25,408 research outputs found

    High pressure gas filter system Patent

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    Developing high pressure gas purification and filtration system for use in test operations of space vehicle

    High pressure helium purifier Patent

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    Apparatus and method capable of receiving large quantity of high pressure helium, removing impurities, and discharging at received pressur

    Proof of a generalized Geroch conjecture for the hyperbolic Ernst equation

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    We enunciate and prove here a generalization of Geroch's famous conjecture concerning analytic solutions of the elliptic Ernst equation. Our generalization is stated for solutions of the hyperbolic Ernst equation that are not necessarily analytic, although it can be formulated also for solutions of the elliptic Ernst equation that are nowhere axis-accessible.Comment: 75 pages (plus optional table of contents). Sign errors in elliptic case equations (1A.13), (1A.15) and (1A.25) are corrected. Not relevant to proof contained in pape

    How to motivate laying hens to use the hen run?

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    In organic agriculture, hens are kept in free range systems. A free range is an enrichment for the hens and brings several advantages for them. Laying hens may show behavioural elements that are not possible in a poultry house. For instance, sunbathing behaviour is only shown in direct sunlight and not in artificial light (Huber, 1987). Hens spend 35.3-47.5% of their time with food searching (Fölsch and Vestergaard, 1981) and, in natural habitats, invertebrate food appears to be an importnat addition to the diet (Savory et al. 1978). Free range systems may also have an influence on animal health and product quality. Lopez-Bote et al. (1998) suggested that some constituents of grass might be of interest for the production of eggs rich in (n-3) fatty acids. In flocks of free range hens, generally only a small proportion of the flock is outside at any one time, and most hens stay near the poultry house. In an account of the uneven distribution of the hens in the free range area, Menzi et al. (1997) found a nutrient and heavy metal overload on the frequently used parts of the run. For a better distribution, they, as well as several label programmes, recommend to structure the outdoor area with trees and installations providing shade and protection for the hens. We attempted to determine management and structural factors that would result in more hens in the run and a more even distribution of the animals in several experiments, with a special emphasis on the idea that the hen run should be easily manageable for the farmer

    Solving the characteristic initial value problem for colliding plane gravitational and electromagnetic waves

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    A method is presented for solving the characteristic initial value problem for the collision and subsequent nonlinear interaction of plane gravitational or gravitational and electromagnetic waves in a Minkowski background. This method generalizes the monodromy transform approach to fields with nonanalytic behaviour on the characteristics inherent to waves with distinct wave fronts. The crux of the method is in a reformulation of the main nonlinear symmetry reduced field equations as linear integral equations whose solutions are determined by generalized (``dynamical'') monodromy data which evolve from data specified on the initial characteristics (the wavefronts).Comment: 4 pages, RevTe

    Electronic instabilities in metal-insulator semiconductor devices

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    Electronic charge injection instability in silicon nitride metal-insulator-semiconductor device
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