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Gravity-Driven Listric Growth Fault and Sedimentation in the Lagoa do Peixe, Rio Grande do Sul Coastal Plain, Brazil
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作者 Bruno Silva da Fontoura Adelir José Strieder +1 位作者 Iran Carlos Stalliviere Corrêa Paulo Rogério Mendes 《Open Journal of Geology》 CAS 2024年第4期594-616,共23页
High frequency, high resolution GPR surveys are successfully applied to investigate near-surface stratification architecture of sedimentary units in coastal plains and to define their depositional conditions. However,... High frequency, high resolution GPR surveys are successfully applied to investigate near-surface stratification architecture of sedimentary units in coastal plains and to define their depositional conditions. However, low frequency GPR surveys to investigate fault-related depositional systems at greater depths are scarce. This survey was designed investigate a > 100 km long linear escarpment that controls the northwest margin of the Lagoa do Peixe, an important lagoon in Rio Grande do Sul Coastal Plain (RGSCP, Brazil). The traditional approach points that RGSCP was developed by juxtaposition of four lagoons/barrier systems as consequence of sea level changes;no deformational structure is admitted to exist before. The low frequency GPR (50 MHz, RTA antenna) and geological surveys carried out in the RGSCP showed the existence of a large, gravity-driven listric growth fault controlling the Lagoa do Peixe escarpment and hangingwall sedimentation. The radargrams in four subareas along the Lagoa do Peixe Growth Fault could be interpreted following the seismic expression of rift-related depositional systems. The radargrams enabled to distinguish three main lagoonal deposition radarfacies. The lower lagoonal radarfacies is a convex upward unit, thicker close to growth fault;the radarfacies geometry indicates that fault displacement rate surpasses the sedimentation rate, and its upper stratum is aged ~3500 <sup>l4</sup>C years BP. The second lagoonal radarfacies is a triangular wedge restricted to the lagoon depocenter, whose geometry indicates that fault displacement and the sedimentation rates kept pace. The upper lagoonal radarfacies is being deposited since 1060 ± 70 <sup>l4</sup>C years BP, under sedimentation rate higher than fault displacement rate. The results indicate that low frequency GPR surveys can help in investigating fault-related depositional systems in coastal zones. They also point to a new approach in dealing with RGSCP stratigraphy. 展开更多
关键词 GPR (Ground-Penetrating Radar) Growth Fault sedimentation Radarfacies Coastal Plain
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Volume-averaged modeling of multiphase solidification with equiaxed crystal sedimentation in a steel ingot
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作者 Xiao-lei Zhu Shuang Cao +5 位作者 Rui Guan Ji Yang Zhe Ning Xin-gang Ai Sheng-li Li Xin-cheng Miao 《China Foundry》 SCIE EI CAS CSCD 2024年第3期229-238,共10页
Macrosegregation is a critical factor that limits the mechanical properties of materials.The impact of equiaxed crystal sedimentation on macrosegregation has been extensively studied,as it plays a significant role in ... Macrosegregation is a critical factor that limits the mechanical properties of materials.The impact of equiaxed crystal sedimentation on macrosegregation has been extensively studied,as it plays a significant role in determining the distribution of alloying elements and impurities within a material.To improve macrosegregation in steel connecting shafts,a multiphase solidification model that couples melt flow,heat transfer,microstructure evolution,and solute transport was established based on the volume-averaged Eulerian-Eulerian approach.In this model,the effects of liquid phase,equiaxed crystals,columnar dendrites,and columnar-to-equiaxed transition(CET)during solidification and evolution of microstructure can be considered simultaneously.The sedimentation of equiaxed crystals contributes to negative macrosegregation,where regions between columnar dendrites and equiaxed crystals undergo significant A-type positive macrosegregation due to the CET.Additionally,noticeable positive macrosegregation occurs in the area of final solidification in the ingot.The improvement in macrosegregation is beneficial for enhancing the mechanical properties of connecting shafts.To mitigate the thermal convection of molten steel resulting from excessive superheating,reducing the superheating during casting without employing external fields or altering the design of the ingot mold is indeed an effective approach to control macrosegregation. 展开更多
关键词 ingot casting multiphase solidification model equiaxed crystal sedimentation microstructure MACROSEGREGATION
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Numerical simulation on sand sedimentation and erosion characteristics around HDPE sheet sand barrier under different wind angles
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作者 ZHANG Kai ZHANG Peili +3 位作者 ZHANG Hailong TIAN Jianjin WANG Zhenghui XIAO Jianhua 《Journal of Mountain Science》 SCIE CSCD 2024年第2期538-554,共17页
