134,414 research outputs found

    Machining dynamics: Fundamentals, applications and practices

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    Information regarding this edited book can be found at this link:Machining dynamics play an essential role in the performance of machine tools and machining processes in manufacturing. Current advances in computational modelling, sensors, diagnostic equipment and analysis tools,3D surface metrology and manufacturing science are giving researchers and practising engineers a new perspective on the machining process. Machining Dynamics: Fundamentals, Applications and Practices reflects the new integrated approach to studying machining dynamics by presenting state-of-the-art applications, practices and research in the field. Written by experts in each field, the first part of the book presents the basic theory, analysis and control methodology in addition to detailed modelling and diagnostic techniques for machining dynamics, while part two focuses on applying the fundamentals of machining dynamics in a variety of machining processes including turning, grinding, gear machining and nontraditional machining. Advanced undergraduate and postgraduate students studying manufacturing engineering and machining technology will find Machining Dynamics: Fundamentals, Applications and Practices a comprehensive and up-to-date introduction to the subject while the book’s thoroughness allows it to serve as a useful reference for manufacturing engineers, production supervisors, planning and application engineers and designers. The Springer Series in Advanced Manufacturing publishes the best teaching and reference material to support students, educators and practitioners in manufacturing technology and management. This international series includes advanced textbooks, research monographs, edited works and conference proceedings covering all subjects in advanced manufacturing. The series focuses on new topics of interest, new treatments of more traditional areas and coverage of the applications of information and communication technology (ICT) in manufacturing

    Gamma-ray Emission from Millisecond Pulsars - An Outergap Perspective

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    In this review paper we explain the following gamma-ray emission features from the millisecond pulsars. (1)Why is the dipolar field of millisecond pulsars so weak but the magnetic pair creation process may still be able to control the size of the outergap? (2)A sub-GeV pulse component could occur in the vicinity of the radio pulse of millisecond pulsars. (3)Orbital modulated gamma-rays should exist in the black widow systems for large viewing angle.Comment: This is the proceeding paper of 3rd Fermi Asian Network Workshop and will be published by Journal of the Korea Space Science Societ

    Internet enabled modelling of extended manufacturing enterprises using the process based techniques

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    The paper presents the preliminary results of an ongoing research project on Internet enabled process-based modelling of extended manufacturing enterprises. It is proposed to apply the Open System Architecture for CIM (CIMOSA) modelling framework alongside with object-oriented Petri Net models of enterprise processes and object-oriented techniques for extended enterprises modelling. The main features of the proposed approach are described and some components discussed. Elementary examples of object-oriented Petri Net implementation and real-time visualisation are presented

    Modelling and simulation of the dynamic cutting process and surface topography generation in nano/micro cutting

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    In nano/micro cutting process, the surface quality is heavily dependent on all the dynamic factors in machining including those from the material, tooling, cutting parameters, servo accuracy, mechanical structure deformation, and non-linear factors as well. The machined surfaces are generated based on the tool profile and the real tool path combining with the various external and internal disturbances. To bridge the gap between the machining conditions and the surface quality, the integrated simulation system presented involves the dynamic cutting process, control/drive system and surface generation module. It takes account all the intricate aspects of the cutting process, such as material heterogeneity, regenerative chatter, built-up edge (BUE), spindle run-out, environmental vibration, and tool interference, etc. The frequency ratio method is used to interpret the surface topography and texture formation. The proposed systematic modelling approach is verified by the cutting experiment

    Experimental investigation on micromilling of oxygen-free, high-conductivity copper using tungsten carbide, chemistry vapour deposition and single-crystal diamond micro tools

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    Insufficient experimental data from various micro tools limit industrial application of the micromilling process. This paper presents an experimental comparative investigation into micromilling of oxygen-free, high-conductivity copper using tungsten carbide (WC), chemistry vapour deposition (CVD) diamond, and single-crystal diamond micromilling tools at a uniform 0.4mm diameter. The experiments were carried out on an ultra-precision micromilling machine that features high dynamic accurate performance, so that the dynamic effect of the machine tool itself on the cutting process can be reduced to a minimum. Micromachined surface roughness and burr height were characterized using white light interferometry, a scanning electron microscope (SEM), and a precision surface profiler. The influence of variation of cutting parameters, including cutting speeds, feedrate, and axial depth of cut, on surface roughness and burr formation were analysed. The experimental results show that there exists an optimum feedrate at which best surface roughness can be achieved. Optical quality surface roughness can be achieved with CVD and natural diamond tools by carefully selecting machining conditions, and surface roughness, Ra, of the order of 10nm can also be obtained when using micromilling using WC tools on the precision micromilling machine.EU FP6 MASMICRO projec

