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Influence of Processing Parameters on Granularity Distribution of Superalloy Powders during PREP 被引量:2
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作者 HuanmingCHEN BenfuHU +2 位作者 YiwenZHANG HuiyingLI QuanmaoYU 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2003年第6期587-590,共4页
In order to investigate the influence of processing parameters on the granularity distribution of superalloy powders during the atomization of plasma rotating electrode processing (PREP), in this paper FGH95 superallo... In order to investigate the influence of processing parameters on the granularity distribution of superalloy powders during the atomization of plasma rotating electrode processing (PREP), in this paper FGH95 superalloy powders is prepared under different processing conditions by PREP and the influence of PREP processing parameters on the granularity distribution of FGH95 superalloy powders is discussed based on fractal geometry theory. The results show that with the increase of rotating velocity of the self-consuming electrode, the fractal dimension of the granularity distribution increases linearly, which results in the increase of the proportion of smaller powders. The change of interval between plasma gun and the self-consuming electrode has a little effect on the granularity distribution, also the fractal dimension of the granularity distribution changed a little correspondingly. 展开更多
关键词 FGH95 superalloy powders granularity distribution Plasma rotating electrode processing (PREP) Fractal dimension
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Integrating Coarse Granularity Part-Level Features with Supervised Global-Level Features for Person Re-Identification 被引量:1
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作者 CAO Jiahao MAO Xiaofei +2 位作者 LI Dongfang ZHENG Qingfang JIA Xia 《ZTE Communications》 2021年第1期72-81,共10页
Person re-identification(Re-ID)has achieved great progress in recent years.However,person Re-ID methods are still suffering from body part missing and occlusion problems,which makes the learned representations less re... Person re-identification(Re-ID)has achieved great progress in recent years.However,person Re-ID methods are still suffering from body part missing and occlusion problems,which makes the learned representations less reliable.In this paper,we pro⁃pose a robust coarse granularity part-level network(CGPN)for person Re-ID,which ex⁃tracts robust regional features and integrates supervised global features for pedestrian im⁃ages.CGPN gains two-fold benefit toward higher accuracy for person Re-ID.On one hand,CGPN learns to extract effective regional features for pedestrian images.On the other hand,compared with extracting global features directly by backbone network,CGPN learns to extract more accurate global features with a supervision strategy.The single mod⁃el trained on three Re-ID datasets achieves state-of-the-art performances.Especially on CUHK03,the most challenging Re-ID dataset,we obtain a top result of Rank-1/mean av⁃erage precision(mAP)=87.1%/83.6%without re-ranking. 展开更多
关键词 person Re-ID SUPERVISION coarse granularity
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A HYBRID GRANULARITY PARALLEL ALGORITHM FOR PRECISE INTEGRATION OF STRUCTURAL DYNAMIC RESPONSES
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作者 Yuanyin Li Xianlong Jin Genguo Li 《Acta Mechanica Solida Sinica》 SCIE EI 2008年第1期28-33,共6页
Precise integration methods to solve structural dynamic responses and the corresponding time integration formula are composed of two parts: the multiplication of an exponential matrix with a vector and the integratio... Precise integration methods to solve structural dynamic responses and the corresponding time integration formula are composed of two parts: the multiplication of an exponential matrix with a vector and the integration term. The second term can be solved by the series solution. Two hybrid granularity parallel algorithms are designed, that is, the exponential matrix and the first term are computed by the fine-grained parallel algorithra and the second term is computed by the coarse-grained parallel algorithm. Numerical examples show that these two hybrid granularity parallel algorithms obtain higher speedup and parallel efficiency than two existing parallel algorithms. 展开更多
关键词 dynamic response precise integration hybrid granularity parallel algorithm
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On Granularity in Information Systems Based on Binary Relation
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作者 Weihua Xu Shihu Liu +1 位作者 Xiaoyan Zhang Wenxiu Zhang 《Intelligent Information Management》 2011年第3期75-86,共12页
In this paper, some important issues of granularity are discussed mainly in information systems (ISs) based on binary relation. Firstly, the vector representation method of knowledge granules is proposed in an infor-m... In this paper, some important issues of granularity are discussed mainly in information systems (ISs) based on binary relation. Firstly, the vector representation method of knowledge granules is proposed in an infor-mation system based on binary relation to eliminate limitations of set representation method. Secondly, operators among knowledge granularity are introduced and some important properties of them are studied carefully. Thirdly, distance between two knowledge granules is established and granular space is constructed based on it. Fourthly, axiomatic definition of knowledge granularity is investigated, and one can find that some existed knowledge granularities are special cases under the definition. In addition, as an application of knowledge granular space, an example is employed to validate some results in our work. 展开更多
