In the past few decades,ion engines have been widely used in deep-space propulsion and satellite station-keeping.The aim of extending the thruster lifetime is still one of the most important parts during the design st...In the past few decades,ion engines have been widely used in deep-space propulsion and satellite station-keeping.The aim of extending the thruster lifetime is still one of the most important parts during the design stage of ion engine.As one of the core components of ion engine,the grid assembly of ion optic systems may experience long-term ion sputtering in extreme electro-thermal environments,which will eventually lead to its structural and electron-backstreaming failures.In this paper,the current studies of the grid assembly erosion process are systematically analyzed from the aspects of sputtering damage process of grid materials,numerical simulations,and measurements of erosion characteristics of grid assembly.The advantages and disadvantages of various erosion prediction models are highlighted,and the key factors and processes affecting the prediction accuracy of grid assembly erosion patterns are analyzed.Three different types of experimental methods of grid assembly erosion patterns are compared.The analysis in this paper is of great importance for selecting the sputter-resistant grid materials,as well as establishing the erosion models and measurement methods to accurately determine the erosion rate and failure modes of grid assembly.Consequently,the working conditions and structure parameters of ion optic systems could be optimized based on erosion models to promote the ion engine lifetime.展开更多
Vegetation plays a major role in soil protection against erosion effects,and studies have also highlighted its importance in retaining sediments from roadside slopes.Yet,hydro-sedimentological studies under natural pr...Vegetation plays a major role in soil protection against erosion effects,and studies have also highlighted its importance in retaining sediments from roadside slopes.Yet,hydro-sedimentological studies under natural precipitation conditions are still scarce in semi-arid areas due to difficulties in monitoring the few and very concentrated precipitation events.Quantifying sediment connectivity and yield at watershed scale,often highly impacted by the erosion of unpaved roads,is necessary for management plans.This study aims to evaluate the efficiency of native vegetation on roadside slope segments in Caatinga biome in retaining sediments and conserving the soil in a semi-arid area of Brazil.Surface runoff,sediment concentration,and yield measurements were measured from 34 natural precipitation events in four years on two slopes with and without vegetation.The runoff coefficients of the plot with no vegetation varied from 3.0%to 58.0%,while in the vegetated plot,they showed variation from 1.0%to 21.0%.The annual specific sediment yield ranged from 4.6 to 138.7 kg/(hm^(2)•a)for the vegetated plot and from 34.9 to 608.5 kg/(hm^(2)•a)for the unvegetated one.These results indicate a 4 to 12 times higher soil loss on the unvegetated slope in relation to the vegetated one and demonstrate that natural Caatinga vegetation acts as an effective barrier against surface-transported sediments.Moreover,natural Caatinga vegetation present on the slope plays an important role in breaking connectivity between sediment flows from unpaved roads and the watershed drainage system.These findings indicate that investments in unpaved road and roadside slope restoration,not only enhance road infrastructure but also promote environmental gains by reducing the impact of erosion.展开更多
This study evaluates the efficacy of sustainable erosion control using slag-based alkali-activated cement crusts under varying rainfall and wind conditions. The rainfall intensities ranged from 30 mm/h to 120 mm/h, wi...This study evaluates the efficacy of sustainable erosion control using slag-based alkali-activated cement crusts under varying rainfall and wind conditions. The rainfall intensities ranged from 30 mm/h to 120 mm/h, with durations ranging from 15 min to 90 min, and crust slopes of ∼2° (gentle) and 30° (steep). Wind tunnel experiments were conducted at wind velocities of 14 m/s, 21 m/s, and 28 m/s to investigate post-rainfall wind erodibility, along with changes in crust strength and microstructure analysis. The findings show the development of hydrated cementitious phases in alkali-activated material, which form around and between the particles during the alkaline activation process. Alkali-activated cement crusts significantly reduced erosion caused by rainfall and subsequent wind by several orders of magnitude. At the highest rainfall intensity of 120 mm/h, rainfall erosion was measured to be 1654.81 kg/m2 for untreated samples and 0.89 kg/m2 for treated samples, demonstrating a substantial 99.95% reduction in erosion due to the treatment. Similarly, at the highest wind speed tested, wind erosion was 122.75 kg/m2 for untreated samples and 0.095 kg/m2 for treated samples, indicating a significant 99.92% reduction in erosion due to the formation of an alkali-activated cement crust on the soil surface. However, exposure of the samples to 120 mm/h rainfall for 90 min resulted in a 5.2-fold increase in wind erosion compared to pre-rainfall conditions. Similarly, penetrometer results indicated a 37%–54% reduction in post-rainfall surface strength.展开更多
To verify the wear resistance and erosion resistance of Ti-doped Ta_(2)O_(5)coating(TTO),a series of TTOs were prepared by magnetron sputtering technology by controlling the power of the Ti target.The change of growth...To verify the wear resistance and erosion resistance of Ti-doped Ta_(2)O_(5)coating(TTO),a series of TTOs were prepared by magnetron sputtering technology by controlling the power of the Ti target.The change of growth structure,microstructure,and tribological properties of TTOs with Ti target power was studied.After the erosion test,the variation of erosion damage behavior of TTOs with mechanical properties under different erosion conditions was further studied.The results show that the TTOs eliminate the roughness,voids,and defects in the material due to the mobility of the adsorbed atoms during the growth process,and a flat and dense smooth surface is obtained.Tribological tests show that the TTOs are mainly characterized by plastic deformation and microcrack wear mechanism.Higher Ti target power can improve the wear resistance of TTOs.Erosion test results reveal that the impact crater,furrow,micro-cutting,brittle spalling,and crack formation are the main wear mechanisms of the TTOs samples under erosion conditions.展开更多
Soil erosion(SE)is a critical form of land degradation that significantly threatens the health of terrestrial ecosystems worldwide.The Qinba Mountains represent a vital geo-ecological transition zone in China.Therefor...Soil erosion(SE)is a critical form of land degradation that significantly threatens the health of terrestrial ecosystems worldwide.The Qinba Mountains represent a vital geo-ecological transition zone in China.Therefore,analyzing the dynamics of SE in relation to climate changes and land use/cover(LULC)change is essential for guiding ecological conservation efforts in this region.The soil erosion intensity(SEI)from 2001 to 2020 was estimated using the Revised Universal Soil Loss Equation(RUSLE).For the period of 2021–2040,SEI projections were made based on CMIP6 data,utilizing the Statistical Downscaling Model alongside the CA-Markov model.Variations in SEI under four distinct shared socio-economic pathways were compared.Additionally,statistical methods were employed to evaluate the long-term impacts of climate and LULC change on SE.Findings indicate that between 2021and 2040,both precipitation and rainfall erosivity are expected to increase by approximately 8%–12%and 3%–14%,respectively.Based on differing socio-economic pathways,the soil erosion rate(SER)is predicted to rise by 12%–32%,with SSP2-4.5 anticipated to result in the highest SER.An analysis of contributing factors revealed that precipitation intensity and total precipitation are likely to escalate SE,while elevated temperatures may mitigate it.Among all types of LULC,barren land is particularly susceptible to erosion and remains a priority for conservation.The generated SEI maps will aid in promoting sustainable land use and provide crucial support for mitigating ecological risks from climate change.展开更多