For the safety of railroad operations,sand barriers are utilized to mitigate wind-sand disaster effects.These disasters,characterized by multi-directional wind patterns,result in diverse angles among the barriers.In t... For the safety of railroad operations,sand barriers are utilized to mitigate wind-sand disaster effects.These disasters,characterized by multi-directional wind patterns,result in diverse angles among the barriers.In this study,using numerical simulations,we examined the behavior of High Density Polyethylene(HDPE)sheet sand barriers under different wind angles,focusing on flow field distribution,windproof efficiency,and sedimentation erosion dynamics.This study discovered that at a steady wind speed,airflow velocity varies as the angle between the airflow and the HDPE barrier changes.Specifically,a 90°angle results in the widest low-speed airflow area on the barrier’s downwind side.If the airflow is not perpendicular to the barrier,it prompts a lateral airflow movement which decreases as the angle expands.The windproof efficiency correlates directly with this angle but inversely with the wind’s speed.Notably,with a wind angle of 90°,wind speed drops by 81%.The minimum wind speed is found at 5.1H(the sand barrier height)on the barrier’s downwind side.As the angle grows,the barrier’s windproof efficiency improves,extending its protective reach.Sedimentation is most prominent on the barrier’s downwind side,as the wind angle shifts from 30°to 90°,the sand sedimentation area on the barrier’s downwind side enlarges by 14.8H.As the angle grows,sedimentation intensifies,eventually overtakes the forward erosion and enlarges the sedimentation area. 展开更多
关键词 Multi-wind direction HDPE sheet sand barrier Numerical simulation Windproof efficiency sedimentation erosion
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Investigation of the Clinical Diagnostic Significance of the T-Cell Test for Tuberculosis combined with Erythrocyte Sedimentation Test in Pulmonary Tuberculosis
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作者 Jialong Wang 《Journal of Clinical and Nursing Research》 2024年第3期55-60,共6页
Objective:To investigate the clinical diagnostic significance of peripheral blood T-cell test(T-spot test)for tuberculosis(TB)infection combined with erythrocyte sedimentation rate(ESR)in pulmonary TB.Methods:41 patie... Objective:To investigate the clinical diagnostic significance of peripheral blood T-cell test(T-spot test)for tuberculosis(TB)infection combined with erythrocyte sedimentation rate(ESR)in pulmonary TB.Methods:41 patients with a clinical diagnosis of TB during hospitalization from January 2020 to April 2023 in our hospital were selected as the experimental group,and 45 patients without TB(bronchopneumonia patients)were selected as the control group.The diagnostic specificity,sensitivity,and accuracy of the T-spot TB test,ESR test,and the combined test of the two were calculated respectively.Results:The sensitivity,specificity,and accuracy of the T-spot TB test combined with ESR for the diagnosis of TB in the experimental group were significantly higher than the individual results of the T-spot TB test and ESR test alone(P<0.05).Conclusion:The T-spot TB test combined with the ESR test for TB diagnosis has greater clinical value than carrying out the tests individually. 展开更多
关键词 Peripheral blood tuberculosis infection T-cell spot test Erythrocyte sedimentation rate test TUBERCULOSIS Clinical diagnosis
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A new formula of recovery factor for non-equilibrium transport of graded suspended sediment in the Middle Yangtze River 被引量:1
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作者 LI Lin-lin XIA Jun-qiang +2 位作者 ZHOU Mei-rong DENG Shan-shan LI Zhi-wei 《Journal of Mountain Science》 SCIE CSCD 2023年第1期87-100,共14页
Suspended sediment concentrations in the Middle Yangtze River(MYR)reduced greatly after the Three Gorges Project operation,causing the composition of bed material to coarsen continuously.However,little is known about ... Suspended sediment concentrations in the Middle Yangtze River(MYR)reduced greatly after the Three Gorges Project operation,causing the composition of bed material to coarsen continuously.However,little is known about the non-equilibrium transport of graded suspended sediment owing to different bed material compositions(BMCs)along the MYR,and it is necessary to determine the magnitude of recovery factor.Using the Markov stochastic process in conjunction with the hiding-exposure effect of non-uniform bed-material,a new formula is proposed for calculating the recovery factor including the effect of different BMCs,and it is incorporated into the non-equilibrium transport equation to simulate the recovery processes of suspended load in both sand-gravel bed and sand bed reaches of the MYR.The results show that:(i)the recovery rate of graded sediment concentrations at Zhicheng was slower than that at Shashi during the period 2003-2007;(ii)the mean recovery factors of the coarse,medium,and fine sediment fractions in the ZhichengShashi reach were 0.152,0.0012,and 0.0005,respectively,and the coarse sediment recovered up to the maximum sediment concentration of 0.138 kg/m3over a distance of 15 km;and(iii)the results of the new formula that can consider the effect of bed material composition are in general agreement with the field observations,and the spatial and temporal delay effects are inversely related to particle size and BMC.Consequently,the BMC effect on the nonequilibrium sediment transport in different reaches of the MYR needs to be considered for higher simulation accuracy. 展开更多
关键词 non-equilibrium sediment transport bed material composition transition probability recovery factor Middle Yangtze River
