8,081 research outputs found

    Liquid acrobatics

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    We experiment with injecting a continuous stream of gas into a shallow liquid, similar to how one might blow into a straw placed at the bottom of a near-empty drink. By varying the angle of the straw (here a metal needle), we observe a variety of dynamics, which we film using a high-speed camera. Most noteworthy is an intermediate regime in which cyclical jets erupt from the air-liquid interface and breakup into air-born droplets. These droplets trace out a parabolic trajectory and bounce on the air-liquid interface before eventually coalescing. The shape of each jet, as well as the time between jets, is remarkably similar and leads to droplets with nearly identical trajectories. The following article accompanies the linked fluid dynamics video submitted to the Gallery of Fluid Motion in 2008.Comment: Accompanies video submission to APS DFD 2008 Gallery of Fluid Motion, low http://ecommons.library.cornell.edu/bitstream/1813/11469/3/Bird_DFD2008_mpeg1.mpg , and high resolution http://ecommons.library.cornell.edu/bitstream/1813/11469/2/Bird_DFD2008_mpeg2.mp

    Alien Registration- Howard, James A. (Brunswick, Cumberland County)

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    https://digitalmaine.com/alien_docs/31626/thumbnail.jp

    Conodont biostratigraphy of the Crawford Group, Southern Uplands, Scotland

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    Extensive new conodont collections from the Crawford Group, the oldest succession in the Southern Uplands of Scotland, support the previously documented biostratigraphical ages for the included formations. The Raven Gill Formation is lower Whitlandian, Arenig (comparable in age to the Dounans Limestone in the Highland Border Complex) and the Kirkton Formation is latest Llandeilian-Aurelucian, Llanvirn to Caradoc in age. It is concluded that there is a significant stratigraphical gap within the Crawford Group. The restricted and probably fault-bounded nature of the Raven Gill outcrops suggests that these may represent olistoliths within a mélange of Llandeilian-Aurelucian age. The chert-bearing succession of the Northern Belt of the Southern Uplands thus represents the juxtaposed sedimentary records of two entirely separate basins – the oldest pre-dates the Grampian assembly of the Laurentian margin, and the younger, the Northern Belt Basin sensu stricto, entirely post-dates this event

    Application of the sequential t-test algorithm for analysing regime shifts to the southern Benguela ecosystem

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    Includes bibliographical references (leaves 69-74).Includes abstract.Long-term ecosystem changes, such as regime shifts, have occurred in several marine ecosystems worldwide. Multivariate statistical methods have been used to detect such changes, but they have to date not been applied to the southern Benguela ecosystem. A weakness of many of the methods is that they require long time series data and do not provide robust results at the end of time series. A new method known as the sequential t-test algorithm for analysing regime shifts (STARS) is applied to a set of biological state variables and environmental and anthropogenic forcing variables in the southern Benguela

    Global Nonexistence Theorems for Quasilinear Evolution Equations with Dissipation

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    The final publication is available at Springer via https://doi.org/10.1007/s002050050032. Levine, Howard A., and James Serrin. "Global Nonexistence Theorems for Quasilinear Evolution Equations with Dissipation." Archive for Rational Mechanics and Analysis 137, no. 4 (1997): 341-361. Posted with permission.</p

    Large diffractive/refractive apertures for space and airborne telescopes

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    Recent work, specifically the Lawrence Livermore National Laboratory (LLNL) Eyeglass and the DARPA MOIRE programs, have evaluated lightweight, easily packaged and deployed, diffractive/refractive membrane transmissive lenses as entrance apertures for large space and airborne telescopes. This presentation describes a new, innovative approach to the theory of diffractive and refractive effects in lenses used as telescope entrance apertures and the fabrication of the necessary large membrane optics. Analyses are presented to indicate how a broadband, highly transmissive diffractive / refractive membrane lens can be developed and fabricated, and potential applications in defense and astronomy are briefly discussed

    Howard R. DuFour: The Cold War Aerospace Technology History Project (Interview 1)

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    James Kohler interviewed Howard DuFour on May 17, 2006 for the Cold War Aerospace Technologies History Project. In the interview Mr. DuFour discusses his role in the development of military technology during the Cold War. This is the first of three interviews with Mr. DuFour

    A Strategic Approach to Agricultural Research Program Planning in Sub-Saharan Africa

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    Recent studies have shown that agricultural research can have high payoffs in Africa, but impact depends on how well technology fits with evolving needs and capacity in the agricultural sector and the rest of the economy. Structural adjustment policies (e.g., market liberalization, currency devaluation) and political change are transforming user demands for new technology and the economic environment in which technology must perform. The challenge is how to design agricultural research as a strategic input to promote broad-based economic growth, structural transformation, and food security in the increasingly market-driven, but fragile, economies of Africa.Food Security, Food Policy, Agricultural Research, Research and Development/Tech Change/Emerging Technologies, Downloads May 2008-July 2009: 44, Q18,

    A Strategic Approach to Agricultural Research Program Planning in Sub-Saharan Africa

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    Research and Development/Tech Change/Emerging Technologies, Downloads May 2008-July 2009: 13,
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