The cut-down is by all means a blow to its apparel industry,making this summer a suffering hot.When winter comes,the export impact begins to appear,if the RMB’s value continues to rise,this would"adding frost to...The cut-down is by all means a blow to its apparel industry,making this summer a suffering hot.When winter comes,the export impact begins to appear,if the RMB’s value continues to rise,this would"adding frost to snow",a Chinese saying for an even worse situation in an already biting-cold weather.展开更多
Damage caused by frost heave leads to costly maintenance in cold regions, like Hokkaido, Japan. Therefore, thestudy of the frost mechanism with experimental and numerical methods has been of great interest. Numerousmo...Damage caused by frost heave leads to costly maintenance in cold regions, like Hokkaido, Japan. Therefore, thestudy of the frost mechanism with experimental and numerical methods has been of great interest. Numerousmodels have been developed to describe the freezing process of saturated soil, which differs from the partiallysaturated conditions in the field. In fact, most subsurface soils are unsaturated. The freezing process of partiallysaturated soils is more complex than saturated soils, as the governing equations show strongly nonlinear characteristics. This study proposes a thermo-hydro-mechanical coupled model considering the heat transfer, waterinfiltration, and deformation of partially saturated soil to reproduce the freezing process of partially saturatedfrost susceptible soils distributed in Hokkaido. This model better considers the water-ice phase change and soilfreezing characteristic curve (SFCC) during freezing under field conditions. The results from the multiphysicssimulations agree well with the frost heave and water migration data from frost heave tests of Touryo soil andFujinomori soil. In addition, this study discussed the influence of the various factors on frost heave amount,including temperature gradients, overburden pressures, water supply conditions, cooling rates, and initial saturation. The simulation results indicate that the frost heave ratio is proportional to the initial degree of saturationand is inversely proportional to the cooling rate and overburden pressure.Moreover, simulation under the open system generates much more frost heave than under the closed system.Finally, the main features of the proposed model are revealed by simulating a closed-system frost heave test. Thesimulation results indicate that the proposed model adequately captures the coupling characteristics of water andice redistribution, temperature development, hydraulic conductivity, and suction in the freezing process. Togetherwith the decreased hydraulic conductivity, the increased suction controls the water flow in the freezing zone. Theinflow water driven by cryogenic suction gradient feeds the ice formation, leads to a rapid increase in total watercontent, expanding the voids that exceed the initial porosity and contributing to the frost heave.展开更多
We investigated the effects of fly ash(FA)content on the mechanical properties of recycled aggregate concrete(RAC)and its regeneration potential under freeze and thaw(F-T)cycles.The physical properties of second-gener...We investigated the effects of fly ash(FA)content on the mechanical properties of recycled aggregate concrete(RAC)and its regeneration potential under freeze and thaw(F-T)cycles.The physical properties of second-generation recycled concrete aggregates(RCA)were used to analyze the regeneration potential of RAC after F-T cycles.Scanning electron microscopy was used to study the interfacial transition zone microstructure of RAC after F-T cycles.Results showed that adding 20%FA to RAC significantly enhanced its mechanical properties and frost resistance.Before the F-T cycles,the compressive strength of RAC with 20%FA reached 48.3 MPa,exceeding research strength target of 40 MPa.A majority of second-generation RCA with FA had been verified to attain class Ⅲ,which enabled their practical application in non-structural projects such as backfill trenches and road pavement.However,the second-generation RCA with 20%FA can achieve class Ⅱ,making it ideal for 40 MPa structural concrete.展开更多