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Effects of sand sedimentation and wind erosion around sand barrier:Numerical simulation and wind tunnel test studies 被引量:4
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作者 ZHANG Kai ZHANG Hai-long +3 位作者 DENG Yu-hui QU Jian-jun WANG Zheng-hui LI Sheng 《Journal of Mountain Science》 SCIE CSCD 2023年第4期962-978,共17页
Based on numerical simulations,this study highlights the sedimentation and erosion problems around a sand barrier through the relationship between the shear stress of the surface around the sand barrier and the critic... Based on numerical simulations,this study highlights the sedimentation and erosion problems around a sand barrier through the relationship between the shear stress of the surface around the sand barrier and the critical shear stress of sand grains.The numerical simulation results were verified using data measured by the wind tunnel test.The results showed that when the porosity was the same,the size and position of the vortex on the leeward side of the sand barrier were related to the inlet wind speed.As the wind speed increased,the vortex volume increased and the positions of the separation and reattachment points moved toward the leeward side.When the porosity of the sand barrier was 30%,the strength of the acceleration zone above the sand barrier was the highest,and the strength of the acceleration zone was negatively correlated with the porosity.Sand erosion and sedimentation distance were related to wind speed.With an increase in wind speed,the sand grain forward erosion or reverse erosion areas on the leeward side of the sand barrier gradually replaced the sedimentation area.With an increase in porosity,the sand sedimentation distance on the leeward side of the sand barrier gradually shortened,and the sand erosion area gradually disappeared.The sand sedimentation distance on the leeward side of the sand barrier with 30%porosity was the longest.The numerical simulation results were in good agreement with the wind tunnel test results.Based on the sand erosion and sedimentation results of the numerical simulation and wind tunnel test,when the porosity was 30%,the protection effect of the High Density Polyethylene(HDPE)board sand barrier was best. 展开更多
关键词 Sand sedimentation Wind erosion Numerical simulation Wind tunnel test
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Provenance and depositional setting of the Late MiocenePleistocene clastic sediments in the eastern Arabian Peninsula and western Iraq using rare earth elements geochemistry 被引量:1
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作者 Salih M.Awadh Zinah S.Al-Ankaz +1 位作者 Mohanad R.A.Al-Owaidi John S.Armstrong-Altrin 《Acta Geochimica》 EI CAS CSCD 2024年第2期399-410,共12页
The sandstones of the Late miocene–Pliocene Dibdibba Formation in the Najaf–Karbala Plateau and Basra were examined to determine their source rocks and origin. The rare earth elements(REE) and trace elements(Sc, Co,... The sandstones of the Late miocene–Pliocene Dibdibba Formation in the Najaf–Karbala Plateau and Basra were examined to determine their source rocks and origin. The rare earth elements(REE) and trace elements(Sc, Co, V, and Th) concentrations in these sandstones revealed that they likely derived from a single source. The steep light rare earth elements(LREE) and flat, heavy rare earth element(HREE) patterns, negative Eu anomaly, and high ΣREE contents in sandstones suggest its derivation from a suggests that a passive continental margin environment and originated from felsic source rocks. The average concentration of ΣREE is 93.5 ppm, which is lower than that of the average crustal compositions like Upper Continental Crust and Post Archean Australian Shale. The higher proportion of LREE compared to HREE implies that these sandstones were recycled and derived from a distal source. The Th/Co, Th/Sc, La/Sc, La/Co, Eu/Eu*and(La/Lu)cn elemental ratios indicated that these Late Miocene–Pliocene sandstones were derived from felsic rocks located in the marginal region of the Arabian Shield. 展开更多
关键词 REE Dibdibba formation Clastic sediments Passive continental margin
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Removal Effect of Coagulating Sedimentation Method on Polyethylene Microplastics in Water
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作者 Shasha LIU Qiongru ZHUANG +3 位作者 Hongji HUANG Xiaodan LIN Yue YANG Jinghua WU 《Asian Agricultural Research》 2023年第9期31-33,43,共4页
Microplastic is a new kind of pollutant.It exists widely in the aquatic environment and seriously endangers the aquatic ecosystem.In this study,the coagulating sedimentation method was used to remove microplastics in ... Microplastic is a new kind of pollutant.It exists widely in the aquatic environment and seriously endangers the aquatic ecosystem.In this study,the coagulating sedimentation method was used to remove microplastics in water.Polyethylene(PE)was selected as the representative of microplastics,polyferric sulfate(PFS),polyaluminum chloride(PAC)and aluminum sulfate(AS)were used as coagulant,and polyacrylamide(PAM)was used as coagulant aid to study the effects of pH,coagulant concentration and sedimentation time on the removal of PE by single and composite coagulant.The results showed that when the dosage of PFS was 0.5 g/L and pH was 5.0,the removal rate could reach 82.14%,which was better than PAC and AS,indicating that PFS had better coagulation and sedimentation performance for PE;the composite coagulant of PFS+PAC+AS(1 g/L+0.2 g/L+0.2 g/L,pH was 5.0)had the highest removal rate of PE,reaching 96.06%;the removal rate of PE increased with the increase in sedimentation time,but considering that the longer sedimentation time has less contribution to the improvement of removal rate,it is recommended that 4 h is appropriate. 展开更多