Soil erosion is one of the major global hazards threatening the food security of the world population.Soil erosion can be a result of both natural and anthropogenic processes.Field monitoring and models(numerical and ...Soil erosion is one of the major global hazards threatening the food security of the world population.Soil erosion can be a result of both natural and anthropogenic processes.Field monitoring and models(numerical and physical)are commonly used to quantify soil erosion.However,field methods are time-consuming and the models inherently work with a level of uncertainty.Soil erosion studies in the Himalayas have been mostly carried out using modelling but there is a lack of sufficient field data to validate the results.We quantified soil erosion in a small catchment(Pranmati)in the Himalayas using the fallout meteoric^(10)Be nuclide for the first time.Based on the^(10)Be flux delivery rates determined from global circulation models(GCM),we calculated the rates of soil erosion at discrete points in the hilltop and mid-slope regions of hillslopes.The erosion rates vary between 17 mm kyr^(-1)to 68 mm kyr^(-1).These rates were determined in pristine areas that are unaffected by anthropogenic activities,thus,indicate the background erosion rates in the region.We established empirical relationships with estimated erosion rates and topographic parameters to assess the sediment dynamics in the hillslopes.It was observed that the sediment redistribution process operates differently in the mid-slope region compared to the hilltop region,due to increasing complexity of the active processes in the mid-slope region.展开更多
The topographic factor(LS factor),derived from the multiplication of the slope length(L)and slope steepness(S)factors,is a vital parameter in soil erosion models.Generated from the digital elevation model(DEM),the LS ...The topographic factor(LS factor),derived from the multiplication of the slope length(L)and slope steepness(S)factors,is a vital parameter in soil erosion models.Generated from the digital elevation model(DEM),the LS factor always varies with the changing DEM resolution,i.e.,the LS factor scale effect.Previous studies have found the phenomenon of the LS factor scale effect,but the underlying causes of this phenomenon has not been well explored.Therefore,how the DEM resolution affects the LS factor and how the scale effect of the L and S factors influence the LS factor scale effect remains unclear.To address these problems,we collected 20 watersheds from the Guangdong Province with different topographic reliefs,and compared the corresponding L,S and LS factors at 10-m and 30-m resolution DEMs.Our results indicate that the S factor,heavily influenced by slope underestimation in coarse-resolution DEMs,makes a difference in the LS factor scale effect.In addition,the LS factor scale effect becomes less significant with increasing reliefs,suggesting the possibility of using 30-m DEM for LS calculation in rugged terrains.Our findings on the underlying mechanisms of the LS factor scale effect help to identify the uncertainty in the LS factor estimation,thereby enhancing the accuracy of soil erosion assessment,particularly in regions with different topographic characteristics and contribute to more effective soil conservation strategies and decision-making.展开更多
The particle size distribution plays a crucial role in the transportation and deposition of eroded sediments.Gaining insights into the related sorting mechanism can significantly enhance our understanding of such proc...The particle size distribution plays a crucial role in the transportation and deposition of eroded sediments.Gaining insights into the related sorting mechanism can significantly enhance our understanding of such processes.In this study,sand-covered slopes were examined.A controlled indoor rainfall simulation was conducted on loess slopes with a 12°incline and a rainfall intensity of 1.5 mm/min.These slopes were then covered with sand layers of varying thicknesses—0.5,1.0,and 1.5 cm—to observe their effects.The findings have revealed that as the thickness of the sand cover increases,the content of sediment particles smaller than 0.054 mm decreases.In contrast,the content of particles larger than 0.054 mm increases after the sixth minute of runoff.The eroded sediment was predominantly composed of silt.During the inter-rill erosion stage,runoff primarily transported particles larger than 0.054 mm.However,in the subsequent rill erosion and combined rill and inter-rill erosion stages,the runoff predominantly carried finer particles,smaller than 0.054 mm.Moreover,the presence of the sand layer significantly influenced the size and form of the eroded sediment particles.Initially,during the first 10 min of runoff,the eroded particles were predominantly larger than 0.054 mm.After this period,however,the particle size shifted,with the majority of particles being smaller than 0.054 mm.This study highlights the intricate relationship between sediment sorting,the thickness of sand covers,and the dynamics of sediment transport under rainfall-induced erosion.展开更多
In this study,the pure erosion behaviour of pure iron and its erosion-corrosion behaviour under different anodic polarization currents were investigated in various cathodic reactions(oxygen reduction,hydrogen ion redu...In this study,the pure erosion behaviour of pure iron and its erosion-corrosion behaviour under different anodic polarization currents were investigated in various cathodic reactions(oxygen reduction,hydrogen ion reduction,and water reduction)using a cylindrical stirring system.The corrosion-enhanced erosion(C-E)rates were determined for each condition.The results revealed that pure iron displayed similar pure erosion behaviour across all three cathodic reactions.When the cathodic reactions involve hydrogen ion reduction or water reduction,the erosion-corrosion of pure iron manifested as uniform damage,with the reduction in hardness being the main cause of the C-E in this case.Conversely,in the case of oxy-gen reduction reaction as the cathodic reaction,the erosion-corrosion presented as pitting damage,with the reduction in hardness resulting from localized concentration of anodic current and the formation of easily worn protruding flaky iron structures at the edges of the pits as the main mechanism of the C-E.Moreover,linear and exponential relationships were found between the C-E rate and the anodic current density for uniform damage and pitting damage,respectively.Finally,the concept of surface equivalent hardness was proposed,along with the establishment of a mathematical model for surface equivalent hardness based on the relationships between the C-E rate and the anodic current density.Utilizing the surface equivalent hardness enables the evaluation of the erosion rate on material surfaces considering the coupled effect.展开更多
Erosion in slurry pumps presents a persistent challenge in industrial applications.This study examines the erosion of the static components of a 150ZJ-C42 centrifugal slurry pump,currently in operation at a beneficiat...Erosion in slurry pumps presents a persistent challenge in industrial applications.This study examines the erosion of the static components of a 150ZJ-C42 centrifugal slurry pump,currently in operation at a beneficiation plant,under varying particle conditions.Utilizing high-precision three-dimensional reverse engineering,the pump’s flow passage geometry was reconstructed to facilitate detailed erosion analysis.Focusing on the front and rear baffles of the pump chamber,as well as the volute,erosion patterns were analyzed for different particle volume concentrations and sizes.The results reveal that the highest erosion damage consistently occurs near the volute tongue,with wear being most severe in regions adjacent to the partition plate near the rear cover.Erosion damage intensity in this area correlates positively with particle diameter.Notably,the average erosion rate in the volute surpasses that of the front and rear chamber liners,reaching a value as high as 6.03×10^(-7)kg·m^(-2)·s^(-1)at a particle concentration of 9%and diameter of 0.1 mm,adversely impacting pump stability.For the pump chamber baffles,increased erosion is observed at a particle diameter of 0.05 mm under constant volume concentration conditions,while higher particle concentrations exacerbate localized erosion.展开更多
Soil erosion in the Hare watershed led to significant land degradation,water pollution,and reduced agricultural productivity.Despite its effects,very few researchers have used combined morphometric and RUSLE model tec...Soil erosion in the Hare watershed led to significant land degradation,water pollution,and reduced agricultural productivity.Despite its effects,very few researchers have used combined morphometric and RUSLE model techniques to quantify soil erosion and thereby prioritize impacted areas.This work used an automated GIS-based tool(SWPT)to prioritize crucial areas based on topohydrological and morphometric factors and predict soil loss in sub-watersheds using the RUSLE model.Land use/cover data were obtained from Landsat imagery,while slope and morphometric information were extracted from digital elevation data with a resolution of 12.5 m.Soil erodibility was determined using Ethiopian soil maps,and rainfall erosivity was computed using meteorological data.An average annual soil loss of 49 t ha-1 yr-1 was observed in the Hare watershed.Sub-watershed 11 was found to be the most affected,with an average annual soil loss of 85.12 t ha-1 yr-1and a compound parameter value(CPV)of 0.059.Subwatershed 17 has the least amount of soil loss,with 3.67t ha-1 yr-1 and a CPV of 1.32.The study emphasizes the usefulness of integrating RUSLE and morphometric analysis for soil and water conservation planning,suggesting a variety of modeling tools in data-sparse locations to quantify and prioritize erosion-prone areas.展开更多
