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A novel twice-interpolation finite element method for solid mechanics problems

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Acta Mechanica sinica 2010年第2期26卷 265-278页

作者： c. Zheng s. c. Wu X. H. Tang j. H. Zhang state Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University 610065 Chengdu China state Key Laboratory of Digital Manufacturing and Equipment Technology Huazhong University of Science and Technology 430074 Wuhan China Department of Mechanical Engineering Centre for Advanced Computations in Engineering Science (ACES)National University of Singapore Singapore 117576 Singapore

Formulation and numerical evaluation of a novel twice-interpolation finite element method （TFEM） is presented for solid mechanics problems. In this method, the trial function for Galerkin weak form is constructed through two stages of consecutive interpolation. The primary interpolation follows exactly the same procedure of standard FEM and is further reproduced according to both nodal values and averaged nodal gradients obtained from primary interpolation. The trial functions thus constructed have continuous nodal gradients and contain higher order polynomial without increasing total freedoms. several benchmark examples and a real dam problem are used to examine the TFEM in terms of accuracy and convergence. compared with standard FEM, TFEM can achieve significantly better accuracy and higher convergence rate, and the continuous nodal stress can be obtained without any smoothing operation. It is also found that TFEM is insensitive to the quality of the elemental mesh. In addition, the present TFEM can treat the incompressible material without any modification.

关键词： Twice-interpolation finite element method·stress smoothing Volumetric locking Mesh distortion

Oxidative stress on plasmid DNA induced by inhalable particles in the urban atmosphere

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chinese science Bulletin 2004年第7期49卷 692-697页

作者： sHIZongbo sHAOLongyi T.P.jones A.G.Whittaker R.j.richards ZHANGPengfei TheKeyLaboratoryofcoalResourcesoftheMinistryofEducationofchina ChinaUniversityofMiningandTechnology.Beijing100083China DepartmentofResourcesandEarthsciences ChinaUniversityofMiningandTechnologyBeijing100083China DepartmentofEarth OceanandPlanetarySciencesCardiffUniversityCardiffCFIO3YEUK schoolofBiosciences CardiffUniversityCardiffCFIO3US.UK

Plasmid DNA assay is a newly-developed in vitro method to investigate bioreactivity of particles. In this paper, this method was used to study the bioreactivity of PM10 (particulate matter with aerodynamic diameter of less than 10 mm) and PM2.5 (particulate matter with aerodynamic diameter of less than 2.5 mm). samples and dust storm particles were collected in 2001 in an urban area, a satellite city and a clean air area in Beijing. A big difference was found for oxidative DNA stress induced by different particulate matter (PM) samples, with the TM50 (particle mass causing 50% damage to DNA) values varying by a factor over 10. This was closely dependent on the sizes of particles as well as the variation in relative proportion of mineral matter. PM2.5 samples generally impose larger oxidative stress on plasmid DNA than PM10 samples. Airborne particles collected during dust storm episodes, usually with a higher proportion of mineral matter, have a much lower oxidative capacity than those collected during non-dust storm episodes. PM samples and their water-soluble fractions usually have similar bioreactivities, demonstrating that oxidative capacity of Beijing airborne particles is mainly sourced from their water-soluble fractions.

关键词：空气输送粒子毒理学金属粒子水溶片段流行病学健康影响氧化性损伤质体DNA分析空气

A novel mesh-free poly-cell Galerkin method

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Acta Mechanica sinica 2009年第4期25卷 517-527页

作者： c. Zheng X. H. Tang j. H. Zhang s. c. Wu state Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University state Key Laboratory of Digital Manufacturing and Equipment Technology Huazhong University of Science and Technology centre for Advanced computations in Engineering science (AcEs) Department of Mechanical EngineeringNational University of Singapore

A novel numerical method is explored and named as mesh-free poly-cell Galerkin method. An improved moving least-square （MLs） scheme is presented, which can avoid the matrix inversion in standard MLs and can be used to construct shape functions possessing delta Kronecher property. A new type of local support is introduced to ensure the alignment of integral domains with the cells of the back-ground mesh, which will reduce the difficult in integration. An intensive numerical study is conducted to test the accuracy of the present method. It is observed that solutions with good accuracy can be obtained with the present method.

