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A 2D DEM-LBM study on soil behaviour due to locally injected fluid

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Particuology 2012年第2期10卷 242-252页

作者： Xilin Cui Jun Li andrew chan David Chapman School of Civil Engineering University of BirminghamEdgbastonBirminghamB152TTUK

Leakage from underground pipes could result in foundations being undermined and cause damage to adjacent infrastructure. Soil particles surrounding the leaking area could be mobilised, displaced, and even washed out of the soil matrix by the leaking fluid, generating a void or cavity. A two-dimensional simulation using a coupled discrete element method and lattice Boltzmann method （DEM-LBM） has been used to investigate the behaviour of a soil bed subject to a locally injected fluid, which represents a leak in a pipe. Various values of inter-particle surface energy were also adopted to model the mechanical effects of cohesive particles. The results suggest that the inter-particle surface energy greatly influences the bed response with respect to the leaking fluid, including the excess pressure initiating the cavity, the cavity shape and its evolution rate.

关键词： Discrete element methodLattice Boltzmann methodGranular bedLocally injected fluidCohesive particlesSurface energy

Calibration and validation of a sand model considering the effects of wave-induced principal stress axes rotation

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Acta Oceanologica Sinica 2015年第7期34卷 105-115页

作者： LIU Peng WANG Zhongtao LI Xinzhong chan andrew State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology General Research Institute of China National Offshore Oil Corporation Faculty of Science and Technology Federation University Australia

Principal stress axes rotation influences the stress-strain behavior of sand under wave loading. A constitutive model for sand, which considers principal stress orientation and is based on generalized plasticity theory, is proposed. The new model, which employs stress invariants and a discrete memory factor during reloading, is original because it quantifies model parameters using experimental data. Four sets of hollow torsion experiments were conducted to calibrate the parameters and predict the capability of the proposed model, which describes the effects of principal stress orientation on the behavior of sand. The results prove the effectiveness of the proposed calibration method.

关键词： principal stress axes rotation constitutive model hollow torsional shear experiment

GPGPU-parallelised hybrid finite-discrete element modelling of rock chipping and fragmentation process in mechanical cutting

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第2期12卷 310-325页

作者： Mojtaba Mohammadnejad Sevda Dehkhoda Daisuke Fukuda Hongyuan Liu andrew chan School of Engineering College of Science and EngineeringUniversity of TasmaniaHobartTAS7001Australia CSIRO Minerals Resources Business UnitQCAT 1 Technology CourtPullenvaleQLD4069Australia Hatch BrisbaneQLD4000Australia Division of Sustainable Resources Engineering Faculty of EngineeringHokkaido UniversityHokkaidoJapan

Mechanical cutting provides one of the most flexible and environmentally friendly excavation *** has attracted numerous efforts to model the rock chipping and fragmentation process,especially using the explicit finite element method(FEM) and bonded particle model(BPM),in order to improve cutting *** study investigates the application of a general-purpose graphic-processing-unit parallelised hybrid finite-discrete element method(FDEM) which enjoys the advantages of both explicit FEM and BPM,in modelling the rock chipping and fragmentation process in the rock scratch test of mechanical rock *** input parameters of FDEM are determined through a calibration procedure of modelling conventional Brazilian tensile and uniaxial compressive tests of limestone,A series of scratch tests with various cutting velocities,cutter rake angles and cutting depths is then modelled using FDEM with calibrated input parameters.A few cycles of cutter/rock interactions,including their engagement and detachment process,are modelled for each case,which is conducted for the first time to the best knowledge of the authors,thanks to the general purpose graphic processing units(GPGPU) *** failure mechanism,cutting force,chipping morphology and effect of various factors on them are discussed on the basis of the modelled ***,it is concluded that GPGPU-parallelised FDEM provides a powerful tool to further study rock cutting and improve cutting efficiencies since it can explicitly capture different fracture mechanisms contributing to the rock chipping as well as chip formation and the separation process in mechanical ***,it is concluded that chipping is mostly owed to the mix-mode Ⅰ-Ⅱ fracture in all cases although mode Ⅱ cracks and mode Ⅰ cracks are the dominant failures in rock cutting with shallow and deep cutting depths,*** chip morphology is found to be a function of cutter velocdty,cutting depth and cutter rake angl