关键词 BINARY RELATION granular Space Information System ROUGH Set
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Dynamic Distribution Model with Prime Granularity for Parallel Computing
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作者 孙济洲 张绍敏 李小图 《Transactions of Tianjin University》 EI CAS 2005年第5期343-347,共5页
Dynamic distribution model is one of the best schemes for parallel volume rendering. How- ever, in homogeneous cluster system.since the granularity is traditionally identical, all processors communicate almost simulta... Dynamic distribution model is one of the best schemes for parallel volume rendering. How- ever, in homogeneous cluster system.since the granularity is traditionally identical, all processors communicate almost simultaneously and computation load may lose balance. Due to problems above, a dynamic distribution model with prime granularity for parallel computing is presented. Granularities of each processor are relatively prime, and related theories are introduced. A high parallel performance can be achieved by minimizing network competition and using a load balancing strategy that ensures all processors finish almost simultaneously. Based on Master-Slave-Gleaner ( MSG) scheme, the parallel Splatting Algorithm for volume rendering is used to test the model on IBM Cluster 1350 system. The experimental results show that the model can bring a considerable improvement in performance, including computation efficiency, total execution time, speed, and load balancing. 展开更多
关键词 granularity parallel computing load balancing dynamic distribution model
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A novel transmission energy minimization algorithm based on fine granularity scalability
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作者 吴彪 张颖 张兆扬 《Journal of Shanghai University(English Edition)》 CAS 2006年第2期123-126,共4页
This paper proposes an optimal solution to choose the number of enhancement layers in fine granularity scalability (FGS) scheme under the constraint of minimum transmission energy, in which FGS is combined with transm... This paper proposes an optimal solution to choose the number of enhancement layers in fine granularity scalability (FGS) scheme under the constraint of minimum transmission energy, in which FGS is combined with transmission energy control, so that FGS enhancement layer transmission energy is minimized while the distortion guaranteed. By changing the bit-plane level and packet loss rate, minimum transmission energy of enhancement layer is obtained, while the expected distortion is satisfied. 展开更多
关键词 fine granularity scalability(FGS) bit-plane level expected distortion transmission energy.
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Granularity of Knowledge Computed by Genetic Algorithms Based on Rough Sets Theory
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作者 Wenyuan Yang Xiaoping Ye +1 位作者 Yong Tang Pingping Wei 《南昌工程学院学报》 CAS 2006年第2期97-101,121,共6页
Rough set philosophy hinges on the granularity of data, which is used to build all its basic concepts, like approximations, dependencies, reduction etc. Genetic Algorithms provides a general frame to optimize problem ... Rough set philosophy hinges on the granularity of data, which is used to build all its basic concepts, like approximations, dependencies, reduction etc. Genetic Algorithms provides a general frame to optimize problem solution of complex system without depending on the domain of problem.It is robust to many kinds of problems.The paper combines Genetic Algorithms and rough sets theory to compute granular of knowledge through an example of information table. The combination enable us to compute granular of knowledge effectively.It is also useful for computer auto-computing and information processing. 展开更多
关键词 granularity of knowledge Genetic Algorithms Pawlak Model Rough Set Theory information table
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Research on the Development Trend and General Applications of the Fuzzy Rough Granularity Computing Theory
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作者 Xin Li 《International Journal of Technology Management》 2016年第5期22-24,共3页
In this paper, we conduct research on the development trend and general applications of the fuzzy rough granular computing theory. Granular computing is a new concept of general information processing and computing pa... In this paper, we conduct research on the development trend and general applications of the fuzzy rough granular computing theory. Granular computing is a new concept of general information processing and computing paradigm which covers all the granularity the study of the theory, methods, techniques and the tools. In many areas are the basic ideas of granular computing, such as the interval analysis, rough set theory, clustering analysis and information retrieval, machine learning, database, etc. With the theory of domain known division of target concept and rule acquisition, in knowledge discovery, data mining and the pattern recognition is widely used. Under this basis, in this paper, we propose the fuzzy rough theory based computing paradigm that gains ideal performance. 展开更多
