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Computational modelling and optimisation of the fabrication of nano-structures using focused ion beam and imprint forming technologies

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Journal of Physics: conference Series 2010年第1期253卷

作者： S Stoyanov C Bailey Y K Tang S Marson A Dyer D Allen M Desmulliez Computational Mechanics and Reliability Group School of Computing and Mathematical Sciences University of Greenwich London SE10 9LS UK Precision Engineering Centre Cranfield University Bedfordshire MK43 0AL UK MicroSystems Engineering Centre Heriot-Watt University Edinburgh EH14 4AS Scotland UK

Focused Ion Beam (FIB) and Nano-Imprint Forming (NIF) have gained recently major interest because of their potential to enable the fabrication of precision engineering parts and to deliver high resolution, low-cost and high-throughput production of fine sub-micrometre structures respectively. Using computational modelling and simulation becomes increasingly important in assessing capabilities and risks of defects with respect to product manufacturability, quality, reliability and performance, as well as controlling and optimising the process parameters. A computational model that predicts the milling depth as function of the ion beam dwell times and a number of process parameters in the case of FIB milling is investigated and experimentally validated. The focus in the NIF study is on modelling the material deformation and the filling of the pattern grooves during the mould pressing using non-linear large deformation finite element analysis with hyperelastic non-compressive material behaviour. Simulation results are used to understand the risk of imperfections in the pattern replication and to identify the optimal process parameters and their interaction.

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Microbial electrolysis cell modelling and simulation using MATLAB

Microbial electrolysis cell modelling and simulation using M...

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19th Australasian Universities Power engineering conference: Sustainable Energy Technologies and Systems, AUPEC'09

作者： Chaudhary, Anil Ozansoy, C.R. School of Engineering and Science Victoria University Melbourne VIC Australia

ISBN: (纸本)9780863967184

Hydrogen is considered as an attractive energy source in the 21 st century and as a fuel to replace conventional fossil fuels. Apart from being a potential source of unlimited clean power, it is also widely used in the chemical process industries and is likely to become a dominant fuel in the transportation sector. Microbial conversion of biomass is a newly developed and unique process, which involves the fermentation of organic substrates such as carbohydrates present in organic wastewater by a consortium of bacteria to produce hydrogen. The study outlined in this paper provides a review of the microbial conversion process and describes the mathematical modelling of the microbial electrolysis cell behaviour in MATLAB.

关键词： MATLAB

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modelling the Long Term Impact of Existing Products on Perceived Value of New Products

Modelling the Long Term Impact of Existing Products on Perce...

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IEEE International conference on Industrial engineering and engineering Management (IEEM 2009)

作者： Yan, B. W. Makinde, O. D. Cape Peninsula Univ Technol Fac Engn Dept Ind & Syst Engn POB 1906 ZA-7535 Bellville South Africa Cape Peninsula Univ Technol Fac Engn ZA-7535 Bellville South Africa

ISBN: (纸本)9781424448692

Innovation, continuous improvement, and changes forced by economics factors and marketing conditions are essential elements for bringing new products successfully in the marketplace;however, market competition with the existing products may have along term impact on the perceived value of the new products. Moreover, whether introducing new products/services or upgrades of existing products/services, better profit can be achieved by applying Lean product development technique and evaluating the long term impact of existing products on perceived value of new products will contribute in maintaining the desired profit margin. In this study, a two compartmental deterministic mathematical model for assessing the long term impact of existing products on perceived value of new products is proposed and analysed qualitatively. Numerical simulations support our analytical conclusions and illustrate possible behaviour scenarios of the model.

关键词： Long term impact Perceived Value Existing products New Products Lean Product Development mathematical Model

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Automatic procedure for realistic 3D finite element modelling of human brain for bioelectromagnetic computations

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Journal of Physics: conference Series 2010年第1期238卷

作者： K Y Aristovich S H Khan School of Engineering and Mathematical Sciences City University London Northampton Square London EC1V 0HB UK

