Exploring mechanism of hidden,steep obliquely inclined bedding landslides using a 3DEC model:A case study of the Shanyang landslide in Shaanxi Province,China

Catastrophic geological disasters frequently occur on slopes with obliquely inclined bedding structures(also referred to as obliquely inclined bedding slopes),where the apparent dip sliding is not readily visible.This phenomenon has become a focal point in landslide research.Yet,there is a lack of studies on the failure modes and mechanisms of hidden,steep obliquely inclined bedding slopes.This study investigated the Shanyang landslide in Shaanxi Province,China.Using field investigations,laboratory tests of geotechnical parameters,and the 3DEC software,this study developed a numerical model of the landslide to analyze the failure process of such slopes.The findings indicate that the Shanyang landslide primarily crept along a weak interlayer under the action of gravity.The landslide,initially following a dip angle with the support of a stable inclined rock mass,shifted direction under the influence of argillization in the weak interlayer,moving towards the apparent dip angle.The slide resistance effect of the karstic dissolution zone was increasingly significant during this process,with lateral friction being the primary resistance force.A reduction in the lateral friction due to karstic dissolution made the apparent dip sliding characteristics of the Shanyang landslide more pronounced.Notably,deformations such as bending and uplift at the slope’s foot suggest that the main slide resistance shifts from lateral friction within the karstic dissolution zone to the slope foot’s resistance force,leading to the eventual buckling failure of the landslide.This study unveils a novel failure mode of apparent dip creep-buckling in the Shanyang landslide,highlighting the critical role of lateral friction from the karstic dissolution zone in its failure mechanism.These insights offer a valuable reference for mitigating risks and preventing disasters related to obliquely inclined bedding landslides.

Effects of heavy metal pollution on farmland soils and crops:A case study of the Xiaoqinling Gold Belt,China

This paper focuses on the heavy metal enrichment and heavy metal pollution degree associated with mining activities in some crops and the soils of different parent materials in the Xiaoqinling Gold Belt.According to the geochemical analysis results of the soils observed in the gold belt,the soils are most highly enriched in Pb,followed by Cr,Cu,and Zn.Furthermore,they are relatively poor in Hg,Cd,and As.It is also shown that the heavy metals in all kinds of soils have the same geochemical characteristics in the gold belt.As for the crops(such as corn and wheat)in the gold belt,Zn and Cu are the most abundant elements,followed by Pb and Cr.Meanwhile,Hg,Cd,and As were found to have relatively low concentrations in the crops.The heavy metals in wheat and corn have the same geochemical characteristics in the gold belt in general.Compared to the aeolian loess soils and the crops therein,heavy metals are more enriched in diluvial and alluvial soils and the crops therein.As shown by relevant studies,the Hg,Pb,Cd,Cu,and Zn pollution are mainly caused by mining activities.Corn and wheat in the gold belt have a high tendency of risk exposure to heavy metal pollution since they are mostly affected by mining activities and feature high background values of heavy metal concentrations.Furthermore,wheat is more liable to be enriched in heavy metals than corn is grown in all types of soils.The Hg pollution in soils leads to Hg accumulation,increasing the risk of Hg uptake in crops,and further affecting human health.This study will provide a scientific basis for the control and management of heavy metals in farmland soils of mining areas.

Microplastic pollution in surface water and sediments of Qinghai-Tibet Plateau: Current status and causes

To study the current status and causes of the microplastic pollution in surface water of the Qinghai-Tibet Plateau,this paper compared the average microplastic abundance in sediments and surface water of the Qinghai-Tibet Plateau and the results are as follows.First,the average microplastic abundance in surface water of the independent rivers and the whole area is 247−2686 items/m^(3) and 856 items/m^(3),respectively.The average microplastic abundance in sediments of independent rivers or lakes and the whole area is 0−933 items/m^(2) and 362 items/m^(2),respectively.Meanwhile,the degree of microplastic pollution in river sediments is higher than that in lake sediments,and the rivers suffering from microplastic pollution mainly include the Brahmaputra River,Tongtian River,and Nujiang River.Second,compared with the microplastic pollution in other areas of the world,the levelof microplastic pollution in the lakes and rivers of the Qinghai-Tibet plateau is not lower than that of well-developed areas with more intensive human activities.Finally,this study suggests that relevant government departments of the Qinghai-Tibet Plateau should strengthen waste management strategies while developing tourism and that much attention should be paid to the impacts of microplastics in the water environment.