关键词 Development TREND APPLICATIONS Fuzzy ROUGH granular COMPUTING THEORY
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Research on the Effects of the Contents of Radioactive Elements on Granularity and Climate Change:An Example of SZK1 and SZK2 Drill Holes Strata in the Fuzhou Basin
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作者 Zheng Rongzhang Xu Xiwei Li Jianping 《Earthquake Research in China》 2006年第4期469-478,共10页
Based on the content of radioactive elements (U, Th, K) of strata in two drill holes in the Fuzhou basin, and combined with the result of spore_pollen analysis, the relationship between radioactivity and lithology and... Based on the content of radioactive elements (U, Th, K) of strata in two drill holes in the Fuzhou basin, and combined with the result of spore_pollen analysis, the relationship between radioactivity and lithology and deposit environments is discussed and the results show that the content of radioactive substances is related to the granularity and lithology in sediment, and it is higher in argillaceous sediment (e.g. silt and clay), lower in sand sediment and in the middle in gravels between the above two kinds of sediment. The content of radioactive substances is also related to paleoclimate. A warm and humid environment is propitious to the deposition of radioactive substances, while a cool and dry climate is just the reverse. 展开更多
关键词 U-Th-K radioactive elements granularity PALEOENVIRONMENT Drill hole Fuzhou Basin
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Effects of salinity and betaine addition on anaerobic granular sludge properties and microbial community succession patterns in organic saline wastewater 被引量:1
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作者 Zhifei Zhang Jinquan Wan +3 位作者 Gang Ye Yan Wang Yuwei Bai Zhicheng Yan 《Journal of Environmental Sciences》 2025年第1期310-321,共12页
In this study,the effects of different salinity gradients and addition of compatible solutes on anaerobic treated effluent water qualities,sludge characteristics and microbial communities were investigated.The increas... In this study,the effects of different salinity gradients and addition of compatible solutes on anaerobic treated effluent water qualities,sludge characteristics and microbial communities were investigated.The increase in salinity resulted in a decrease in particle size of the granular sludge,which was concentrated in the range of 0.5-1.0 mm.The content of EPS(extracellular polymeric substances)in the granular sludge gradually increased with increasing salinity and the addition of betaine(a typical compatible solute).Meanwhile,the microbial community structure was significantly affected by salinity,with high salinity reducing the diversity of bacteria.At higher salinity,Patescibacteria and Proteobacteria gradually became the dominant phylum,with relative abundance increasing to 13.53%and 12.16%at 20 g/L salinity.Desulfobacterota and its subordinate Desulfovibrio,which secrete EPS in large quantities,dominated significantly after betaine addition.Their relative abundance reached 13.65%and 7.86%at phylum level and genus level.The effect of these changes on the treated effluent was shown as the average chemical oxygen demand(COD)removal rate decreased from 82.10%to 79.71%,78.01%,68.51%and 64.55%when the salinity gradually increased from 2 g/L to 6,10,16 and 20 g/L.At the salinity of 20 g/L,average COD removal increased to 71.65%by the addition of 2 mmol/L betaine.The gradient elevated salinity and the exogenous addition of betaine played an important role in achieving stability of the anaerobic system in a highly saline environment,which provided a feasible strategy for anaerobic treatment of organic saline wastewater. 展开更多
关键词 Organic saline wastewater Anaerobic granular sludge Compatible solute Extracellular polymeric substance Microbial community
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2,3,5,4'-Tetrahydroxystilbene-2-O-β-glucoside Alleviates PCOS-like Characteristics by Upregulating The Expression of CYP19A1 in Granular Cells of Sinus Follicles to Inhibit Inflammatory Response
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作者 YAO Jian-Feng XU Bo +5 位作者 LIU Pin-Yue CHENG Di WEI Le PAN Xin-Yun MO Zhong-Cheng LI Ming 《生物化学与生物物理进展》 北大核心 2025年第3期735-750,共16页
