2,222 research outputs found

    S.R. Lewis letter to Z. Eastman, March 5, 1874

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    Brief letter from S.R. Lewis to Z. Eastman, marking the announcement of an abolitionists' reunion to be held in Chicago in June of 1875. Lewis requests that Eastman, given his close acquaintance with Benjamin Lundy, prepare a public statement of remembrance on Lundy and his contributions to the anti-slavery movement. Benjamin Lundy (1789-1839) was a prominent Quaker abolitionist best known for his development of abolitionist periodicals. His Genius of Universal Emancipation was first published in 1821 from his home in Mt. Pleasant, Ohio, and enjoyed a wide circulation across the antebellum United States. In the 1820s, the young William Lloyd Garrison came to work for The Genius. Benjamin Lundy traveled widely seeking subscriptions to The Genius, giving talks about the anti-slavery movement, and observing and documenting the conditions of enslaved people across the Americas. He was also involved in the establishment of freed slave colonies in Mexico

    Modelling and optimization of a permanent-magnet machine in a flywheel

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    This thesis describes the derivation of an analytical model for the design and optimization of a permanent-magnet machine for use in an energy storage flywheel. A prototype of this flywheel is to be used as the peak-power unit in a hybrid electric city bus. The thesis starts by showing the feasibility of using a flywheel energy storage system for this application, as opposed to other energy storage technologies. It then continues by describing a prototype flywheel system and the required electrical machine: a radial-flux external-rotor permanent-magnet synchronous machine without slots in the stator iron and with a shielding cylinder. An analytical model for the machine is derived, based on 2D electromagnetic field calculations, including the reaction field of the eddy currents in the shielding cylinder. Torque and losses are calculated by means of the Theorem of Poynting and the Lorentz force. Such a machine was built and the analytical model has been validated by experimental measurements. Lastly, the thesis suggests and implements a machine optimization algorithm.Information Technology and System

    Design metrics for evaluating the propulsive efficiency of future ships

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    There is an increasing need for the ship design process to take account of environmental issues such as the emission of greenhouse gases and the likely extension of a carbon dioxide charging mechanism to international shipping. These issues, together with the need for economic viability, provide further incentives to improve the efficiency of propulsion of ships. The main components of powering are firstly reviewed. Individual components and other power saving devices are identified which should contribute to improvements in the overall efficiency of propulsion. Suitable design metrics and procedures, taking into account economic and environmental factors, are recommended for the design of future ships

    Description of S.R. Krom's system and machinery for dry crushing and concentrating ores.

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    Cover title.Mode of access: Internet.MAIN; TN500.K7 1876: Introduction signed by author, S.R. Krom
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