Enhanced silicate weathering(ESW)is a geoengineering method aimed at accelerating carbon dioxide(CO_(2))removal(CDR)from atmosphere by increasing the weathering flux of silicate rocks and minerals.It has emerged as a ...Enhanced silicate weathering(ESW)is a geoengineering method aimed at accelerating carbon dioxide(CO_(2))removal(CDR)from atmosphere by increasing the weathering flux of silicate rocks and minerals.It has emerged as a promising strategy for CDR.Theoretical studies underscore ESW’s substantial potential for CDR and its diverse benefits for crops when applied to croplands.However,the well-known significant discrepancies in silicate weathering rates between laboratory and field conditions introduce uncertainty in CDR through ESW.By compiling data from recent literature,we calculated and compared CDR efficiency(t CO_(2)t^(-1)_(silicate)ha^(-1)y^(-1))observed in mesocosm experiments and field trials.The findings indicate that CDR efficiencies in field trials are comparable to or exceeding that observed in mesocosm experiments by 1-3 orders of magnitude,particularly evident with wollastonite application.The hierarchy of CDR efficiency among silicates suitable for ESW is ranked as follows:olivine≥wollastonite>basalt>albite≥anorthite.We suggest the potential role of biota,especially fungi,in contributing to higher CDR efficiencies observed in field trials compared to mesocosm experiments.We further emphasize introducing fungi known for their effectiveness in silicate weathering could potentially enhance CDR efficiency through ESW in croplands.But before implementing fungal-facilitated ESW,three key questions need addressing:(i)How does the community of introduced fungi evolve over time?(ii)What is the long-term trajectory of CDR efficiency following fungal introduction?and(iii)Could fungal introduction lead to organic matter oxidation,resulting in elevated CO_(2)emissions?These investigations are crucial for optimizing the efficiency and sustainability of fungal-facilitated ESW strategy.展开更多
Black soil is essential for maintaining regional food security and promoting global agricultural production.Understanding the weathering process of parent material and the accumulation of organic carbon is crucial to ...Black soil is essential for maintaining regional food security and promoting global agricultural production.Understanding the weathering process of parent material and the accumulation of organic carbon is crucial to comprehending the developmental history and future trends of black soil,especially against the background of large-scale global cultivation and climate change.Although the importance of black soil formation and evolution cannot be ignored,the relevant research is still very scarce.In this study,a typical eight-meter-deep soil core was collected from the Keshan area of the Songnen Plain,Northeast China,where surface black soil developed on paleo-sediments.Using^(14)C dating,the formation age of the black soil was determined.Based on the characteristics of the geochemical composition,grain size and the magnetic susceptibility of the sediments,it was demonstrated that the black soil and its parent material originated from reworked loess.Furthermore,the mass transfer coefficient(τ)of some elements was determined,in order to explore the soil weathering process.By calculating the transported amount of alkaline and alkaline-earth elements,the weathering rate of parent material to black soil was found to be weak,at 0.16 kEq·ha^(-1)·year^(-1).Combining the results of dating and carbon density in the different layers of black soil,the accumulation rate of organic carbon was determined as follows:rapidly increasing in the initial period of 13.2-2.2 ka,reaching its maximum average value of 34.0 g·cm^(-2)·a^(-1)at 2.2-0.8 ka,then showing a decreasing trend with an average value of-77.5 g·cm^(-2)·a^(-1).Compared with regional climate change,Keshan black soil has developed under a colder and wetter climate during the Holocene.Predictably,ongoing global warming may lead to the degradation of black soils in the Songnen Plain,as well as in other regions.Our results will enrich geological knowledge of black soil formation and future evolutionary trends.展开更多
Weathering steel exhibits excellent corrosion resistance and is widely used in bridges,towers,railways,highways,and other engineering projects that are exposed to the atmosphere for long periods of time.However,before...Weathering steel exhibits excellent corrosion resistance and is widely used in bridges,towers,railways,highways,and other engineering projects that are exposed to the atmosphere for long periods of time.However,before the formation of stable rust layers,weathering steel is prone to liquid rust sagging and spattering,leading to environmental pollution and city appearance concerns.These factors limit the application and development of weathering steel.In this study,a rapid and environmentally friendly method was de-veloped by introducing alloying elements,specifically investigating the role of Sn in the rapid stabilization of rust layers in marine atmo-spheric environments.The rust layer formed on weathering low-alloy steel exposed to prolonged outdoor conditions and laboratory im-mersion experiments was explored using electron probe micro-analyzer(EPMA),micro-Raman,X-ray photoelectron spectroscopy(XPS),and electrochemical measurements.Results showed an optimal synergistic effect between Sn and Cr,which facilitated the accelerated densification of the rust layer.This beneficial effect enhanced the capability of the rust layer to resist Cl^(-)erosion and improved the protec-tion performance of the rust layer.展开更多
Permanently shadowed regions(PSRs)on the Moon are potential reservoirs for water ice,making them hot spots for future lunar exploration.The water ice in PSRs would cause distinctive changes in space weathering there,i...Permanently shadowed regions(PSRs)on the Moon are potential reservoirs for water ice,making them hot spots for future lunar exploration.The water ice in PSRs would cause distinctive changes in space weathering there,in particular reduction-oxidation processes that diff er from those in illuminated regions.To determine the characteristics of products formed during space weathering in PSRs,the lunar meteorite NWA 10203 with artifi cially added water was irradiated with a nanosecond laser to simulate a micro-meteorite bombardment of lunar soil containing water ice.The TEM results of the water-incorporated sample showed distinct amorphous rims that exhibited irregular thickness,poor stratifi cation,the appearance of bubbles,and a reduced number of npFe^(0).Additionally,EELS analysis showed the presence of ferric iron at the rim of the nanophase metallic iron particles(npFe^(0))in the amorphous rim with the involvement of water.The results suggest that water ice is another possible factor contributing to oxidation during micrometeorite bombardment on the lunar surface.In addition,it off ers a reference for a new space weathering model that incorporates water in PSRs,which could be widespread on asteroids with volatiles.展开更多
Dry-wet cycle is a key factor in surface weathering of earthen heritage,which remains insufficiently explained.It involves the interaction of humidity,stress,and damage.Using the RFPA(realistic failure process analysi...Dry-wet cycle is a key factor in surface weathering of earthen heritage,which remains insufficiently explained.It involves the interaction of humidity,stress,and damage.Using the RFPA(realistic failure process analysis)numerical method,this study reproduced the processes of humidity diffusion,deformation,stress,and damage evolution under dry-wet cycles in the soil site of Suoyang City,China.The numerical results indicate that the drying phase following rainfall has the most significant deteriorative impact on the earthen heritage.The evaporation of surface moisture during this phase causes volume shrinkage,which in turn generates tensile stress and leads to the formation of numerous desiccation cracks.Desiccation cracks provide channels for moisture diffusion,which further exacerbates generation of the cracks,leading to a mutual promotion between the two phenomena.Furthermore,during the wetting phase,the model elements undergo hygroscopic expansion,resulting in a slight increase in strain and displacement.Previously formed cracks may exhibit temporary narrowing or closure,but will revert during the subsequent drying phase.Ultimately,the overall displacement increases with the number of dry-wet cycles.The findings provide a theoretical foundation for protection against surface weathering and other damage in earthen heritage in arid regions.展开更多