Objective To investigate whether 2,3,5,4'-tetrahydroxystilbene-2-O-β-glucoside(TSG)ameliorated polycystic ovary syndrome(PCOS)-like characteristics by inhibiting inflammation.Methods PCOS models were established ... Objective To investigate whether 2,3,5,4'-tetrahydroxystilbene-2-O-β-glucoside(TSG)ameliorated polycystic ovary syndrome(PCOS)-like characteristics by inhibiting inflammation.Methods PCOS models were established by injecting subcutaneously with dehydroepiandrosterone into female Sprague-Dawley rats,followed by receiving intraperitoneal injection of TSG.The granular cells(GCs)KGN were transfected with small interfering RNAs(si-NC and si-CYP19A1).The cells were preincubated with lipopolysaccharide(LPS)and then treated with or without TSG.The estrous cycle was monitored using vaginal exfoliated cells.The morphology of ovarian follicles was analyzed by H&E staining.ELISA was used to analyze estradiol(E2),testosterone(T),follicle stimulating hormone(FSH),luteinizing hormone(LH),IL-6,TNF-α,AGEs,CRP and Omentin-1 levels in serum.Immunohistochemistry was performed to analyze PCNA and CYP19A1 expressions in the GCs of ovaries.Tunel staining was executed to detect the apoptosis of GCs.Quantitative polymerase chain reaction(qPCR)and Western blot were implemented to measure the expression of CYP19A1 in the ovaries and transfected cells.qPCR was used to analyze the expression of IL-6 and TNF-αin the transfected cells treated with LPS and TSG.Results The estrous cycles were restored in TSG group.Compared with model group,the sinus follicles were reduced and corpus luteums were increased in TSG group.TSG group showed increased E2,and decreased T and LH,compared with model group.Pro-inflammatory factors(IL-6,TNF-α,CRP and AGEs)were decreased,and anti-inflammatory factor(Omentin-1)was increased in TSG group compared with those in model group.TSG could partially inhibit decrease of PNCA-positive GCs and increase of Tunel-positive GCs caused by PCOS.The CYP19A1 expression of GCs in TSG group was upregulated compared with model group.The expressions of IL-6 and TNFαin si-CYP19A1 cells were increased compared with si-NC cells.Compared with cells(si-NC and si-CYP19A1)treated without LPS,the expressions of IL-6 and TNF-αcells were increased,and the expression of CYP19A1 was downregulated in LPS-preincubated cells.Compared with cells treated with LPS,the expression of IL-6 and TNF-αwere decreased,and the expression of CYP19A1 was increased in cells treated with LPS and TSG.Compared with si-NC cells treated with LPS and TSG,the expressions of IL-6 and TNF-αcells were increased in the si-CYP19A1 cells treated with LPS and TSG.Conclusion TSG could alleviate PCOS-like characteristics by increasing the expression of CYP19A1 in GCs to inhibit inflammatory response. 展开更多
关键词 2 3 5 4'-tetrahydroxystilbene-2-O-β-glucoside granular cells CYP19A1 polycystic ovary syndrome inflammatory response
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Multi-Granularity Neighborhood Fuzzy Rough Set Model on Two Universes
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作者 Ju Wang Xinghu Ai Li Fu 《Journal of Intelligent Learning Systems and Applications》 2024年第2期91-106,共16页
The two universes multi-granularity fuzzy rough set model is an effective tool for handling uncertainty problems between two domains with the help of binary fuzzy relations. This article applies the idea of neighborho... The two universes multi-granularity fuzzy rough set model is an effective tool for handling uncertainty problems between two domains with the help of binary fuzzy relations. This article applies the idea of neighborhood rough sets to two universes multi-granularity fuzzy rough sets, and discusses the two-universes multi-granularity neighborhood fuzzy rough set model. Firstly, the upper and lower approximation operators are defined in the two universes multi-granularity neighborhood fuzzy rough set model. Secondly, the properties of the upper and lower approximation operators are discussed. Finally, the properties of the two universes multi-granularity neighborhood fuzzy rough set model are verified through case studies. 展开更多
关键词 Fuzzy Set Two Universes Multi-granularity Rough Set Multi-granularity Neighborhood Fuzzy Rough Set
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Density-driven segregation of binary granular mixtures in a vertically vibrating drum:The role of filling fraction
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作者 Anghao Li Zaizheng Wang +2 位作者 Haoyu Shi Min Sun Decai Huang 《Chinese Physics B》 2025年第10期417-425,共9页
This paper investigates the influence of filling fraction on the segregation patterns of binary granular mixtures in a vertically vibrating drum through experiments and simulations.Glass and stainless steel spherical ... This paper investigates the influence of filling fraction on the segregation patterns of binary granular mixtures in a vertically vibrating drum through experiments and simulations.Glass and stainless steel spherical grains,which differ in mass density,are used to give rise to density-driven segregation.The results reveal four segregation patterns,including Brazil nut effect segregation,counterclockwise two-eye-like segregation,dumpling-like segregation and clockwise twoeye-like segregation.The theoretical analysis demonstrates that grains predominantly exhibit counterclockwise convection at low filling fractions,while clockwise convection dominates at high filling fractions.Competition between buoyancy and convection forces determines the final stable segregation pattern.These findings provide valuable insights into controlling segregation in granular systems,which is crucial for optimizing industrial processes in fields such as pharmaceuticals and chemical engineering. 展开更多
关键词 granular matter granular flow segregation mechanism discrete element method(DEM)