The erosion process and kinetics of PbTe particles in a selenium melt were investigated.The results reveal that the limiting step of the reaction is controlled by product layer diffusion and the interfacial chemical r...The erosion process and kinetics of PbTe particles in a selenium melt were investigated.The results reveal that the limiting step of the reaction is controlled by product layer diffusion and the interfacial chemical reaction at low temperatures(573,583,and 593 K),but the limiting step is controlled by boundary layer diffusion at high temperatures(603 and 613 K).The Se-and Te-atom diffusion in the product layer becomes unbalanced as the product layer thickens,with Kirkendall voids generating in the product layer accelerating PbTe particle erosion.After the PbTe impurities in the selenium melt evolve into PbSe and Te,Te is evenly distributed in the selenium melt owing to the solubility of Se and Te.This study serves to clarify the evolution behavior of PbTe impurities in the selenium melt and the reason that Te often occurs in Se.展开更多
The Darjeeling Himalayan region,characterized by its complex topography and vulnerability to multiple environmental hazards,faces significant challenges including landslides,earthquakes,flash floods,and soil loss that...The Darjeeling Himalayan region,characterized by its complex topography and vulnerability to multiple environmental hazards,faces significant challenges including landslides,earthquakes,flash floods,and soil loss that critically threaten ecosystem stability.Among these challenges,soil erosion emerges as a silent disaster-a gradual yet relentless process whose impacts accumulate over time,progressively degrading landscape integrity and disrupting ecological sustainability.Unlike catastrophic events with immediate visibility,soil erosion’s most devastating consequences often manifest decades later through diminished agricultural productivity,habitat fragmentation,and irreversible biodiversity loss.This study developed a scalable predictive framework employing Random Forest(RF)and Gradient Boosting Tree(GBT)machine learning models to assess and map soil erosion susceptibility across the region.A comprehensive geo-database was developed incorporating 11 erosion triggering factors:slope,elevation,rainfall,drainage density,topographic wetness index,normalized difference vegetation index,curvature,soil texture,land use,geology,and aspect.A total of 2,483 historical soil erosion locations were identified and randomly divided into two sets:70%for model building and 30%for validation purposes.The models revealed distinct spatial patterns of erosion risks,with GBT classifying 60.50%of the area as very low susceptibility,while RF identified 28.92%in this category.Notable differences emerged in high-risk zone identification,with GBT highlighting 7.42%and RF indicating 2.21%as very high erosion susceptibility areas.Both models demonstrated robust predictive capabilities,with GBT achieving 80.77%accuracy and 0.975 AUC,slightly outperforming RF’s 79.67%accuracy and 0.972 AUC.Analysis of predictor variables identified elevation,slope,rainfall and NDVI as the primary factors influencing erosion susceptibility,highlighting the complex interrelationship between geo-environmental factors and erosion processes.This research offers a strategic framework for targeted conservation and sustainable land management in the fragile Himalayan region,providing valuable insights to help policymakers implement effective soil erosion mitigation strategies and support long-term environmental sustainability.展开更多
The hydro-mechanical responses of vegetated deposited slopes are complex and far from clear.On one hand,the soils in deposited slopes are typically poorly consolidated and widely graded,making them vulnerable to inter...The hydro-mechanical responses of vegetated deposited slopes are complex and far from clear.On one hand,the soils in deposited slopes are typically poorly consolidated and widely graded,making them vulnerable to internal erosion during rainfall infiltration.On the other hand,vegetation plays a significant role in influencing the hydro-mechanical properties of the soil at the slope surface.This paper presents a coupled seepage-erosion model to investigate the rainfall-induced internal erosion process within vegetated deposited slopes and its impact on slope stability.The detailed seepage-erosion coupling processes were simulated for a series of 1D rooted soil columns with varying root distributions,as well as 2D vegetated layered slopes under both light and heavy rainfall conditions.The numerical results reveal that roots can significantly mitigate rainfall-induced internal erosion,even with shallow root lengths.However,their protective effect on the slope increases as the root density in the superficial soil layer increases.Transpiration can rapidly restore matric suction in the shallow soil during rain intervals,slowing the rainfall-induced seepage-erosion process and thereby increasing slope stability.However,in the absence of transpiration,roots may either accelerate or inhibit the seepage-erosion process,depending on the specific rainfall conditions.展开更多
Soil erosion from water has become a relevant issue at global level.In Guinea in particular,erosion has worrying effects,due to natural conditions and human impact,especially in the Nzérékore city in forest ...Soil erosion from water has become a relevant issue at global level.In Guinea in particular,erosion has worrying effects,due to natural conditions and human impact,especially in the Nzérékore city in forest region.This paper proposed a soil erosion modeling by rainfall effect in the prefecture of N'Zérékoré.To achieve this objective,monthly and annual rainfall data for the N'Zérékorécity were collected at the meteorological station over the period from 1980 to 2024.The analysis of rainfall aggressiveness was possible using the Fournier index.For data processing,we used Microsoft Excel,Python and the ARIMA(AutoRegressive Integrated Moving Average)model for soil aggressiveness predicted by rainfall.It was found that,from 2000 to 2009,erosion was higher compared to other periods with a rate of 60%,or 6 years of high rainfall aggression.From the periods 1990 to 1999 and 2010 to 2019,the lowest rainfall aggressiveness was recorded,with 60%or 6 years of low erosivity.However,from period 1980 to 1989 the highest rate(70%)of very high rainfall erosivity was recorded.The results show three levels of rainfall aggressiveness on an annual scale:a very high level of erosivity with a rate of 22.2%or 10 years,followed by a high level of 35.6%or 16 years of strong erosion.The moderate erosivity level corresponds to 42.2%or 19 years.The model predicts a stability of the erosivity index around 77.14 over the period 2025-2034.During the forty(45)years the rainfall erosivity index was very unstable characterized by strong erosion,however it would be stable in the next ten(10)years.展开更多
Low erosion high-energy propellant is one of the research directions to extend the weapon’s life and improve the weapon’s capability.In this study,energetic propellants containing different corrosion inhibitors were...Low erosion high-energy propellant is one of the research directions to extend the weapon’s life and improve the weapon’s capability.In this study,energetic propellants containing different corrosion inhibitors were designed and prepared.Close bomb tests and semi-confined bomb experiments were used to investigate the burning and erosion properties of the propellants.The mechanism of erosion-reducing of titanium dioxide(titania,TiO_(2)),talc,and octaphenylsilsesquioxane(OPS)on the propellant was comparatively analyzed.The results show that OPS has the lowest burning rate and the longest burning time,and a minimized loss of fire force,with the best effect of explosion heat reduction.The erosion reduction efficiency of OPS is twice that of TiO_(2) and talc.The mechanism analysis shows that the decomposition and heat absorption of OPS can effectively reduce the thermal erosion effect and carbon erosion,and the gas produced can reduce the loss of chamber pressure and form a uniformly distributed nano-SiO_(2) protective layer.This solid-state high-efficiency organosilicon erosion inhibitor is an important guide for designing high-energy low-erosion gun propellants.展开更多