Realistic computer modelling of biological objects requires building of very accurate and realistic computer models based on geometric and material data, type, and accuracy of numerical analyses. This paper presents some of the automatic tools and algorithms that were used to build accurate and realistic 3D finite element (FE) model of whole-brain. These models were used to solve the forward problem in magnetic field tomography (MFT) based on Magnetoencephalography (MEG). The forward problem involves modelling and computation of magnetic fields produced by human brain during cognitive processing. The geometric parameters of the model were obtained from accurate Magnetic Resonance Imaging (MRI) data and the material properties – from those obtained from Diffusion Tensor MRI (DTMRI). The 3D FE models of the brain built using this approach has been shown to be very accurate in terms of both geometric and material properties. The model is stored on the computer in Computer-Aided Parametrical Design (CAD) format. This allows the model to be used in a wide a range of methods of analysis, such as finite element method (FEM), Boundary Element Method (BEM), Monte-Carlo Simulations, etc. The generic model building approach presented here could be used for accurate and realistic modelling of human brain and many other biological objects.

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Road vehicle suspension modelling

Road vehicle suspension modelling

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作者： Popescu, Marius-Constantin Bulucea, Cornelia Aida Perescu-Popescu, Liliana Faculty of Electromechanical and Environmental Engineering University of Craiova Romania Elena Cuza College of Craiova Romania

ISBN: (纸本)9789604741281

The paper presents experimental results on modelling and simulation of vehicle suspension. Testing the performance practice of suspension dampers is performed using a device called Spider8, which is achieved by a mathematical model to assess the behaviour and performance suspension behaviour experimentally tested through simulation environment under MATLAB/Simulink. From the experimental data damper, model coefficients are determined suspension. Simulation results are compared with experimental data, after which the developed model is validated.

关键词： Magnetic levitation vehicles

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A framework of trans-boundary water conflict model based on qualitative simulation of behavior

A framework of trans-boundary water conflict model based on ...

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International conference on Management and Service Science, MASS 2009

作者： Niu, Wenjuan Wang, Huimin Qiu, Lei State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Institute of Management Science Hohai University Nanjing China

ISBN: (纸本)9781424446391

Applying computer simulation management experiment method to study the issue of trans-boundary water conflict is proposed in the paper. Based on the thought that the nature of water conflict is strained relations among peoples due to water benefit disputes, a trans-boundary water conflict system is regarded as a complex network system composed of conflict players and the interrelationships among them. So, the paper focuses on the fact that to solve water conflict, to control the human behaviours is the key issue. Therefore, firstly, by reviewing the status quo of water conflict model and the related researches, the existing problems of the present studies are analyzed and the computer simulation management experiment method is proposed to set up a human behaviour model and a water conflict multi-agent system. And then, a framework of trans-boundary water conflict model based on qualitative simulation of human behaviour is designed, including the network graph model of trans-boundary water conflict system, agent behaviour modelling, conflict relationship modelling and the model functions of conflict early warning and control. The framework diagram is given in the paper and the related technologies are pointed out. The paper aims at finding out an effective method to study and solve trans-boundary water conflict on the basis of understanding, early warning and controlling human behaviour in trans-boundary water conflict. ©2009 IEEE.

关键词： Multi agent systems

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TURBULENT IMPINGING FLOW SIMULATION FOR HIGH-LEVEL WASTE STORAGE AND PROCESSING APPLICATIONS

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11th International conference on Environmental Remediation and Radioactive Waste Management

作者： Rhea, S. Fairweather, M. Univ Leeds Sch Proc Environm & Mat Engn Inst Particle Sci & Engn Leeds LS2 9JT W Yorkshire England

ISBN: (纸本)9780791843390

The efficient storage and processing of high-level nuclear waste could be improved by a better understanding of the behaviour of the particle-laden fluid flows involved. This work reports a mathematical modelling study of impinging single-and two-phase turbulent jets that is of relevance to the flows used industrially to prevent the settling of solid particles in storage tanks, and to re-suspend particles that form a bed. A computational fluid dynamic model, that embodies a Lagrangian particle tracking technique, is applied to the prediction of these flows. Predictions in the free flow and wall regions, and along the stagnation line, of the single-phase flow are in reasonable accord with data, although the addition of particles results in less satisfactory agreement between predictions and measurements. The influence of particles is, however, reproduced qualitatively by the mathematical model, with quantitative differences attributable to a lack of particle drag in the simulations. Uncertainties in experimental parameters may be responsible for some of the differences between predictions and data, and examination of the data used casts doubts on its reliability. Further work is required in terms of the use of more advanced turbulence modelling techniques, and the provision of detailed and reliable data sets.