Enhanced weathering(EW)of ultramafi c rocks from the Muslim Bagh Ophiolite,Pakistan,has been studied in laboratory experiments to explore carbon sequestration as a climate change mitigation strategy for coastal and op...Enhanced weathering(EW)of ultramafi c rocks from the Muslim Bagh Ophiolite,Pakistan,has been studied in laboratory experiments to explore carbon sequestration as a climate change mitigation strategy for coastal and open sea environments.The research focused on a cost-eff ective ex situ experiment to examine the eff ects of EW reaction pathways arising from the interactions among rock powder,seawater and CO_(2).The experimental fi ltrates from diff erent milled peridotite samples exhibit a decrease in the Mg/Ca ratio as the specifi c surface area increases,which accelerates reaction rates.This suggests that the leached Mg from the original rock may have been consumed in the formation of brucite,serpentine and carbonates during EW.Similar reaction pathways are also responsible for the chemical alterations observed in amphibolite,albeit to varying degrees.On the other hand,the experimental residues showed an increase in loss on ignition compared to the original rock,indicating that EW has facilitated the incorporation of H 2 O and CO_(2) into secondary mineral structures through various reaction pathways,leading to the formation of brucite,serpentine and carbonates.Thermal gravimetric analysis of the experimental residues confi rms the presence of these minerals based on their decomposition temperatures.Additionally,XRD analysis identifi ed a range of carbonates in the residues of both peridotite and amphibolite samples,validating the occurrence of carbonation reactions.SEM images reveal textural changes in both samples,supporting the formation of secondary minerals through EW,consistent with observations from the petrographic study of untreated samples.Control experiments on CO_(2) absorption in seawater showed a decrease in pH,highlighting ocean acidifi cation from increased CO_(2) emissions.However,when rock powder was added to the seawater-CO_(2) mixture,the pH increased.This suggests that the EW of ultramafi c rock powders can sequester CO_(2) while raising seawater pH through the formation of secondary minerals.This research could serve as an analog for EW applications,considering the worldwide abundance of ultramafi c rocks and the availability of coastal and open ocean environments.However,further research is required to understand the behavior of other elements and their impacts on ocean chemistry in EW processes before applying CO_(2) sequestration strategies.展开更多
A micro-layered structure was observed in the stable rust layer through dry–wet cycle corrosion tests.The microstructure,element distribution,and corrosion resistance mechanism of this layer structure in the marine i...A micro-layered structure was observed in the stable rust layer through dry–wet cycle corrosion tests.The microstructure,element distribution,and corrosion resistance mechanism of this layer structure in the marine industrial atmosphere were investigated by focused ion beam–scanning electron microscopy and high-resolution transmission electron microscopy.The inner rust layer of weathering steel(WS)exhibited layered enrichment of Cr,Cu,Ti,and other alloying elements.This layered structure comprised a fully amorphous region rich in Cr and Ti,as well as an amorphous and nanocrystalline region rich in Fe but poor in Cr.Only the completely amorphous region of the inner rust layer demonstrated a strong adsorption effect on Cl^(−).Cr-rich amorphous region played a pivotal role in reducing the corrosion of WS in the marine industrial atmospheric environment.The interface between the amorphous and nanocrystalline regions,as well as cracks within the interlayer,facilitated Cl^(−)transport,while the intact interlayer effectively hindered HSO_(3)^(−).展开更多
Rock classification plays a crucial role in various fields such as geology,engineering,and environmental studies.Employing deep learning AI(artificial intelligence)methods has a high potential to significantly improve...Rock classification plays a crucial role in various fields such as geology,engineering,and environmental studies.Employing deep learning AI(artificial intelligence)methods has a high potential to significantly improve the accuracy and efficiency of this task.The paper delves into the exploration of two cuttingedge AI techniques,namely Mask DINO and Mask R-CNN(convolutional neural network),as means to identify rock weathering grades and rock types.The results demonstrate that Mask DINO,which is a Detection Transformer(DETR),outperforms Mask R-CNN for the aforementioned purposes.Mask DINO achieved f-1 scores of 91% and 86% in weathering grade detection and rock type detection,as opposed to the Mask R-CNN's f-1 scores of 84% and 75%,respectively.These findings underscore the substantial potential of employing DETR algorithms like Mask DINO for automatic classification of both rock type and weathering states.Although the study examines only two AI models,the data processing and other techniques developed in this study may serve as a foundation for future advancements in the field.By incorporating these advanced AI techniques,logging personnel can obtain valuable references to aid their work,ultimately contributing to the advancement of geological and related fields.展开更多
Carbonic acid produced by the dissolution of atmospheric and soil CO_(2)in water is usually the most dominant catalyst for chemical weathering,but a sulfuric aciddriven phenomenon,different from usual,was found in the...Carbonic acid produced by the dissolution of atmospheric and soil CO_(2)in water is usually the most dominant catalyst for chemical weathering,but a sulfuric aciddriven phenomenon,different from usual,was found in the orogenic belt watersheds dominated by silicate bedrock.This study,rooted in comprehensive field investigations in the Manas River Basin(MRB)north of the Tianshan Mountains,delves into the mechanisms and impacts of sulfuric and carbonic acid as catalysts driving diff erent types of chemical weathering in the Central Asian Orogenic Belt.Quantitative analyses elucidate that carbonate weathering constitutes 52.4%of the total chemical weathering,while silicate and evaporite account for 18.6%and 25.3%,respectively,with anthropogenic activities and atmospheric precipitation having little eff ect.The estimated total chemical weathering rate in MRB is approximately 0.075×10^(6)mol/km^(2)/year.Quantitative findings further suggest that,preceding carbonate precipitation(<10^(4)year),chemical weathering can absorb CO_(2).Subsequently,and following carbonate precipitation(10^(4)-10^(7)year),it will release CO_(2).The release significantly surpasses the global average CO_(2)consumption,contributing to a noteworthy climate impact.This study underscores the distinctive weathering mechanisms,wherein sulfuric acid emerges as the predominant catalyst.The quantity of sulfuric acid as a catalyst is approximately three times that of carbonic acid.Sulfuric acid-driven carbonate rock weathering(SCW)is identified as the sole chemical weathering type with a net CO_(2)release eff ect.SCW CO_(2)release flux(5176 mol/km^(2)/year)is roughly 2.5 times the CO_(2)absorption by Ca-Mg silicate weathering,highlighting the pivotal role of chemical weathering in sourcing atmospheric CO_(2)over the timescales of carbonate precipitation and sulfate reduction.Lastly,this study posits that catalyst and transport limitations are the most plausible critical factors in MRB.The interplay between sulfuric acid and dissolved CO_(2)competitively shapes the types and rates of chemical weathering reactions.展开更多
This study investigated the effects of weathering depth and thickness on the failure mechanisms of rock samples through experimental and numerical methods.The first configuration involved conducting artificial weather...This study investigated the effects of weathering depth and thickness on the failure mechanisms of rock samples through experimental and numerical methods.The first configuration involved conducting artificial weathering on limestone using the freezing and thawing(F-T)for 40 cycles.The mechanical parameters of the samples were measured at the end of the 40th cycle.In the second configuration,a series of specimens underwent salt crystallization(S-C)tests for 20 cycles.Experimental results were validated using discrete element method(DEM).Next,the weathered limestone model with dimensions of 108 mm54 mm were prepared.The weathering layers were tested at four different thicknesses(i.e.2.5 mm,5 mm,7.5 mm,and 10 mm)and three different positions(at the surface,5 mm under the rock surface,and 10 mm under the rock surface).According to the results,weathering depth and thickness have a considerable effect on the failure process.The results also showed a correlation between the values of compressive strength and failure mechanisms associated with the weathering layer.The numerical results revealed that the tension crack was the dominant factor.Additionally,with increasing weathering thickness,Young's modulus,crack initiation stress,and final strength decreased in constant weathering depth.The results also demonstrated that the failure progress of the numerical models was similar to that observed in the laboratory.展开更多