Considering the comprehensive morphology and genesis of Podzols of the Stolowe Mountains,and the still-possible impact of frost actions and other processes related to cold climate on these soils,the main aims of this ...Considering the comprehensive morphology and genesis of Podzols of the Stolowe Mountains,and the still-possible impact of frost actions and other processes related to cold climate on these soils,the main aims of this study were to determine whether(i)the heterogeneous Podzols in the Stolowe Mountains underwent a phase of development in a cold climate,resulting in frost action features visible on the micromorphological level,and whether(ii)contemporary cryopedogenic traces are masked by the translocation of organic matter due to the podzolisation process.Four soil profiles were investigated,revealing distinct layers corresponding to different periods of soil formation.Under field observation,no explicit frost-related characteristics were observed.Nevertheless,micromorphological analysis revealed cappings of fine materials on grains or peds,as well as development of granostriated(or any striated)b-fabric that resulted from the alternating effects of thawing and freezing processes.Moreover,micromorphological analysis revealed the presence of microstructures that could be the result of cryogenic processes,such as platy,angular blocky and lenticular features,as well as plane,vugh and star-shaped void types.The translocation of organic matter during podzolisation modified or concealed the frost-related features that developed during the late Pleistocene and early Holocene.This is evident,for instance,in the accumulation of organic matter on cappings and within soil voids,which further hinders the identification of frost-related characteristics and the interpretation of the soil's evolution.Macromorphological observations enhanced with micromorphological analyses revealed three distinct layers:(i)a young upper layer composed of loose,sandy material;(ii)a deeper layer containing a spodic horizon with frost actions,involving pedofeatures associated with the Pleistocene cold climate and(iii)a deeper subsoil basal layer.The abovementioned microstructures,combined with lithological discontinuity,support the hypothesised polygenetic origin of Podzols in the studied region.展开更多
In cold regions,the frost-heave of soil can cause uneven railway subgrades,affecting the safety and efficiency of high-speed railways.This study proposes a novel PCW-iTransformer model for predicting frost heave,which...In cold regions,the frost-heave of soil can cause uneven railway subgrades,affecting the safety and efficiency of high-speed railways.This study proposes a novel PCW-iTransformer model for predicting frost heave,which integrates PCHIP data interpolation,CEEMDAN signal decomposition,and WPT denoising to extract sequential features.Compared to existing models like Autoformer,Crossformer,and DLinear,PCW-iTransformer achieves a reduction of 19.1%-34.5%in error metrics and an improvement of 2.8%-4.6%in the coefficient of determination.Additionally,a fused parameter model based on normalized moisture and temperature improves prediction accuracy,reducing MSE,MAE,and RMSE by up to 7.6%.The model also demonstrates robustness under data scarcity,maintaining stable performance with 40%continuous or 60%random missing data.Overall,PCW-iTransformer provides a reliable approach for predicting frost heave,offering valuable insights for the maintaining and long-term stability of high-speed railway subgrades in cold regions.展开更多
Frost accumulation on the evaporator fins of air source heat pumps(ASHPs)severely degrades heat transfer performance and overall system efficiency.To address this,the present study employs computational fluid dynamics...Frost accumulation on the evaporator fins of air source heat pumps(ASHPs)severely degrades heat transfer performance and overall system efficiency.To address this,the present study employs computational fluid dynamics(CFD)to investigate how fin spacing influences frosting behavior,emphasizing the coupled evolution of frost thickness,density,airflow,and temperature distribution within fin channels.Results reveal that fin spacing is a key parameter governing both the extent and rate of frost growth.Wider fin spacing enhances frost accumulation,with a final frost mass of 6.41 g at 12 mm,about 71.8%higher than at 4 mm.In contrast,narrower spacing suppresses frost formation by accelerating airflow.The frost layer exhibits a distinct two-stage growth pattern:at 12 mm spacing,the early-stage average thickness growth rate reaches 0.021 mm/min,nearly 4.3 times that at 4 mm.Frost density follows similar initial trends across different spacings but diverges later due to thermal resistance and airflow variations.展开更多