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Fuzzy Dynamic Optimal Model for COVID-19 Epidemic in India Based on Granular Differentiability
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作者 KHATUA Debnarayan DE Anupam +3 位作者 KAR Samarjit SAMANTA Eshan SEKH Arif Ahmed GUHA ADHYA Debashree 《Journal of Shanghai Jiaotong university(Science)》 2025年第3期545-560,共16页
The pandemic SARS-CoV-2 has become an undying virus to spread a sustainable disease named COVID-19 for upcoming few years.Mortality rates are rising rapidly as approved drugs are not yet available.Isolation from the i... The pandemic SARS-CoV-2 has become an undying virus to spread a sustainable disease named COVID-19 for upcoming few years.Mortality rates are rising rapidly as approved drugs are not yet available.Isolation from the infected person or community is the preferred choice to protect our health.Since humans are the only carriers,it might be possible to control the positive rate if the infected population or host carriers are isolated from each other.Isolation alone may not be a proper solution.These are the resolutions of previous research work carried out on COVID-19 throughout the world.The present scenario of the world and public health is knocking hard with a big question of critical uncertainty of COVID-19 because of its imprecise database as per daily positive cases recorded all over the world and in India as well.In this research work,we have pre-sented an optimal control model for COVID-19 using granular differentiability based on fuzzy dynamical systems.In the first step,we created a fuzzy Susceptible-Exposed-Infected-Asymptomatic-Hospitalized-Recovered-Death(SEIAHRD)model for COVID-19,analyzed it using granular differentiability,and reported disease dynamics for time-independent disease control parameters.In the second step,we upgraded the fuzzy dynamical system and granular differentiability model related to time-dependent disease control parameters as an optimal control problem invader.Theoretical studies have been validated with some practical data from the epidemic COVID-19 related to the Indian perspective during first wave and early second wave. 展开更多
关键词 COVID-19 ASYMPTOMATIC SUSCEPTIBLE fuzzy dynamical system granular differentiability
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Resilient behavior of unbound granular material: A review
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作者 Hugo Alexander Rondon-Quintana Fredy Alberto Reyes-Lizcano Juan Gabriel Bastidas-Martinez 《Journal of Road Engineering》 2025年第3期394-413,共20页
When a vehicle moves over a flexible pavement structure,it generates loading and unloading cycles that produce recoverable(resilient)and permanent(plastic)deformations in the granular base and subbase layers,which are... When a vehicle moves over a flexible pavement structure,it generates loading and unloading cycles that produce recoverable(resilient)and permanent(plastic)deformations in the granular base and subbase layers,which are made of unbound granular materials(UGMs).The primary parameter used to evaluate the resilient response of UGMs in pavements is the resilient modulus(MR).The MR is widely used in calculating stress-strain states for flexible pavement design and as a control parameter during the construction process.It is also employed to understand the progression of distresses,such as fatigue cracking and rutting.The main objective of this study was to conduct a literature review on the resilient behavior of UGMs.This manuscript presents and describes the MR and the factors that influence it.It also outlines the evolution of the mathematical equations most commonly used to estimate and predict this physical parameter.Conclusions and recommendations for future research are provided at the end of the article.Despite the large amount of research done on the subject,the resilient behavior of UGM has not yet been fully understood.This is since these materials are highly heterogeneous and show nonlinear-anisotropic behavior under different cyclic loading paths and water contents.Likewise,these materials undergo different behaviors depending on their macro and microscopic properties(gradation,density,porosity,texture,mineralogy,particle geometry and orientation,temperature,among others).On the other hand,the main limitation of the mathematical equations is that their parameters are difficult to determine experimentally and are not constants of the material(they are state variables that can change with multiple factors).Additionally,these equations do not consider the boundary conditions to which UGM in pavements are exposed.Moreover,they are obtained from repeated load triaxial(RLT)tests,which cannot simulate the three cyclic stress components(vertical,horizontal,and shear)to which UGMs are subjected in a pavement.In recent years,there has been an increase in studies evaluating the use of recycled aggregates and the effect of temperature(particularly at subzero temperatures),but more research is still needed to reach definitive conclusions. 展开更多
关键词 Flexible pavement Resilient behavior Resilient modulus Unbound granular materials
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A granular thermodynamic framework-based coupled multiphasesubstance flow model considering temperature driving effect