Microplastic pollution in Yellow River,China:Current status and research progress of biotoxicological effects

This study aims to comprehensively assess the environmental risks of microplastics in the Yellow River,achieving the following results through comprehensive research.The average microplastic abundances in the river waters and sediments are 5358-654000 n/m3 and 43.57-615 items/kg,respectively,and there are fewer microplastics in water samples than in sediments.Microplastics in the study area can be divided into five types according to their occurrence morphologies,namely fragments,foams,films,fibers,and particles.The most widely distributed pollution types in sediments include debris,fibers,and particles.In contrast,fibers are the dominant type in water samples,accounting for 68.18%‒98.93%.The chemical components of the microplastics include polyethylene,polypropylene,polystyrene,polyethylene terephthalate,and polyvinyl chloride.The microplastics are in four colors,with white accounting for a higher proportion.The grain size of the microplastics in tributaries or lakes of the Yellow River is less than 2 mm,which makes them liable to enter organisms for enrichment.Furthermore,the sources of the microplastics are closely related to agricultural and industrial production and biological activities in habitats and exhibit seasonal and hydrological characteristics.The microplastics in the study area show the adsorption of metals and nonmetals to different degrees,which increases the pollution risks of heavy metals combined with microplastics.In addition,microplastics can accumulate in organisms in the Yellow River and cause physical,biochemical,and other damage to aquatic organisms,thus further posing carcinogenic risks to human beings.Therefore,it is necessary to study,monitor,and control the pollution and effects of microplastics in the Yellow River,in order to provide theoretical references for the control of pollution and ecological risk of microplastics in the river.

Migration and speciation transformation mechanisms of mercury in undercurrent zones of the Tongguan gold mining area, Shaanxi Loess Plateau and impact on the environment

In order to study the migration and transformation mechanism of Hg content and occurrence form in subsurface flow zone of gold mining area in Loess Plateau and its influence on water environment,the field in-situ infiltration test and laboratory test were carried out in three typical sections of river-side loess,alluvial and proluvial strata in Tongguan gold mining area of Shaanxi Province,and the following results were obtained:(1)The source of Hg in subsurface flow zone is mainly caused by mineral processing activities;(2)the subsurface flow zone in the study area is in alkaline environment,and the residual state,iron and manganese oxidation state,strong organic state and humic acid state of mercury in loess are equally divided in dry and oxidizing environment;mercury in river alluvial or diluvial strata is mainly concentrated in silt,tailings and clayey silt soil layer,and mercury has certain stability,and the form of mercury in loess is easier to transform than the other two media;(3)under the flooding condition,most of mercury is trapped in the silt layer in the undercurrent zone where the sand and silt layers alternate with each other and the river water and groundwater are disjointed,and the migration capacity of mercury is far less than that of loess layer and alluvial layer with close hydraulic connection;(4)infiltration at the flood level accelerates the migration of pollutants to the ground;(5)the soil in the undercurrent zone is overloaded and has seriously exceeded the standard.Although the groundwater monitoring results are safe this time,relevant enterprises or departments should continue to pay attention to improving the gold extraction process,especially vigorously rectify the small workshops for illegal gold extraction and the substandard discharge of the three wastes,and intensify efforts to solve the geological environmental problems of mines left over from history.At present,the occurrence form of mercury in the undercurrent zone is relatively stable,but the water and soil layers have been polluted.The risk of disjointed groundwater pollution can not be ignored while giving priority to the treatment of loess and river alluvial landform areas with close hydraulic links.The research results will provide a scientific basis for water conservancy departments to groundwater prevention and control in water-deficient areas of the Loess Plateau.

