1,249 research outputs found

    On gauge transformation property of coordinate independent SO(9) vector states in SU(2) Matrix Theory

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    We investigate coordinate independent SO(9) vector states in SU(2) Matrix theory. There are 36 vector states, and we determine what representations of SU(2) they are decomposed into. Among them we find a unique set of states transforming in adjoint representation. We show that this set of states can appear as the linear term in the coordinate matrices in Taylor expansion of zero energy bound state wavefunction around the origin i.e. it satisfies the condition of full supersymmetry.Comment: 21 pages, no figure, v2: minor correction v3: signs in (3.46) and (3.51) corrected, further calculation on the linear term of the expansion of the wavefunction added, and the conclusion about it changed, v3: minor change in the references, version published in JHE

    The Corralitos Observatory program for the detection of lunar transient phenomena

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    This is a final report on the establishment, observing procedures, and observational results of a survey program for the detection of lunar transient phenomena (LTP's) by electro-optical image conversion means. For survey, a unique detection system with an image orthicon was used as the primary element in conjunction with a 24-in. f/20 Cassegrainian telescope. Observations in three spectral ranges, with 6,466 man-hours of observing, were actually performed during the period from October 27, 1965, to April 26, 1972. Within this entire period, no color or feature change within the detection capabilities of the instrumentation was observed, either independently or in follow up of amateur LTP reports, with the exception of one general bluing and several localized bluings (probably ascribable to the effects of the terrestrial atmosphere) that were observed solely by the Corralitos system. A table is presented indicating amateur and professional reports of LTP's and the results of efforts to confirm these reports through the Corralitos system

    Geologic Mapping of the Meridiani Region, Mars

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    The light toned bedrock that has been observed at the Mars Exploration Rover Opportunity landing site is an upper layer in a sequence >600 m thick in places. These outcrops contain mineral and textural signatures that require interaction of, and possibly formation from, water. Many distinct layers are visible in the remote sensing data (e.g. Figure 1) and no work has ever characterized the full set of these materials that cover an area >3 105 km2 spanning 20 of longitude. Thus, whatever water-related process( es?) altered, and possibly formed, the rocks at the Opportunity landing site extended over a vast region of Mars. Yet many questions remain to be answered, such as: (1) in what capacity did water form and alter the deposits?, (2) what are the temporal and spatial relations with other major events known from ancient Mars?, and (3) would this type of environment have been conducive to the development of life? To address these questions we are completing a detailed geologic, stratigraphic, and thermophysical properties study of this widespread terrain. Specifically, we are drafting a 1:2M-scale geological map covering the full extent of these water-related deposits. In tandem with the mapping, Hynek and Phillips [1] have conducted a preliminary stratigraphic analysis of the stack of materials. After mapping is complete, we will study the thermophysical properties of the varied layers to derive possible compositional information of the materials. These tasks serve several purposes including gaining an understanding of the complex nature of these materials, their potential source region(s), and their timing of emplacement. All of these efforts are necessary to place the observations by the Opportunity Rover in a broader context and prepare for potential future landed missions to the region. Understanding the large-scale paleohydrology of Mars is central to NASA s goals and vital for determining if life ever arose on the planet

    Extensive Noachian fluvial systems in Arabia Terra: Implications for early Martian climate

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    Valley networks are some of the strongest lines of evidence for extensive fluvial activity on early (Noachian; >3.7 Ga) Mars. However, their purported absence on certain ancient terrains, such as Arabia Terra, is at variance with patterns of precipitation as predicted by "warm and wet" climate models. This disagreement has contributed to the development of an alternative "icy highlands" scenario, whereby valley networks were formed by the melting of highland ice sheets. Here, we show through regional mapping that Arabia Terra shows evidence for extensive networks of sinuous ridges. We interpret these ridge features as inverted fluvial channels that formed in the Noachian, before being subject to burial and exhumation. The inverted channels developed on extensive aggrading flood plains. As the inverted channels are both sourced in, and traverse across, Arabia Terra, their formation is inconsistent with discrete, localized sources of water, such as meltwater from highland ice sheets. Our results are instead more consistent with an early Mars that supported widespread precipitation and runoff