关键词 Microplastics Coagulating sedimentation Polyethylene(PE) REMOVAL
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The control of astronomical cycles on lacustrine fine-grained event Sedimentation——A case study of the Chunshang sub-member of the upper Es_(4) in the Dongying Sag
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作者 Tian-Yu Xu Jun Peng +4 位作者 Le-Dan Yu Hao-Dong Han Yi-Ming Yang Yao Zeng Yu-Bin Wang 《Petroleum Science》 SCIE EI CAS CSCD 2023年第3期1395-1410,共16页
Fine-grained lacustrine sedimentation controlled by astronomical cycles remains a research weakness in sedimentology studies,as most studies have concentrated on how astronomical cycles affect the normal lacustrine fi... Fine-grained lacustrine sedimentation controlled by astronomical cycles remains a research weakness in sedimentology studies,as most studies have concentrated on how astronomical cycles affect the normal lacustrine fine-grained sedimentation,but how they affect the lacustrine fine-grained event sedimen-tation has been rarely studied.Therefore,this work researched the characteristics of event sedimentation by systematically observing the cores from 30 cored wells in the Shahejie Formation of the Dongying Sag at a depth of over 1800 m,with more than 4000 thin sections being authenticated and over 1000 whole rocks being analyzed by X-ray diffraction(XRD).The research object was the Chunshang Sub-member of Upper Es_(4) in the Fanye 1 well,as it had the most comprehensive analysis data and underwent the most continuous coring.We divided astronomical cycles into different orders and made corresponding curves using the gamma-ray(GR)curve,spectral analysis,power spectrum estimation,and module extreme values,there were 6 long eccentricity periods,22 short eccentricity periods,65.5 obliquity cycles,and 110.5 precession cycles in this sub-member.On this basis,this study analyzed the control of astronomical cycles on the lacustrine fine-grained event sedimentation,and the research shows deposits were developed by slide-slump,turbidities,hyperpycnites,and tempestites in the Chunshang Sub-member of the Upper Es_(4),with higher long eccentricity,the monsoon climate contributes to the formation of storm currents,while with lower long eccentricity,the surface deposits are severely eroded by rivers and rainfalls,thus developing the slide-slump,turbidities,and hyperpycnites.The relationship between the lacustrine fine-grained event sedimentation and astronomical cycles was studied in this case study,which can promote research on fine-grained sedimentary rocks in genetic dynamics and boost the theoretical and disciplinary development in fine-grained sedimentology. 展开更多
关键词 Astronomical cycle Fine-grained event sedimentation Long eccentricity Chunshang sub-member of the upper Es_(4) Dongying Sag
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Cycles of fine-grained sedimentation and their influences on organic matter distribution in the second member of Paleogene Kongdian Formation in Cangdong Sag,Bohai Bay Basin,East China
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作者 ZHAO Xianzheng PU Xiugang +10 位作者 YAN Jihua JIN Fengming SHI Zhannan CHAI Gongquan HAN Wenzhong LIU Yan JIANG Wenya CHEN Changwei ZHANG Wei FANG Zheng XIE Delu 《Petroleum Exploration and Development》 SCIE 2023年第3期534-546,共13页
According to the theory of sequence stratigraphy based on continental transgressive-regressive(T-R)cycles,a 500 m continuous core taken from the second member of Kongdian Formation(Kong 2 Member)of Paleogene in Well G... According to the theory of sequence stratigraphy based on continental transgressive-regressive(T-R)cycles,a 500 m continuous core taken from the second member of Kongdian Formation(Kong 2 Member)of Paleogene in Well G108-8 in the Cangdong Sag,Bohai Bay Basin,was tested and analyzed to clarify the high-frequency cycles of deep-water fine-grained sedimentary rocks in lacustrine basins.A logging vectorgraph in red pattern was plotted,and then a sequence stratigraphic framework with five-order high-frequency cycles was formed for the fine-grained sedimentary rocks in the Kong 2 Member.The high-frequency cycles of fine-grained sedimentary rocks were characterized by using different methods and at different scales.It is found that the fifth-order T cycles record a high content of terrigenous clastic minerals,a low paleosalinity,a relatively humid paleoclimate and a high density of laminae,while the fifth-order R cycles display a high content of carbonate minerals,a high paleosalinity,a dry paleoclimate and a low density of laminae.The changes in high-frequency cycles controlled the abundance and type of organic matter.The T cycles exhibit relatively high TOC and abundant endogenous organic matters in water in addition to terrigenous organic matters,implying a high primary productivity of lake for the generation and enrichment of shale oil. 展开更多
关键词 fine-grained sediment high-frequency cycle lamina density organic matter Paleogene Kong 2 Member Cangdong Sag Bohai Bay Basin