关键词： MPG cO-MsL Mesh-free Meshless Voronoi diagram

Kingfisher Attacks the china Market

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Frontiers of Business Research in china 2012年第1期6卷 156-168页

作者： M j Foster c s Tseng Kingston Business school Kingston Upon Thames KT2 7LB UK Department of Marketing City University of Hong Kong Hong Kong China

This article examines the entry to the chinese market of Kingfisher plc under its B＆Q brand, operating in the DIY or home improvement market. It is a pedagogically oriented case in the international strategy area, which deals with both the mode of market development by the company in china and some of the softer issues arising from that process relating to HR in the company and the inevitable cultural challenges it faced. The story begins in the mid-1990s and goes through to the early summer of 2010. On the one hand, the entry has been successful： B＆Q is now a significant presence in china, holding number one position in their chosen market, which is primarily highly fragmented; there is some concentration in four key cities in the wealthy east coast region; and it has made profits over a fair portion over the last decade. Lessons were learned from the initial mistakes and the core sales proposition in china has been crafted to differ from that in the original UK home base. However, for the last three completed financial years, losses have been booked and significant changes have been made or were planned at the time of writing. some changes were inevitable, but which were they （other than those where the chinese government changed its rules）？

关键词： Multinational corporation (MNc) retailing do-it-yourself (DIY) china regulation market development

Morphological, Physical, Mechanical, chemical and Thermal characterization of sustainable Indian Areca Fruit Husk Fibers （Areca catechu L.） as Potential Alternate for Hazardous synthetic Fibers

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journal of Bionic Engineering 2016年第1期13卷 156-165页

作者： j. s. Binoj R. Edwin Raj V. s. sreenivasan c. Rexin Thusnavis Department of Mechanical Engineering St. Xavier' s Catholic College of Engineering Nagercoil - 629003 India Department of Mechanical Engineering VV College of Engineering Tisaiyanvilai - 627657 India Department of chemistry St. Xavier' s Catholic College of Engineering Nagercoil - 629003 lndia

Natural fibers can play a major role in composite industry due to its renewable, biodegradable, and eco-friendly properties. Areca Fruit Husk （AFH） is rich in fiber, but is wasted in large quantity from tobacco industries. comprehensive characterization of AFH fiber is done to examine its morphological, physical, mechanical, chemical and thermal properties. High cellulose content of the fiber （57.35 wt%） provides better tensile strength （231.66 MPa） whereas the porous surface morphology （40.8 %） ensures better bonding with the matrix. Moreover, the low density of the fiber （0.78 ***^-3） makes it an attractive alternative for hazardous synthetic fibers. The semi-crystalline nature and large crystalline size of the fiber reduce the water absorption char- acteristics. The thermo gravimetric analysis confirms its stability up to 240℃, which is higher than the polymerization tem- perature. The results confirm the potential of AFH fibers as a reinforcement in bio-reinforced polymer composites for automo- tive and structural applications.

关键词： bio-reinforced polymer composites Areca husk fibers physical properties chemical properties

seismic health monitoring of Rc frame structures using smart aggregates

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Earthquake Engineering and Engineering Vibration 2013年第1期12卷 25-32页

作者： Wen-I Liao c.H.Lin j.s.Hwang G.song Department of civil Engineering Taipei University of Techology (NTUT) Department of construction Engineering Taiwan University of Science and Technology Department of Mechanical Engineering University of Houston

structural health monitoring of Rc structures under seismic loads has recently attracted much attention in the earthquake engineering research community. In this study, a piezoceramic-based device called ＂smart aggregate＂ was used for the health monitoring of Rc frame structures under earthquake excitations. Three Rc moment frames instrumented with smart aggregates were tested using a shaketable with different ground excitation intensities. Distributed piezoceramic- based smart aggregates were embedded in the Rc structures and used to monitor their health condition during the tests. The sensitivity and effectiveness of the proposed piezoceramic-based approach were investigated and evaluated by analyzing the measured responses. The displacement ductility demand of the structural members was calculated and compared with the damage index determined from the health monitoring system. The comparison shows that the damage index is compatible with the calculated ductility demand.