Image-based computational models have been used for vulnerable plaque progression and rupture predictions,and good results have been reported.However,mechanisms and predictions for plaque erosion are underinvestigated...Image-based computational models have been used for vulnerable plaque progression and rupture predictions,and good results have been reported.However,mechanisms and predictions for plaque erosion are underinvestigated.Patient-specific fluid-structure interaction(FSI)models based on optical coherence tomography(OCT)follow-up data from patients with plaque erosion and who received conservative antithrombotic treatment(using medication,no stenting)to identify risk factors that could be used to predict the treatment outcome.OCT and angiography datawere obtained from10 patientswho received conservative antithrombotic treatment.Five participants had worse outcomes(WOG,stenosis severity≥70%at one-year follow-up),while the other five had better outcomes(BOG,stenosis severity<70%at one-year follow-up).Patient-specific 3D FSI models were constructed to obtain morphological and biomechanical risk factor values(a total of nine risk factors)for comparison and prediction.A logistic regressionmodel was used to identify optimal predictors with the best treatment outcome prediction accuracies.Our results indicated that the combination of wall shear stress(WSS),lipid percent,and thrombus burden was the best group predictor according to the mean area under the curve(AUC)of 0.96(90%confidence interval=(0.85,1.00)).WSS was the best single predictor withmean AUC=0.70(90%confidence interval=(0.20,1.00)).Thrombus burden was the only risk factor showing statistically significant group difference,suggesting its crucial role in the outcomes of conservative anti-thrombotic therapy.This pilot study indicated that integratingmorphological and biomechanical risk factors could improve treatment outcome prediction accuracy in patients with plaque erosion compared to predictions using single predictors.Large-scale patient studies are needed to further validate our findings.展开更多
To address the challenges posed by tunnel construction in the alpine region,silica fume mixed concrete is commonly used as a construction material.The correlation between silica fume content and the lining life requir...To address the challenges posed by tunnel construction in the alpine region,silica fume mixed concrete is commonly used as a construction material.The correlation between silica fume content and the lining life requires immediate investigation.In view of this phenomenon,the durability of unit lining concrete is predicted by analyzing three key indicators:carbonation depth,relative dynamic elastic modulus,and residual quality.This prediction is achieved by integrating the Entropy Weight Method,Grey theory life prediction model and BP artificial neural networks using data from tests and predictions of these indicators.Then,the Entropy Weight-Grey theory-BP Network Model is compared with other methods to analyze the predicted life.Finally,verify the sci-entificity of this model,and the optimum silica fume content of unit concrete lining is verified.The results showed,1)The addition of silica fume will accelerate the carbonization of unit concrete lining,and slow down the freeze-thaw cycle and sulfate erosion.2)The utilization of artificial neural networks is essential for enhancing the realism of the data,as it emphasizes the significance of silica fume content.3)Silica fume content of 10%results in the longest life and is the most suitable for lining construction.4)A comparison between single-factor and multi-factor predictions indicates that the multi-factor approach yields a longer maximum life.This improvement can be attributed to the inclusion of additional factors,such as freeze-thaw cycles and carbonation,which enhance the predicted life when employing these methods.In conclusion,the Entropy Weight-Grey Theory-BP Network life prediction Model is well-suited for tunnel lining in the alpine sulfate area of northwest China.展开更多
The southern Tibetan Plateau has undergone accelerated warming that exceeds the global average,which has intensified surface hydrological processes.However,the mechanisms underlying drought effects on water-driven ero...The southern Tibetan Plateau has undergone accelerated warming that exceeds the global average,which has intensified surface hydrological processes.However,the mechanisms underlying drought effects on water-driven erosion under current climate change remain poorly understood.This paper aims to reveal the spatiotemporal changes in water-induced erosion in typical areas of the southern Tibetan Plateau using the Revised Universal Soil Loss Equation(RUSLE).Additionally,it seeks to identify the driving forces through the threshold segmentation method based on multi-timescale Standardized Precipitation Evapotranspiration Index(SPEI)data.The results showed that the average soil erosion in the study area from 2001 to 2019 was 46.90 t ha-1 a-1,with an overall significant decreasing trend(p<0.05).Significant decreases were observed in 40.86%of the areas.The relationship between soil erosion and SPEI was predominantly positive,with the strongest correlation observed between soil erosion and meteorological and agricultural drought.Areas experiencing significant decreases in soil erosion driven by intensified drought accounted for 24.55%of the total area,followed by 10.51%attributed to multiple factors and 6.66%influenced predominantly by human activities.Conversely,abnormal increases in soil erosion were noted in 1.02%of the total area.These findings underscore the impact of drought changes on soil erosion in typical areas of the southern Tibetan Plateau,offering insights for future research on the relationship between soil erosion and climate variability in fragile ecosystems.展开更多
To elucidate the relationship between pipeline erosion and wear during slurry transportation,this study considers three key influencing parameters,namely,the ratio of inlet to outlet pipe diameter,the length of the va...To elucidate the relationship between pipeline erosion and wear during slurry transportation,this study considers three key influencing parameters,namely,the ratio of inlet to outlet pipe diameter,the length of the variable diameter section,and the roughness of the pipe wall.The impact of these factors on pipeline erosion and wear is analyzed using a single-factor analysis approach.In particular,the Fluent software is employed to conduct the required numerical simulations for variable diameter elbows of varying morphologies.The results indicate that as the inlet to outlet diameter ratio increases,the wear on the pipe inlet and the outer wall of the elbow becomes increasingly pronounced.Notably,when the diameter ratio exceeds 0.8,there is a significant escalation in wear on both the inner and outer elbow walls.Initially,the maximum erosion rate decreases sharply with increasing diameter ratio before a stable condition is attained.Erosion wear in the variable diameter section exhibits a distinct layered distribution pattern.In this region,the wear range for a 40 mm length of the pipe body is relatively small;however,once this length exceeds 40 mm,the wear range expands,ultimately covering the entire pipe section.The length of the variable diameter section significantly influences the maximum erosion rate of the pipeline,with sections shorter than 80 mm experiencing the most severe effects,and showing an exponential decline in erosion rate.As the wall roughness gradually increases,the wear area on both cheeks of the bend section rapidly expands and tends to deepen further.When the roughness reaches 4 mm,the pipeline wear experiences a dramatic shift,resulting in extensive“spot-like”wear patterns emerging at the bottom and sides of the horizontal flow section,which previously exhibited no wear.展开更多
基金co-supported by the National Key R&D Program of China(No.2022YFB3403500)the National Natural Science Foundation of China(No.NSFC52202460)the China Postdoctoral Science Foundation(Nos.2021M690392,2021TQ0036,and 2023TQ0031)。
文摘In the past few decades,ion engines have been widely used in deep-space propulsion and satellite station-keeping.The aim of extending the thruster lifetime is still one of the most important parts during the design stage of ion engine.As one of the core components of ion engine,the grid assembly of ion optic systems may experience long-term ion sputtering in extreme electro-thermal environments,which will eventually lead to its structural and electron-backstreaming failures.In this paper,the current studies of the grid assembly erosion process are systematically analyzed from the aspects of sputtering damage process of grid materials,numerical simulations,and measurements of erosion characteristics of grid assembly.The advantages and disadvantages of various erosion prediction models are highlighted,and the key factors and processes affecting the prediction accuracy of grid assembly erosion patterns are analyzed.Three different types of experimental methods of grid assembly erosion patterns are compared.The analysis in this paper is of great importance for selecting the sputter-resistant grid materials,as well as establishing the erosion models and measurement methods to accurately determine the erosion rate and failure modes of grid assembly.Consequently,the working conditions and structure parameters of ion optic systems could be optimized based on erosion models to promote the ion engine lifetime.