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Effect of Co on Solidification Characteristics and Microstructural Transformation of Non-equilibrium Solidified Cu-Ni Alloys
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作者 安红恩 Bih-Lii Chua +1 位作者 Ismail Saad Willey Yun Hsien Liew 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第2期444-453,共10页
Non-equilibrium solidification structures of Cu55Ni45 and Cu55Ni43Co2 alloys were prepared by the molten glass purification cycle superheating method.The variation of the recalescence phenomenon with the degree of und... Non-equilibrium solidification structures of Cu55Ni45 and Cu55Ni43Co2 alloys were prepared by the molten glass purification cycle superheating method.The variation of the recalescence phenomenon with the degree of undercooling in the rapid solidification process was investigated using an infrared thermometer.The addition of the Co element affected the evolution of the recalescence phenomenon in Cu-Ni alloys.The images of the solid-liquid interface migration during the rapid solidification of supercooled melts were captured by using a high-speed camera.The solidification rate of Cu-Ni alloys,with the addition of Co elements,was explored.Finally,the grain refinement structure with low supercooling was characterised using electron backscatter diffraction(EBSD).The effect of Co on the microstructural evolution during nonequilibrium solidification of Cu-Ni alloys under conditions of small supercooling is investigated by comparing the microstructures of Cu55Ni45 and Cu55Ni43Co2 alloys.The experimental results show that the addition of a small amount of Co weakens the recalescence behaviour of the Cu55Ni45 alloy and significantly reduces the thermal strain in the rapid solidification phase.In the rapid solidification phase,the thermal strain is greatly reduced,and there is a significant increase in the characteristic undercooling degree.Furthermore,the addition of Co and the reduction of Cu not only result in a lower solidification rate of the alloy,but also contribute to the homogenisation of the grain size. 展开更多
关键词 non-equilibrium solidification recalescence effect solidification character microstructure
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Preparation of Laser Cladding Coating Undercooling Cu-based Alloy and Co on Non-equilibrium Solidification Structure
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作者 田徐铭 CAO Shichao +3 位作者 HOU Kai HOU Xiaopeng WANG Hongfu 张煜 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第2期463-472,共10页
The effect of the gradient content of Co element on the solidification process of Cu-based alloy under deep under cooling conditions was explored.The non-equilibrium solidification structure of the under cooled alloy ... The effect of the gradient content of Co element on the solidification process of Cu-based alloy under deep under cooling conditions was explored.The non-equilibrium solidification structure of the under cooled alloy samples were analyzed.It is found that the rapidly solidified alloy has undergone twice grain refinement during the undercooling process.Characterization and significance of the maximum undercooling refinement structure of Cu60Ni35Co5 at T=253 K were analyzed.High-density defects were observed,such as dislocations,stacking faults networks,and twinning structures.The standard FCC diffraction pattern represents that it is still a single-phase structure.Based on the metallographic diagram,EBSD and TEM data analysis,it is illustrated that the occurrence of grain refinement under high undercooling is due to stress induced recrystallization.In addition,the laser cladding technology is used to coat Co-based alloy(Stellite12) coating on 304 stainless steel substrate;the microstructure of the coating cross-section was analyzed.It was found that the microstructure of the cross-section is presented as columnar crystals,planar crystals,and disordered growth direction,so that the coating has better hardness and wear resistance.By electrochemical corrosion of the substrate and coating,it can be seen that the Co and Cr elements present in the coating are more likely to form a dense passivation film,which improved the corrosion resistance of the coating. 展开更多
关键词 non-equilibrium solidification structure UNDERCOOLING RECRYSTALLIZATION laser cladding coating
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An analytical transient coal permeability model:Sorption non-equilibrium index-based swelling switch
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作者 Xingxing Liu Jishan Liu +2 位作者 Liang Chen Jinchang Sheng Huimin Wang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第4期1175-1191,共17页
