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prediction of preferential fluid flow in porous structures based on topological network models: Algorithm and experimental validation

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Science China(Technological Sciences) 2018年第8期61卷 1217-1227页

作者： JU Yang LIU peng ZHANg DongShuang DONg JiaBin ranjith p.g. CHANg Chun State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology State Key Laboratory for geomechanics and Deep Underground Engineering China University of Mining and Technology School of Mechanics and Civil Engineering China University of Mining & Technology School of Resources and Safety Engineering China University of Mining & Technology Institute of Mechanics Chinese Academy of Science Department of Civil Engineering Monash University

The understanding and prediction of preferential fluid flow in porous media have attracted considerable attention in various engineering fields because of the implications of such flows in leading to a non-equilibrium fluid flow in the subsurface. In this study, a novel algorithm is proposed to predict preferential flow paths based on the topologically equivalent network of a porous structure and the flow resistance of flow paths. The equivalent flow network was constructed using poiseuille's law and the maximal inscribed sphere algorithm. The flow resistance of each path was then determined based on Darcy's law. It was determined that fluid tends to follow paths with lower flow resistance. A computer program was developed and applied to an actual porous structure. To validate the algorithm and program, we tested and recorded two-dimensional(2 D) water flow using an ablated perspex sheet featuring the same porous structure investigated using the analytical calculations. The results show that the measured preferential flow paths are consistent with the predictions.

关键词： preferential flow porous structure topological networks flow resistance Darcy's law experimental validation

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未固结流砂地层采油过程中出砂情况模拟实验

石油勘探与开发 2017年第5期44卷 811-816页

作者： pERERA M S A ranjith p g RATHNAWEERA T D DE SILVA g p D LIU T Department of Civil Engineering Monash University Department of Infrastructure Engineering The University of Melbourne

为了研究未固结流砂储集层在采油过程中的出砂情况和影响出砂的主要因素,进行了不同条件下的出砂过程模拟实验。使用水洗白砂、黏土(高岭土)和蒸馏水制成未固结流砂地层模型,利用新开发的出砂模拟装置进行了模拟实验,并分析了作用于地... 详细信息

为了研究未固结流砂储集层在采油过程中的出砂情况和影响出砂的主要因素,进行了不同条件下的出砂过程模拟实验。使用水洗白砂、黏土(高岭土)和蒸馏水制成未固结流砂地层模型,利用新开发的出砂模拟装置进行了模拟实验,并分析了作用于地层的拖曳力和地层胶结特征对出砂的影响。研究表明,随着拖曳力的增加,出砂速度和产油速度都加快;随着胶结物含量的增加,出砂量和产油量明显降低,甚至在胶结物含量较高的情况下出砂量几乎为零。地层压力大的油藏在开采期间由于产生了较大的拖曳力更可能出砂,而拖曳力和有效地层应力共同影响油藏的总体产油量。可以根据地层黏土含量估计出砂情况,从而通过采取适当的防砂措施尽可能减少出砂量。某些情况下油藏比气藏更容易出砂。

关键词：流砂地层出砂采油工艺黏土含量胶结程度拖曳力

performances of fissured red sandstone after thermal treatment with constant-amplitude and low-cycle impacts

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Journal of Rock Mechanics and geotechnical Engineering 2024年第2期16卷 561-587页

作者： Yongjun Chen Tubing Yin p.g.ranjith Xibing Li Qiang Li Dengdeng Zhuang School of Resources and Safety Engineering Central South UniversityChangsha410083China Department of Civil Engineering Monash UniversityMelbourne3800Australia Oulu Mining School University of OuluOuluFI-90014Finland

In the engineering practices,it is increasingly common to encounter fractured rocks perturbed by temperatures and frequent dynamic *** this paper,the dynamic behaviors and fracture characteristics of red sandstone considering temperatures(25℃,200℃,400℃,600℃,and 800℃)and fissure angles(0°,30°,60°,and 90°)were evaluated under constant-amplitude and low-cycle(CALC)impacts actuated by a modified split Hopkinson pressure bar(SHpB)***,fracture morphology and second-order statistics within the grey-level co-occurrence matrix(gLCM)were examined using scanning electron microscopy(SEM).Meanwhile,the deep analysis and discussion of the mechanical response were conducted through the synchronous thermal analyzer(STA)test,numerical simulations,one-dimensional stress wave theory,and material *** multiple regression models between response variables and interactive effects of independent variables were established using the response surface method(RSM).The results demonstrate the fatigue strength and life diminish as temperatures rise and increase with increasing fissure angles,while the strain rate exhibits an inverse ***,the peak stress intensification and strain rate softening observed during CALC impact exhibit greater prominence at increased fissure *** failure is dominated by tensile damage with concise evolution paths and intergranular cracks as well as the compressor-crushed zone which may affect the failure mode after 400℃.The second-order statistics of gLCM in SEM images exhibit a considerable dependence on the ***,thermal damage dominated by thermal properties controls the material structure and wave impedance and eventually affects the incident wave *** tensile wave reflected from the fissure surface is the inherent mechanism responsible for the angle effect exhibited by the fatigue strength and ***,the peak stress intensification and strain rate softening during impact are determ