Chemical weathering can occur on Earth and other rocky planets with liquid water on their surfaces.As the Curiosity Mission has revealed that fluvio-lacustrine depositional environments once prevailed in Gale Crater,i...Chemical weathering can occur on Earth and other rocky planets with liquid water on their surfaces.As the Curiosity Mission has revealed that fluvio-lacustrine depositional environments once prevailed in Gale Crater,investigation of sediment geochemistry to interpret chemical weathering history and the possible influence of climate fluctuation seems feasible on Mars.This study examines the relationship between temperature and the degree of weathering inferred from weathering indices,and applies the suitable weathering indices to a compilation of published datasets from Gale Crater sediment.The selected weathering indices(CIA,CIW,PIA,V,W,and WIP)consistently suggest an increase followed by a more gradual increase and decrease in weathering intensity up-section,which might reflect climate variations.However,diagenetic and/or hydrothermal alteration seem to have overprinted the primary weathering signature.展开更多
The corrosion behavior and mechanism of 3Ni weathering steel in a simulated oceanic atmospheric environment are investigated in order to comprehend the impacts of La,as determined through electrochemical analysis and ...The corrosion behavior and mechanism of 3Ni weathering steel in a simulated oceanic atmospheric environment are investigated in order to comprehend the impacts of La,as determined through electrochemical analysis and rust layer characterization.The results of this study demonstrate that the addition of La enhances the corrosion resistance of 3Ni weathering steel in the marine atmospheric environment,thereby reducing the corrosion rate and improving the protection of the rust layer.The influence of La on corrosion resistance can be attributed to two primary factors.Firstly,La functions as a grain refiner,minimizing the potential difference of the micro-regions on the substrate surface,thereby significantly reducing the corrosion of bare steel in the marine environment.Secondly,La inhibits the process of Fe_(3)O_(4) oxidation back toγ-FeOOH during corrosion at the local site,thus decreasing the formation ofγ-FeOOH and enhancing the charge transfer resistance.This research work may serve as a reference for expanding the application of rare earth elements in the field of weathering steel.展开更多
Ni-advanced weathering steel holds paramount importance in marine atmospheric environments,especially those with heightened Cl^(−)concentrations.The meticulous compositional design plays a crucial role in establishing...Ni-advanced weathering steel holds paramount importance in marine atmospheric environments,especially those with heightened Cl^(−)concentrations.The meticulous compositional design plays a crucial role in establishing a rust layer capable of withstanding intrusion by Cl^(−),making it imperative for the viability of coating-free weathering steel in marine atmospheric environments.This study explores the corrosion evolution and corrosion-resistant mechanisms within a steady-state rust layer in 3Ni weathering steel,with a particular focus on the role of Mo in challenging marine atmospheric conditions.The findings unequivocally demonstrate that the augmentation of the protective properties of the rust layer is directly correlated with an increase in Mo content,transitioning from 0.5 to 1.5 wt.%.This transition is most evident in the reduction of the corrosion rate for the 3Ni-Mo steel,dropping from an initial 1.74 mm a^(−1)to a robust 1.31 mm a^(−1)after 768 h of corrosion exposure.The heightened Mo content expedites the formation of a stable and durable rust layer,significantly enriching the proportion ofα-FeOOH within this protective layer.The stabilized rust layer of 3Ni-Mo weathering steel exhibits a distinct three-layer structure,comprising an outer layer primarily ofγ-FeOOH,an intermediate layer mainly composed of Fe_(2)O_(3)/Fe_(3)O_(4),and an inner layer predominantly composed ofα-FeOOH andβ-FeOOH.Additionally,an alkaline interface enriched with NiFe_(2)O_(4)and CuFe_(2)O_(4)develops between the inner layer and the substrate.Firstly,Mo promotes the deposition of MoO_(2),MoO_(3),and molybdate on both the inner layer and alkaline steel-rust interface to repair corrosion pits and fill cracks.Secondly,Mo facilitates the generation of compounds such as NiFe_(2)O_(4)and CuFe_(2)O_(4),which heightens the electronegativity of the intermediate rust layer and the steel-rust interface,preventing Cl^(−)-induced interface acidification and pitting corrosion.The higher Mo content expedites the formation of this alkaline interface and promotes inner layer densification.Most significantly,Mo creates additional nucleation sites for hydroxide oxides through oxide formation,leading to the formation of nano-sizedα-FeOOH andβ-FeOOH within the inner layer thereby enhancing the stability and compactness of the inner layer.These synergistic effects fortify the resilience of 3Ni-Mo advanced weathering steel in corrosive environments,ultimately strengthening its capacity to withstand environmental challenges.展开更多
This study is thefirst attempt to assess the nature of the soil,especially on the western side of the Porali Plain in Balochistan;a new emerging agriculture hub,using weathering and pollution indices supplemented by mu...This study is thefirst attempt to assess the nature of the soil,especially on the western side of the Porali Plain in Balochistan;a new emerging agriculture hub,using weathering and pollution indices supplemented by multi-variate analysis based on geochemical data.The outcomes of this study are expected to help farmers in soil manage-ment and selecting suitable crops for the region.Twenty-five soil samples were collected,mainly from the arable land of the Porali Plain.After drying and coning-quarter-ing,soil samples were analyzed for major and trace ele-ments using the XRF technique;sieving and hydrometric methods were employed for granulometric analysis.Esti-mated data were analyzed using Excel,SPSS,and Surfer software to calculate various indices,correlation matrix,and spatial distribution.The granulometric analysis showed that 76%of the samples belonged to loam types of soil,12%to sand type,and 8%to silt type.Weathering indices:CIA,CIW,PIA,PWI,WIP,CIX,and ICV were calculated to infer the level of alteration.These indices reflect mod-erate to intense weathering;supported by K_(2)O/AI_(2)O_(3),Rb/K_(2)O,Rb/Ti,and Rb/Sr ratios.Assessment of the geo-ac-cumulation and Nemerow Pollution indices pinpoint rela-tively high concentrations of Pb,Ni,and Cr concentration in the soils.The correlation matrix and Principal Compo-nent Analysis show that the soil in this study area is mainly derived from the weathering of igneous rocks of Bela Ophiolite(Cretaceous age)and Jurassic sedimentary rocks of Mor Range having SEDEX/MVT type mineralization.Weathering may result in the undesirable accumulation of certain trace elements which adversely affects crops.展开更多
The polystyrene (PS) materials tend to yellow over time. The yellowing phenomenon is an indicator of the material’s reduced performance and structural integrity. In the natural environment, sunlight is a major contri...The polystyrene (PS) materials tend to yellow over time. The yellowing phenomenon is an indicator of the material’s reduced performance and structural integrity. In the natural environment, sunlight is a major contributor to the yellowing, and elevated temperatures can accelerate the chemical reactions that lead to yellowing. The natural environmental factors are difficult to control, making it challenging to predict the yellowing process accurately. In this paper, we established a model to quantify the relationship between the yellowing index and key factors, solar radiation and temperature, from outdoor monitored climatic data. The model is trained and tested by the datasets collected from atmospheric exposure test stations located in Guangzhou and Qionghai. Same kinds of PS materials were exposed to external natural environments at the stations for one year. The parameters were estimated by least squares method. The results indicated that the model fits training and testing datasets well with R2 of 0.980 and 0.985, respectively.展开更多