关键词： smart aggregate health monitoring Rc frame shaketable piezoceramic

A model to determine soiling,shading and thermal losses from PV yield data

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clean Energy 2022年第2期6卷 372-391页

作者： s.Ghosh j.N.Roy c.chakraborty Advanced Technology Development centre Indian Institute of Technology Kharagpur721302India Department of Electrical Engineering Indian Institute of Technology Kharagpur721302India

Apart from being a clean source of energy,photovoltaic(PV)power plants are also a source of income generation for its investors and ***,mitigation of system losses is crucial for economic operation of PV *** losses due to soiling,shading and temperature in PV plants go as high as 50%.Much of these losses are unaccounted initially,which can jeopardize the economic viability of PV *** paper aims to provide a model to determine losses due to soiling,shading and temperature using quantities like irradiance,cell temperature,Dc power and current,which are readily available in PV yield data captured by the remote monitoring system,without involving any additional sensors or *** this study,soiling,shading and thermal losses were calculated using PV yield data obtained from a 30-kWp PV plant located in Kharagpur,*** results showed soiling and shading losses as high as 25.7%and 9.7%,respectively,in the month of *** loss was verified by measuring transmittance loss of coupon glasses installed in the vicinity of the *** loss was verified by shadow simulation using an architectural tool(sketchUp).Array thermal loss obtained using the proposed methodology was found to be in line with the estimated value obtained from PVsyst ***,using time-series data,the energy losses corresponding to soiling,shading and temperature effects were calculated by a numerical-integration *** monetary loss due to these energy losses thus obtained provides criteria for deciding when to mitigate the sources of these losses.

关键词： solar photovoltaics solar PV plant soiling losses solar shading losses solar PV system losses

EFFEcTs OF cHEMIcAL MODIFIcATIONs AND MMT NANOcLAY ADDITION ON TRANsPORT PHENOMENA OF NATURALLY WOVEN cOcONUT sHEATH/POLYEsTER NANOcOMPOsITEs

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chinese journal of Polymer science 2013年第8期31卷 1074-1086页

作者： N. Rajini j.T. Winowlin jappes s. Rajakarunakaran c. Bennet centre for composite Materials Department of Mechanical Engineering Kalasalingam University center for Advanced Materials Department of Mechanical Engineering Cape Institute of Technology Levengipuram

studies on the behavior of molecular transport properties such as thermal conductivity, gas permeability, volume and surface resistivity have been carried out for the naturally woven coconut sheath （cs） fiber reinforced composites with the addition of nanoclay and chemical treatment of fiber. The compression molding technique was used to fabricate the coconut sheath/clay reinforced hybrid composites. The morphological studies such as X-ray diffractogram （XRD）, transmission electron microscopy （TEM） and scanning electron microscopy （sEM） have been carried out for polyester nanocomposites and coconut sheath fiber. The decreased gas permeability, thermal conductivity and volume and surface resistivity have been observed with increasing the weight percentage of nanoclay in polyester matrix. In chemical modifications, the alkali and silane treated coconut sheath reinforced composites have shown great influence on the transport properties due to the increasing hydrophilic nature by the topographical changes at the fiber surface. Dielectric strength has also been reported in this paper for all types of composites. Infra-red （IR） spectra have also been taken to study the physical and chemical structural changes of treated coconut sheath.

关键词： Nanoclay coconut sheath Gas permeability TEM sEM FTIR.

MIcROsTRUcTUREs AND THE sTRUcTURE sTABILITY OF INcONEL 725, A NEW AGE-HARDENABLE cORROsION REsIsTANT sUPERALLOY

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Acta Metallurgica sinica(English Letters) 2003年第2期16卷 145-150页

作者： j.X.Dong M.c.Zhang s.K.Mannan school of Materials science and Engineering University of Science and Technology BeijingBeijing 100083ChinaSchool of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083ChinaSpecial Metals CorporationHuntingtonWV25705USA

INcONEL725 is a highly corrosion resistant nickel based alloy capable of being age-hardened to high strength levels. The micro structure observations and the phase identification after a standard heat treatment were investigated. The results show that the precipitation phases include the strengthening phasesγ', γ', and 8 phase, primary carbide phase Tic, as well as M6 c carbide and a little extent Mc (mainly Tic) precipitates which nucleate mainly at grain boundaries. An isothermal aging study was carried out on this alloy for up to 10 000 hours at 593℃. This additional aging did not affect the tensile strength. However, micro structures show that the thermal exposure has a little additional effect. With increasing the exposure time, the size of γ' phase slightly increases, almost no change for γ' phase, while M6c carbides precipitated at grain boundaries have an increased and complex tendency on a few grain boundaries. The experimental results illustrate the excellent structure stability of the age-hardenable IN725 at 593℃.

关键词： superalloy INcONEL725 micro structure long-term exposure