Dangerous rock masses in cold regions subjected to repeated freeze–thaw cycles can cause progressive deterioration in structural planes and rock mechanical properties,which significantly reduces the overall stability...Dangerous rock masses in cold regions subjected to repeated freeze–thaw cycles can cause progressive deterioration in structural planes and rock mechanical properties,which significantly reduces the overall stability and often triggers collapses or landslides.Existing studies focus mostly on singlescale or single-factor analyses but cannot fully capture the coupled mechanisms driving instability under freeze-thaw conditions.This study aimed to establish a theoretical framework to quantitatively characterize the evolution of rock mass stability,thereby providing a sound basis for hazard prediction and prevention.By integrating limit equilibrium theory with rock frost heave and circular hole expansion theory,mechanical models for sliding-and toppling-type dangerous rock masses were established.Three key factors were incorporated:frost heave forces acting on throughgoing structural planes,rock property deterioration in nonpenetrative sections,and progressive freezing depth development.A theoretical relationship between the stability coefficient and the number of freeze-thaw cycles was derived.By considering the Zimei Peaks rock masses in Gansu Province as the case study and conducting parametric analyses,the results revealed that the stability coefficient rapidly decreases during the initial cycles,followed by a slower decrease and eventual stabilization.The coefficient decreased 4.5 times more during the first 15 cycles than during the subsequent 15 cycles.Moreover,stability degradation was strongly influenced by the freezing temperature,initial porosity,and rock debris loss ratio,with critical thresholds determined at a 3.8%porosity and a 0.83 debris loss ratio.The findings indicated that stability deterioration is governed by the coupled effects of frost heave loading,microstructural damage accumulation,and freezing depth development,with clear stagedependent and threshold-driven patterns.This work provides not only a quantitative explanation of instability mechanisms in cold-region rock masses but also practical guidance for engineering stability assessment and disaster mitigation.展开更多
Understanding the phenology and productivity of Populus species is crucial for effective management and conservation strategies amid climate change.We investigated leaf budbreak timing,susceptibility to cold damage,le...Understanding the phenology and productivity of Populus species is crucial for effective management and conservation strategies amid climate change.We investigated leaf budbreak timing,susceptibility to cold damage,leaf dynamics,and biomass production of 168 Populus genotypes with diverse provenances in the southeastern United States.Our study revealed significant variation in budbreak timing across different taxa and years,with genotypes inheriting traits adapted to their parents’local climates.Temperature emerged as a key factor triggering budbreak,while leaf development depended on other environmental cues such as photoperiod.Notably,budbreak occurred approximately 20 days earlier in 2023 compared to 2022 due to higher accumulated degree days(ADDs).Short-rotation-coppice(SRC)management delayed budbreak by five to ten days.Cold damage was significant in 2023,particularly for genotypes from northern provenances and those with P.maximowiczii parentage.Severe damage was also observed in eastern cottonwood(Populus deltoides×Populus deltoides(D×D))genotypes,despite most having southeastern US parentages.Leaf dynamics,including leaf duration and leaf area index(LAI),varied across taxa and sites,with earlier budbreak correlating with extended growing seasons and increased LAI.Biomass production was intricately linked to phenological events,with earlier budbreak leading to increased biomass production and greater susceptibility to cold damage.Our findings highlight the importance of genetics,environment,and coppicing management in understanding and managing Populus phenology and biomass production.These insights provide valuable guidance for developing effective breeding,conservation,and management strategies for Populus species in the context of climate change.展开更多
Uneven frost heave deformation can shorten the operational lifespan of foundation engineering.Clarifying the mechanisms of uneven frost heave facilitates the targeted mitigation of frost damage.This study focused on a...Uneven frost heave deformation can shorten the operational lifespan of foundation engineering.Clarifying the mechanisms of uneven frost heave facilitates the targeted mitigation of frost damage.This study focused on a water conveyance channel in Jilin Province,northern China,and found after monitoring that the frost heave at the channel bottom lining exceeded that at the crest by 44.5 mm,with the freezing temperature at the bottom being over 2℃lower than that at the crest.Soil columns with an initial gravimetric moisture content of 12%,16%,18%,and 20%were then prepared.The effects of temperature and moisture content on frost heave were analyzed under two freezing conditions(-5℃and-10℃)through unidirectional freezing tests.A coupled thermo-hydro-mechanical(THM)frost heave model,validated by the test results,was further established.In the soil with an initial moisture content of 20%,the formation of ice lenses associated with substantial water migration contributed to a large temperature gradient,which can jointly induce frost heave.Under the-10℃condition,the temperature gradient in the soil column with a 20%initial moisture content reached 0.84℃/cm,the total water migration reached 10.72%,and the frost heave deformation was 1.86 mm.The THM coupling results indicated that,under the interaction of a large temperature gradient and moisture accumulation,the volumetric ice content remained high in the bottom soil during freezing and peaked at 0.36.The frost damage to the bottom soil was severe,and the maximum deformation reached 57 mm.展开更多