Wooden buildings play a very important role in China’s construction and landscape architecture industry.In order to explore the weathering characteristics of the surface layer of landscape wooden buildings,the main c...Wooden buildings play a very important role in China’s construction and landscape architecture industry.In order to explore the weathering characteristics of the surface layer of landscape wooden buildings,the main causes of weathering were analyzed on the basis of summarizing the common types of weathering characterization.The results showed that the weathering characterization was mainly reflected in the surface defects of wood structures,such as cracking,discoloration,peeling,wind erosion wear,and so on.The coating technology on the surface of constructions was the main artificial factor affecting the surface defects of constructions.In the case of similar surface decoration conditions,sunlight and moisture were the main natural factors affecting the weathering of wooden buildings,which will promote the process of weathering.展开更多
Exploring the relationship between weathering and erosion is essential for understanding the evolution of landscapes and formation of soil under the influence of climate, tectonics, and topography. We measured the bul...Exploring the relationship between weathering and erosion is essential for understanding the evolution of landscapes and formation of soil under the influence of climate, tectonics, and topography. We measured the bulk chemistry of regoliths and calculated their weathering rates and intensity in three locations in China: Inner Mongolia in the mid-temperate semi-humid zone; Jiangxi Province, in the mid-subtropical humid zone; and Hainan Province, in the tropical humid zone. These profiles exhibited increased weathering with increasing temperature and precipitation.The low-gradient profile exhibited stronger weathering of saprolite than of soil, whereas the high-gradient profile showed a more constant weathering pattern. The regolith in the cold climate was the product of easily weatherable minerals, whereas weathering of K-feldspar and even secondary minerals occurred in hot and humid climates. The weathering of subtropical profiles was both supply-and kinetic-limited, controlled by weathering and erosion. The tropical profile experienced supply-limited weathering,indicating slow erosion and an intense weathering profile;the mid-temperate profile was not classifiable due to weak erosion and weathering. Long-term weathering fluxes of these profiles show that Si, Na, and K(or Mg) represent thebulk of the mass lost through weathering. This study underscores that weathering of granitic regolith is controlled by both climatic conditions and landscape.展开更多
With the development of the hyperspectral remote sensing technique,extensive chemical weathering profiles have been identified on Mars.These weathering sequences,formed through precipitation-driven leaching processes,...With the development of the hyperspectral remote sensing technique,extensive chemical weathering profiles have been identified on Mars.These weathering sequences,formed through precipitation-driven leaching processes,can reflect the paleoenvironments and paleoclimates during pedogenic processes.The specific composition and stratigraphic profiles mirror the mineralogical and chemical trends observed in weathered basalts on Hainan Island in south China.In this study,we investigated the laboratory reflectance spectra of a 53-m-long drilling core of a thick basaltic weathering profile collected from Hainan Island.We established a quantitative spectral model by combining the genetic algorithm and partial least squares regression(GA-PLSR)to predict the chemical properties(SiO2,Al2O3,Fe2O3)and index of laterization(IOL).The entire sample set was divided into a calibration set of 25 samples and a validation set of 12 samples.Specifically,the GA was used to select the spectral subsets for each composition,which were then input into the PLSR model to derive the chemical concentration.The coefficient of determination(R2)values on the validation set for SiO2,Al2O3,Fe2O3,and the IOL were greater than 0.9.In addition,the effects of various spectral preprocessing techniques on the model accuracy were evaluated.We found that the spectral derivative treatment boosted the prediction accuracy of the GA-PLSR model.The improvement achieved with the second derivative was more pronounced than when using the first derivative.The quantitative model developed in this work has the potential to estimate the contents of similar weathering basalt products,and thus infer the degree of alteration and provide insights into paleoclimatic conditions.Moreover,the informative bands selected by the GA can serve as a guideline for designing spectral channels for the next generation of spectrometers.展开更多
Four kinds of iron oxide pigments were added into wood-fiber/high-density-polyethylene composites （WF/HDPE） at three different concentrations, to determine the effects of pigments on the changes in the color and mec...Four kinds of iron oxide pigments were added into wood-fiber/high-density-polyethylene composites （WF/HDPE） at three different concentrations, to determine the effects of pigments on the changes in the color and mechanical properties of the composites before and after UV accelerated weathering. HDPE, wood fibers, pigments and other processing additives were dry-mixed in a high-speed mixer. The mixtures were extruded by two-step extrusion process with a self-designed twin-screw/single-screw extruder system. Color of the samples was determined according to CIE 1976 L^＊a^＊b^＊ system by a spec- trophotometer and the bending properties were tested to evaluate the mechanical properties before and after accelerated UV weathering. The result shows that the modulus of elasticity of WF/HDPE did not obvi- ously changed after incorporating with the pigments, but the bending strength increased. After accelerated aging for 2000 h, both color and mechanical properties significantly changed. Iron oxide red and black performed better than the other two pigments, and the pigments dosage of 2.28% in the composites is favourable.展开更多
Rice-hull powder is widely used in manufacturing reinforced plastic composites.However,its weathering ability is rarely considered.We studied the performance of two types of rice-hull-polyethylene（RH-PE） composites ...Rice-hull powder is widely used in manufacturing reinforced plastic composites.However,its weathering ability is rarely considered.We studied the performance of two types of rice-hull-polyethylene（RH-PE） composites after they were exposed outdoor to natural weathering for two years.The samples did not change in bending strength and elasticity modulus.At the end of the testing period,colour lightness had increased by more than 23% and total colour had changed by more than 9 units.This means the colour evidently differentiate from the original colour that the customers choose.The analyses of Fourier-transform infrared（FTIR） and X-ray photoelectron spectroscopy（XPS） showed that oxidation had occurred on sample surfaces.Red lumber presented an obvious C=O peak after weathering,while yellow lumber did not present an obvious peak as evidence of oxidation.Both types of lumbers showed a reduction of lignocellulosic groups and amorphous regions of PE.展开更多
基金funded by the National Natural Science Foundation of China(Nos.42173059 and 41991322)。
文摘Enhanced silicate weathering(ESW)is a geoengineering method aimed at accelerating carbon dioxide(CO_(2))removal(CDR)from atmosphere by increasing the weathering flux of silicate rocks and minerals.It has emerged as a promising strategy for CDR.Theoretical studies underscore ESW’s substantial potential for CDR and its diverse benefits for crops when applied to croplands.However,the well-known significant discrepancies in silicate weathering rates between laboratory and field conditions introduce uncertainty in CDR through ESW.By compiling data from recent literature,we calculated and compared CDR efficiency(t CO_(2)t^(-1)_(silicate)ha^(-1)y^(-1))observed in mesocosm experiments and field trials.The findings indicate that CDR efficiencies in field trials are comparable to or exceeding that observed in mesocosm experiments by 1-3 orders of magnitude,particularly evident with wollastonite application.The hierarchy of CDR efficiency among silicates suitable for ESW is ranked as follows:olivine≥wollastonite>basalt>albite≥anorthite.We suggest the potential role of biota,especially fungi,in contributing to higher CDR efficiencies observed in field trials compared to mesocosm experiments.We further emphasize introducing fungi known for their effectiveness in silicate weathering could potentially enhance CDR efficiency through ESW in croplands.But before implementing fungal-facilitated ESW,three key questions need addressing:(i)How does the community of introduced fungi evolve over time?(ii)What is the long-term trajectory of CDR efficiency following fungal introduction?and(iii)Could fungal introduction lead to organic matter oxidation,resulting in elevated CO_(2)emissions?These investigations are crucial for optimizing the efficiency and sustainability of fungal-facilitated ESW strategy.