关键词： Red sandstone Temperature Fissure Constant-amplitude and low-cycle(CALC) impact Fatigue failure Response surface method(RSM)

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地应力对水压致裂裂纹扩展影响的数值模拟

辽宁工程技术大学学报（自然科学版） 2013年第1期32卷 115-118页

作者：陈庚徐涛唐春安 ranjith p g 大连大学材料破坏力学中心辽宁大连116622 成都理工大学地质灾害防治与环境保护国家重点实验室四川成都610059 大连理工大学土木工程学院辽宁大连116024 莫纳什大学土木工程系

研究岩石在渗流-应力作用下裂纹萌生、扩展的破坏机制问题,采用岩石破裂过程分析软件对不同地应力水平和含不同倾角裂纹下水压致裂裂纹扩展进行了数值模拟研究,结果表明:在内孔水压作用下,随着地应力由80 Mpa逐渐减少到45 Mpa时,形成的... 详细信息

研究岩石在渗流-应力作用下裂纹萌生、扩展的破坏机制问题,采用岩石破裂过程分析软件对不同地应力水平和含不同倾角裂纹下水压致裂裂纹扩展进行了数值模拟研究,结果表明:在内孔水压作用下,随着地应力由80 Mpa逐渐减少到45 Mpa时,形成的平直裂纹由垂直于水平主应力方向逐渐向偏离水平主应力的方向发展,同时周围伴随着许多随机裂纹;预制裂纹水压致裂可以看出水压是穿过预制裂纹的,该成果为石油工业提高石油开采率提供了理论基础和科学依据.

关键词：渗流-应力耦合非均匀性岩石破裂水压致裂数值模拟裂纹扩展水平主应力石油工业

Decellularized extracellular matrix-based composite scaffolds for tissue engineering and regenerative medicine

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Regenerative Biomaterials 2024年第3期3卷 1-29页

作者： peiyao Xu ranjith Kumar Kankala Shibin Wang Aizheng Chen Institute of Biomaterials and Tissue Engineering Huaqiao UniversityXiamenFujian 361021PR China Fujian provincial Key Laboratory of Biochemical Technology(Huaqiao University) XiamenFujian 361021PR China

Despite the considerable advancements in fabricating polymeric-based scaffolds for tissue engineering,the clinical transformation of these scaffolds remained a big challenge because of the difficulty of simulating native organs/tissues'*** a kind of natural tissue-derived biomaterials,decellularized extracellular matrix(dECM)-based scaffolds have gained attention due to their unique biomimetic properties,providing a specific microenvironment suitable for promoting cell proliferation,migration,attachment and regulating *** medical applications of dECM-based scaffolds have addressed critical challenges,including poor mechanical strength and insufficient *** promoting the reconstruction of damaged tissues or organs,dif-ferent types of dECM-based composite platforms have been designed to mimic tissue microenvironment,including by integrating with natural polymer or/and syntenic polymer or adding bioactive *** this review,we summarized the research progress of dECM-based composite scaffolds in regenerative medicine,highlighting the critical challenges and future perspectives related to the medical application of these composite materials。

关键词： decellularized extracellular matrix polymer bioactive factors composites tissue engineering

Bibliometric analysis of research challenges and trends in urban underground space

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Deep Underground Science and Engineering 2024年第2期3卷 207-215页

作者： You Zhang Liang Zheng Lingling He Yuyong Jiao Hanfa peng ranjith pgamage Faculty of Engineering China University of GeosciencesWuhanChina Department of Civil Engineering Monash UniversityClaytonVictoriaAustralia Sinohydro Engineering Bureau Co. LtdPower ChinaXiningChina 4Wuhan Geomatic InstituteWuhanChina

The utilization and development of urban underground space play a crucial role in optimizing the layout of civic architecture and enhancing the urban ecological environment,which contributes toward increasing the overall carrying capacity and promoting sustainable development in *** delve into the research progress of urban underground space,knowledge maps were created using the information visualization software *** literature was systematically extracted from three prominent databases,namely,Web of Science,Scopus,and China National Knowledge *** to the bibliometric analysis of the co-citation and core words co-occurrence,the trends and challenges of research on urban underground space were *** highlighted by the results obtained,it still remains highly challenging to achieve interdisciplinary collaboration in urban underground space research;the research trends of urban underground space consist of collaborative planning and whole life cycle sustainable development,multisource geological data informatization and resource evaluation,infrastructure design optimization,and intelligent *** knowledge map,drawn using bibliometric methods,offers a quantitative analysis of literature retrieval across various *** is recognized as an essential tool for exploring and identifying challenges and trends in urban underground space.