One reference in the original manuscript contained incorrect bibliographic information and cited a non-existent publication:Traczyk A(1999)Pleistocene debris cover beds and block-debris tongues in the north-western pa...One reference in the original manuscript contained incorrect bibliographic information and cited a non-existent publication:Traczyk A(1999)Pleistocene debris cover beds and block-debris tongues in the north-western part of theŚlęża Massif(Poland)and their formation under permafrost conditions.Geographia Polonica 81(1).This erroneous reference has now been removed from the references list.展开更多
Frost heave in water-bearing rock masses poses significant threats to geotechnical engineering.This paper developed a novel three-dimensional(3D)frost model,based on the combined finite-discrete element method(FDEM),t...Frost heave in water-bearing rock masses poses significant threats to geotechnical engineering.This paper developed a novel three-dimensional(3D)frost model,based on the combined finite-discrete element method(FDEM),to investigate the frost heave process in rock masses where thermal transfer,water migration,water-ice phase transition(ice growth)and ice-rock interaction are explicitly simulated.The proposed model is first validated against existing experimental and analytical solutions,and further applied to investigate path-dependent frost heave behavior under various freezing conditions.Results show that freezing direction plays a vital role in the dynamic ice growth and ice-rock interaction,thus affecting the frost heave behavior.In the top-down freezing regime,ice plugs form first at the crack's top surface,sealing the crack and preventing water migration,which can amplify ice pressure.Parametric studies,including rock Young's modulus,ice-rock friction,and rock hydraulic conductivity,further reveal that the temporal aspects of ice development and rock mechanical response strongly affect ice-rock interaction and hence the frost heave mechanism.Furthermore,some typical phenomena(e.g.water/ice extrusion and frost cracking)can also be well captured in this model.This novel numerical framework sheds new light on frost heave behavior and enriches our understanding of frost heave mechanisms and ice-rock interaction processes within cold environment engineering projects.展开更多
[Objective]The aim was to understand the change characteristics of sugarcane traits and evaluate the cold tolerance of sugarcane varieties under the drought and frost conditions.[Method] The experiment was carried out...[Objective]The aim was to understand the change characteristics of sugarcane traits and evaluate the cold tolerance of sugarcane varieties under the drought and frost conditions.[Method] The experiment was carried out in Ziyuan County,Guangxi Province where the frost occurred often with 21 domestic and abroad sugarcane varieties（elites）.[Result] There were significant changes in the brix,green leaf number and photosynthetic rate of sugarcane before and after light frost and decreased more in cold-sensitive varieties.However,the correlation was only significant between the damage rate of stem length and internode,percentage of green leaves after heavy frost in relation to sugarcane brix and brix changes after light frost.Further analysis showed that the evaluation for cold tolerance of sugarcane would be more simple and reliable with traits of the damage rate of stem length and percentage of upper green leaves.The evaluation for varieties indicated that if it was not carried out for cold-tolerance identification in breeding program,the percentage of sugarcane varieties with good cold-tolerance will be lower than30%,and higher than 60% with poor cold-tolerance in subtropical and tropical regions.[Conclusion] This study had provided theoretical basis for the cold-resistant evaluation of sugar cane and the breeding of the varieties of cold-resistant.展开更多
文摘The cut-down is by all means a blow to its apparel industry,making this summer a suffering hot.When winter comes,the export impact begins to appear,if the RMB’s value continues to rise,this would"adding frost to snow",a Chinese saying for an even worse situation in an already biting-cold weather.