基金financially supported by the Science and Technology Innovation Foundation of the Command Center of Integrated Natural Resources Survey Center(KC20230002)the China Geological Survey Project(DD20230471,DD20220855 and DD20243282)+1 种基金the National Natural Science Foundation of China(41872100)the National Key R&D Plan(2022YFC2903402)。
文摘Black soil is essential for maintaining regional food security and promoting global agricultural production.Understanding the weathering process of parent material and the accumulation of organic carbon is crucial to comprehending the developmental history and future trends of black soil,especially against the background of large-scale global cultivation and climate change.Although the importance of black soil formation and evolution cannot be ignored,the relevant research is still very scarce.In this study,a typical eight-meter-deep soil core was collected from the Keshan area of the Songnen Plain,Northeast China,where surface black soil developed on paleo-sediments.Using^(14)C dating,the formation age of the black soil was determined.Based on the characteristics of the geochemical composition,grain size and the magnetic susceptibility of the sediments,it was demonstrated that the black soil and its parent material originated from reworked loess.Furthermore,the mass transfer coefficient(τ)of some elements was determined,in order to explore the soil weathering process.By calculating the transported amount of alkaline and alkaline-earth elements,the weathering rate of parent material to black soil was found to be weak,at 0.16 kEq·ha^(-1)·year^(-1).Combining the results of dating and carbon density in the different layers of black soil,the accumulation rate of organic carbon was determined as follows:rapidly increasing in the initial period of 13.2-2.2 ka,reaching its maximum average value of 34.0 g·cm^(-2)·a^(-1)at 2.2-0.8 ka,then showing a decreasing trend with an average value of-77.5 g·cm^(-2)·a^(-1).Compared with regional climate change,Keshan black soil has developed under a colder and wetter climate during the Holocene.Predictably,ongoing global warming may lead to the degradation of black soils in the Songnen Plain,as well as in other regions.Our results will enrich geological knowledge of black soil formation and future evolutionary trends.
基金support of the National Natural Science Foundation of China(No.52171063).
文摘Weathering steel exhibits excellent corrosion resistance and is widely used in bridges,towers,railways,highways,and other engineering projects that are exposed to the atmosphere for long periods of time.However,before the formation of stable rust layers,weathering steel is prone to liquid rust sagging and spattering,leading to environmental pollution and city appearance concerns.These factors limit the application and development of weathering steel.In this study,a rapid and environmentally friendly method was de-veloped by introducing alloying elements,specifically investigating the role of Sn in the rapid stabilization of rust layers in marine atmo-spheric environments.The rust layer formed on weathering low-alloy steel exposed to prolonged outdoor conditions and laboratory im-mersion experiments was explored using electron probe micro-analyzer(EPMA),micro-Raman,X-ray photoelectron spectroscopy(XPS),and electrochemical measurements.Results showed an optimal synergistic effect between Sn and Cr,which facilitated the accelerated densification of the rust layer.This beneficial effect enhanced the capability of the rust layer to resist Cl^(-)erosion and improved the protec-tion performance of the rust layer.
基金support from the Youth Innovation Promotion Association,Chinese Academy of Sciences(2020395)Strategic Priority Research Program of the Chinese Academy of Sciences grant XDB 41000000(Y.L.)+4 种基金National Natural Science Foundation of China(Nos.42273042 and 41931077)"From 0 to 1"Original Exploration Cultivation Project,Institute of Geochemistry,Chinese Academy of Sciences(DHSZZ2023-3)Guizhou Provincial Foundation for Excellent Scholars Program(No.GCC[2023]088)Guizhou Provincial Science and Technology Projects:QKHJCZK[2023]-General 473NSFC Young Scientist Fund(Nos.42303041 and 42403043)。
文摘Permanently shadowed regions(PSRs)on the Moon are potential reservoirs for water ice,making them hot spots for future lunar exploration.The water ice in PSRs would cause distinctive changes in space weathering there,in particular reduction-oxidation processes that diff er from those in illuminated regions.To determine the characteristics of products formed during space weathering in PSRs,the lunar meteorite NWA 10203 with artifi cially added water was irradiated with a nanosecond laser to simulate a micro-meteorite bombardment of lunar soil containing water ice.The TEM results of the water-incorporated sample showed distinct amorphous rims that exhibited irregular thickness,poor stratifi cation,the appearance of bubbles,and a reduced number of npFe^(0).Additionally,EELS analysis showed the presence of ferric iron at the rim of the nanophase metallic iron particles(npFe^(0))in the amorphous rim with the involvement of water.The results suggest that water ice is another possible factor contributing to oxidation during micrometeorite bombardment on the lunar surface.In addition,it off ers a reference for a new space weathering model that incorporates water in PSRs,which could be widespread on asteroids with volatiles.
基金supported by National Natural Science Foundation of China(Grant No.42050201)National Key Research and Development Program of China(Grant No.2020YFC1522200)。
文摘Dry-wet cycle is a key factor in surface weathering of earthen heritage,which remains insufficiently explained.It involves the interaction of humidity,stress,and damage.Using the RFPA(realistic failure process analysis)numerical method,this study reproduced the processes of humidity diffusion,deformation,stress,and damage evolution under dry-wet cycles in the soil site of Suoyang City,China.The numerical results indicate that the drying phase following rainfall has the most significant deteriorative impact on the earthen heritage.The evaporation of surface moisture during this phase causes volume shrinkage,which in turn generates tensile stress and leads to the formation of numerous desiccation cracks.Desiccation cracks provide channels for moisture diffusion,which further exacerbates generation of the cracks,leading to a mutual promotion between the two phenomena.Furthermore,during the wetting phase,the model elements undergo hygroscopic expansion,resulting in a slight increase in strain and displacement.Previously formed cracks may exhibit temporary narrowing or closure,but will revert during the subsequent drying phase.Ultimately,the overall displacement increases with the number of dry-wet cycles.The findings provide a theoretical foundation for protection against surface weathering and other damage in earthen heritage in arid regions.