基金the National Council for Scientific and Technological Development (CNPq) for funding the field studies and for the research productivity fellowship (CNPq/PQ) awarded to Pedro Henrique Augusto MEDEIROS and José Carlos de ARAúJOthe Coordination for the Improvement of Higher Education Personnel (CAPES) for the doctoral scholarship awarded to Teresa Raquel Lima FARIAS (2117/13-4)the Foundation for the Support of Scientific and Technological Development in the State of Ceará (FUNCAP) for the master scholarship awarded to Maria Thereza Rocha CHAVES。
文摘Vegetation plays a major role in soil protection against erosion effects,and studies have also highlighted its importance in retaining sediments from roadside slopes.Yet,hydro-sedimentological studies under natural precipitation conditions are still scarce in semi-arid areas due to difficulties in monitoring the few and very concentrated precipitation events.Quantifying sediment connectivity and yield at watershed scale,often highly impacted by the erosion of unpaved roads,is necessary for management plans.This study aims to evaluate the efficiency of native vegetation on roadside slope segments in Caatinga biome in retaining sediments and conserving the soil in a semi-arid area of Brazil.Surface runoff,sediment concentration,and yield measurements were measured from 34 natural precipitation events in four years on two slopes with and without vegetation.The runoff coefficients of the plot with no vegetation varied from 3.0%to 58.0%,while in the vegetated plot,they showed variation from 1.0%to 21.0%.The annual specific sediment yield ranged from 4.6 to 138.7 kg/(hm^(2)•a)for the vegetated plot and from 34.9 to 608.5 kg/(hm^(2)•a)for the unvegetated one.These results indicate a 4 to 12 times higher soil loss on the unvegetated slope in relation to the vegetated one and demonstrate that natural Caatinga vegetation acts as an effective barrier against surface-transported sediments.Moreover,natural Caatinga vegetation present on the slope plays an important role in breaking connectivity between sediment flows from unpaved roads and the watershed drainage system.These findings indicate that investments in unpaved road and roadside slope restoration,not only enhance road infrastructure but also promote environmental gains by reducing the impact of erosion.
文摘This study evaluates the efficacy of sustainable erosion control using slag-based alkali-activated cement crusts under varying rainfall and wind conditions. The rainfall intensities ranged from 30 mm/h to 120 mm/h, with durations ranging from 15 min to 90 min, and crust slopes of ∼2° (gentle) and 30° (steep). Wind tunnel experiments were conducted at wind velocities of 14 m/s, 21 m/s, and 28 m/s to investigate post-rainfall wind erodibility, along with changes in crust strength and microstructure analysis. The findings show the development of hydrated cementitious phases in alkali-activated material, which form around and between the particles during the alkaline activation process. Alkali-activated cement crusts significantly reduced erosion caused by rainfall and subsequent wind by several orders of magnitude. At the highest rainfall intensity of 120 mm/h, rainfall erosion was measured to be 1654.81 kg/m2 for untreated samples and 0.89 kg/m2 for treated samples, demonstrating a substantial 99.95% reduction in erosion due to the treatment. Similarly, at the highest wind speed tested, wind erosion was 122.75 kg/m2 for untreated samples and 0.095 kg/m2 for treated samples, indicating a significant 99.92% reduction in erosion due to the formation of an alkali-activated cement crust on the soil surface. However, exposure of the samples to 120 mm/h rainfall for 90 min resulted in a 5.2-fold increase in wind erosion compared to pre-rainfall conditions. Similarly, penetrometer results indicated a 37%–54% reduction in post-rainfall surface strength.
文摘To verify the wear resistance and erosion resistance of Ti-doped Ta_(2)O_(5)coating(TTO),a series of TTOs were prepared by magnetron sputtering technology by controlling the power of the Ti target.The change of growth structure,microstructure,and tribological properties of TTOs with Ti target power was studied.After the erosion test,the variation of erosion damage behavior of TTOs with mechanical properties under different erosion conditions was further studied.The results show that the TTOs eliminate the roughness,voids,and defects in the material due to the mobility of the adsorbed atoms during the growth process,and a flat and dense smooth surface is obtained.Tribological tests show that the TTOs are mainly characterized by plastic deformation and microcrack wear mechanism.Higher Ti target power can improve the wear resistance of TTOs.Erosion test results reveal that the impact crater,furrow,micro-cutting,brittle spalling,and crack formation are the main wear mechanisms of the TTOs samples under erosion conditions.
基金National Natural Science Foundation of China(Youth Program),No.42201110。
文摘Soil erosion(SE)is a critical form of land degradation that significantly threatens the health of terrestrial ecosystems worldwide.The Qinba Mountains represent a vital geo-ecological transition zone in China.Therefore,analyzing the dynamics of SE in relation to climate changes and land use/cover(LULC)change is essential for guiding ecological conservation efforts in this region.The soil erosion intensity(SEI)from 2001 to 2020 was estimated using the Revised Universal Soil Loss Equation(RUSLE).For the period of 2021–2040,SEI projections were made based on CMIP6 data,utilizing the Statistical Downscaling Model alongside the CA-Markov model.Variations in SEI under four distinct shared socio-economic pathways were compared.Additionally,statistical methods were employed to evaluate the long-term impacts of climate and LULC change on SE.Findings indicate that between 2021and 2040,both precipitation and rainfall erosivity are expected to increase by approximately 8%–12%and 3%–14%,respectively.Based on differing socio-economic pathways,the soil erosion rate(SER)is predicted to rise by 12%–32%,with SSP2-4.5 anticipated to result in the highest SER.An analysis of contributing factors revealed that precipitation intensity and total precipitation are likely to escalate SE,while elevated temperatures may mitigate it.Among all types of LULC,barren land is particularly susceptible to erosion and remains a priority for conservation.The generated SEI maps will aid in promoting sustainable land use and provide crucial support for mitigating ecological risks from climate change.
