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Distinct root system acclimation patterns of seagrass Zostera japonica in sediments of different trophic status:a research by x-ray computed tomography

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Journal of Oceanology and Limnology 2021年第6期39卷 2267-2280页

作者： xiaoyue SONG Yi ZHOU Jiangning ZENG Lu SHOU xiaomei ZHANG Shidong YUE Wei GAO Weihua FENG Zhifu WANG Ping DU Key Laboratory of Marine Ecosystem Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China CAS Key Laboratory of Marine Ecology and Environmental Sciences Institute of OceanologyChinese Academy of SciencesQingdao 266071China College of Tropical Crops Hainan UniversityHaikou 570228China Key Laboratory of Engineering Oceanography Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China

Conspecific seagrass living in differing environments may develop different root system acclimation *** applied x-ray computed tomography(CT)for imaging and quantifying roots systems of Zostera japonica collected from typical oligotrophic and eutrophic sediments in two coastal sites of northern China,and determined sediment physicochemical properties that might influence root system morphology,density,and *** trophic status of sediments had little influence on the *** root length,and diameters of root and ***,*** in oligotrophic sediment developed the root system with longer rhizome node,deeper rhizome distribution,and larger allocation to below-ground tissues in order to acquire more nutrients and relieve the N *** the lower root and rhizome densities of *** in eutrophic sediment were mainly caused by fewer shoots and shorter longevity,which was resulted from the more serious sulfide *** results systematically revealed the effect of sediment trophic status on the phenotypic plasticity,quantity,and distribution of *** root system,and demonstrated the feasibly of x-ray CT in seagrass root system research.

关键词： Zostera japonica root system acclimation pattern sediment trophic status x-ray computed tomography

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Quantification of 3D macropore networks in forest soils in Touzhai valley(Yunnan,China)using x-ray computed tomography and image analysis

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Journal of Mountain Science 2017年第3期14卷 474-491页

作者： ZHANG Jia-ming xU Ze-min LI Feng HOU Ru-ji REN Zhe Department of Civil Engineering Kunming University of Science and TechnologyKunming 650500China Department of Earth Sciences Kunming University of Science and TechnologyKunming 650093China Water Transportation Planning and Design Institute of Yunnan Kunming 650051China

The three dimensional （3D） geometry of soil macropores largely controls preferential flow, which is a significant infiltrating mechanism for rainfall in forest soils and affects slope stability. However, detailed studies on the 3D geometry of macropore networks in forest soils are rare. The intense rainfall-triggered potentially unstable slopes were threatening the villages at the downstream of Touzhai valley （Yunnan, China）. We visualized and quantified the 3D macropore networks in undisturbed soil columns （Histosols） taken from a forest hillslope in Touzhai valley, and compared them with those in agricultural soils （corn and soybean in USA; barley, fodder beet and red fescue in Denmark） and grassland soils in USA. We took two large undisturbed soil columns （250 mm^25o mmxsoo mm）, and scanned the soil columns at in-situ soil water content conditions using x-ray computed tomography at a voxel resolution of 0.945 × 0.945 × 1.500o mm^3. After reconstruction and visualization, we quantified the characteristics of macropore networks. In the studied forest soils, the main types of maeropores were root channels, inter-aggregate voids, maeropores without knowing origin, root-soil interfaee and stone-soil interface. While maeropore networks tend to be more eomplex, larger, deeper and longer. The forest soils have high maeroporosity, total maeropore wall area density, node density, and large maeropore volume, hydraulie radius, mean maeropore length, angle, and low tortuosity. The findings suggest that maeropore networks in the forest soils have high inter- connectivity, vertical continuity, linearity and less vertically oriented.