基金supported by internal grant from Sultan Qaboos University(IG/DVC/ESRC/21/01).
文摘Enhanced weathering(EW)of ultramafi c rocks from the Muslim Bagh Ophiolite,Pakistan,has been studied in laboratory experiments to explore carbon sequestration as a climate change mitigation strategy for coastal and open sea environments.The research focused on a cost-eff ective ex situ experiment to examine the eff ects of EW reaction pathways arising from the interactions among rock powder,seawater and CO_(2).The experimental fi ltrates from diff erent milled peridotite samples exhibit a decrease in the Mg/Ca ratio as the specifi c surface area increases,which accelerates reaction rates.This suggests that the leached Mg from the original rock may have been consumed in the formation of brucite,serpentine and carbonates during EW.Similar reaction pathways are also responsible for the chemical alterations observed in amphibolite,albeit to varying degrees.On the other hand,the experimental residues showed an increase in loss on ignition compared to the original rock,indicating that EW has facilitated the incorporation of H 2 O and CO_(2) into secondary mineral structures through various reaction pathways,leading to the formation of brucite,serpentine and carbonates.Thermal gravimetric analysis of the experimental residues confi rms the presence of these minerals based on their decomposition temperatures.Additionally,XRD analysis identifi ed a range of carbonates in the residues of both peridotite and amphibolite samples,validating the occurrence of carbonation reactions.SEM images reveal textural changes in both samples,supporting the formation of secondary minerals through EW,consistent with observations from the petrographic study of untreated samples.Control experiments on CO_(2) absorption in seawater showed a decrease in pH,highlighting ocean acidifi cation from increased CO_(2) emissions.However,when rock powder was added to the seawater-CO_(2) mixture,the pH increased.This suggests that the EW of ultramafi c rock powders can sequester CO_(2) while raising seawater pH through the formation of secondary minerals.This research could serve as an analog for EW applications,considering the worldwide abundance of ultramafi c rocks and the availability of coastal and open ocean environments.However,further research is required to understand the behavior of other elements and their impacts on ocean chemistry in EW processes before applying CO_(2) sequestration strategies.
基金supported by the High-quality Scientific Research Cultivation Project of Bengbu University(Grant No.2021pyxm03)the Natural Science Foundation of the Higher Education Institutions of Anhui Province(Grant No.KJ2021A1118)+1 种基金the Provincial Quality Engineering Project of Anhui Universities(Grant No.2022zygzts066)the Discipline(Major)Leadership Development Program of Anhui Province(DTR2023057).
文摘A micro-layered structure was observed in the stable rust layer through dry–wet cycle corrosion tests.The microstructure,element distribution,and corrosion resistance mechanism of this layer structure in the marine industrial atmosphere were investigated by focused ion beam–scanning electron microscopy and high-resolution transmission electron microscopy.The inner rust layer of weathering steel(WS)exhibited layered enrichment of Cr,Cu,Ti,and other alloying elements.This layered structure comprised a fully amorphous region rich in Cr and Ti,as well as an amorphous and nanocrystalline region rich in Fe but poor in Cr.Only the completely amorphous region of the inner rust layer demonstrated a strong adsorption effect on Cl^(−).Cr-rich amorphous region played a pivotal role in reducing the corrosion of WS in the marine industrial atmospheric environment.The interface between the amorphous and nanocrystalline regions,as well as cracks within the interlayer,facilitated Cl^(−)transport,while the intact interlayer effectively hindered HSO_(3)^(−).
基金supported by the Construction Industry Council(Grant No.CICR/01/22)the support from the General Research Fund(Grant No.17206822)of the Research Grants Council(Hong Kong).
文摘Rock classification plays a crucial role in various fields such as geology,engineering,and environmental studies.Employing deep learning AI(artificial intelligence)methods has a high potential to significantly improve the accuracy and efficiency of this task.The paper delves into the exploration of two cuttingedge AI techniques,namely Mask DINO and Mask R-CNN(convolutional neural network),as means to identify rock weathering grades and rock types.The results demonstrate that Mask DINO,which is a Detection Transformer(DETR),outperforms Mask R-CNN for the aforementioned purposes.Mask DINO achieved f-1 scores of 91% and 86% in weathering grade detection and rock type detection,as opposed to the Mask R-CNN's f-1 scores of 84% and 75%,respectively.These findings underscore the substantial potential of employing DETR algorithms like Mask DINO for automatic classification of both rock type and weathering states.Although the study examines only two AI models,the data processing and other techniques developed in this study may serve as a foundation for future advancements in the field.By incorporating these advanced AI techniques,logging personnel can obtain valuable references to aid their work,ultimately contributing to the advancement of geological and related fields.
基金support from the Third Xinjiang Scientific Expedition Program(2021XJKK0803)the National Natural Science Foundation of China(No.41930640)the Project of the Second Comprehensive Scientific Investigation on the Qinghai-Tibetan Plateau(2019QZKK1003)。
文摘Carbonic acid produced by the dissolution of atmospheric and soil CO_(2)in water is usually the most dominant catalyst for chemical weathering,but a sulfuric aciddriven phenomenon,different from usual,was found in the orogenic belt watersheds dominated by silicate bedrock.This study,rooted in comprehensive field investigations in the Manas River Basin(MRB)north of the Tianshan Mountains,delves into the mechanisms and impacts of sulfuric and carbonic acid as catalysts driving diff erent types of chemical weathering in the Central Asian Orogenic Belt.Quantitative analyses elucidate that carbonate weathering constitutes 52.4%of the total chemical weathering,while silicate and evaporite account for 18.6%and 25.3%,respectively,with anthropogenic activities and atmospheric precipitation having little eff ect.The estimated total chemical weathering rate in MRB is approximately 0.075×10^(6)mol/km^(2)/year.Quantitative findings further suggest that,preceding carbonate precipitation(<10^(4)year),chemical weathering can absorb CO_(2).Subsequently,and following carbonate precipitation(10^(4)-10^(7)year),it will release CO_(2).The release significantly surpasses the global average CO_(2)consumption,contributing to a noteworthy climate impact.This study underscores the distinctive weathering mechanisms,wherein sulfuric acid emerges as the predominant catalyst.The quantity of sulfuric acid as a catalyst is approximately three times that of carbonic acid.Sulfuric acid-driven carbonate rock weathering(SCW)is identified as the sole chemical weathering type with a net CO_(2)release eff ect.SCW CO_(2)release flux(5176 mol/km^(2)/year)is roughly 2.5 times the CO_(2)absorption by Ca-Mg silicate weathering,highlighting the pivotal role of chemical weathering in sourcing atmospheric CO_(2)over the timescales of carbonate precipitation and sulfate reduction.Lastly,this study posits that catalyst and transport limitations are the most plausible critical factors in MRB.The interplay between sulfuric acid and dissolved CO_(2)competitively shapes the types and rates of chemical weathering reactions.