Distribution, characteristics, and research status of microplastics in the trunk stream and main lakes of the Yangtze River: A review

Microplastic pollution has become an environmental issue of great concern owing to the persistence of microplastics and their potential adverse effects on biota.The Yangtze River is the longest river in China and the third-longest river in the world,and the microplastics in this river will affect the health of a large population living along with it.To ensure the survival safety of people,it is essential to plan ahead and investigate in advance in order to understand the microplastic pollution in the river and work out countermeasures.This paper reviews the literature concerning the microplastic pollution in the Yangtze River basin and analyzes the abundance,shapes,colors,and composition of microplastics in the water bodies and sediments in the trunk stream and main lakes of the Yangtze River.The results are as follows.Compared to other river basins in China and abroad,the microplastics in the Yangtze River basin have a moderate abundance and high spatial heterogeneity.Owing to the barrier effect of the Three Gorges Dam on microplastics,the abundance of microplastics in the Three Gorges Reservoir is generally an order of magnitude higher than that in other sections of the river.Most microplastics in the water bodies and sediments are less than 1 mm in size and are transparent and colorful.In terms of shapes,they are dominated by fibers,followed by fragments and films.In terms of composition,the microplastics in the source region of the Yangtze River are mainly composed of nylon and polyethylene,while the microplastics in the surface water from the lower reaches of the Jinsha River to the Yangtze River estuary are dominated by polypropylene and polyethylene.The microplastics are primarily derived from the secondary microplastics in the environment,and relatively intensive human activities increase the abundance of microplastics.These results serve as bases for understanding and preventing microplastic pollution in the Yangtze River.

Treatment of lower part of glenoid fractures through a novel axillary approach:A case report

BACKGROUND Based on the location and size of the fracture block,open reduction and internal fixation can be employed or assisted for shoulder arthroscopy in the treatment of glenoid fractures.However,the treatment of lower part of glenoid fractures through a novel axillary approach has not been reported so far.CASE SUMMARY A 22-year-old right-handed man was transferred to our outpatient clinic because of right shoulder injury during a traffic accident.X-ray examination after admission suggested the fracture of the lower part of the right glenoid and an ipiselial proximal humeral fracture.Three-dimensional(3D)computed tomography(CT)further suggested that the size of the fracture block of the lower part of the right glenoid was 3.4 mm×16.2 mm.The patient was diagnosed as the fracture of the lower part of the glenoid,also known as bony Bankart lesion without shoulder dislocation.After general anesthesia,the patient was surgically treated with the open reduction internal fixation through a novel axillary approach.3D CT and shoulder joint function were reexamined at 12 mo of followup,showing acceptable recovery.CONCLUSION This case report describes a novel axillary approach adopted in an open reduction with cannulated screw and wire anchor internal fixation.After a follow-up for more than 12 mo,3D CT and shoulder joint function examinations display a good recovery.

Current situation and human health risk assessment of fluoride enrichment in groundwater in the Loess Plateau:A case study of Dali County,Shaanxi Province,China

This study aims to investigate the mechanisms and health risks of fluoride enrichment in groundwater in the Loess Plateau,China.By taking Dali County,Shaanxi Province,China as an example,this study obtains the following results through field investigation and the analyses of water,soil,and crop samples.(1)The groundwater can be divided into two major types,namely the Quaternary pore-fissure water and Karst water.The Karst area and sandy area have high-quality groundwater and serve as the target areas for optional water supply.The groundwater in the study area is slightly alkaline and highly saline.Meanwhile,high-fluoride groundwater is mainly distributed in the loess and river alluvial plains in the depression area of the Guanzhong Basin and the discharge areas of the groundwater,with the highest fluoride concentration exceeding seven times the national standard.(2)Fluoride in groundwater mainly originates from a natural source and human activities.The natural source refers to the fluoride-bearing minerals in rocks and soil,and the fluoride from this source is mainly controlled by natural factors such as climate,geologic setting,pH,specific hydrochemical environment,ion exchange,and mineral saturation.Human activities in modern life can be further divided into industrial and agricultural sources primarily.(3)The health risks of fluoride contamination are very high in the Loess Plateau,especially for children compared to adults.Meanwhile,the risks of fluoride exposure through food intake are higher than those through drinking water intake.The authors suggest selecting target areas to improve water supply and ensure the safety of drinking water in the study area.Besides,it is necessary to plant crops with low fluoride content or cash crops and to conduct groundwater treatment to reduce the fluoride concentration in drinking water.These results will provide a theoretical basis for safe water supply in the faulted basin areas in the Loess Plateau.