关键词： Slope stability Touzhai valley Rainfall infiltration Forest soils x-ray computed tomography 3D macropore networks

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Microstructure Evolution of Sandstone Cemented by Microbe Cement Using x-ray computed tomography

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Journal of Wuhan University of Technology(Materials Science) 2013年第6期28卷 1134-1139页

作者： RONG Hui QIAN Chunxiang School of Materials Science and Engineering Southeast University Jiangsu Key Laboratory of Construction Material Research Institute of Green Construction Materials Southeast University

The bio-sandstone, which was cemented by microbe cement, was firstly prepared, and then the microstructure evolution process was studied by x-ray computed tomography （x-CT） technique. The experimental results indicate that the microstructure of bio-sandstone becomes dense with the development of age. The evolution of inner structure at different positions is different due to the different contents of microbial induced precipitation calcite. Besides, the increase rate of microbial induced precipitation calcite gradually decreases because of the reduction of microbe absorption content with the decreasing pore size in bio-sandstone.

关键词： microbe cement bio-sandstone microstructure evolution x-ray computed tomography calcite

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Non-destructive 3D geometric modeling of maize root-stubble in-situ via x-ray computed tomography

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International Journal of Agricultural and Biological Engineering 2020年第3期13卷 174-179页

作者： xu Zhao Luyu xing Shifan Shen Jiaming Liu Daixing Zhang School of Mechanical Engineering&Automation University of Science and Technology LiaoningAnshan 114051China

No-tillage seeding has become an important approach to improve crop productivity,which needs colters of high performance to cut the root-stubble-soil ***,the difficulty of maize root-stubbles three-dimensional(3D)modeling hinders finite element(FE)simulation to improve development efficiency of such colters because of maize root system complexity and opaque nature of the ***,the non-destructive 3D geometric model of the maize root-stubble in-situ can be established via x-ray computed tomography(CT)following by a systematic *** whole procedure includes CT scanning of the maize root-stubble-soil composite sample,image reconstruction via filtered back-projection(FBP)with the Hanning filter,segmentation of root-stubble via a variational level set method,and post-processing via morphological *** 3D reconstruction model of the maize root-stubble in-situ presents a complete,complex and in-situ geometrical morphology,which cannot be realized via other methods,including the destructive modelling after washing via *** study is the first to build a 3D geometric model of a maize root-stubble in-situ via CT,which opens up new possibilities for simulation of root-stubble-soil cutting using FEM,and much other research related to plant root-stubbles.

关键词： maize root-stubble non-destructive modeling x-ray computed tomography variational level set method

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In situ compression and x-ray computed tomography of flow battery electrodes

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Journal of Energy Chemistry 2018年第5期27卷 1353-1361页

作者： Rhodri Jervis Matt D.R.Kok Tobias P.Neville Quentin Meyer Leon D.Brown Francesco Iacoviello Jeff T.Gostick Dan J.L.Brett Paul R.Shearing Electrochemical Innovation Lab Department of Chemical Engineering University College London Department of Chemical Engineering McGill University Porous Media Engineering and Analysis Lab Department of Chemical Engineering University of Waterloo

Redox flow batteries offer a potential solution to an increase in renewable energy generation on the grid by offering long-term, large-scale storage and regulation of power. However, they are currently un- derutilised due to cost and performance issues, many of which are linked to the microstructure of the porous carbon electrodes used. Here, for the first time, we offer a detailed study of the in situ effects of compression on a commercially available carbon felt electrode. Visualisation of electrode structure us- ing x-ray computed tomography shows the non-linear way that these materials compress and various metrics are used to elucidate the changes in porosity, pore size distribution and tortuosity factor under compressions from 0%-90%.