基金This research was supported in part by Grant-in-Aids for Scientific Research(A,16H02360)and(B,17H03307)from the Japan Society for the Promotion of Science(JSPS)KAKENHI.
文摘Damage caused by frost heave leads to costly maintenance in cold regions, like Hokkaido, Japan. Therefore, thestudy of the frost mechanism with experimental and numerical methods has been of great interest. Numerousmodels have been developed to describe the freezing process of saturated soil, which differs from the partiallysaturated conditions in the field. In fact, most subsurface soils are unsaturated. The freezing process of partiallysaturated soils is more complex than saturated soils, as the governing equations show strongly nonlinear characteristics. This study proposes a thermo-hydro-mechanical coupled model considering the heat transfer, waterinfiltration, and deformation of partially saturated soil to reproduce the freezing process of partially saturatedfrost susceptible soils distributed in Hokkaido. This model better considers the water-ice phase change and soilfreezing characteristic curve (SFCC) during freezing under field conditions. The results from the multiphysicssimulations agree well with the frost heave and water migration data from frost heave tests of Touryo soil andFujinomori soil. In addition, this study discussed the influence of the various factors on frost heave amount,including temperature gradients, overburden pressures, water supply conditions, cooling rates, and initial saturation. The simulation results indicate that the frost heave ratio is proportional to the initial degree of saturationand is inversely proportional to the cooling rate and overburden pressure.Moreover, simulation under the open system generates much more frost heave than under the closed system.Finally, the main features of the proposed model are revealed by simulating a closed-system frost heave test. Thesimulation results indicate that the proposed model adequately captures the coupling characteristics of water andice redistribution, temperature development, hydraulic conductivity, and suction in the freezing process. Togetherwith the decreased hydraulic conductivity, the increased suction controls the water flow in the freezing zone. Theinflow water driven by cryogenic suction gradient feeds the ice formation, leads to a rapid increase in total watercontent, expanding the voids that exceed the initial porosity and contributing to the frost heave.
基金Funded by the Natural Science Foundation of Jiangsu Province(No.BK20220626)the National Natural Science Foundation of China(No.52078068)+2 种基金Science and Technology Innovation Foundation of NIT(No.KCTD006)Jiangsu Marine Structure Service Performance Improvement Engineering Research CenterKey Laboratory of Jiangsu"Marine Floating Wind Power Technology and Equipment"。
文摘We investigated the effects of fly ash(FA)content on the mechanical properties of recycled aggregate concrete(RAC)and its regeneration potential under freeze and thaw(F-T)cycles.The physical properties of second-generation recycled concrete aggregates(RCA)were used to analyze the regeneration potential of RAC after F-T cycles.Scanning electron microscopy was used to study the interfacial transition zone microstructure of RAC after F-T cycles.Results showed that adding 20%FA to RAC significantly enhanced its mechanical properties and frost resistance.Before the F-T cycles,the compressive strength of RAC with 20%FA reached 48.3 MPa,exceeding research strength target of 40 MPa.A majority of second-generation RCA with FA had been verified to attain class Ⅲ,which enabled their practical application in non-structural projects such as backfill trenches and road pavement.However,the second-generation RCA with 20%FA can achieve class Ⅱ,making it ideal for 40 MPa structural concrete.