文摘This study investigated the effects of weathering depth and thickness on the failure mechanisms of rock samples through experimental and numerical methods.The first configuration involved conducting artificial weathering on limestone using the freezing and thawing(F-T)for 40 cycles.The mechanical parameters of the samples were measured at the end of the 40th cycle.In the second configuration,a series of specimens underwent salt crystallization(S-C)tests for 20 cycles.Experimental results were validated using discrete element method(DEM).Next,the weathered limestone model with dimensions of 108 mm54 mm were prepared.The weathering layers were tested at four different thicknesses(i.e.2.5 mm,5 mm,7.5 mm,and 10 mm)and three different positions(at the surface,5 mm under the rock surface,and 10 mm under the rock surface).According to the results,weathering depth and thickness have a considerable effect on the failure process.The results also showed a correlation between the values of compressive strength and failure mechanisms associated with the weathering layer.The numerical results revealed that the tension crack was the dominant factor.Additionally,with increasing weathering thickness,Young's modulus,crack initiation stress,and final strength decreased in constant weathering depth.The results also demonstrated that the failure progress of the numerical models was similar to that observed in the laboratory.
基金supported by the NRF grant funded by the Korean Government(MSIT,No.2022R1A2C1004798)Global-Learning&Academic research institution for Master’s·PhD students,and Postdocs(LAMP)Program of the National Research Foundation of Korea(NRF)grant funded by the Ministry of Education(No.RS-2023-00301702).
文摘Chemical weathering can occur on Earth and other rocky planets with liquid water on their surfaces.As the Curiosity Mission has revealed that fluvio-lacustrine depositional environments once prevailed in Gale Crater,investigation of sediment geochemistry to interpret chemical weathering history and the possible influence of climate fluctuation seems feasible on Mars.This study examines the relationship between temperature and the degree of weathering inferred from weathering indices,and applies the suitable weathering indices to a compilation of published datasets from Gale Crater sediment.The selected weathering indices(CIA,CIW,PIA,V,W,and WIP)consistently suggest an increase followed by a more gradual increase and decrease in weathering intensity up-section,which might reflect climate variations.However,diagenetic and/or hydrothermal alteration seem to have overprinted the primary weathering signature.
基金G.Niu,R.Yuan,H.B.Wu,C.J.Shang,and X.P.Mao appreciate the support from the National Key R&D Program of China(No.2021YFB3701700)G.Niu appreciates the support from the National Natural Science Foundation of China(No.52304389)the China Postdoctoral Science Foundation(No.2022M720402).
文摘The corrosion behavior and mechanism of 3Ni weathering steel in a simulated oceanic atmospheric environment are investigated in order to comprehend the impacts of La,as determined through electrochemical analysis and rust layer characterization.The results of this study demonstrate that the addition of La enhances the corrosion resistance of 3Ni weathering steel in the marine atmospheric environment,thereby reducing the corrosion rate and improving the protection of the rust layer.The influence of La on corrosion resistance can be attributed to two primary factors.Firstly,La functions as a grain refiner,minimizing the potential difference of the micro-regions on the substrate surface,thereby significantly reducing the corrosion of bare steel in the marine environment.Secondly,La inhibits the process of Fe_(3)O_(4) oxidation back toγ-FeOOH during corrosion at the local site,thus decreasing the formation ofγ-FeOOH and enhancing the charge transfer resistance.This research work may serve as a reference for expanding the application of rare earth elements in the field of weathering steel.
基金the National Key R&D Program of China(No.2021YFB3701700)Gang Niu appreciates the support from the National Natural Science Foundation of China(No.52304389)+2 种基金Gang Niu and Huibin Wu appreciate the support from the Fundamental Research Funds for the Central Universities(No.FRFBD-23-01)Gang Niu appreciates the support from the China Postdoctoral Science Foundation(No.2022M720402)Na Gong appreciates the support from the Structural Metal Alloy Program(SMAP),Grant No.A18B1b0061,and Manufacturing of Multi-Material Net-Shape Parts with Heterogeneous Properties(MMNH),Grantno.M22K5a0045 inA∗STAR.
文摘Ni-advanced weathering steel holds paramount importance in marine atmospheric environments,especially those with heightened Cl^(−)concentrations.The meticulous compositional design plays a crucial role in establishing a rust layer capable of withstanding intrusion by Cl^(−),making it imperative for the viability of coating-free weathering steel in marine atmospheric environments.This study explores the corrosion evolution and corrosion-resistant mechanisms within a steady-state rust layer in 3Ni weathering steel,with a particular focus on the role of Mo in challenging marine atmospheric conditions.The findings unequivocally demonstrate that the augmentation of the protective properties of the rust layer is directly correlated with an increase in Mo content,transitioning from 0.5 to 1.5 wt.%.This transition is most evident in the reduction of the corrosion rate for the 3Ni-Mo steel,dropping from an initial 1.74 mm a^(−1)to a robust 1.31 mm a^(−1)after 768 h of corrosion exposure.The heightened Mo content expedites the formation of a stable and durable rust layer,significantly enriching the proportion ofα-FeOOH within this protective layer.The stabilized rust layer of 3Ni-Mo weathering steel exhibits a distinct three-layer structure,comprising an outer layer primarily ofγ-FeOOH,an intermediate layer mainly composed of Fe_(2)O_(3)/Fe_(3)O_(4),and an inner layer predominantly composed ofα-FeOOH andβ-FeOOH.Additionally,an alkaline interface enriched with NiFe_(2)O_(4)and CuFe_(2)O_(4)develops between the inner layer and the substrate.Firstly,Mo promotes the deposition of MoO_(2),MoO_(3),and molybdate on both the inner layer and alkaline steel-rust interface to repair corrosion pits and fill cracks.Secondly,Mo facilitates the generation of compounds such as NiFe_(2)O_(4)and CuFe_(2)O_(4),which heightens the electronegativity of the intermediate rust layer and the steel-rust interface,preventing Cl^(−)-induced interface acidification and pitting corrosion.The higher Mo content expedites the formation of this alkaline interface and promotes inner layer densification.Most significantly,Mo creates additional nucleation sites for hydroxide oxides through oxide formation,leading to the formation of nano-sizedα-FeOOH andβ-FeOOH within the inner layer thereby enhancing the stability and compactness of the inner layer.These synergistic effects fortify the resilience of 3Ni-Mo advanced weathering steel in corrosive environments,ultimately strengthening its capacity to withstand environmental challenges.
基金supported by the Dean Faculty of Science,University of Karachi research grant.
文摘This study is thefirst attempt to assess the nature of the soil,especially on the western side of the Porali Plain in Balochistan;a new emerging agriculture hub,using weathering and pollution indices supplemented by multi-variate analysis based on geochemical data.The outcomes of this study are expected to help farmers in soil manage-ment and selecting suitable crops for the region.Twenty-five soil samples were collected,mainly from the arable land of the Porali Plain.After drying and coning-quarter-ing,soil samples were analyzed for major and trace ele-ments using the XRF technique;sieving and hydrometric methods were employed for granulometric analysis.Esti-mated data were analyzed using Excel,SPSS,and Surfer software to calculate various indices,correlation matrix,and spatial distribution.The granulometric analysis showed that 76%of the samples belonged to loam types of soil,12%to sand type,and 8%to silt type.Weathering indices:CIA,CIW,PIA,PWI,WIP,CIX,and ICV were calculated to infer the level of alteration.These indices reflect mod-erate to intense weathering;supported by K_(2)O/AI_(2)O_(3),Rb/K_(2)O,Rb/Ti,and Rb/Sr ratios.Assessment of the geo-ac-cumulation and Nemerow Pollution indices pinpoint rela-tively high concentrations of Pb,Ni,and Cr concentration in the soils.The correlation matrix and Principal Compo-nent Analysis show that the soil in this study area is mainly derived from the weathering of igneous rocks of Bela Ophiolite(Cretaceous age)and Jurassic sedimentary rocks of Mor Range having SEDEX/MVT type mineralization.Weathering may result in the undesirable accumulation of certain trace elements which adversely affects crops.
