9,441 research outputs found

    New research on bioregenerative air/water purification systems

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    For the past several years, air and water purification systems have been developed and used. This technology is based on the combined activities of plants and microorganisms as they function in a natural environment. More recently, researchers have begun to address the problems associated with indoor air pollution. Various common houseplants are currently being evaluated for their abilities to reduce concentrations of volatile organic compounds (VOCS) such as formaldehyde and benzene. With development of the Space Exploration Initiative, missions will increase in duration, and problems with resupply necessitates implementation of regenerative technology. Aspects of bioregenerative technology have been included in a habitat known as the BioHome. The ultimate goal is to use this technology in conjunction with physicochemical systems for air and water purification within closed systems. This study continued the risk assessment of bioregenerative technology with emphasis on biological hazards. In an effort to evaluate the risk for human infection, analyses were directed at enumeration of fecal streptococci and enteric viruses with the BioHome waste water treatment system

    Correlation between fracture surface morphology and toughness in Zr-based bulk metallic glasses

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    Fracture surfaces of Zr-based bulk metallic glasses of various compositions tested in the as-cast and annealed conditions were analyzed using scanning electron microscopy. The tougher samples have shown highly jagged patterns at the beginning stage of crack propagation, and the length and roughness of this jagged pattern correlate well with the measured fracture toughness values. These jagged patterns, the main source of energy dissipation in the sample, are attributed to the formation of shear bands inside the sample. This observation provides strong evidence of significant “plastic zone” screening at the crack tip

    Tachyons, Supertubes and Brane/Anti-Brane Systems

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    We find supertubes with arbitrary (and not necessarily planar) cross section; the stability against the D2-brane tension is due to a compensation by the local momentum generated by Born-Infeld fields. Stability against long-range supergravity forces is also established. We find the corresponding solutions of the infinite-N M(atrix) model. The supersymmetric D2/anti-D2 system is a special case of the general supertube, and we show that there are no open-string tachyons in this system via a computation of the open-string one-loop vacuum energy.Comment: 1+23 pages, 2 figures, LaTeX. V2, 1+28 pages: Further generalization to non-planar cross-sections and addition of an entirely new section with the explicit supergravity solutions. V3, 1+30 pages: Bound on the angular momentum added, other minor changes in Section

    Пейзаж как важнейший компонент раскрытия личности персонажей

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    Актуальным и необходимым для изучения и раскрытия особенностей личности является пейзаж. Описание пейзажа в повести “Саба ола, хайыр ола” играет особую роль, поскольку насыщает его аллегорическим и сакральным смыслом сакральный

    High power Nb-doped LiFePO<sub>4</sub> Li-ion battery cathodes; pilot-scale synthesis and electrochemical properties

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    AbstractHigh power, phase-pure Nb-doped LiFePO4 (LFP) nanoparticles are synthesised using a pilot-scale continuous hydrothermal flow synthesis process (production rate of 6 kg per day) in the range 0.01–2.00 at% Nb with respect to total transition metal content. EDS analysis suggests that Nb is homogeneously distributed throughout the structure. The addition of fructose as a reagent in the hydrothermal flow process, followed by a post synthesis heat-treatment, affords a continuous graphitic carbon coating on the particle surfaces. Electrochemical testing reveals that cycling performance improves with increasing dopant concentration, up to a maximum of 1.0 at% Nb, for which point a specific capacity of 110 mAh g−1 is obtained at 10 C (6 min for the charge or discharge). This is an excellent result for a high power cathode LFP based material, particularly when considering the synthesis was performed on a large pilot-scale apparatus

    IR Kuiper Belt Constraints

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    We compute the temperature and IR signal of particles of radius aa and albedo α\alpha at heliocentric distance RR, taking into account the emissivity effect, and give an interpolating formula for the result. We compare with analyses of COBE DIRBE data by others (including recent detection of the cosmic IR background) for various values of heliocentric distance, RR, particle radius, aa, and particle albedo, α\alpha. We then apply these results to a recently-developed picture of the Kuiper belt as a two-sector disk with a nearby, low-density sector (40<R<50-90 AU) and a more distant sector with a higher density. We consider the case in which passage through a molecular cloud essentially cleans the Solar System of dust. We apply a simple model of dust production by comet collisions and removal by the Poynting-Robertson effect to find limits on total and dust masses in the near and far sectors as a function of time since such a passage. Finally we compare Kuiper belt IR spectra for various parameter values.Comment: 34 pages, LaTeX, uses aasms4.sty, 11 PostScript figures not embedded. A number of substantive comments by a particularly thoughtful referee have been addresse

    Irrigating Alfalfa in South Dakota

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    Alfalfa performs admirably an irrigated crop in South Dakota-so well that it is often neglected. When given attention, it can realistically maintain irrigated yields of 6 to 7 TIA each year in most of South Dakota where 1 to 2 T are produced on dryland. Irrigated land that will produce 100-130 bu corn will produce 5-7 T alfalfa. On poorer irrigated land that produces 50-70 hu corn, one can expect 3-5 T alfalfa. Alfalfa has higher water requirements for peak yields than most other crops. It may not reach its full potential yield in any part of the stale without irrigation. Alfalfa is produced on 2.2 million acres dryland and irrigated land combined) in every county in South Dakota. By contrast, even when corn is irrigated, it is adapted to only about two thirds of the slate. If the marketing problems of transportation and fluctuating prices are overcome, alfalfa could become the state\u27s number one irrigated crop

    Implementation of an efficient Bayesian search for gravitational wave bursts with memory in pulsar timing array data

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    The standard Bayesian technique for searching pulsar timing data for gravitational wave (GW) bursts with memory (BWMs) using Markov Chain Monte Carlo (MCMC) sampling is very computationally expensive to perform. In this paper, we explain the implementation of an efficient Bayesian technique for searching for BWMs. This technique makes use of the fact that the signal model for Earth-term BWMs (BWMs passing over the Earth) is fully factorizable. We estimate that this implementation reduces the computational complexity by a factor of 100. We also demonstrate that this technique gives upper limits consistent with published results using the standard Bayesian technique, and may be used to perform all of the same analyses that standard MCMC techniques can perform.Comment: 19 pages, 3 figures, 1 table. Submitted to Astrophysical Journa
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