关键词： Redox flow battery x-ray computed tomography Compression Carbon felt RFB

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Use of x-ray computed tomography to study structures and particle contacts of granite residual soil

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Journal of Central South University 2019年第4期26卷 938-954页

作者： SUN Yin-lei TANG Lian-sheng School of Earth Sciences and Engineering Sun Yat-sen University Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes

A small problem about soil particle regularization and contacts but essential to geotechnical engineering was *** soils sourced from Guangzhou and xiamen were sieved into five different particle scale ranges(dx-ray micro computed tomography method was used to reconstruct the microstructure of granite residual *** particle was identified and regularized using principal component analysis(PCA).The particle contacts and geometrical characteristics in 3D space were analyzed and summarized using statistical *** results demonstrate that the main types of contact among the particles are face-face,face-angle,face-edge,edge-edge,edge-angle and angle-angle contacts for particle sizes less than 0.2 *** the particle sizes are greater than 0.2 mm,the contacts are effectively summarized as face-face,face-angle,face-edge,edge-edge,edge-angle,angle-angle,sphere-sphere,sphere-face,sphere-edge and sphere-angle *** differences in porosity among the original sample,reconstructed sample and regularized sample are closely related to the water-swelling and water-disintegrable characteristics of granite residual soil.

关键词： x-ray computed tomography granite residual soil reconstruction regularization particle contact

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Three-dimensional visualization and quantification of microporosity in aluminum castings by x-ray micro-computed tomography

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Journal of Materials Science & Technology 2021年第6期65卷 99-107页

作者： Cheng Gu Yan Lu Alan A.Luo Department of Materials Science and Engineering The Ohio State University2041 College Rd N.ColumbusOhio 43210USA Department of Integrated Systems Engineering The Ohio State University1971 NeilAve.ColumbusOhio 43210USA

Porosity is a major issue in solidification processing of metallic *** this work,wedge die casting experiments were designed to investigate the effect of cooling rate on microporosity in an aluminum alloy *** information including dendrites and porosity were measured and observed by optical microscopy and x-ray micro-computed tomography(xMCT).The effects of cooling rate on secondary dendrite arm spacing(SDAS)and porosity were *** relationship between SDAS and cooling rate was established and validated using a mathematical ***-dimensional(3-D)porosity information,including porosity percentage,pore volume,and pore number,was determined by *** the cooling rate decreasing from a lower to a higher position of the wedge die,the observed pore number decreases,the porosity percentage increases,and the equivalent pore radius *** of the pores was discussed as an empirical criterion to distinguish the types of *** different cooling rates,the larger the equivalent pore radius is,the lower the sphericity of the *** research suggests that xMCT is a useful tool to provide critical 3-D porosity information for integrated computational materials engineering(ICME)design and process optimization of solidification products.

关键词： x-ray computed tomography Casting micropore Quantitative evaluation Al alloy

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Evaluation of granule structure and strength properties of green packed beds in iron ore sintering using high-resolution x-ray tomography and uniaxial compression testing

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Particuology 2021年第4期19卷 157-166页

作者： Mingxi Zhou Hao Zhou State Key Laboratory of Clean Energy Utilization Institute for Thermal Power EngineeringZhejiang UniversityHangzhou 310027China

The strength properties of green sinter beds,including the Young’s modulus and maximum bed strain,were evaluated using uniaxial compression *** green-sinter-bed samples were scanned using x-ray computed tomography(xCT),and the geometry characteristics of the granules were quantified by xCT image *** orthogonal array method was applied to determine the concomitant effects of the moisture,hydrated lime,and concentrate contents on the bed strength *** bed strain was observed when the granules had a thin adhering layer and increased interlock contacts,which had a great capacity to resist the applied load *** optimal combination for decreasing the bed maximum strain was 5.8%moisture,2%hydrated lime,and 0%*** moisture and concentrate contents were the most significant factors determining the green bed *** the moisture and concentrate contents produced granules with a thicker and more deformable adhering layer,resulting in a more compact *** addition of hydrated lime inhibited rearrangement,deformation,and fracture of the granules in green sinter bed during compression.

