15,924 research outputs found

    Hybrid Magnetic Suspension Actuator for Precision Motion Control

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    Market structure, Regulation and the Speed of Mobile Network Penetration

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    The speed of market penetration (i.e. diffusion) is an important summary measure of how well the market works for potential consumers of a new product. This paper identifies the structural features associated with rapid diffusion of mobile telephony. We use a sample of thirty countries over the sixteen years in which average penetration rose from 2% to 97% of the population (earlier studies observed only the initial years of diffusion during which there was typically only one or two networks). We find a non-monotonic effect of market structure, with three firms maximising consumer uptake. Privatization and independent regulation are also important positive factors. Further results show that the market structure effect works only partially through the level of prices

    Experimental Study of the Role of Atomic Interactions on Quantum Transport

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    We report an experimental study of quantum transport for atoms confined in a periodic potential and compare between thermal and BEC initial conditions. We observe ballistic transport for all values of well depth and initial conditions, and the measured expansion velocity for thermal atoms is in excellent agreement with a single-particle model. For weak wells, the expansion of the BEC is also in excellent agreement with single-particle theory, using an effective temperature. We observe a crossover to a new regime for the BEC case as the well depth is increased, indicating the importance of interactions on quantum transport.Comment: 4 pages, 3 figure

    In-situ steel solidification imaging in continuous casting using magnetic induction tomography

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    : Solidification process in continuous casting is a critical part of steel production. The speed and quality of the solidification process determines the quality of final product. Computational fluid dynamics (CFD) simulations are often used to describe the process and design of its control system, but so far, there is no any tool that provides an on-line measurement of the solidification front of hot steel during the continuous casting process. This paper presents a new tool based on magnetic induction tomography (MIT) for real time monitoring of this process. The new MIT system was installed at the end of the secondary cooling chamber of a casting unit and tested during several days in a real production process. MIT is able to create an internal map of electrical conductivity of hot steel deep inside the billet. The image of electrical conductivity is then converted to temperature profile that allows the measurement of the solid, mushy and liquid layers. In this study, such a conversion is done by synchronizing in one time step the MIT measurement and the thermal map generated with the actual process parameters available at that time. The MIT results were then compared with the results obtained of the CFD and thermal modelling of the industrial process. This is the first in-situ monitoring of the interior structure during a real continuous casting.The SHELL-THICK project has received funding from EU Research Fund for Coal and Steel under grant number 709830. This study reflects only the author's views and the European Commission is not responsible for any use that may be made of the information contained therein

    The need for open data sharing in the era of global pandemics

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    Since the start of the pandemic, data on different countries’ case counts has been readily available. However, not all data is equally useful. In this post, Bernardo Gutierrez and Sabrina Li, from the Open COVID-19 Data Working Group and the Oxford Martin School, outline the need for much more detailed, open and accessible sharing to inform science and policymaking. The authors argue for open, accessible data sharing and highlight the need for data collection processes to be increasingly homogenised
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