关键词： Turbulence Uncertainty Particulate matter Flow (Dynamics) Simulation Drag (Fluid dynamics) Modeling engineering simulation Storage tanks Radioactive wastes Storage Flow simulation Jets Fluid dynamics Reliability Computational fluid dynamics

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modelling Normative Frameworks Using Answer Set Programing

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10th International conference on Logic Programming and Nonmonotonic Reasoning

作者： Cliffe, Owen De Vos, Marina Padget, Julian Univ Bath Dept Comp Sci Bath BA2 7AY Avon England

ISBN: (纸本)9783642042379

Norms and regulations play an important role in the governance of human society. Social rules Such as laws, conventions and contracts prescribe and regulate our behaviour, however it is possible for us to break these rules at our discretion and face the consequences. By providing the means to describe and reason about norms in a computational context, normative frameworks may be applied to software systems allowing for automated reasoning about the consequences of socially acceptable and unacceptable behaviour. In this paper, we outline our mathematical formulation for normative frameworks and describe how its semantics can be represented in ASP. thus enabling the construction of models of normative systems that can be subjected to formal verification and that can act as functional repositories of normative knowledge for the software components that participate in them.

关键词： Semantics

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A Model of Probability Matching in a Two-Choice Task Based on Stochastic Control of Learning in Neural Cell-Assemblies 9

A Model of Probability Matching in a Two-Choice Task Based o...

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9th International conference on Cognitive Modeling, ICCM 2009

作者： Belavkin, Roman V. Huyck, Christian R. School of Engineering and Information Sciences Middlesex University LondonNW4 4BT United Kingdom

Donald Hebb proposed a hypothesis that specialised groups of neurons, called cell-assemblies (CAs), form the basis for neural encoding of symbols in the human mind. It is not clear, however, how CAs can be re-used and combined to form new representations as in classical symbolic systems. We demonstrate that Hebbian learning of synaptic weights alone is not adequate for all tasks, and that additional meta-control processes should be involved. We describe an earlier proposed architecture (Belavkin & Huyck, 2008) implementing such a process, and then evaluate it by modelling the probability matching phenomenon in a classic two-choice task. The model and its results are discussed in view of mathematical theory of learning, and existing cognitive architectures as well as some hypotheses about neural functioning in the brain. © ICCM *** rights reserved.

关键词： Decision making

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modelling guided waves in complex structures-part 1-Rail

Modelling guided waves in complex structures-part 1-Rail

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48th Annual conference of the British Institute of Non-Destructive Testing, BINDT 2009

作者： Gharaibeh, Yousef Ennaceur, Chiraz Mudge, Peter Balachandran, Wamadeva Section TWI Granta Park Great Abington Cambridge CB216AL United Kingdom School of Engineering and Design Brunel University Uxbridge Middlesex London UB83PH United Kingdom

ISBN: (纸本)9781617827891

Long Range Ultrasonic Testing (LRUT) uses guided waves in the kilohertz range to inspect many metres of an elongated component from a single point of access. This technique is well developed for structures having a simple geometry, such as plates, rods and pipes. However, this is a relatively new technology and there is still much to learn about the behaviour of guided waves and their application in complex structures. mathematical modelling techniques provide an efficient method of investigating this behaviour. This paper illustrates how modelling techniques have been used to design long range tests for railway rails. Part 2 of this work concentrates on application of modelling to wave propagation in plastic coated wire bundles. Utilising ultrasonic guided waves for the inspection of rails is challenging. This is mainly due to the irregular cross-sectional geometry of the rail, the existence of a large number of wave modes in the kilohertz range and the presence of a substantial dispersion effect. The aims of this work were: - To identify suitable wave modes that can be generated and propagated in each section of the rail (i.e. the head, web and foot), - To find a suitable means of excitation (i.e. transducer design) for the selected wave modes - To demonstrate the ability of the identified wave modes to detect flaws ABAQUS CAE, a Finite Element Analysis (FEA) software package, was used as a tool to provide a better understanding of the behaviour of guided waves in the rail structure. The FEA tool was used to examine the possibilities for generating and propagating guided waves in rails. Experimental trials were also conducted to validate the findings of the FEA. The findings demonstrate the ability of the identified wave modes to detect a range of different types of flaw at different locations within the rail cross-section over long test lengths. © (2009) by the British Institute of Non-Destructive Testing All rights reserved.

关键词： Guided electromagnetic wave propagation

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