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作者 Bing Bai Haiyan Wu +2 位作者 Rui Zhou Nan Wu Bixia Zhang 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第9期5816-5828,共13页
Based on the energy dissipation caused by consolidation deformation of the porous media under external force and migration of the internal suspended substances,a coupled multiphase-substance flow(CMF)model was establi... Based on the energy dissipation caused by consolidation deformation of the porous media under external force and migration of the internal suspended substances,a coupled multiphase-substance flow(CMF)model was established.This model introduced the new concepts,such as particle temperature and particle entropy,to describe energy dissipation at meso-level.This model used a potential energy density function and migration coefficients to establish the corresponding connection between the dissipative force and dissipative flow.This viewpoint unifies the deformation,seepage,and suspended substance migration of geotechnical materials under the framework of granular thermodynamics.It can reflect the evolution of effective stress in the solid matrix of multi-components in a particle-reorganized state,and considers the temperature driving effect.The proposed CMF model is validated using the experimental results under coupled migration of heavy metal ions(HMs)and suspended particles(SPs).The calculation results demonstrated that the CMF model can describe the flow process under the conditions of arbitrary changes in different suspended substance types,injection concentrations,and injection velocities. 展开更多
关键词 GROUNDWATER granular thermodynamics Multiphase substance Coupled migration Consolidation deformation
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Effect of Libration on Fluid Flow and Granular Medium Dynamics in a Rotating Cylindrical Annulus
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作者 Denis Polezhaev Alexey Vjatkin Victor Kozlov 《Fluid Dynamics & Materials Processing》 2025年第5期1051-1061,共11页
The dynamics of fluid and non-buoyant particles in a librating horizontal annulus is studied experimentally.In the absence of librations,the granular material forms a cylindrical layer near the outer boundary of the a... The dynamics of fluid and non-buoyant particles in a librating horizontal annulus is studied experimentally.In the absence of librations,the granular material forms a cylindrical layer near the outer boundary of the annulus and undergoes rigid-body rotation with the fluid and the annulus.It is demonstrated that the librational liquefaction of the granular material results in pattern formation.This self-organization process stems from the excitation of inertial modes induced by the oscillatory motion of liquefied granular material under the influence of the gravitational force.The inertial wave induces vortical fluid flow which entrains particles from rest and forms eroded areas that are equidistant from each other along the axis of rotation.Theoretical analysis and experiments demonstrate that a liquefied layer of granular material oscillates with a radian frequency equal to the angular velocity of the annulus and interacts with the inertial wave it excites.The new phenomenon of libration-induced pattern formation is of practical interest as it can be used to control multiphase flows and mass transfer in rotating containers in a variety of industrial processes. 展开更多
关键词 FLUID granular medium ROTATION librations inertial waves pattern formation
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Comparative study of hydro-mechanical behaviors of compacted bentonite powder and granular bentonite
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作者 Zhao Zhang Wen-Sheng Geng +4 位作者 Wei-Min Ye Yong He Wei Su Qiong Wang Yong-Gui Chen 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第3期1757-1769,共13页
In the deep geological disposal repository of high-level radioactive waste,buffer/backfill materials typically consist of compacted bentonite block and granular bentonite.As these materials undergo a long-term hydrati... In the deep geological disposal repository of high-level radioactive waste,buffer/backfill materials typically consist of compacted bentonite block and granular bentonite.As these materials undergo a long-term hydration,it is anticipated that the two forms of bentonite materials(i.e.compacted bentonite powder(CBP)and granular bentonite(GB))are expected to exhibit differing hydro-mechanical behaviors due to the differences in their structures.This work aims to investigate the differences in swelling pressure and compressibility through a series of swelling pressure tests,compression tests and mercury intrusion porosimetry(MIP)tests.The experimental results demonstrated that swelling pressure curves of the CBP specimens showed higher first peak values and more pronounced collapse than those of the GB specimens at a given dry density,regardless of vapor-water hydration or liquid-water hydration.The final swelling pressures of the two materials were similar at the same dry density,suggesting an independent correlation between swelling pressure and dry density.At the high suction range,the compression curves exhibited an obvious bi-linear pattern for the CBP specimens and a significant nonlinearity for the GB specimens.Meanwhile,the CBP specimens presented higher pre-consolidation pressures and larger compression indices than the GB specimens at a given suction.As suction decreased,the compression curves of the two materials gradually approached each other and their differences were reduced accordingly.After reaching saturation,a good consistency between them was observed whether for final swelling pressure or compressibility.Pore structure analysis revealed that the two materials both presented an initially double structure,and their differences were primarily manifested at the macrostructural level.Eventually,the differences in swelling pressure or compression curves of the two materials were well interpreted by combining microstructural evolutions. 展开更多