基金financially supported by Council of Scientific and Industrial Research(CSIR)(grant no.09/045(1399)/2015-EMR-I)the Ministry of Earth Sciences(Mo ES),Government of India(grant no.Mo ES/P.O.(Geo)/95/2017)。
文摘Soil erosion is one of the major global hazards threatening the food security of the world population.Soil erosion can be a result of both natural and anthropogenic processes.Field monitoring and models(numerical and physical)are commonly used to quantify soil erosion.However,field methods are time-consuming and the models inherently work with a level of uncertainty.Soil erosion studies in the Himalayas have been mostly carried out using modelling but there is a lack of sufficient field data to validate the results.We quantified soil erosion in a small catchment(Pranmati)in the Himalayas using the fallout meteoric^(10)Be nuclide for the first time.Based on the^(10)Be flux delivery rates determined from global circulation models(GCM),we calculated the rates of soil erosion at discrete points in the hilltop and mid-slope regions of hillslopes.The erosion rates vary between 17 mm kyr^(-1)to 68 mm kyr^(-1).These rates were determined in pristine areas that are unaffected by anthropogenic activities,thus,indicate the background erosion rates in the region.We established empirical relationships with estimated erosion rates and topographic parameters to assess the sediment dynamics in the hillslopes.It was observed that the sediment redistribution process operates differently in the mid-slope region compared to the hilltop region,due to increasing complexity of the active processes in the mid-slope region.
基金funded by the Guangdong Major Project of Basic and Applied Basic Research(2021B0301030007)the Supplemental Funds for Major Scientific Research Projects of Beijing Normal University,Zhuhai(ZHPT2023013)+1 种基金the National Natural Science Foundation of China(42301387)the Science and Technology Program of Guangdong(No.2024B1212070012)。
文摘The topographic factor(LS factor),derived from the multiplication of the slope length(L)and slope steepness(S)factors,is a vital parameter in soil erosion models.Generated from the digital elevation model(DEM),the LS factor always varies with the changing DEM resolution,i.e.,the LS factor scale effect.Previous studies have found the phenomenon of the LS factor scale effect,but the underlying causes of this phenomenon has not been well explored.Therefore,how the DEM resolution affects the LS factor and how the scale effect of the L and S factors influence the LS factor scale effect remains unclear.To address these problems,we collected 20 watersheds from the Guangdong Province with different topographic reliefs,and compared the corresponding L,S and LS factors at 10-m and 30-m resolution DEMs.Our results indicate that the S factor,heavily influenced by slope underestimation in coarse-resolution DEMs,makes a difference in the LS factor scale effect.In addition,the LS factor scale effect becomes less significant with increasing reliefs,suggesting the possibility of using 30-m DEM for LS calculation in rugged terrains.Our findings on the underlying mechanisms of the LS factor scale effect help to identify the uncertainty in the LS factor estimation,thereby enhancing the accuracy of soil erosion assessment,particularly in regions with different topographic characteristics and contribute to more effective soil conservation strategies and decision-making.
基金research was funded bymultiple sources,including the Guangxi Natural Science Foundation of Youth Fund(2020GXNSFBA159004)the National Natural Science Foundation Project of China(51779204)the Guilin University of Technology High-Level Talent Research Startup Project(GUTQDJJ2018069).
文摘The particle size distribution plays a crucial role in the transportation and deposition of eroded sediments.Gaining insights into the related sorting mechanism can significantly enhance our understanding of such processes.In this study,sand-covered slopes were examined.A controlled indoor rainfall simulation was conducted on loess slopes with a 12°incline and a rainfall intensity of 1.5 mm/min.These slopes were then covered with sand layers of varying thicknesses—0.5,1.0,and 1.5 cm—to observe their effects.The findings have revealed that as the thickness of the sand cover increases,the content of sediment particles smaller than 0.054 mm decreases.In contrast,the content of particles larger than 0.054 mm increases after the sixth minute of runoff.The eroded sediment was predominantly composed of silt.During the inter-rill erosion stage,runoff primarily transported particles larger than 0.054 mm.However,in the subsequent rill erosion and combined rill and inter-rill erosion stages,the runoff predominantly carried finer particles,smaller than 0.054 mm.Moreover,the presence of the sand layer significantly influenced the size and form of the eroded sediment particles.Initially,during the first 10 min of runoff,the eroded particles were predominantly larger than 0.054 mm.After this period,however,the particle size shifted,with the majority of particles being smaller than 0.054 mm.This study highlights the intricate relationship between sediment sorting,the thickness of sand covers,and the dynamics of sediment transport under rainfall-induced erosion.
基金supported by the National Key Research and Development Program(No.2022YFC2806200)the National Key Research and Development Program(No.2023YFC2810800)the Natural Science Foundation of China(No.52001055).
文摘In this study,the pure erosion behaviour of pure iron and its erosion-corrosion behaviour under different anodic polarization currents were investigated in various cathodic reactions(oxygen reduction,hydrogen ion reduction,and water reduction)using a cylindrical stirring system.The corrosion-enhanced erosion(C-E)rates were determined for each condition.The results revealed that pure iron displayed similar pure erosion behaviour across all three cathodic reactions.When the cathodic reactions involve hydrogen ion reduction or water reduction,the erosion-corrosion of pure iron manifested as uniform damage,with the reduction in hardness being the main cause of the C-E in this case.Conversely,in the case of oxy-gen reduction reaction as the cathodic reaction,the erosion-corrosion presented as pitting damage,with the reduction in hardness resulting from localized concentration of anodic current and the formation of easily worn protruding flaky iron structures at the edges of the pits as the main mechanism of the C-E.Moreover,linear and exponential relationships were found between the C-E rate and the anodic current density for uniform damage and pitting damage,respectively.Finally,the concept of surface equivalent hardness was proposed,along with the establishment of a mathematical model for surface equivalent hardness based on the relationships between the C-E rate and the anodic current density.Utilizing the surface equivalent hardness enables the evaluation of the erosion rate on material surfaces considering the coupled effect.
基金The authors gratefully acknowledge the filnancial support of the National Natural Science Foundation of China(Grant No.52369018)the Major Training Program of University Research and Innovation Platform of Gansu Provincial Department of Education(No.2024CXPT-09)+1 种基金the Administration of Central Funds Guiding the Local Science and Technology Development,China(Grant No.23ZYQA0320)the Double First-Class Key Program of Gansu Provincial Department of Education,Grant No.GCJ2022-38.
文摘Erosion in slurry pumps presents a persistent challenge in industrial applications.This study examines the erosion of the static components of a 150ZJ-C42 centrifugal slurry pump,currently in operation at a beneficiation plant,under varying particle conditions.Utilizing high-precision three-dimensional reverse engineering,the pump’s flow passage geometry was reconstructed to facilitate detailed erosion analysis.Focusing on the front and rear baffles of the pump chamber,as well as the volute,erosion patterns were analyzed for different particle volume concentrations and sizes.The results reveal that the highest erosion damage consistently occurs near the volute tongue,with wear being most severe in regions adjacent to the partition plate near the rear cover.Erosion damage intensity in this area correlates positively with particle diameter.Notably,the average erosion rate in the volute surpasses that of the front and rear chamber liners,reaching a value as high as 6.03×10^(-7)kg·m^(-2)·s^(-1)at a particle concentration of 9%and diameter of 0.1 mm,adversely impacting pump stability.For the pump chamber baffles,increased erosion is observed at a particle diameter of 0.05 mm under constant volume concentration conditions,while higher particle concentrations exacerbate localized erosion.