Long-term permeability experiments have indicated that sorption-induced swelling can switch from internal to bulk depending on the evolutive sorption status.However,this sorption swelling switch mechanism has not been... Long-term permeability experiments have indicated that sorption-induced swelling can switch from internal to bulk depending on the evolutive sorption status.However,this sorption swelling switch mechanism has not been considered in current analytical permeability models.This study introduces a normalized sorption non-equilibrium index(SNEI)to characterize the sorption status,quantify the dynamical variations of matrix swelling accumulation and internal swelling partition,and formulate the sorption swelling switch model.The incorporation of this index into the extended total effective stress concept leads to an analytical transient coal permeability model.Model results show that the sorption swelling switch itself results in the permeability switch under stress-constrained conditions,while the confined bulk swelling suppresses the permeability recovery to the continuous reduction under displacement-constrained conditions.Model verifications show that current experimental observations correspond to the early stages of the transient process,and they could be extended to the whole process with these models.This study demonstrates the importance of the sorption swelling switch in determining permeability evolution using simple boundary conditions.It provides new insights into experimentally revealing the sorption swelling switch in the future,and underscores the requirement of a rigorous model for complex coupled processes in large-scale coal seams. 展开更多
关键词 Coal permeability Sorption swelling switch Sorption non-equilibrium Boundary conditions
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MXene Sediment-Based Poly(vinyl alcohol)/Sodium Alginate Aerogel Evaporator with Vertically Aligned Channels for Highly Efficient Solar Steam Generation
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作者 Tian Wang Meng Li +12 位作者 Hongxing Xu Xiao Wang Mingshu Jia Xianguang Hou Shuai Gao Qingman Liu Qihang Yang Mingwei Tian Lijun Qu Zhenhua Song Xiaohu Wu Lili Wang Xiansheng Zhang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第10期638-654,共17页
Solar-driven interfacial evaporation from seawater is considered an effective way to alleviate the emerging freshwater crisis because of its green and environmentally friendly characteristics.However,developing an eva... Solar-driven interfacial evaporation from seawater is considered an effective way to alleviate the emerging freshwater crisis because of its green and environmentally friendly characteristics.However,developing an evaporator with high efficiency,stability,and salt resistance remains a key challenge.MXene,with an internal photothermal conversion efficiency of 100%,has received tremendous research interest as a photothermal material.However,the process to prepare the MXene with monolayer is inefficient and generates a large amount of“waste”MXene sediments(MS).Here,MXene sediments is selected as the photothermal material,and a three-dimensional MXene sediments/poly(vinyl alcohol)/sodium alginate aerogel evaporator with vertically aligned pores by directional freezing method is innovatively designed.The vertical porous structure enables the evaporator to improve water transport,light capture,and high evaporation rate.Cotton swabs and polypropylene are used as the water channel and support,respectively,thus fabricating a self-floating evaporator.The evaporator exhibits an evaporation rate of 3.6 kg m^(-2)h^(-1)under one-sun illumination,and 18.37 kg m^(-2)of freshwater is collected in the condensation collection device after 7 h of outdoor sun irradiation.The evaporator also displays excellent oil and salt resistance.This research fully utilizes“waste”MS,enabling a self-floating evaporation device for freshwater collection. 展开更多
关键词 MXene sediments Porous structure DESALINATION Self-floating
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Microplastics in sediment of the Three Gorges Reservoir:abundance and characteristics under different environmental conditions
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作者 Wang LI Bo ZU +2 位作者 Yiwei LIU Juncheng GUO Jiawen LI 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第1期101-112,共12页
Freshwater microplastic pollution is an urgent issue of global concern,and research on the distribution in reservoirs is lacking.We investigated the microplastic pollution levels in wet sediments collected from the Th... Freshwater microplastic pollution is an urgent issue of global concern,and research on the distribution in reservoirs is lacking.We investigated the microplastic pollution levels in wet sediments collected from the Three Gorges Reservoir,the largest reservoir of China.Results show that microplastics were ubiquitous in the sediments of the Three Gorges Reservoir,and their abundance ranged from 59 to 276 pp/kg(plastic particles per kg,dry weight).Economic development and total population were important factors affecting the spatial heterogeneity of microplastic abundance,and the contribution of large cities along the reservoir to microplastic pollution should be paid with more attention.Fibrous microplastics were the most abundant type of microplastic particles in reservoir sediments,whereas polystyrene,polypropylene,and polyamide were the main types of polymers.The apparent spatial heterogeneity in morphology and color of microplastics is attributed to different anthropogenic or landbased pollution sources.Moreover,the accumulation of microplastics near the inlet of tributaries reflects the role of potential contributors of tributaries.More importantly,multiple bisphenols(BPs)and heavy metals detected at the microplastic surfaces indicate that microplastics can act as carriers of these pollutants in the environment in the same way as sediments did,which may alter the environmental fate and toxicity of these pollutants.Therefore,we conclude that the Three Gorges Reservoir had been contaminated with microplastics,which posed a stress risk for organisms who ingest them along with their associated pollutants(BPs,heavy metals). 展开更多