基金financed by the Wroclaw University of Environmental and Life Sciences(Poland)。
文摘Considering the comprehensive morphology and genesis of Podzols of the Stolowe Mountains,and the still-possible impact of frost actions and other processes related to cold climate on these soils,the main aims of this study were to determine whether(i)the heterogeneous Podzols in the Stolowe Mountains underwent a phase of development in a cold climate,resulting in frost action features visible on the micromorphological level,and whether(ii)contemporary cryopedogenic traces are masked by the translocation of organic matter due to the podzolisation process.Four soil profiles were investigated,revealing distinct layers corresponding to different periods of soil formation.Under field observation,no explicit frost-related characteristics were observed.Nevertheless,micromorphological analysis revealed cappings of fine materials on grains or peds,as well as development of granostriated(or any striated)b-fabric that resulted from the alternating effects of thawing and freezing processes.Moreover,micromorphological analysis revealed the presence of microstructures that could be the result of cryogenic processes,such as platy,angular blocky and lenticular features,as well as plane,vugh and star-shaped void types.The translocation of organic matter during podzolisation modified or concealed the frost-related features that developed during the late Pleistocene and early Holocene.This is evident,for instance,in the accumulation of organic matter on cappings and within soil voids,which further hinders the identification of frost-related characteristics and the interpretation of the soil's evolution.Macromorphological observations enhanced with micromorphological analyses revealed three distinct layers:(i)a young upper layer composed of loose,sandy material;(ii)a deeper layer containing a spodic horizon with frost actions,involving pedofeatures associated with the Pleistocene cold climate and(iii)a deeper subsoil basal layer.The abovementioned microstructures,combined with lithological discontinuity,support the hypothesised polygenetic origin of Podzols in the studied region.
基金supported by National Key R&D Program of China(Grant No.2022YFB2603301)the National Natural Science Foundation of China(Grant No.52178376)Science and Technology Research and Development Program of China Railway Group Limited(Grant No.2023-Major Project-04).
文摘In cold regions,the frost-heave of soil can cause uneven railway subgrades,affecting the safety and efficiency of high-speed railways.This study proposes a novel PCW-iTransformer model for predicting frost heave,which integrates PCHIP data interpolation,CEEMDAN signal decomposition,and WPT denoising to extract sequential features.Compared to existing models like Autoformer,Crossformer,and DLinear,PCW-iTransformer achieves a reduction of 19.1%-34.5%in error metrics and an improvement of 2.8%-4.6%in the coefficient of determination.Additionally,a fused parameter model based on normalized moisture and temperature improves prediction accuracy,reducing MSE,MAE,and RMSE by up to 7.6%.The model also demonstrates robustness under data scarcity,maintaining stable performance with 40%continuous or 60%random missing data.Overall,PCW-iTransformer provides a reliable approach for predicting frost heave,offering valuable insights for the maintaining and long-term stability of high-speed railway subgrades in cold regions.
基金supported by the Shandong Provincial Natural Science Foundation(ZR2023QE325).
文摘Frost accumulation on the evaporator fins of air source heat pumps(ASHPs)severely degrades heat transfer performance and overall system efficiency.To address this,the present study employs computational fluid dynamics(CFD)to investigate how fin spacing influences frosting behavior,emphasizing the coupled evolution of frost thickness,density,airflow,and temperature distribution within fin channels.Results reveal that fin spacing is a key parameter governing both the extent and rate of frost growth.Wider fin spacing enhances frost accumulation,with a final frost mass of 6.41 g at 12 mm,about 71.8%higher than at 4 mm.In contrast,narrower spacing suppresses frost formation by accelerating airflow.The frost layer exhibits a distinct two-stage growth pattern:at 12 mm spacing,the early-stage average thickness growth rate reaches 0.021 mm/min,nearly 4.3 times that at 4 mm.Frost density follows similar initial trends across different spacings but diverges later due to thermal resistance and airflow variations.