关键词： Numerical simulation Finite-discrete element method(FDEM) Rock cutting Chipping Cracking

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阿司匹林用于结直肠癌预防(英文)

化学进展 2013年第9期25卷 1450-1453页

作者： andrew T.chan Division of Gastroenterology Massachusetts General Hospital

一直以来,实验室研究、流行病学调查和最近的随机对照临床试验都表明阿司匹林可以降低结直肠癌的风险。出于对潜在的副作用如胃肠道出血的考虑,此前美国预防医学工作组的专家曾经建议对于处于平均风险的普通人群不要常规使用阿司匹林来... 详细信息

一直以来,实验室研究、流行病学调查和最近的随机对照临床试验都表明阿司匹林可以降低结直肠癌的风险。出于对潜在的副作用如胃肠道出血的考虑,此前美国预防医学工作组的专家曾经建议对于处于平均风险的普通人群不要常规使用阿司匹林来预防结直肠癌。然而,最近的高质量证据表明,阿司匹林不仅可以预防结直肠癌,对其它癌症也有预防作用。因此,值得重新考虑阿司匹林是否可常规用于癌症预防这个问题。本文总结了这些支持阿司匹林化学预防功效的有力证据,认为阿司匹林广泛的抗癌效应加上它在预防心血管疾病中的作用可能推动阿司匹林在众多患者中的长期应用。

关键词：阿司匹林结直肠癌随机对照试验非阿司匹林非甾体抗炎药化学预防

Tackling Global Grand Challenges in Our Cities

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Engineering 2016年第1期2卷 10-15页

作者： andrew Ka-Ching chan FREng Chairman Arup Group Trusts

In this Opening Session of the 2nd Global Grand Challenges Summit, the distinguished speakers before me have already done a great deal to set the scene and lay out some of the big issues and possible ways forward. No doubt we will hear more about the astounding developments we are seeing in information commu- nications technology （ICT） and other technologies in many sectors and of the opportunities they bring to help tackle our grand chal- lenges. And if I look through the prism of my own sector-design engineering in the built environment-I see exactly the same thing： Rapid advances in our thinking are taking place at dizzying speeds. Much of that is being driven by interdisciplinary collab- orations ranging well beyond the orbit of traditional engineering and construction.

关键词：信息通信技术设计工程跨学科合作轨道驱动开幕式 ICT

Pulmonary cystic disease associated with integumentary and renal manifestations

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The Journal of Biomedical Research 2013年第6期27卷 515-519页

作者： Katherine S.Cayetano Timothy E.Albertson andrew L.chan Department of Internal Medicine Division of Pulmonary Critical Care and Sleep Medicine University of CaliforniaDavis School of Medicine Veteran's Administration Northern California Health Care System

A 69-year-old man with multiple skin lesions on his face, neck and upper torso, which first appeared in the 3rd decade of his life, was admitted to our hospital. He had cystic changes in his lungs noted on chest computed to- mography （CT） scanning, as well as a left kidney mass. This patient exhibited a rare complex of renal, cutaneous and pulmonary manifestations, eponymously named Birt-Hogg-Dube syndrome, with characteristic skin features （fibrofolliculomas, trichodiscomas and acrochordons）. This syndrome is due to an autosomal dominant germ-line mutation of thefolliculin （FLCN） gene located at chromosome 17p11.2. Diagnosis and differentiation from other disease complexes including the skin, kidneys and lungs are important in prognostication and management of po- tentially life-threatening complications such as renal cell carcinoma and pneumothoraces.

关键词： pulmonary cystic disease Birt-Hogg-Dube syndrome folliculin mutation

Comparison of SCS and Green-Ampt Methods in Surface Runoff-Flooding Simulation for Klang Watershed in Malaysia

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Open Journal of Modern Hydrology 2013年第3期3卷 102-114页

作者： Reza Kabiri andrew chan Ramani Bai Faculty of Engineering University of Nottingham Malaysia Campus Kajang Malaysia.

