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A method for assessing nanomaterial dispersion quality based on principal component analysis of particle size distribution data

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Particuology 2015年第5期13卷 30-38页

作者： r.Tantra C.Oksel K.N.robinson A.Sikora X.z.wang T.A.Wilkins National Physical Laboratory Institute of Particle Science and Engineering School of Chemical and Process EngineeringUniversity of Leeds

Seemingly contradictory findings between studies are a major issue in nanoecotoxicological research and have been explained as a result of the lack of comparability between assay methods, with dispersion of nanomaterials being identified as a key factor. Here we show the use of a multivariate method, principal component analysis （PCA）, as a tool in protocol development and categorization of dispersion quality. results show the significance of particle concentration within a protocol, and its effect on repeatability. Our results suggest that future studies should involve the use of PCA as a powerful data exploration tool to facilitate method development, comparability and integration of data across different laboratories.

关键词： Nanomaterial characterization Principal component analysis Nanotoxicology Dispersion Particle size distribution

Large eddy simulation of turbulent diffusion flame combustion using a conserved scalar methodology

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航空动力学报 2007年第7期22卷 1106-1117页

作者： K. wang z. Yang J. J. McGuirk Department of Aeronautical and Automotive EngineeringLoughborough University Loughborough Leicestershire LE11 3TU UK

The present paper describes an LES prediction of turbulent diffusion flame combustion in a simplifled axi-symmetric combustor *** calculations are carried out using a well-tested finite volume incompressible LES code which has been modified to handle variable density and reacting *** basic mixture fraction conserved scalar method *** with the chemical state relationships described by fast *** turbulence-chemistry interaction is modelled by a sub-grid PDF method and the PDF is assumed to follow a Beta-function *** LES predictions have been time-averaged over 3.5 flow-through times to generate the mean radial profiles of mixture fraction,product mass fraction,temperature,axial velocity and axial *** agreement of the LES predictions with the experimental data is good for all the above quantities at four different axial positions with largest differences at the first measurement *** LES method also provides information on the unsteady nature of turbulent diffusion *** turbulent reacting flows with large density ratio,it was found necessary to use a relaxation method in order to remove unphysical high-frequency fluctuations and to maintain numerical stability.

关键词：大涡模拟湍流扩散数量方法论弛豫法燃烧理论

Human Toxicosis Caused by Moldy rice Contaminated with Fusarium and T-2 Toxin

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Biomedical and Environmental Sciences 1993年第1期6卷 65-70页

作者： z G wang J N Feng z Tong zhejiang Institute of Food Safety Control and Inspection Hangzhou China.

This is the first report on human toxicosis in China caused by moldy rice contaminated with Fusarium and T-2 toxin due to heavy rainfall during rice harvest season. One hundred and sixty-five persons ate the moldy rice and ninety-seven persons fall ill of food poisoning. The incidence was 58.8% and latent period was 10-30 min. The chief symptoms were nausea, dizziness, vomiting, chills, abdominal distension, abdominal pain, thoracic stuffiness and diarrhea. The fungi isolated from the moldy rice were predominantly Fusarium heterosporum (F. heterosporum) and F. graminearum. T-2 toxin was found in these moldy rice and the highest level was 420 ppb. The chief causative agent of intoxication was T-2 toxin.

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Shape Memory Alloy-reinforced Metal-Matrix Composites:A review

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Acta Metallurgica Sinica(English Letters) 2014年第5期27卷 739-761页

作者： D.r.Ni z.Y.Ma Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

Metal-matrix composites reinforced with shape memory alloys （SMA, including long fiber, short fiber, and particle） are ＂intelligent materials＂ with many special physical and mechanical properties, such as high damping property, high tensile strength, and fatigue resistance. In this review article, the fabrication method, microstructure, interface reaction, modeling, and physical and mechanical properties of the composites are addressed. Particular emphasis has been given to （a） fabrication and microstructure of aluminum matrix composites reinforced with SMAs, and （b） shape memory effect on the physical and mechanical properties of the composites. While the bulk of the information is related to aluminum matrix composites, important results are now available for other metal-matrix composites.

关键词： Metal-matrix composites Shape memory alloy Fabrication method Microstructure Interface reaction Mechanical properties

An Aluminide Surface Layer Containing Lower-Al on Ferritic-Martensitic Steel Formed by Lower-Temperature Aluminization

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Journal of Materials Science & Technology 2015年第12期31卷 1268-1273页

作者： S.Guo z.B.wang K.Lu Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

An aluminide（AlFe and α-（FeAl）） surface layer containing lower-Al was formed on ferritic-martensitic steel P92 by means of surface mechanical attrition treatment（SMAT） combined with a duplex aluminization process at lower temperatures,i.e.a packed aluminization followed by a diffusion annealing treatment below its tempering *** tests indicated that the lower-Al surface layer formed on the SMAT sample is more resistant to cracking and has better adhesion to the substrate in comparison with the Al 5Fe 2 layer formed on the as-received sample after the duplex aluminization *** steam oxidation measurements showed that the oxidation resistance is increased significantly by the lower-Al surface layer due to the formation of a protective（Fe,Cr）Al 2O 4 *** rate constant of oxidation was estimated to decrease from-0.849 mg^2 cm^-4h^-1 of the as-received material to^0.011 mg^2 cm^-4 h^-1 of the AlFe layer at 700 ℃.