    Technology Transfer, Foreign Direct Investment and International Trade

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    By developing a Ricardian trade model that features technology transfer via foreign direct investment (FDI), we show that technology transfer via multinational enterprises (MNEs) increases world output and trade in goods and services. When there are many goods a continuous reduction in the cost of technology transfer will cause increasingly more technologically advanced goods to go through the product cycle, i.e., goods initially produced in the advanced North are later produced in the backward South as a result of increased technology transfer via MNEs.

    Low carbon manufacturing: Characterization, theoretical models and implementation

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    Today, the rising of carbon dioxide (CO2) emissions is becoming the crucial factor for global warming especially in industrial sectors. Therefore, the research to reduce carbon intensity and enhance resources utilization in manufacturing industry is starting to be a timely topic. Low carbon manufacturing (LCM) can be referred to the manufacturing process that produces low carbon emissions intensity and uses energy and resources efficiently and effectively during the process as well. In this paper, the concepts of LCM are discussed and the LCM associated theoretical models, characterization and implementation perspective explored. The paper is structured in four parts. Firstly, the conception of low carbon manufacturing is critically reviewed then the characterization of low carbon manufacturing is discussed and formulated. Third part, the theoretical models are developed with initial models by using the theory from supply chain modeling and linear programming solutions (LP). The models show the relationship of resource utilizations and related variables for LCM in two levels: shop-floor and extended supply chain. Finally, the pilot implementations of LCM are discussed with two approaches: desktop or micro machines and devolved manufacturing. The paper is concluded with further discussions on the potential and application of LCM for manufacturing industry

    Rapid manufacturing as a tool for agile manufacturing: applications and implementation perspectives

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    Manufacturing engineers and technologists around the globe are already well familiar with manufacturing methodologies and systems developments in the last part of the twentieth century. Many are probably also familiar with the current state of Rapid Prototyping (RP) technologies, especially in the areas of concept model making and prototype development. They may not however, be so familiar with the more recent developments of these technologies towards Rapid Manufacturing (RM) and the directions which the applications of RM technologies are taking for agile manufacturing purposes in particular. This paper critically reviews the various technologies currently available, outlines development trends in RM, discusses the approach, application and implementation perspectives by which these RM technologies are applied for increasing agility and responsiveness in manufacturing. Furthermore, the paper describes two case study examples to further illustrate the application scenarios in agile manufacturing before concluding remarks

    Probing the properties of the pulsar wind via studying the dispersive effects in the pulses from the pulsar companion in a double neutron-star binary system

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    The velocity and density distribution of e±e^\pm in the pulsar wind are crucial distinction among magnetosphere models, and contains key parameters determining the high energy emission of pulsar binaries. In this work, a direct method is proposed, which might probe the properties of the wind from one pulsar in a double-pulsar binary. When the radio signals from the first-formed pulsar travel through the relativistic e±e^\pm flow in the pulsar wind from the younger companion, the components of different radio frequencies will be dispersed. It will introduce an additional frequency-dependent time-of-arrival delay of pulses, which is function of the orbital phase. In this paper, we formulate the above-mentioned dispersive delay with the properties of the pulsar wind. As examples, we apply the formula to the double pulsar system PSR J0737-3039A/B and the pulsar-neutron star binary PSR B1913+16. For PSR J0737-3039A/B, the time delay in 300\,MHz is 10μ\lesssim10\mus near the superior-conjunction, under the optimal pulsar wind parameters, which is \sim half of the current timing accuracy. For PSR B1913+16, with the assumption that the neutron star companion has a typical spin down luminosity of 103310^{33}\,ergs/s, the time delay is as large as 1020μ10\sim20\mus in 300\,MHz. The best timing precision of this pulsar is 5μ\sim5\mus in 1400\,MHz. Therefore, it is possible that we can find this signal in archival data. Otherwise, we can set an upper-limit on the spin down luminosity. Similar analysis can be apply to other eleven known pulsar-neutron star binariesComment: 6 pages, 6 figures, accepted for publication in MNRA

    Semi-Competing Risks on A Trivariate Weibull Survival Model

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    A setting of a trivairate survival function using semi-competing risks concept is proposed. The Stanford Heart Transplant data is reanalyzed using a trivariate Weibull distribution model with the proposed survival function
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