    Geologic Mapping of the Meridiani Region of Mars

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    The Mars Exploration Rover Opportunity observed an upper layer of a more than 600-m-thick sequence of light toned outcrops that characterize the Meridiani region of Mars. Results from the rover analyses have shown that the bedrock contains mineral and textural characteristics that require at least the interaction of, and possibly an overall formation by, water-related mechanisms in order to be explained [1]. Additionally, remote sensing studies of the region have suggested that the rocks sampled in places by the MER rover consist of many distinct layers extending over an area of more than 3 10(exp 5) sq km spanning 20deg of longitude [2]

    Stability of the magnetic Schr\"odinger operator in a waveguide

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    The spectrum of the Schr\"odinger operator in a quantum waveguide is known to be unstable in two and three dimensions. Any enlargement of the waveguide produces eigenvalues beneath the continuous spectrum. Also if the waveguide is bent eigenvalues will arise below the continuous spectrum. In this paper a magnetic field is added into the system. The spectrum of the magnetic Schr\"odinger operator is proved to be stable under small local deformations and also under small bending of the waveguide. The proof includes a magnetic Hardy-type inequality in the waveguide, which is interesting in its own

    On the existence of impurity bound excitons in one-dimensional systems with zero range interactions

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    We consider a three-body one-dimensional Schr\"odinger operator with zero range potentials, which models a positive impurity with charge κ>0\kappa > 0 interacting with an exciton. We study the existence of discrete eigenvalues as κ\kappa is varied. On one hand, we show that for sufficiently small κ\kappa there exists a unique bound state whose binding energy behaves like κ4\kappa^4, and we explicitly compute its leading coefficient. On the other hand, if κ\kappa is larger than some critical value then the system has no bound states

    Halite as a Methane Sequestration Host: A Possible Explanation for Periodic Methane Release on Mars, and a Surface-accessible Source of Ancient Martian Carbon

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    We present the hypothesis that halite may play a role in methane sequestration on the martian surface. In terrestrial examples, halite deposits sequester large volumes of methane and chloromethane. Also, examples of chloromethane-bearing, approximately 4.5 Ga old halite from the Monahans meteorite show that this system is very stable unless the halite is damaged. On Mars, methane may be generated from carbonaceous material trapped in ancient halite deposits and sequestered. The methane may be released by damaging its halite host; either by aqueous alteration, aeolian abrasion, heating, or impact shock. Such a scenario may help to explain the appearance of short-lived releases of methane on the martian surface. The methane may be of either biogenic or abiogenic origin. If this scenario plays a significant role on Mars, then martian halite deposits may contain samples of organic compounds dating to the ancient desiccation of the planet, accessible at the surface for future sample return missions

    Forced-convection, dispersed-flow film boiling

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    This report presents the latest results of an investigation of the characteristics of dispersed flow film boiling. Heat transfer data are presented for vertical upflow of nitrogen in an electrically heated tube, 0.4 in. I.D. and 8 ft long. Heat fluxes up to 18,000 Btu/ft 2-hr and mass fluxes up to 200,000 lbm/ft 2-hr were investigated. By variation of the startup procedure, it was possible to operate in two distinct regimes of film boiling. By preheating the tube before introducing the flow, film boiling was observed throughout the test tube. If the flow was established before applying power, film boiling was initiated downstream of the inlet. For similar conditions, the local heat transfer coefficients were different in the two cases due to the different degrees of thermal nonequilibrium. The data for both regimes were satisfactorily predicted by a modified version of the nonequilibrium model presented in earlier reports. The model was also applied to available data for methane, propane, and water. By modification of the empirical constant governing the direct wall-to-droplet heat transfer, these data were generally predicted to within 10 percent. The tests were repeated with tight-fitting, full-length twisted tapes installed in the test tube. Considerable augmentation of the heat transfer was achieved, with the heat transfer coefficient being increased by as much as a factor of 3 with the tightest tape twist. For the higher mass fluxes, it was observed that the tape promoted droplet deposition to such an extent that a continuous liquid film could be reestablished on the wall near the test section exit. The tape-generated swirl flow did not improve the "burnout" condition, primarily due to the fact that a liquid streamer forms on the twisted tape. The semiempirical model gave a reasonable prediction of the heat transfer coefficient when the effects of the swirl flow were included.Sponsored by the National Science Foundation D. S. R

    Singularities of relativistic membranes

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    AbstractPointing out a crucial relation with caustics of the eikonal equation we discuss the singularity formation of 2-dimensional surfaces that sweep out 3-manifolds of zero mean curvature in R</jats:p
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