关键词： Packed bed strength Iron ore sintering x-ray computed tomography Uniaxial compression test Granule properties

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Formation of primary intermetallic phases in the interaction of Fe-containing melts of recycled Al-Si alloys with Al_(2)O_(3)and Al_(2)O_(3)-C filter materials:Aμ-CT study

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Journal of Materials Science & Technology 2024年第17期184卷 88-100页

作者： H.Becker B.Fankhänel A.Charitos S.Baier-Stegmaier A.Leineweber W.Pantleon Institute of Materials Science TU Bergakademie FreibergGustav-Zeuner-Straße 509599 FreibergGermany Institute of Nonferrous Metallurgy and Purest Materials TU Bergakademie FreibergLeipziger Straße 3409599 FreibergGermany Department of Physics Technical Univeristy of DenmarkFysikvej 3102800 Kgs.LyngbyDenmark Department of Civil and Mechanical Engineering Technical Univeristy of DenmarkProduktionstorvet 4252800 Kgs.LyngbyDenmark

Fe is the most detrimental impurity element in recycled Al-Si alloys due to the formation of brittle,primary,Fe-containing,intermetallic particles during *** removal from the Al-Si melts *** filtration can reduce the Fe *** active filter materials can facilitate the formation of these particles for their removal and contribute to the production of high-quality,recycled Al-Si *** interaction of the alloy with the filter material can lead to modification of the thermodynamics of the alloy or of the kinetics of the particle ***-resolved,three-dimensional microstructural inves-tigations have been carried out to study the formation of primary intermetallic particles in Al7.1Si1.5Fe and Al7.1Si0.75Fe0.75Mn alloy melts in contact with Al_(2)O_(3)and Al_(2)O_(3)-C filter substrate material during a melt conditioning treatment at 620°*** microstructures,in particular the primary intermetallic particlesαc andαh,have been characterized by computed tomography(CT)and supplementary scanning electron microscopy(SEM).As expected by thermodynamics,the total volume fraction of primary par-ticles remains unchanged by the interaction with the substrate ***,kinetic advantages for Fe-removal efficiency can be achieved by an accelerated and preferred selective particle formation in contact with the Al_(2)O_(3)-C ***,particle formation is discussed in view of its different stages:nucleation,growth,and ripening.

关键词： Aluminum alloys Intermetallic phases Solidification x-ray computed tomography Scanning electron microscopy

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Characterization on the formation of porosity and tensile properties prediction in die casting Mg alloys

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Journal of Magnesium and Alloys 2022年第7期10卷 1857-1867页

作者： Zixin Li Dejiang Li Wenke Zhou Bo Hu xingfeng Zhao Jingya Wang Ming Qin Jiangkun xu xiaoqin Zeng National Engineering Research Center of Light Alloy Net Forming School of Materials Science and EngineeringShanghai Jiao Tong University800 Dongchuan RoadShanghai 200240China Hitachi(China)Research&Development Corporation Rui Jin BuildingNo.205 Maoming Road(S)Shanghai 200020China The State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University800 Dongchuan RoadShanghai 200240China

The 3D visualization of the porosity in high-pressure die casting(HPDC)Mg alloys AZ91D and Mg4Ce2Al0.5Mn(EA42)was investigated by x-ray computed *** was demonstrated that the volumetric porosity at the near-gate location for alloy EA42 was significantly higher than that far from the gate *** difference resulted from the low valid time during intensified casting pressure *** of alloy EA42 exhibited a narrow pore distribution in the side view(~0.5 mm)compared to the wide distribution(~1.8 mm)of alloy AZ91D,which was mainly attributed to the formation mechanism of the defect *** formation of microporosity in the defect band of alloy EA42 was inhibited because of the significant latent heat released by a large amount of the Al11Ce3phase segregated in the defect band during ***,an effective estimator(Z-Propagation)was introduced,which is proposed to predict the projected area fraction of the porosity(f)involved during tensile failure with better effectiveness compared with traditional methods based on the actual fractured *** coupling the Z-Propagation method with the critical local strain model,the logarithmic fracture strain and true fracture stress of the specimens were predicted within 3.03%and 1.65%of the absolute value of the average relative error(AARE),respectively.

关键词： High-pressure die casting Porosity Tensile property Magnesium alloy x-ray computed tomography

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