Microplastic contamination in lacustrine sediments in the Qinghai-Tibet Plateau:Current status and transfer mechanisms

This paper aims to investigate the present situation and transfer mechanisms of microplastics in lacustrine sediments in the Qinghai-Tibet Plateau.The study surveyed the average abundance of microplastics in sediments.The abundance of microplastics in sediments of lakes from the Qinghai-Tibet Plateau is 17.22-2643.65 items/kg DW and 0-60.63 items/kg DW based on the data of the Qinghai Lake and the Siying Co Basin.The microplastic abundance in sediments from small and medium lakes is very high compared to that in other areas in the world.Like microplastics in other lakes of the world,those in the lakes in the Qinghai-Tibet Plateau mainly include organic polymers PA,PET,PE,and PP and are primarily in the shape of fibers and fragments.The microplastic pollution of lacustrine sediments in the Qinghai-Tibet Plateau is affected by natural changes and by human activities,and the concentration of microplastics in lacustrine ecosystems gradually increases through food chains.Furthermore,the paper suggests the relevant administrative departments of the Qinghai-Tibet Plateau strengthen waste management while developing tourism and pay much attention to the impacts of microplastics in water environments.This study provides a reference for preventing and controlling microplastic contamination in the Qinghai-Tibet Plateau.

Additive manufacturing of Cu-AI-Mn shape memory alloy with enhanced superelasticity

The Cu-based shape memory alloy(SMA)with highly oriented columnar crystals is an ideal candidate for the commercial application,especially the ones obtained through rapid cooling via additive manufacturing method.In this work,Cu_(71)Al_(18)Mn_(11)(at%)shape memory alloy with strong<001>texture columnar grains was successfully prepared by selective laser melting(SLM).An L27(313)orthogonal array was designed to systematically investigate the effects of laser power,scanning speed,scanning spacing,layer thickness and their interactions on the forming quality of Cu_(71)Al_(18)Mn_(11)alloys.Cu_(71)Al_(18)Mn_(11)alloys with density of 7.3204 g·cm^(-3)and relative density of 99.18%were successfully prepared when the laser power,scanning speed,scanning distance and layer thickness were 240 W,1000 mm·s^(-1),0.11 mm and 25μm,the transformation onset temperature(Ms),martensite phase transformation termination temperature(Mf),austenite phase transformation onset temperature(AS)and austenite phase transformation termination temperature(Af)are-21.84,-26.04,-15.75 and-12.36℃,respectively.The compression strength and fracture strain along the building direction(BD)were significantly superior to the scanning direction(SD),while the superelasticity of compression along the SD reached 2.50%,which was better than that of2.32%along BD.The mechanical property and superelasticity anisotropy due to the formation of columnar grains and texture were discussed.This study shows that SLM is a proposed method for the preparation of Cu-Al-Mn SMAs with high superelasticity,which provides a new strategy for enhancing the shape memory alloy superelasticity.

Arsenic and fluoride co-enrichment of groundwater in the loess areas and associated human health risks:A case study of Dali County in the Guanzhong Basin

This study aims to reveal the occurrence and origin of typical groundwater with high arsenic and fluoride concentrations in the loess area of the Guanzhong Basin—a Neogene faulted basin.Key findings are as follows:(1)Groundwater samples with high arsenic and fluoride concentrations collected from the loess area and the terraces of the Weihe River accounted for 26%and 30%,respectively,of the total samples,with primary hydrochemical type identified as HCO_3-Na.The karst and sand areas exhibit relatively high groundwater quality,serving as preferred sources for water supply.It is recommended that local governments fully harness groundwater in these areas;(2)groundwater with high arsenic and fluoride concentrations in the loess area and the alluvial plain of rivers in Dali County is primarily distributed within the Guanzhong Basin,which represents the drainage zone of groundwater;(3)arsenic and fluoride in groundwater originate principally from natural and anthropogenic sources;(4)the human health risk assessments reveal that long-term intake of groundwater with high arsenic and fluoride concentrations pose cancer or non-cancer risks,which are more serious to kids compared to adults.This study provides a theoretical basis for the prevention and treatment of groundwater with high arsenic and fluoride concentrations in loess areas.