The main aim in this research is comparison the parameters of some storm events in the watershed using two loss models in Unit hydrograph method by HEC-HMS. SCS Curve Number and Green-Ampt methods by developing loss model as a major component in runoff and flood modeling. The study is conducted in the Kuala Lumpurwatershed with674 km2 area located in Klang basin inMalaysia. The catchment delineation is generated for the Klang watershed to get sub-watershed parameters by using HEC-GeoHMS extension in ARCGIS. Then all the necessary parameters are assigned to the models applied in this study to run the runoff and flood model. The results showed that there was no significant difference between the SCS-CN and Green-Ampt loss method applied in the Klang watershed. Estimated direct runoff and Peak discharge (r = 0.98) indicates a statistically positive correlations between the results of the study. And also it has been attempted to use objective functions in HEC-HMS (percent error peaks and percent error volume) to classify the methods. The selection of best method is on the base of considering least difference between the results of simulation to observed events in hydrographs so that it can address which model is suit for runoff-flood simulation in Klang watershed. Results showed that SCS CN and Green-Ampt methods, in three events by fitting with percent error in peak and percent error in volume had no significant difference.

关键词： SCS Curve Number Green-Ampt Loss Method GIS HEC-Geo-HMS HEC-HMS Runoff Flood Modeling

Editorial for Multiscale&Multifield Coupling in Geomechanics

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 1919-1921页

作者： Min Wang Pengzhi Pan andrew H.C.chan Y.T.Feng T-3 Fluid Dynamics and Solid Mechanics Theoretical DivisionLos Alamos National LaboratoryNew MexicoUSA Institute of Rock and Soil Mechanics Chinese Academy of SciencesWuhanChina School of Engineering University of TasmaniaTasmaniaAustralia College of Engineering Swansea UniversityWalesUK

We are delighted to serve as guest editors for this special issue in the Journal of Rock Mechanics and Geotechnical *** purpose of this special issue is dedicated to gathering the latest research work on Multiscale&Multifield Coupling in Geomechanics,where we delve into the intricate interplay of various fields and scales that govern the behavior of *** total,30 manuscripts from USA,China,UK,Germany,Canada,India and United Arab Emirates are selected to be included in this issue.

关键词： materials. gathering mechanics

On the apparent line-of-sight alignment of the peak X-ray intensity of the magnetosheath and the tangent to the magnetopause,as viewed by SMILE-SXI

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Earth and Planetary Physics 2024年第1期8卷 155-172页

作者： andrew Read Department of Physics&Astronomy University of LeicesterLeicesterLE17RHUK

The Soft X-ray Imager(SXI)on board the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)spacecraft will be able to view the Earth’s magnetosheath in soft *** images of the X-ray emission visible from the position of SMILE are created for a range of solar wind densities by using 3 years of the SMILE mission orbit,together with models of the expected X-ray emissivity from the Earth’s *** from global magnetohydrodynamic simulations and a simple model for exospheric neutral densities are used to compare the locations of the lines of sight along which integrated soft X-ray intensities peak with the lines of sight lying tangent to surfaces(defined here to be the magnetopause)along which local soft X-ray intensities peak or exhibit their strongest gradients,or both,for strongly southward interplanetary magnetic field conditions when no depletion or low-latitude boundary layers are ***,in the parameter space of the various times and seasons,orbital phases,solar wind conditions,and magnetopause models,the alignment of the X-ray emission peak with the magnetopause tangent is good,or is not,is *** main results are as *** spacecraft needs to be positioned well outside the magnetopause;low-altitude times near perigee are not *** addition,there are seasonal aspects:dayside-apogee orbits are generally very good because the spacecraft travels out sunward at high altitude,but nightside-apogee orbits,behind the Earth,are bad because the spacecraft only rarely leaves the ***-apogee and dawnapogee orbits are ***-apogee orbits worsen slightly over the first three mission years,whereas nightside-apogee orbits improve ***,many more times of good agreement with the peak-to-tangent hypothesis occur when the solar wind is in a high-density state,as opposed to a low-density *** a high-density state,the magnetopause is compressed,and the spacecraft is more often a good d

关键词： X-rays magnetosphere magnetosheath magnetopause Solar wind Magnetosphere Ionosphere Link Explorer(SMILE) Earth solar wind charge exchange