关键词： bibliometric analysis knowledge groups urban underground space VOSviewer

NIR-switchable local hydrogen generation by tandem bimetallic MOFs nanocomposites for enhanced chemodynamic therapy

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Regenerative Biomaterials 2024年第1期3卷 58-68页

作者： Jun Zhong Xiang Zheng Yuan Wen Yuewei Li Jianting Zhang ranjith Kumar Kankala Shibin Wang Aizheng Chen Institute of Biomaterials and Tissue Engineering Huaqiao UniversityXiamen 361021China Fujian provincial Key Laboratory of Biochemical Technology Huaqiao UniversityXiamen 361021China Fujian provincial Key Laboratory of Biomass Low-Carbon Conversion Huaqiao UniversityXiamen 361021China

The inadequate quantity of hydrogen peroxide(H_(2)O_(2))in cancer cells promptly results in the constrained success of chemodynamic therapy(CDT).Significant efforts made throughout the years;nevertheless,researchers are still facing the great challenge of designing a CDT agent and securing H_(2)O_(2) supply within the tumor *** this study,taking advantage of H_(2)O_(2) level maintenance mechanism in cancer cells,a nanozyme-based bimetallic metal-organic frameworks(MOFs)tandem reactor is fabricated to elevate intracellular H_(2)O_(2) levels,thereby enhancing *** addition,under nearinfrared excitation,the upconversion nanoparticles(UCNps)loaded into the MOFs can perform photocatalysis and generate hydrogen,which increases cellular susceptibility to radicals induced from H_(2)O_(2),inhibits cancer cell energy,causes DNA damages and induces tumor cell apoptosis,thus improving CDT therapeutic efficacy *** proposed nanozyme-based bimetallic MOFs-mediated CDT and UCNps-mediated hydrogen therapy act as combined therapy with high efficacy and low toxicity.

关键词： chemodynamic therapy nanozyme bimetallic MOFs gas therapy

Reinforcement Learning in process Industries:Review and perspective

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 283-300页

作者： Oguzhan Dogru Junyao Xie Om prakash ranjith Chiplunkar Jansen Soesanto Hongtian Chen Kirubakaran Velswamy Fadi Ibrahim Biao Huang Department of Chemical and Materials Engineering University of AlbertaEdmontonT6G 1H9Canada IEEE

This survey paper provides a review and perspective on intermediate and advanced reinforcement learning(RL)techniques in process industries. It offers a holistic approach by covering all levels of the process control hierarchy. The survey paper presents a comprehensive overview of RL algorithms,including fundamental concepts like Markov decision processes and different approaches to RL, such as value-based, policy-based, and actor-critic methods, while also discussing the relationship between classical control and RL. It further reviews the wide-ranging applications of RL in process industries, such as soft sensors, low-level control, high-level control, distributed process control, fault detection and fault tolerant control, optimization,planning, scheduling, and supply chain. The survey paper discusses the limitations and advantages, trends and new applications, and opportunities and future prospects for RL in process industries. Moreover, it highlights the need for a holistic approach in complex systems due to the growing importance of digitalization in the process industries.

关键词： process control process systems engineering reinforcement learning

Experimental study on the influence of hydrostatic stress on the Lode angle effect of porous rock

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International Journal of Mining Science and Technology 2022年第4期32卷 727-735页

作者： Zhenlong Song Zhenguo Zhang p.g.ranjith Wanchun Zhao Chao Liu Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhenGuangdong 518055China State Key Laboratory of Coalmine Disaster Dynamics and Control Chongqing UniversityChongqing 400030China Deep Earth Energy Research Laboratory Department of Civil EngineeringMonash UniversityMelbourneVictoria 3800Australia School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China School of Electrical Engineering&Information Northeast Petroleum UniversityDaqing 163318China

To investigate the deformation mechanisms of rock under hydrostatic stress, destructive experiments were conducted on sandstone under different levels of hydrostatic stress and stress Lode angles. The results reveal that the shape of the strength envelope on the π plane gradually changes from the shape of the Lade criterion to the shape of the Drucker-prage criterion with an increase in hydrostatic ***, there exists a deviation between the strain and stress paths for porous rocks on the π plane,and the deviation decreases with an increase in stress Lode angle and hydrostatic stress. A rock failure hypothesis based on the rock porous structure was proposed to investigate the reasons for the abovementioned phenomena. It was found that the shear expansion in the minimum principal stress direction is the dominant factor affecting the Lode angle effect(LAE);the magnitude of the hydrostatic stress induces the variation of the porous structure and influences the shear expansion. Therefore, the hydrostatic stress state affects the LAE. The failure hypothesis proposed in this paper can clarify the hydrostatic stress effect, LAE, and the variation of the rock strength envelope shape.

关键词： Lode angle effect Hydrostatic stress effect Strength envelope curve porous structure