关键词 microplastics Three Gorges Reservoir sediment BISPHENOL heavy metal
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Microplastic and Heavy Metals Distributions in Urban Rivers Sediments,China
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作者 SONG Dandan SHANG Yujun +4 位作者 WANG Xiuli ZHUANG Yuwei GUO Hui BI Shuping HU Jianjun 《Journal of Ocean University of China》 SCIE CAS CSCD 2024年第4期1015-1025,共11页
This study investigated the distribution of microplastics and heavy metals,along with the interaction between the two in the sediments of urban rivers in China.Results showed that the abundance of microplastics ranged... This study investigated the distribution of microplastics and heavy metals,along with the interaction between the two in the sediments of urban rivers in China.Results showed that the abundance of microplastics ranged from 2412±187.5 to 7638±1312items kg^(-1)dry sediment across different survey stations,with an average abundance at(4388±713)items kg^(-1)dry sediment.Upon further categorization,it was found that transparent fragments were the primary color and type of microplastics present.The potential ecological risk index(RI)of heavy metals in sediments suggested a low level of ecological risk within a majority of the urban rivers studied.Cd was identified as the main potential ecological risk factor in the sediments of the studied areas.There was a relatively good significant linear relationship between the RI of heavy metals and the abundance of microplastics,bolstering the linkage between these two environmental pollutants.However,the concentrations of heavy metals in microplastics were not dependent on their corresponding contents in sediments.In fact,the concentration of Cu,Cd,and As in microplastics were higher than those in the sediments.This finding confirmed that microplastics could serve as carriers of heavy metals and introduce potential risks to aquatic wildlife and human through the food chain. 展开更多
关键词 microplastic heavy metals risk assessment river sediments
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Effects of Different Cations on the Flocculation and Sedimentation of Static Fine-Grained
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作者 Xiaomin Liu Yaotian Yang +2 位作者 Rui Wang Wenjuan Wang Qiang Luo 《Journal of Environmental & Earth Sciences》 2023年第2期1-14,共14页
Natural water bodies mostly contain cations,and the type and content of these cations are the main factors affecting the flocculation of fine-grained cohesive sediments and the floc sedimentation rate at the interface... Natural water bodies mostly contain cations,and the type and content of these cations are the main factors affecting the flocculation of fine-grained cohesive sediments and the floc sedimentation rate at the interface between clear and turbid water.From the microscopic aspect,this study examined the changing patterns of porosity and the fractal dimension of the flocs of fine-grained cohesive sediments.Sedimentation experiments under different sediment contents and electrolyte conditions were conducted,and microscopic images of the flocs were analysed using Image-Pro Plus(IPP)and MATLAB based on the fractal theory.From the macroscopic aspect,this study experimentally investigated the flocculation and sedimentation of fine-grained cohesive sediments and proposed a sedimentation rate equation by introducing an ion concentration-related parameter into an existing sedimentation rate equation(stagnation zone)based on the adsorption isotherm equation.The equation proposed in this study was validated with measured data.The calculated values were in good agreement with the measured values,with a relative error of 16%.The findings of this study provide a reference for further research on the flocculation and sedimentation of fine-grained cohesive sediments in different water bodies. 展开更多
关键词 FLOCS ELECTROLYTE Fractal dimension POROSITY sedimentation rate
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Tracing suspended and bed sediments during high and low water periods using geochemical characteristics-Case study:Vazrood watershed,northern Iran
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作者 KARIMI Nabiyeh GHOLAMI Leila +1 位作者 KAVIAN Ataollah KHALEDI DARVISHAN Abdulvahed 《Journal of Mountain Science》 SCIE CSCD 2024年第2期470-483,共14页
Complete and comprehensive information about sediment dynamic and identification of hotspots of sediment production and transport are necessary for understanding the erosion processes and increasing the efficiency of ... Complete and comprehensive information about sediment dynamic and identification of hotspots of sediment production and transport are necessary for understanding the erosion processes and increasing the efficiency of soil and water conservation practices.Numerous studies used the sediment fingerprint techniques to investigate the contribution of different sources in suspended and bed sediment yield of the watersheds.However,the contribution of various land use/land covers in suspended and bed sediment yield for the great Caspian Sea basin is in an aura of ambiguity and the present study was conducted to gather information about an important part of this area in northern Iran,where rangelands are located upstream of Hyrcanian forests and dense agricultural lands are located downstream.The surface soil of different land use/land covers including forest,rangeland,agriculture and