文摘Soil erosion in the Hare watershed led to significant land degradation,water pollution,and reduced agricultural productivity.Despite its effects,very few researchers have used combined morphometric and RUSLE model techniques to quantify soil erosion and thereby prioritize impacted areas.This work used an automated GIS-based tool(SWPT)to prioritize crucial areas based on topohydrological and morphometric factors and predict soil loss in sub-watersheds using the RUSLE model.Land use/cover data were obtained from Landsat imagery,while slope and morphometric information were extracted from digital elevation data with a resolution of 12.5 m.Soil erodibility was determined using Ethiopian soil maps,and rainfall erosivity was computed using meteorological data.An average annual soil loss of 49 t ha-1 yr-1 was observed in the Hare watershed.Sub-watershed 11 was found to be the most affected,with an average annual soil loss of 85.12 t ha-1 yr-1and a compound parameter value(CPV)of 0.059.Subwatershed 17 has the least amount of soil loss,with 3.67t ha-1 yr-1 and a CPV of 1.32.The study emphasizes the usefulness of integrating RUSLE and morphometric analysis for soil and water conservation planning,suggesting a variety of modeling tools in data-sparse locations to quantify and prioritize erosion-prone areas.
基金National Key Research and Development Program of China(No.2022YFC2904900)the National Natural Science Foundation of China(No.U1902221).
文摘The erosion process and kinetics of PbTe particles in a selenium melt were investigated.The results reveal that the limiting step of the reaction is controlled by product layer diffusion and the interfacial chemical reaction at low temperatures(573,583,and 593 K),but the limiting step is controlled by boundary layer diffusion at high temperatures(603 and 613 K).The Se-and Te-atom diffusion in the product layer becomes unbalanced as the product layer thickens,with Kirkendall voids generating in the product layer accelerating PbTe particle erosion.After the PbTe impurities in the selenium melt evolve into PbSe and Te,Te is evenly distributed in the selenium melt owing to the solubility of Se and Te.This study serves to clarify the evolution behavior of PbTe impurities in the selenium melt and the reason that Te often occurs in Se.
文摘The Darjeeling Himalayan region,characterized by its complex topography and vulnerability to multiple environmental hazards,faces significant challenges including landslides,earthquakes,flash floods,and soil loss that critically threaten ecosystem stability.Among these challenges,soil erosion emerges as a silent disaster-a gradual yet relentless process whose impacts accumulate over time,progressively degrading landscape integrity and disrupting ecological sustainability.Unlike catastrophic events with immediate visibility,soil erosion’s most devastating consequences often manifest decades later through diminished agricultural productivity,habitat fragmentation,and irreversible biodiversity loss.This study developed a scalable predictive framework employing Random Forest(RF)and Gradient Boosting Tree(GBT)machine learning models to assess and map soil erosion susceptibility across the region.A comprehensive geo-database was developed incorporating 11 erosion triggering factors:slope,elevation,rainfall,drainage density,topographic wetness index,normalized difference vegetation index,curvature,soil texture,land use,geology,and aspect.A total of 2,483 historical soil erosion locations were identified and randomly divided into two sets:70%for model building and 30%for validation purposes.The models revealed distinct spatial patterns of erosion risks,with GBT classifying 60.50%of the area as very low susceptibility,while RF identified 28.92%in this category.Notable differences emerged in high-risk zone identification,with GBT highlighting 7.42%and RF indicating 2.21%as very high erosion susceptibility areas.Both models demonstrated robust predictive capabilities,with GBT achieving 80.77%accuracy and 0.975 AUC,slightly outperforming RF’s 79.67%accuracy and 0.972 AUC.Analysis of predictor variables identified elevation,slope,rainfall and NDVI as the primary factors influencing erosion susceptibility,highlighting the complex interrelationship between geo-environmental factors and erosion processes.This research offers a strategic framework for targeted conservation and sustainable land management in the fragile Himalayan region,providing valuable insights to help policymakers implement effective soil erosion mitigation strategies and support long-term environmental sustainability.
基金supported by National Natural Science Foundation of China(Grant No.42372330)Science and Technology Research Program of Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(Grant No.IMHE-CXTD-01-IMHE-ZYTS-12)Sichuan Science and Technology Program(Grant No.2024NSFSC0102).
文摘The hydro-mechanical responses of vegetated deposited slopes are complex and far from clear.On one hand,the soils in deposited slopes are typically poorly consolidated and widely graded,making them vulnerable to internal erosion during rainfall infiltration.On the other hand,vegetation plays a significant role in influencing the hydro-mechanical properties of the soil at the slope surface.This paper presents a coupled seepage-erosion model to investigate the rainfall-induced internal erosion process within vegetated deposited slopes and its impact on slope stability.The detailed seepage-erosion coupling processes were simulated for a series of 1D rooted soil columns with varying root distributions,as well as 2D vegetated layered slopes under both light and heavy rainfall conditions.The numerical results reveal that roots can significantly mitigate rainfall-induced internal erosion,even with shallow root lengths.However,their protective effect on the slope increases as the root density in the superficial soil layer increases.Transpiration can rapidly restore matric suction in the shallow soil during rain intervals,slowing the rainfall-induced seepage-erosion process and thereby increasing slope stability.However,in the absence of transpiration,roots may either accelerate or inhibit the seepage-erosion process,depending on the specific rainfall conditions.
文摘Soil erosion from water has become a relevant issue at global level.In Guinea in particular,erosion has worrying effects,due to natural conditions and human impact,especially in the Nzérékore city in forest region.This paper proposed a soil erosion modeling by rainfall effect in the prefecture of N'Zérékoré.To achieve this objective,monthly and annual rainfall data for the N'Zérékorécity were collected at the meteorological station over the period from 1980 to 2024.The analysis of rainfall aggressiveness was possible using the Fournier index.For data processing,we used Microsoft Excel,Python and the ARIMA(AutoRegressive Integrated Moving Average)model for soil aggressiveness predicted by rainfall.It was found that,from 2000 to 2009,erosion was higher compared to other periods with a rate of 60%,or 6 years of high rainfall aggression.From the periods 1990 to 1999 and 2010 to 2019,the lowest rainfall aggressiveness was recorded,with 60%or 6 years of low erosivity.However,from period 1980 to 1989 the highest rate(70%)of very high rainfall erosivity was recorded.The results show three levels of rainfall aggressiveness on an annual scale:a very high level of erosivity with a rate of 22.2%or 10 years,followed by a high level of 35.6%or 16 years of strong erosion.The moderate erosivity level corresponds to 42.2%or 19 years.The model predicts a stability of the erosivity index around 77.14 over the period 2025-2034.During the forty(45)years the rainfall erosivity index was very unstable characterized by strong erosion,however it would be stable in the next ten(10)years.
基金supported by the China Postdoc-toral Science Foundation(No.2023M732495)the Shanxi Provincial Basic Research Program(Nos.202103021223180 and 202203021221120)the Deanship of Scientific Research at Northern Border University,Arar,KSA for funding this research work through the project number“NBU-FPEJ-2024-1261-02”.
