and(5)experimentally determined critical collapse pressures is consistent with the theoretical solution of limit analysis.
基金The World Class Professor(WCP)Program of the Directorate of Resources,Directorate General of Higher Education,Ministry of Education and Culture in 2023 supports this studythe JAPAN-ASEAN Science and Technology Innovation Platform(JASTIP-WP4)+3 种基金the University of Bengkulu's International Collaboration Research Fund(2183/UN30.15/LT/2019)for partial fundingthe C2F Fund for Postdoctoral Fellowship from Chulalongkorn Universitythe Thailand Science Research and Innovation Fund Chulalongkorn University(DISF68210001)the National Research Council of Thailand(N42A670572)。
文摘The research findings on the ground motion and liquefaction potential analyses during the 2018 Great Indonesia Earthquake(M_(w)7.5)are significant and crucial.The earthquake triggered soil-structure damage due to liquefaction.This study,which thoroughly investigated four sites at Palu,was conducted by performing a comprehensive ground motion parameter analysis.The ground motion characteristics were presented and justified,particularly for the most impacted direction.Ground motion predictions were analysed to define the spectral accelerations,and matching spectral accelerations were conducted to produce ground motions for each site.Non-linear seismic ground response analysis based on the hyperbolic model of pressure pressure-dependent was performed to investigate cyclic soil behaviour.The results revealed that ground motion is crucial in significant soil damage,and the earthquake energy could trigger deep liquefaction.As the most significant ground motion,the vertical ground motion is essential in determining deep liquefaction.The discussion on the impact of liquefaction based on the results of the numerical analysis is presented.Significant ground motion with a longer duration could have a substantial impact on deep liquefaction in the study area.These findings depict how the 2018 Indonesia Earthquake(M_(w)7.5)triggered a mega-liquefaction in Palu City.The results could enhance the understanding of the importance of seismic hazard assessment.It is recommended that site investigation and soil improvement should be planned to counteract liquefaction damage before construction.This study also suggests conducting seismic hazard assessments for city development to minimise the potential disaster impact in the study area.
基金supported by the National Natural Science Foundation of China(Grant No.72334003)the National Key Research and Development Program of China(Grant No.2022YFB2702804)+1 种基金the Shandong Key Research and Development Program(Grant No.2020ZLYS09)the Jinan Program(Grant No.2021GXRC084-2).
文摘With the continuous advancement of unmanned technology in various application domains,the development and deployment of blind-spot-free panoramic video systems have gained increasing importance.Such systems are particularly critical in battlefield environments,where advanced panoramic video processing and wireless communication technologies are essential to enable remote control and autonomous operation of unmanned ground vehicles(UGVs).However,conventional video surveillance systems suffer from several limitations,including limited field of view,high processing latency,low reliability,excessive resource consumption,and significant transmission delays.These shortcomings impede the widespread adoption of UGVs in battlefield settings.To overcome these challenges,this paper proposes a novel multi-channel video capture and stitching system designed for real-time video processing.The system integrates the Speeded-Up Robust Features(SURF)algorithm and the Fast Library for Approximate Nearest Neighbors(FLANN)algorithm to execute essential operations such as feature detection,descriptor computation,image matching,homography estimation,and seamless image fusion.The fused panoramic video is then encoded and assembled to produce a seamless output devoid of stitching artifacts and shadows.Furthermore,H.264 video compression is employed to reduce the data size of the video stream without sacrificing visual quality.Using the Real-Time Streaming Protocol(RTSP),the compressed stream is transmitted efficiently,supporting real-time remote monitoring and control of UGVs in dynamic battlefield environments.Experimental results indicate that the proposed system achieves high stability,flexibility,and low latency.With a wireless link latency of 30 ms,the end-to-end video transmission latency remains around 140 ms,enabling smooth video communication.The system can tolerate packet loss rates(PLR)of up to 20%while maintaining usable video quality(with latency around 200 ms).These properties make it well-suited for mobile communication scenarios demanding high real-time video performance.
基金funded by the training Program for College Students’Innovation and Entrepreneurship of Jiamusi University in Jiamusi City,Heilongjiang Province(grant number S202410222123).
文摘This study presents a sustainable approach for the valorization of spent coffee grounds(CG)by converting them into carboxylated cellulose nanofibrils(CG-TCNF)via formic acid/hydrogen peroxide pretreatment followed by TEMPO/NaClO/NaClO_(2)-mediated oxidation.The pretreatment efficiently removed lignin,hemicellulose,and other non-cellulosic components,yielding purified cellulose(CG-C)with high crystallinity(CrI=84%).Subsequent regioselective oxidation introduced carboxyl groups at the C6 position of cellulose chains,achieving a high carboxylate content of 1.4 mmol/g.The resulting CG-TCNF exhibited a well-dispersed nanofibrillar morphology with an average width of 3.57 nm and a high specific surface area of 265 m^(2)/g.Comprehensive characterization confirmed the successful oxidation and nanofibrillation:Fourier TransformInfaraed(FT-IR)Spectroscopy revealed the characteristic carboxylate absorption bands,X-ray Diffraction(XRD)showed preserved cellulose I structurewith a slight reduction in crystallinity(CrI=79.2%),and zeta potential measurements indicated good colloidal stability(-45.23 mV)in aqueous suspension.Thermal analysis demonstrated that the introduced carboxyl groups reduced the thermal stability of the nanofibrils compared to the precursor cellulose.This work establishes a novel route for directly transforming coffee grounds into functional nanocellulose,highlighting its potential as a sustainable feedstock for high-value nanomaterials.
基金National Natural Science Foundation of China under Grant Nos.U2139208 and 52278516Key Laboratory of Earthquake Engineering and Engineering Vibration,China Earthquake Administration under Grant No.2024D15Key Laboratory of Soft Soil Characteristic and Engineering Environment,Tianjin Chengjian University under Grant No.2022SCEEKL003。
文摘This study presents an effective hybrid simulation approach for simulating broadband ground motion in complex near-fault locations.The approach utilizes a deterministic approach based on the spectral element method(SEM),which is used to simulate low-frequency ground motion(f<1 Hz)by incorporating an innovative efficient discontinuous Galerkin(DG)method for grid division to accurately model basin sedimentary layers at reduced costs.It also introduces a comprehensive hybrid source model for high-frequency random scattering and a nonlinear analysis module for basin sedimentary layers.Deterministic outcomes are combined with modified three-dimensional stochastic finite fault method(3D-EXSIM)simulations of high-frequency ground motion(f>1 Hz).A fourth-order Butterworth filter with zero phase shift is employed for time-domain filtering of low-and high-frequency time series at a crossover frequency of 1 Hz,merging the low and high-frequency ground motions into a broadband time series.Taking an Ms 6.8 Luding earthquake,as an example,this hybrid method was used for a rapid and efficient simulation analysis of broadband ground motion in the region.The accuracy and efficiency of this hybrid method were verified through comparisons with actually observed station data and empirical attenuation curves.Deterministic method simulation results revealed the effects of mountainous topography,basin effects,nonlinear effects within the basin’s sedimentary layers,and a coupling interaction between the basin and the mountains.The findings are consistent with similar studies,showing that near-fault sedimentary basins significantly focus and amplify strong ground motion,and the soil’s nonlinear behavior in the basin influences ground motion to varying extents at different distances from the fault.The mountainous topography impacts the basin’s response to ground motion,leading to barrier effects.This research provides a scientific foundation for seismic zoning,urban planning,and seismic design in nearfault mountain basin regions.