streambank lands were sampled in 30 points.Suspended and bed sediments were sampled in the watershed outlet in two high and low water periods.Geochemical characteristics of soil and sediment samples containing 59 elements were measured using ICP-OES GBC Integra.The reliable and suitable tracers from 59 elements were then selected using Range test,Kruskal-Wallis and Discriminant Function Analysis,respectively,in FingerPro package of R software.The results showed that for suspended sediment,streambank and rangeland had the highest contributions of 86.2%and 47.5%,respectively,in two high and low water periods.For bed sediment,in two high and low water periods,rangeland and streambank had the highest contributions of 73.8%and 84.4%,respectively.Land use change and especially human activities such as agriculture,road construction and development of residential areas along the main river riparian zone has led to a significant increase in suspended and bed sediments. 展开更多
关键词 Caspian Sea basin FingerPro GEOCHEMISTRY sediment transport Tracer combination
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Radiative heat transfer analysis of a concave porous fin under the local thermal non-equilibrium condition:application of the clique polynomial method and physics-informed neural networks
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作者 K.CHANDAN K.KARTHIK +3 位作者 K.V.NAGARAJA B.C.PRASANNAKUMARA R.S.VARUN KUMAR T.MUHAMMAD 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第9期1613-1632,共20页
The heat transfer through a concave permeable fin is analyzed by the local thermal non-equilibrium(LTNE)model.The governing dimensional temperature equations for the solid and fluid phases of the porous extended surfa... The heat transfer through a concave permeable fin is analyzed by the local thermal non-equilibrium(LTNE)model.The governing dimensional temperature equations for the solid and fluid phases of the porous extended surface are modeled,and then are nondimensionalized by suitable dimensionless terms.Further,the obtained nondimensional equations are solved by the clique polynomial method(CPM).The effects of several dimensionless parameters on the fin's thermal profiles are shown by graphical illustrations.Additionally,the current study implements deep neural structures to solve physics-governed coupled equations,and the best-suited hyperparameters are attained by comparison with various network combinations.The results of the CPM and physicsinformed neural network(PINN)exhibit good agreement,signifying that both methods effectively solve the thermal modeling problem. 展开更多
关键词 heat transfer FIN porous fin local thermal non-equilibrium(LTNE)model physics-informed neural network(PINN)
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Diversity, Ecology, and Environmental Significance of Foraminifera in Al Hamama and Susah Coastal Regions, Northeastern Libya: Insights from Holocene Sediments
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作者 Belkasim Khameiss Husamaldeen Zubi 《Journal of Environmental Protection》 2024年第1期13-25,共13页
This research initiative, conducted along the coastal zones of Al Hamama and Susah in northeastern Libya, aimed to enhance our understanding of Holocene benthic foraminifera assemblages and the paleoenvironmental para... This research initiative, conducted along the coastal zones of Al Hamama and Susah in northeastern Libya, aimed to enhance our understanding of Holocene benthic foraminifera assemblages and the paleoenvironmental parameters in the region. We meticulously gathered five sediment samples to analyze the composition of foraminifera populations within the unconsolidated sedimentary deposits adjacent to these locations. We successfully identified nine distinct benthic foraminifera species, including Amphistegina lobifera, Eliphidium crispum, Sigmoilinita tenuis, Sorites orbiculus, Stomatorbina concentrica, Peneroplis planatus, Pseudotriloculina rotunda, Pyrgoella sphaera, and Triloculina schreberiana. Notably, Eliphidium crispum and Amphistegina lobifera emerged as the most prevalent species. These foraminifera species exhibited distinct ecological preferences, shedding light on paleoenvironmental conditions and climatic fluctuations during the Quaternary Period in the Susah and Al Hamama coastal regions. The presence of Orbulina universa, a planktonic foraminifera species, further enriched our understanding of the paleoenvironment by providing insights into specific water depths and temperature ranges. This research significantly contributes to paleoceanography and environmental reconstruction, highlighting the invaluable use of foraminifera as proxies for exploring past environmental changes. Additionally, the study investigated the impacts of anthropogenic influences on benthic ecosystems in the Al Hamama and Susah coastal areas. These influences included reworked foraminifera specimens and the effects of karst formations, acid rain, and eutrophication. Notably, human-induced factors have visibly affected biogenic fauna and ecosystem dynamics in the study area. Consequently, this research provides valuable insights into paleoenvironmental conditions and ecological dynamics within the Susah and Al Hamama coastal regions, emphasizing the crucial role of foraminifera in reconstructing historical environmental fluctuations. 展开更多
关键词 Al Hamama Susah Northeastern Libya Holocene sediments
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