关键词： Surface mechanical attrition treatment (SMAT) Ferritic-martensitic steel Lower-temperature aluminization Aluminide Steam oxidation

Interaction between Struts and Swirl Flow in Gas Turbine Exhaust Diffusers

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Journal of Thermal Science 2005年第4期14卷 314-320页

作者： roman z.PIETrASCH Joerg r.SEUME Turbomachinery Laboratory University of Hannover Appelstr. 9 D-31678 Hannover Germany

The increasing use of gas turbines in combined cycle power plants together with the high amount of kinetic energy in modem gas turbine exhaust flows focuses attention on the design of gas turbine diffusers as the connecting part between the Brayton/Joule and the rankine parts of the combined cycle. A scale model of a typical gas turbine exhaust diffuser is investigated experimentally. The test rig consists of a radial type, variable swirl generator which provides the exhaust flow corresponding to different gas turbine operating conditions. Static pressure measurements are carried out along the outer diffuser walls and along the hub of the annular part and along the centerline of the conical diffuser. Velocity distributions at several axial positions in the annular and conical diffuser have been measured using a Laser Doppler Velocimeter （LDV）. Pressure recovery coefficients and velocity profiles are depicted as a function of diffuser length for several combinations of swirl strength, tip flow and strut geometries. The diffuser without struts achieved a higher pressure recovery than the diffuser with struts at all swirl angle settings. The diffuser with cylindrical struts achieved a higher pressure recovery than the diffuser with profiled struts at all swirl angle ***. Inlet flows with swirl angles over 18° affected the pressure recovery negatively for all strut configurations.

关键词： gas turbine exhaust diffuser swirl struts pressure recovery coefficient.

A method for analyzing on-line video images of crystallization at high-solid concentrations

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Particuology 2008年第1期6卷 9-15页

作者： Jian Wan Cai Y. Ma Xue z. wang Institute of Particle Science and Engineering School of Process Environmental and Materials Engineering University of Leeds Leeds LS2 9JT UK

recent research has demonstrated that on-line video imaging is a very promising technique for monitoring crystallization processes. The bottleneck in applying the technique for real-time closed-loop control is considered as image analysis that needs to be robust, fast and able to handle varied image qualities due to temporal variations of operating conditions such as mixing and solid concentrations. Image analysis at highsolid concentrations turns out to be extremely challenging because crystals tend to overlap or attach to each other and the boundaries between the crystals are usually ambiguous. This paper presents an image segmentation algorithm that can effectively deal with images taken at high-solid concentrations. The method segments crystals attached to each other along the mostly related concave points on the contours of crystal blocks. The detailed procedure is introduced with application to crystallization of L-glutamic acid in a hot-stage reactor.

关键词： Crystallization High-solid concentrations Image processing Multi-scale segmentation Watershed segmentation Crystal size distribution

Effect of Carbon Nanotube Orientation on Mechanical Properties and Thermal Expansion Coefficient of Carbon Nanotube-reinforced Aluminum Matrix Composites

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Acta Metallurgica Sinica(English Letters) 2014年第5期27卷 901-908页

作者： z.Y.Liu B.L.Xiao W.G.wang z.Y.Ma School of Materials Science and Engineering Dalian University of Technology Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences School of Mechanical Engineering Liaoning Shihua University

Carbon nanotube-reinforced 2009Al （CNT/2009Al） composites with randomly oriented CNTs and aligned CNTs were fabricated by friction stir processing （FSP） and FSP-rolling, respectively. The CNT/2009A1 composites with aligned CNTs showed much better tensile properties at room temperature and elevated temperature compared with those with the randomly oriented CNTs, which is mainly attributed to larger equivalent aspect ratio of the CNTs and avoidance of preferential fracture problems. However, much finer grain size was not beneficial to obtaining high strength above 473 K. The aligned CNTs resulted in tensile anisotropy, with the best tensile properties being achieved along the direction of CNT aligning. As the off-axis angle increased, the tensile properties were reduced due to the weakening of the load transfer ability. Furthermore, aligned CNTs resulted in much lower coefficient of thermal expansion compared with randomly oriented CNTs.

关键词： Carbon nanotubes Metal matrix composites Mechanical properties Coefficient of thermalexpansion Friction stir processing

Fluid-Structure Interaction Analysis of Flexible Plate with Partitioned Coupling Method

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China Ocean Engineering 2019年第6期33卷 713-722页

作者： W.z.,Lim r.Y.,Xiao Faculty of Computing Engineering and the Built EnvironmentBirmingham City UniversityBirminghamB47XGUnited Kingdom Department of Urban Engineering School of The Built Environment and ArchitectureLondon South Bank UniversityBorough RoadLondonSE10AAUnited Kingdom

The development and rapid usage of numerical codes for fluid-structure interaction(FSI) problems are of great relevance to researchers in many engineering fields such as civil engineering and ocean engineering. This multidisciplinary field known as FSI has been expanded to engineering fields such as offshore structures, tall slender structures and other flexible structures applications. The motivation of this paper is to investigate the numerical model of two-way coupling FSI partitioned flexible plate structure under fluid flow. The adopted partitioned method and approach utilized the advantage of the existing numerical algorithms in solving the two-way coupling fluid and structural interactions. The flexible plate was subjected to a fluid flow which causes large deformation on the fluid domain from the oscillation of the flexible plate. Both fluid and flexible plate are subjected to the interaction of load transfer within two physics by using the strong and weak coupling methods of MFS and Load Transfer Physics Environment, respectively. The oscillation and deformation results have been validated which demonstrate the reliability of both strong and weak method in resolving the two-way coupling problem in contribution of knowledge to the feasibility field study of ocean engineering and civil engineering.

关键词： fluid-structure interaction flexible plate structure two-way coupling partitioned method numerical simulation