41,286 research outputs found

    Automation of Bosch reaction for CO2 reduction

    Get PDF
    System for collecting excess carbon dioxide in space cabin is described. System collects carbon dioxide exhaled by human inhabitants and decomposes gas into carbon and water by reaction with hydrogen in presence of catalyst. Diagram of equipment involved in reaction is included

    J.R.R. Tolkien: Romanticist and Poet (2017) by Julian Eilmann

    Get PDF
    Book review , by John R. Holmes, of J.R.R. Tolkien: Romanticist and Poet (2017) by Julian Eilman

    Catalyst cartridge for carbon dioxide reduction unit

    Get PDF
    A catalyst cartridge, for use in a carbon dioxide reducing apparatus in a life support system for space vehicles, is described. The catalyst cartridge includes an inner perforated metal wall, an outer perforated wall space outwardly from the inner wall, a base plate closing one end of the cartridge, and a cover plate closing the other end of the cartridge. The cover plate has a central aperture through which a supply line with a heater feeds a gaseous reaction mixture comprising hydrogen and carbon dioxide at a temperature from about 1000 to about 1400 F. The outer surfaces of the internal wall and the inner surfaces of the outer wall are lined with a ceramic fiber batting material of sufficient thickness to prevent carbon formed in the reaction from passing through it. The portion of the surfaces of the base and cover plates defined within the inner and outer walls are also lined with ceramic batting. The heated reaction mixture passes outwardly through the inner perforated wall and ceramic batting and over the catalyst. The solid carbon product formes is retained within the enclosure containing the catalyst. The solid carbon product formed is retained within the enclosure containing the catalyst. The water vapor and unreacted carbon dioxide and any intermediate products pass through the perforations of the outer wall

    Fore and Aft: Abstraction in Tolkien’s “Ishness” Designs

    Get PDF
    Though Tolkien\u27s artwork tended toward the figural, there was a period during his undergraduate years in which he created abstracts under the name of Ishnesses. This essay examines the nature of abstraction, how it relates to medieval concepts of art, and how it relates to Tolkien\u27s visionary painting of subjects not in the primary world but in the Middle-earth of his vast imagination. Fore and Aft: Abstraction, Vanishing Point and Symmetry in Tolkien’s “Ishness” Design

    On the role of oil-film bearings in promoting shaft instability: Some experimental observations

    Get PDF
    The occurrence of oil whirl instability in rigid and flexible rotor systems was investigated. The effect of various bearing parameters on the oil whirl frequency and amplitude of rigid and flexible shafts supported on fluid film bearings was also studied

    Simulation of mass storage systems operating in a large data processing facility

    Get PDF
    A mass storage simulation program was written to aid system designers in the design of a data processing facility. It acts as a tool for measuring the overall effect on the facility of on-line mass storage systems, and it provides the means of measuring and comparing the performance of competing mass storage systems. The performance of the simulation program is demonstrated

    Dynamical Systems, Stability, and Chaos

    Full text link
    In this expository and resources chapter we review selected aspects of the mathematics of dynamical systems, stability, and chaos, within a historical framework that draws together two threads of its early development: celestial mechanics and control theory, and focussing on qualitative theory. From this perspective we show how concepts of stability enable us to classify dynamical equations and their solutions and connect the key issues of nonlinearity, bifurcation, control, and uncertainty that are common to time-dependent problems in natural and engineered systems. We discuss stability and bifurcations in three simple model problems, and conclude with a survey of recent extensions of stability theory to complex networks.Comment: 28 pages, 10 figures. 26/04/2007: The book title was changed at the last minute. No other changes have been made. Chapter 1 in: J.P. Denier and J.S. Frederiksen (editors), Frontiers in Turbulence and Coherent Structures. World Scientific Singapore 2007 (in press

    Investigation of squeeze-film dampers

    Get PDF
    Squeeze film dampers are a means of curing instabilities in rotating shaft assemblies. Their efficiency depends very much on the condition of the oil, which in turn depends on inlet and outlet arrangements, on damper geometry and on the flexibility of the rotor and surrounding structure. Rig investigations in which structural flexibility is included experimentally are discussed. Comparisons are made between measured and predicted results

    On a new symmetry of the solutions of the wave equation in the background of a Kerr black hole

    Get PDF
    This short paper derives the constant of motion of a scalar field in the gravitational field of a Kerr black hole which is associated to a Killing tensor of that space-time. In addition, there is found a related new symmetry operator S for the solutions of the wave equation in that background. That operator is a partial differential operator with a leading order time derivative of the first order that commutes with a normal form of the wave operator. That form is obtained by multiplication of the wave operator from the left with the reciprocal of the coefficient function of its second order time derivative. It is shown that S induces an operator that commutes with the generator of time evolution in a formulation of the initial value problem for the wave equation in the setting of strongly continuous semigroups
    • …
    corecore