文摘Low erosion high-energy propellant is one of the research directions to extend the weapon’s life and improve the weapon’s capability.In this study,energetic propellants containing different corrosion inhibitors were designed and prepared.Close bomb tests and semi-confined bomb experiments were used to investigate the burning and erosion properties of the propellants.The mechanism of erosion-reducing of titanium dioxide(titania,TiO_(2)),talc,and octaphenylsilsesquioxane(OPS)on the propellant was comparatively analyzed.The results show that OPS has the lowest burning rate and the longest burning time,and a minimized loss of fire force,with the best effect of explosion heat reduction.The erosion reduction efficiency of OPS is twice that of TiO_(2) and talc.The mechanism analysis shows that the decomposition and heat absorption of OPS can effectively reduce the thermal erosion effect and carbon erosion,and the gas produced can reduce the loss of chamber pressure and form a uniformly distributed nano-SiO_(2) protective layer.This solid-state high-efficiency organosilicon erosion inhibitor is an important guide for designing high-energy low-erosion gun propellants.
基金supported in part by National Sciences Foundation of China grants 11972117a Jiangsu Province Science and Technology Agency under grant number BE2016785+4 种基金support from Natural Science Foundation of China(81827806 and 62135002)support from Natural Science Foundation of China(81722025)Key R&D Project of Heilongjiang Province grant 2022ZX06C07support from the Natural Science Foundation of Shandong Province under grant number ZR2024QA110Shandong Province Medical Health Science and Technology Project(Nos.202425020256,and 202403010254).
文摘Image-based computational models have been used for vulnerable plaque progression and rupture predictions,and good results have been reported.However,mechanisms and predictions for plaque erosion are underinvestigated.Patient-specific fluid-structure interaction(FSI)models based on optical coherence tomography(OCT)follow-up data from patients with plaque erosion and who received conservative antithrombotic treatment(using medication,no stenting)to identify risk factors that could be used to predict the treatment outcome.OCT and angiography datawere obtained from10 patientswho received conservative antithrombotic treatment.Five participants had worse outcomes(WOG,stenosis severity≥70%at one-year follow-up),while the other five had better outcomes(BOG,stenosis severity<70%at one-year follow-up).Patient-specific 3D FSI models were constructed to obtain morphological and biomechanical risk factor values(a total of nine risk factors)for comparison and prediction.A logistic regressionmodel was used to identify optimal predictors with the best treatment outcome prediction accuracies.Our results indicated that the combination of wall shear stress(WSS),lipid percent,and thrombus burden was the best group predictor according to the mean area under the curve(AUC)of 0.96(90%confidence interval=(0.85,1.00)).WSS was the best single predictor withmean AUC=0.70(90%confidence interval=(0.20,1.00)).Thrombus burden was the only risk factor showing statistically significant group difference,suggesting its crucial role in the outcomes of conservative anti-thrombotic therapy.This pilot study indicated that integratingmorphological and biomechanical risk factors could improve treatment outcome prediction accuracy in patients with plaque erosion compared to predictions using single predictors.Large-scale patient studies are needed to further validate our findings.
基金funded by the Technology Funding Scheme of China Construction Second Engineering Bureau LTD(2020ZX150002)the National Natural Science Foundation Project of China(12262018).
文摘To address the challenges posed by tunnel construction in the alpine region,silica fume mixed concrete is commonly used as a construction material.The correlation between silica fume content and the lining life requires immediate investigation.In view of this phenomenon,the durability of unit lining concrete is predicted by analyzing three key indicators:carbonation depth,relative dynamic elastic modulus,and residual quality.This prediction is achieved by integrating the Entropy Weight Method,Grey theory life prediction model and BP artificial neural networks using data from tests and predictions of these indicators.Then,the Entropy Weight-Grey theory-BP Network Model is compared with other methods to analyze the predicted life.Finally,verify the sci-entificity of this model,and the optimum silica fume content of unit concrete lining is verified.The results showed,1)The addition of silica fume will accelerate the carbonization of unit concrete lining,and slow down the freeze-thaw cycle and sulfate erosion.2)The utilization of artificial neural networks is essential for enhancing the realism of the data,as it emphasizes the significance of silica fume content.3)Silica fume content of 10%results in the longest life and is the most suitable for lining construction.4)A comparison between single-factor and multi-factor predictions indicates that the multi-factor approach yields a longer maximum life.This improvement can be attributed to the inclusion of additional factors,such as freeze-thaw cycles and carbonation,which enhance the predicted life when employing these methods.In conclusion,the Entropy Weight-Grey Theory-BP Network life prediction Model is well-suited for tunnel lining in the alpine sulfate area of northwest China.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFE0121900)the National Natural Science Foundation of China(Grant No.42377168)the Ongoing Engineering Project in Xizang of Huaneng,China(JC2022/D01).
文摘The southern Tibetan Plateau has undergone accelerated warming that exceeds the global average,which has intensified surface hydrological processes.However,the mechanisms underlying drought effects on water-driven erosion under current climate change remain poorly understood.This paper aims to reveal the spatiotemporal changes in water-induced erosion in typical areas of the southern Tibetan Plateau using the Revised Universal Soil Loss Equation(RUSLE).Additionally,it seeks to identify the driving forces through the threshold segmentation method based on multi-timescale Standardized Precipitation Evapotranspiration Index(SPEI)data.The results showed that the average soil erosion in the study area from 2001 to 2019 was 46.90 t ha-1 a-1,with an overall significant decreasing trend(p<0.05).Significant decreases were observed in 40.86%of the areas.The relationship between soil erosion and SPEI was predominantly positive,with the strongest correlation observed between soil erosion and meteorological and agricultural drought.Areas experiencing significant decreases in soil erosion driven by intensified drought accounted for 24.55%of the total area,followed by 10.51%attributed to multiple factors and 6.66%influenced predominantly by human activities.Conversely,abnormal increases in soil erosion were noted in 1.02%of the total area.These findings underscore the impact of drought changes on soil erosion in typical areas of the southern Tibetan Plateau,offering insights for future research on the relationship between soil erosion and climate variability in fragile ecosystems.
基金supported by the project of the Educational Department of Liaoning Province(No.LJKMZ20220825)the National Natural Science Foundation of China(51774199).
文摘To elucidate the relationship between pipeline erosion and wear during slurry transportation,this study considers three key influencing parameters,namely,the ratio of inlet to outlet pipe diameter,the length of the variable diameter section,and the roughness of the pipe wall.The impact of these factors on pipeline erosion and wear is analyzed using a single-factor analysis approach.In particular,the Fluent software is employed to conduct the required numerical simulations for variable diameter elbows of varying morphologies.The results indicate that as the inlet to outlet diameter ratio increases,the wear on the pipe inlet and the outer wall of the elbow becomes increasingly pronounced.Notably,when the diameter ratio exceeds 0.8,there is a significant escalation in wear on both the inner and outer elbow walls.Initially,the maximum erosion rate decreases sharply with increasing diameter ratio before a stable condition is attained.Erosion wear in the variable diameter section exhibits a distinct layered distribution pattern.In this region,the wear range for a 40 mm length of the pipe body is relatively small;however,once this length exceeds 40 mm,the wear range expands,ultimately covering the entire pipe section.The length of the variable diameter section significantly influences the maximum erosion rate of the pipeline,with sections shorter than 80 mm experiencing the most severe effects,and showing an exponential decline in erosion rate.As the wall roughness gradually increases,the wear area on both cheeks of the bend section rapidly expands and tends to deepen further.When the roughness reaches 4 mm,the pipeline wear experiences a dramatic shift,resulting in extensive“spot-like”wear patterns emerging at the bottom and sides of the horizontal flow section,which previously exhibited no wear.