基金the financial support provided by the Major Science and Technology Project of Xinjiang Uygur Autonomous Region(Grant NO.2024A01003)the National Natural Science Foundation of China(Grant NO.51508556)+3 种基金the Key Support Project of the National Natural Science Foundation of China Joint Fund(Grant No.U24B2039)the Natural Science Foundation of Jiangxi Province(Grant NO.20232BAB203079,20224BAB213045)Program of China Scholarship Council(Grant NO.202406430056)the Fundamental Research Funds for the Central Universities(Ph.D.Top Innovative Talents Fund of CUMTB)(Grant NO.BBJ2025081)。
文摘Dangerous rock masses in cold regions subjected to repeated freeze–thaw cycles can cause progressive deterioration in structural planes and rock mechanical properties,which significantly reduces the overall stability and often triggers collapses or landslides.Existing studies focus mostly on singlescale or single-factor analyses but cannot fully capture the coupled mechanisms driving instability under freeze-thaw conditions.This study aimed to establish a theoretical framework to quantitatively characterize the evolution of rock mass stability,thereby providing a sound basis for hazard prediction and prevention.By integrating limit equilibrium theory with rock frost heave and circular hole expansion theory,mechanical models for sliding-and toppling-type dangerous rock masses were established.Three key factors were incorporated:frost heave forces acting on throughgoing structural planes,rock property deterioration in nonpenetrative sections,and progressive freezing depth development.A theoretical relationship between the stability coefficient and the number of freeze-thaw cycles was derived.By considering the Zimei Peaks rock masses in Gansu Province as the case study and conducting parametric analyses,the results revealed that the stability coefficient rapidly decreases during the initial cycles,followed by a slower decrease and eventual stabilization.The coefficient decreased 4.5 times more during the first 15 cycles than during the subsequent 15 cycles.Moreover,stability degradation was strongly influenced by the freezing temperature,initial porosity,and rock debris loss ratio,with critical thresholds determined at a 3.8%porosity and a 0.83 debris loss ratio.The findings indicated that stability deterioration is governed by the coupled effects of frost heave loading,microstructural damage accumulation,and freezing depth development,with clear stagedependent and threshold-driven patterns.This work provides not only a quantitative explanation of instability mechanisms in cold-region rock masses but also practical guidance for engineering stability assessment and disaster mitigation.
基金funded by the USDA National Institute of Food and Agriculture(USDA-NIFA)through the APPS grant(Advancing Populus Pathways in the Southeast,2018-68005-27636)United States Department of Energy(DOE)through the PoSIES(Populus in the Southeast for Integrated Ecosystem Services,DE-EE0009280)USDA-NIFA McIntire Stennis grant(MISZ-067050).
文摘Understanding the phenology and productivity of Populus species is crucial for effective management and conservation strategies amid climate change.We investigated leaf budbreak timing,susceptibility to cold damage,leaf dynamics,and biomass production of 168 Populus genotypes with diverse provenances in the southeastern United States.Our study revealed significant variation in budbreak timing across different taxa and years,with genotypes inheriting traits adapted to their parents’local climates.Temperature emerged as a key factor triggering budbreak,while leaf development depended on other environmental cues such as photoperiod.Notably,budbreak occurred approximately 20 days earlier in 2023 compared to 2022 due to higher accumulated degree days(ADDs).Short-rotation-coppice(SRC)management delayed budbreak by five to ten days.Cold damage was significant in 2023,particularly for genotypes from northern provenances and those with P.maximowiczii parentage.Severe damage was also observed in eastern cottonwood(Populus deltoides×Populus deltoides(D×D))genotypes,despite most having southeastern US parentages.Leaf dynamics,including leaf duration and leaf area index(LAI),varied across taxa and sites,with earlier budbreak correlating with extended growing seasons and increased LAI.Biomass production was intricately linked to phenological events,with earlier budbreak leading to increased biomass production and greater susceptibility to cold damage.Our findings highlight the importance of genetics,environment,and coppicing management in understanding and managing Populus phenology and biomass production.These insights provide valuable guidance for developing effective breeding,conservation,and management strategies for Populus species in the context of climate change.
基金funding support from the National Natural Science Foundation of China(Grants Nos.42330708 and 42302329)the Graduate Innovation Research Program of Jilin University(Grant No.2024CX118).
