4,779 research outputs found

    Infusion extractor

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    This invention relates to an apparatus and method of removing desirable constituents from an infusible material by infusion extraction. A piston operating in a first chamber draws a solvent into the first chamber where it may be heated, and then moves the heated solvent into a second chamber containing the infusible material, where infusion extraction takes place. The piston then moves the solvent containing the extract through a filter into the first chamber, leaving the extraction residue in the second chamber. The method is applicable to operation in low or micro-gravity environments

    Method of hybrid plume plasma propulsion

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    A technique for producing thrust by generating a hybrid plume plasma exhaust is disclosed. A plasma flow is generated and introduced into a nozzle which features one or more inlets positioned to direct a flow of neutral gas about the interior of the nozzle. When such a neutral gas flow is combined with the plasma flow within the nozzle, a hybrid plume is constructed including a flow of hot plasma along the center of the nozzle surrounded by a generally annular flow of neutral gas, with an annular transition region between the pure plasma and the neutral gas. The temperature of the outer gas layer is below that of the pure plasma and generally separates the pure plasma from the interior surfaces of the nozzle. The neutral gas flow both insulates the nozzle walls from the high temperatures of the plasma flow and adds to the mass flow rate of the hybrid exhaust. The rate of flow of neutral gas into the interior of the nozzle may be selectively adjusted to control the thrust and specific impulse of the device

    Method of infusion extraction

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    Apparatus and method of removing desirable constituents from an infusible material by infusion extraction, where a piston operating in a first chamber draws a solvent into the first chamber where it may be heated, and then moves the heated solvent into a second chamber containing the infusible material, and where infusion extraction takes place. The piston then moves the solvent containing the extract through a filter into the first chamber, leaving the extraction residue in the second chamber

    Parameters in ablation heat sheilds

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    The desired result of this paper is a method of determining temperature distribution and burn off rate in a semi-infinite rod or shield subjected to a large heat flux. The possible methods of determination were investigated, and it was felt that an analytical approach turned out to be the most feasible. The analytical analysis employed involves the use of the Fourier\u27s general equation for one dimensional heat flow. Transformations from stationary to moving coordinates reduces the problem from unsteady state to steady state boundary conditions. The resulting equations can be applicable to the extent for the heat flow problems involving the change of phase --Abstract, page 2

    Infusion Extractor

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    Apparatus and method of removing desirable constituents from an infusible material by infusion extraction, where a piston operating in a first chamber draws a solvent into the first chamber where it may be heated, and then moves the heated solvent into a second chamber containing the infusible material, and where infusion extraction takes place. The piston then moves the solvent containing the extract through a filter into the first chamber, leaving the extraction residue in the second chamber

    Characterization of Plasma Discharges in a High-Field Magnetic Tandem Mirror

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    High density magnetized plasma discharges in open-ended geometries, like Tandem Mirrors, have a variety of space applications. Chief among them is the production of variable Specific Impulse (I(sub sp)) and variable thrust in a magnetic nozzle. Our research group is pursuing the experimental characterization of such discharges in our high-field facility located at the Advanced Space Propulsion Laboratory (ASPL). These studies focus on identifying plasma stability criteria as functions of density, temperature and magnetic field strength. Plasma heating is accomplished by both Electron and Ion Cyclotron Resonance (ECR and ICR) at frequencies of 2-3 Ghz and 1-30 Mhz respectively, for both Hydrogen and Helium. Electron density and temperature has measured by movable Langmuir probes. Macroscopic plasma stability is being investigated in ongoing research

    Do as I say, not as I do:a lexical distributional account of English locative verb class acquisition

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    Children overgeneralise verbs to ungrammatical structures early in acquisition, but retreat from these overgeneralisations as they learn semantic verb classes. In a large corpus of English locative utterances (e.g., the woman sprayed water onto the wall/wall with water), we found structural biases which changed over development and which could explain overgeneralisation behaviour. Children and adults had similar verb classes and a correspondence analysis suggested that lexical distributional regularities in the adult input could help to explain the acquisition of these classes. A connectionist model provided an explicit account of how structural biases could be learned over development and how these biases could be reduced by learning verb classes from distributional regularities

    Lexical distributional cues, but not situational cues, are readily used to learn abstract locative verb-structure associations.

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    Children must learn the structural biases of locative verbs in order to avoid making overgeneralisation errors (e.g., *I filled water into the glass). It is thought that they use linguistic and situational information to learn verb classes that encode structural biases. In addition to situational cues, we examined whether children and adults could use the lexical distribution of nouns in the post-verbal noun phrase to assign novel verbs to locative classes. In Experiment 1, children and adults used lexical distributional cues to assign verb classes, but were unable to use situational cues appropriately. In Experiment 2, adults generalised distributionally-learned classes to novel verb arguments, demonstrating that distributional information can cue abstract verb classes. Taken together, these studies show that human language learners can use a lexical distributional mechanism that is similar to that used by computational linguistic systems that use large unlabelled corpora to learn verb meaning

    The VISTA spacecraft: Advantages of ICF (Inertial Confinement Fusion) for interplanetary fusions propulsion applications

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    Inertial Confinement Fusion (ICF) is an attractive engine power source for interplanetary manned spacecraft, especially for near-term missions requiring minimum flight duration, because ICF has inherent high power-to-mass ratios and high specific impulses. We have developed a new vehicle concept called VISTA that uses ICF and is capable of round-trip manned missions to Mars in 100 days using A.D. 2020 technology. We describe VISTA's engine operation, discuss associated plasma issues, and describe the advantages of DT fuel for near-term applications. Although ICF is potentially superior to non-fusion technologies for near-term interplanetary transport, the performance capabilities of VISTA cannot be meaningfully compared with those of magnetic-fusion systems because of the lack of a comparable study of the magnetic-fusion systems. We urge that such a study be conducted
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