Towards superior lithium-sulfur batteries with metal-organic frameworks and their derivatives

Lithium-sulfur batteries(LSBs)are one of the most promising energy storage devices in the future due to their high theoretical specific capacity(1675 mA·h·g^(-1))and energy density(2600 W·h·kg^(-1)).However,the severe capacity decay caused by the shuttle effect of polysulfides needs to be addressed before the practical application.Metal-organic frameworks(MOFs)and their derivatives are known for their large specific surface area,high porosity,abundant functional groups,and good chemical stability.Thus,they have been widely investigated in LSBs.This review introduces the principles of the LSBs and origination of the shuttle effect first summarizes various methods of limiting polysulfide diffusion by MOFs and their derivatives both in cathodes and separators,and provides an in-depth discussion of the immobilization mechanisms,which helps to understand the advantages and disadvantages of each method.The mechanisms,such as structure and pore size tuning,chemical absorption,and catalytic conversion,are discussed.Finally,based on the method of MOFs and their derivatives to inhibit the diffusion of polysulfides,the application prospect of MOFs and their derivatives in LSBs technology are proposed.

3D porous PTFE membrane filled with PEO-based electrolyte for all solid-state lithium-sulfur batteries

Owing to the low cost and high theoretical energy density,lithium-sulfur battery has become one of the most promising energy storage battery systems.However,the inherent cycle instability and safety problems of traditional liquid lithium-sulfur batteries greatly limit their commercial applications.In this work,polytetrafluoroethylene(PTFE)membrane was introduced into Li_(7)La_(3)Zr_(2)O_(12)(LLZO)@poly(ethylene oxide)(PEO)-based composite electrolyte as a supporting framework to prepare a new PTFE@LLZO@PEO composite electrolyte for lithium-sulfur battery.The introduction of PTFE membrane further improved the mechanical properties and thermal stability of the electrolyte.The ionic conductivity of the prepared PTFE@LLZO@PEO solid electrolyte was5.03×10^(-5)S·cm^(-1)at 30℃and 2.54×10^(-4)S·cm^(-1)at60℃.Moreover,the symmetric battery exhibited high cycle stability(300 h).The Li-S battery based on PTFE@LLZO@PEO electrolyte exhibited excellent electrochemical performance.

Solvothermal growth of Zn_(2)SnO_(4) for efficient dye-sensitized solar cells

Zn_(2)SnO_(4)plates,particles and spheres are suc-cessfully prepared via a facile synthesis way by carefully adjusting the solvothermal conditions,which are further applied as photoanodes in dye-sensitized solar cells(DSSCs)to explore the relationships between the pho-toanode nanostructure and the photovoltaic performances.As a result,the DSSCs based on Zn_(2)SnO_(4)spheres pho-toanode showcased the best power conversion efficiency(PCE,4.85%),compared to Zn_(2)SnO_(4)plates(3.80%)and particles(4.13%).It is found that Zn_(2)SnO_(4)spheres exhibit the highest light-scattering abilities,as evidenced by ultraviolet–visible(UV–Vis)diffuse reflectance spectra.Additionally,investigations on dynamic electron transport and recombination properties via intensity-modulated photovoltage/photocurrent spectroscopy(IMVS/IMPS),and electrochemical impedance spectroscopy(EIS)mea-surements demonstrate that the Zn_(2)SnO_(4)spheres-based DSSCs possess the fastest electron transport rate,the longest electron lifetime,the highest electron collection efficiency(ηc c),and the largest charge recombination resistance,compared with the Zn_(2)SnO_(4)plates and particles,all of which are highly beneficial for the powder conversion efficiency enhancements.