文摘Uneven frost heave deformation can shorten the operational lifespan of foundation engineering.Clarifying the mechanisms of uneven frost heave facilitates the targeted mitigation of frost damage.This study focused on a water conveyance channel in Jilin Province,northern China,and found after monitoring that the frost heave at the channel bottom lining exceeded that at the crest by 44.5 mm,with the freezing temperature at the bottom being over 2℃lower than that at the crest.Soil columns with an initial gravimetric moisture content of 12%,16%,18%,and 20%were then prepared.The effects of temperature and moisture content on frost heave were analyzed under two freezing conditions(-5℃and-10℃)through unidirectional freezing tests.A coupled thermo-hydro-mechanical(THM)frost heave model,validated by the test results,was further established.In the soil with an initial moisture content of 20%,the formation of ice lenses associated with substantial water migration contributed to a large temperature gradient,which can jointly induce frost heave.Under the-10℃condition,the temperature gradient in the soil column with a 20%initial moisture content reached 0.84℃/cm,the total water migration reached 10.72%,and the frost heave deformation was 1.86 mm.The THM coupling results indicated that,under the interaction of a large temperature gradient and moisture accumulation,the volumetric ice content remained high in the bottom soil during freezing and peaked at 0.36.The frost damage to the bottom soil was severe,and the maximum deformation reached 57 mm.
文摘One reference in the original manuscript contained incorrect bibliographic information and cited a non-existent publication:Traczyk A(1999)Pleistocene debris cover beds and block-debris tongues in the north-western part of theŚlęża Massif(Poland)and their formation under permafrost conditions.Geographia Polonica 81(1).This erroneous reference has now been removed from the references list.
基金supported by the Natural Sciences and Engineering Research Council of Canada(Grant Nos.Discovery 341275,and CRDPJ 543894-19)NSERC/Energi Simulation Industrial Research Chair programState Key Laboratory of Geohazard Prevention and Geoenvironment Protection Open Fund(Grant No.SKLGP2024K001).
文摘Frost heave in water-bearing rock masses poses significant threats to geotechnical engineering.This paper developed a novel three-dimensional(3D)frost model,based on the combined finite-discrete element method(FDEM),to investigate the frost heave process in rock masses where thermal transfer,water migration,water-ice phase transition(ice growth)and ice-rock interaction are explicitly simulated.The proposed model is first validated against existing experimental and analytical solutions,and further applied to investigate path-dependent frost heave behavior under various freezing conditions.Results show that freezing direction plays a vital role in the dynamic ice growth and ice-rock interaction,thus affecting the frost heave behavior.In the top-down freezing regime,ice plugs form first at the crack's top surface,sealing the crack and preventing water migration,which can amplify ice pressure.Parametric studies,including rock Young's modulus,ice-rock friction,and rock hydraulic conductivity,further reveal that the temporal aspects of ice development and rock mechanical response strongly affect ice-rock interaction and hence the frost heave mechanism.Furthermore,some typical phenomena(e.g.water/ice extrusion and frost cracking)can also be well captured in this model.This novel numerical framework sheds new light on frost heave behavior and enriches our understanding of frost heave mechanisms and ice-rock interaction processes within cold environment engineering projects.
基金Supported by National Science and Technology Support Program(2008BADB8B01,2007BAD30B02,2007BAD30B05)Modern Agricultural Technology System Special Fund Project(nycytx-024-01-03)Guangxi Scientific and Technological Project(0782004-2,0782004-5)~~
文摘[Objective]The aim was to understand the change characteristics of sugarcane traits and evaluate the cold tolerance of sugarcane varieties under the drought and frost conditions.[Method] The experiment was carried out in Ziyuan County,Guangxi Province where the frost occurred often with 21 domestic and abroad sugarcane varieties（elites）.[Result] There were significant changes in the brix,green leaf number and photosynthetic rate of sugarcane before and after light frost and decreased more in cold-sensitive varieties.However,the correlation was only significant between the damage rate of stem length and internode,percentage of green leaves after heavy frost in relation to sugarcane brix and brix changes after light frost.Further analysis showed that the evaluation for cold tolerance of sugarcane would be more simple and reliable with traits of the damage rate of stem length and percentage of upper green leaves.The evaluation for varieties indicated that if it was not carried out for cold-tolerance identification in breeding program,the percentage of sugarcane varieties with good cold-tolerance will be lower than30%,and higher than 60% with poor cold-tolerance in subtropical and tropical regions.[Conclusion] This study had provided theoretical basis for the cold-resistant evaluation of sugar cane and the breeding of the varieties of cold-resistant.