文摘The polystyrene (PS) materials tend to yellow over time. The yellowing phenomenon is an indicator of the material’s reduced performance and structural integrity. In the natural environment, sunlight is a major contributor to the yellowing, and elevated temperatures can accelerate the chemical reactions that lead to yellowing. The natural environmental factors are difficult to control, making it challenging to predict the yellowing process accurately. In this paper, we established a model to quantify the relationship between the yellowing index and key factors, solar radiation and temperature, from outdoor monitored climatic data. The model is trained and tested by the datasets collected from atmospheric exposure test stations located in Guangzhou and Qionghai. Same kinds of PS materials were exposed to external natural environments at the stations for one year. The parameters were estimated by least squares method. The results indicated that the model fits training and testing datasets well with R2 of 0.980 and 0.985, respectively.
基金Science and technology research projects of colleges and universities in Inner Mongolia(NJZY22511)Funds for basic scientific research in universities of Inner Mongolia:Key project of Philosophy and Social Science Foundation of Inner Mongolia Agricultural University(BR220603)。
文摘Wooden buildings play a very important role in China’s construction and landscape architecture industry.In order to explore the weathering characteristics of the surface layer of landscape wooden buildings,the main causes of weathering were analyzed on the basis of summarizing the common types of weathering characterization.The results showed that the weathering characterization was mainly reflected in the surface defects of wood structures,such as cracking,discoloration,peeling,wind erosion wear,and so on.The coating technology on the surface of constructions was the main artificial factor affecting the surface defects of constructions.In the case of similar surface decoration conditions,sunlight and moisture were the main natural factors affecting the weathering of wooden buildings,which will promote the process of weathering.
基金supported by the National Natural Science Foundation of China(Grant Nos.4121000441661144042+1 种基金 41603018)National Basic Research Program(973project)of China(2013CB956401)
文摘Exploring the relationship between weathering and erosion is essential for understanding the evolution of landscapes and formation of soil under the influence of climate, tectonics, and topography. We measured the bulk chemistry of regoliths and calculated their weathering rates and intensity in three locations in China: Inner Mongolia in the mid-temperate semi-humid zone; Jiangxi Province, in the mid-subtropical humid zone; and Hainan Province, in the tropical humid zone. These profiles exhibited increased weathering with increasing temperature and precipitation.The low-gradient profile exhibited stronger weathering of saprolite than of soil, whereas the high-gradient profile showed a more constant weathering pattern. The regolith in the cold climate was the product of easily weatherable minerals, whereas weathering of K-feldspar and even secondary minerals occurred in hot and humid climates. The weathering of subtropical profiles was both supply-and kinetic-limited, controlled by weathering and erosion. The tropical profile experienced supply-limited weathering,indicating slow erosion and an intense weathering profile;the mid-temperate profile was not classifiable due to weak erosion and weathering. Long-term weathering fluxes of these profiles show that Si, Na, and K(or Mg) represent thebulk of the mass lost through weathering. This study underscores that weathering of granitic regolith is controlled by both climatic conditions and landscape.
基金National Key Research and Development Project(Grant No.2019YFE0123300)National Natural Science Foundation of China(Grant Nos.42072337,42241111,and 42241129)+1 种基金Pandeng Program of National Space Science Center,Chinese Academy of Sciences.Xing Wu also acknowledges support from the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology(Grant No.2022QNRC001)China Postdoctoral Science Foundation(Grant No.2021M700149).
文摘With the development of the hyperspectral remote sensing technique,extensive chemical weathering profiles have been identified on Mars.These weathering sequences,formed through precipitation-driven leaching processes,can reflect the paleoenvironments and paleoclimates during pedogenic processes.The specific composition and stratigraphic profiles mirror the mineralogical and chemical trends observed in weathered basalts on Hainan Island in south China.In this study,we investigated the laboratory reflectance spectra of a 53-m-long drilling core of a thick basaltic weathering profile collected from Hainan Island.We established a quantitative spectral model by combining the genetic algorithm and partial least squares regression(GA-PLSR)to predict the chemical properties(SiO2,Al2O3,Fe2O3)and index of laterization(IOL).The entire sample set was divided into a calibration set of 25 samples and a validation set of 12 samples.Specifically,the GA was used to select the spectral subsets for each composition,which were then input into the PLSR model to derive the chemical concentration.The coefficient of determination(R2)values on the validation set for SiO2,Al2O3,Fe2O3,and the IOL were greater than 0.9.In addition,the effects of various spectral preprocessing techniques on the model accuracy were evaluated.We found that the spectral derivative treatment boosted the prediction accuracy of the GA-PLSR model.The improvement achieved with the second derivative was more pronounced than when using the first derivative.The quantitative model developed in this work has the potential to estimate the contents of similar weathering basalt products,and thus infer the degree of alteration and provide insights into paleoclimatic conditions.Moreover,the informative bands selected by the GA can serve as a guideline for designing spectral channels for the next generation of spectrometers.
基金supported by the National Natural Science Foundation of China (30671644, 30771680)
文摘Four kinds of iron oxide pigments were added into wood-fiber/high-density-polyethylene composites （WF/HDPE） at three different concentrations, to determine the effects of pigments on the changes in the color and mechanical properties of the composites before and after UV accelerated weathering. HDPE, wood fibers, pigments and other processing additives were dry-mixed in a high-speed mixer. The mixtures were extruded by two-step extrusion process with a self-designed twin-screw/single-screw extruder system. Color of the samples was determined according to CIE 1976 L^＊a^＊b^＊ system by a spec- trophotometer and the bending properties were tested to evaluate the mechanical properties before and after accelerated UV weathering. The result shows that the modulus of elasticity of WF/HDPE did not obvi- ously changed after incorporating with the pigments, but the bending strength increased. After accelerated aging for 2000 h, both color and mechanical properties significantly changed. Iron oxide red and black performed better than the other two pigments, and the pigments dosage of 2.28% in the composites is favourable.
基金funded by National Natural Science Foundation of China 30671644 and NCET
文摘Rice-hull powder is widely used in manufacturing reinforced plastic composites.However,its weathering ability is rarely considered.We studied the performance of two types of rice-hull-polyethylene（RH-PE） composites after they were exposed outdoor to natural weathering for two years.The samples did not change in bending strength and elasticity modulus.At the end of the testing period,colour lightness had increased by more than 23% and total colour had changed by more than 9 units.This means the colour evidently differentiate from the original colour that the customers choose.The analyses of Fourier-transform infrared（FTIR） and X-ray photoelectron spectroscopy（XPS） showed that oxidation had occurred on sample surfaces.Red lumber presented an obvious C=O peak after weathering,while yellow lumber did not present an obvious peak as evidence of oxidation.Both types of lumbers showed a reduction of lignocellulosic groups and amorphous regions of PE.