关键词 Bentonite powder granular bentonite Swelling pressure Compression Hydro-mechanical behaviors
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Protective effect and mechanisms of defense pile on bridge pier impacted by granular flows
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作者 WU Yihan ZHU Zhiyuan +1 位作者 ZHENG Lu BI Yuzhang 《Journal of Mountain Science》 2025年第8期2960-2980,共21页
Bridge pier failures from granular flow impacts are common.Installing defense piles upstream is an effective mitigation strategy,yet their protective mechanisms and standardized design guidelines are unclear.This stud... Bridge pier failures from granular flow impacts are common.Installing defense piles upstream is an effective mitigation strategy,yet their protective mechanisms and standardized design guidelines are unclear.This study employed 3D discrete element method to analyze the influence of defense pile size and placement on its performance across 219 scenarios,providing a detailed examination of their protective mechanisms.Results show that optimizing these factors can reduce the maximum impact force on bridge piers by up to 94%.In terms of size,a critical height threshold is identified,beyond which increasing pile height does not enhance protection.This threshold depends on the movement height of granular particles at the slope base.Protection effectiveness varies with pile size:when H≤0.05 h(H is the height of defense piles,h is the height of bridge),protection marginally improves with increasing height and diameter;for 0.05 h<H<0.15 h,protection strongly correlates with both parameters;for H≥0.15 h,diameter becomes the dominant factor.In terms of placement,an optimal longitudinal distance exists between the defense pile and the bridge pier.The larger the diameter,the greater the optimal longitudinal distance.However,the transverse distance is inversely related to protection effectiveness.Mechanistic analysis shows that defense piles are more effective at redirecting particles to prevent direct collisions with the pier(contributing 100%impact energy reduction before the non-dimensional travel time t*=7.01 and 63%–100%afterward)than at reducing particle velocity.This study provides insights into the protective mechanisms of defense piles and informs strategies for optimizing bridge pier protection in granular flow-prone regions. 展开更多
关键词 granular flow Defense pile Bridge pier Discrete element method
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Dilation on granular flows:Insight for friction weakening on debris avalanches
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作者 Yuxiang Hu Congjiang Li +2 位作者 Qingyang Zhu Haibo Li Jiawen Zhou 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第12期8161-8171,共11页
Debris avalanches are a major concern due to their high mobility.However,the mechanism of friction weakening in debris avalanches remains poorly understood.This study systematically investigates the friction weakening... Debris avalanches are a major concern due to their high mobility.However,the mechanism of friction weakening in debris avalanches remains poorly understood.This study systematically investigates the friction weakening mechanism of granular flows using rotation drum experiments,large-scale chute experiments,and numerical simulations.Notably,dilation of granular flows is a characteristic feature associated with friction weakening.The results indicate that dilation occurs synchronously with friction weakening during the motion of granular flows,as evidenced by the motion patterns and force interactions of debris avalanches.Collision contacts were identified as the primary driver of particle dilation.An optimal collision strength can induce dilation of granular flows,reducing contact between the sliding body and substrate,thereby leading to friction weakening.The peak collision strength of granular flows during movement is determined by fragment size.The critical condition for triggering friction weakening in debris avalanches is identified as the peak Savage number(Ns,p)greater than 1.06.A mathematical model based on the granular inertial collision-friction coupling equation was developed.This study provides compelling evidence that the fractal dimension of various types of high-speed debris avalanches tends to stabilize within a narrow range. 展开更多
关键词 granular avalanches Movement process friction weakening Physical experiments Numerical simulation
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