75,919 research outputs found

    A novel dry coal feeding concept for high-pressure gasifiers

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    A novel dry coal feeding concept was developed for injecting ground coal into high-pressure gasifiers. Significant power savings are projected because the coal is injected directly with a ram and there is no requirement for pumping large volumes of gas or fluid against pressure. A novel feature of the concept is that a new seal zone is formed between the ram and injection tube each cycle. The seal zone comprises a mixture of a small quantity of finely ground coal and a fluid. To demonstrate the feasibility of the concept, coal was injected into a 1000-psi chamber with an experimental device having a 7-1/2-inch-diameter ram and a 28-inch-long stroke

    Nuclear radiation environment analysis for thermoelectric outer planet spacecraft

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    Neutron and gamma ray transport calculations were performed using Monte Carlo methods and a three-dimensional geometric model of the spacecraft. The results are compared with similar calculations performed for an earlier design

    Rocketdyne's advanced coal slurry pumping program

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    The Rocketdyne Division of Rockwell International Corporation is conducting a program for the engineering, fabrication, and testing of an experimental/prototype high-capacity, high-pressure centrifugal slurry feed pump for coal liquefaction purposes. The abrasion problems in a centrifugal slurry pump are primarily due to the manner in which the hard, solid particles contained in the slurry are transported through the hydraulic flow passages within the pump. The abrasive particles can create scraping, grinding, cutting, and sandblasting effects on the various exposed parts of the pump. These critical areas involving abrasion and impact erosion wear problems in a centrifugal pump are being addressed by Rocketdyne. The mechanisms of abrasion and erosion are being studied through hydrodynamic analysis, materials evaluation, and advanced design concepts

    NASA's AVE 7 experiment: 25-mb sounding data

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    The AVE 7 Experiment is described and tabulated rawinsonde data at 25 mb internals from the surface to 25 mb for the 24 stations participating in the experiment are presented. Soundings were taken between 0000GMT May 2 and 1200 GMT May 3, 1978. The methods of data processing and the accuracy are briefly discussed. Selected synoptic charts prepared from the data are presented as well as an example of contact data. A tabulation of adverse weather events that occured during the AVE 7 period, including freezing temperature, snow, tornadoes, damaging winds, and flooding, is presented

    Chiral approach to antikaon s- and p-wave interactions in dense nuclear matter

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    The properties of the antikaons in nuclear matter are investigated from a chiral unitary approach which incorporates the s- and p-waves of the KˉN{\bar K}N interaction. To obtain the in-medium meson-baryon amplitudes we include, in a self-consistent way, Pauli blocking effects, meson self-energies corrected by nuclear short-range correlations and baryon binding potentials. We pay special attention to investigating the validity of the on-shell factorization, showing that it cannot be applied in the evaluation of the in-medium corrections to the p-wave amplitudes. In nuclear matter at saturation energy, the Λ\Lambda and Σ\Sigma develop an attractive potential of about -30 MeV, while the Σ\Sigma^* pole remains at the free space value although its width gets sensibly increased to about 80 MeV. The antikaon also develops a moderate attraction that does not support the existence of very deep and narrow bound states, confirming the findings of previous self-consistent calculations.Comment: 29 pages, 12 figures, published in Physical Review

    Introduction to orbital flight planning (1)

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    This workbook is designed for students interested in space flight planning, who after training, may serve as flight planning aides. Routine flight planning activities requiring engineering-type calculations and analysis are covered. Practice exercises and brief instructions are given for the programming and use of the hand calculator as well as the calculation of position and velocity in the orbital plane. Calculation of relative orbital position is also covered with emphasis upon celestial coordinates and time measurement

    Study of inducer load and stress Interim report, 15 Feb. 1968 - 15 Oct. 1968

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    Literature survey, analytic formulations, and test rig designs for cavitating inducers in rocket engine turbopump

    Targeting kidney mesangium by nanoparticles of defined size

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    Nanoparticles are being investigated for numerous medical applications and are showing potential as an emerging class of carriers for drug delivery. Investigations on how the physicochemical properties (e.g., size, surface charge, shape, and density of targeting ligands) of nanoparticles enable their ability to overcome biological barriers and reach designated cellular destinations in sufficient amounts to elicit biological efficacy are of interest. Despite proven success in nanoparticle accumulation at cellular locations and occurrence of downstream therapeutic effects (e.g., target gene inhibition) in a selected few organs such as tumor and liver, reports on effective delivery of engineered nanoparticles to other organs still remain scarce. Here, we show that nanoparticles of ~75 ± 25-nm diameters target the mesangium of the kidney. These data show the effects of particle diameter on targeting the mesangium of the kidney. Because many diseases originate from this area of the kidney, our findings establish design criteria for constructing nanoparticle-based therapeutics for targeting diseases that involve the mesangium of the kidney
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