4,436 research outputs found

    Advanced flight deck/crew station simulator functional requirements

    Get PDF
    This report documents a study of flight deck/crew system research facility requirements for investigating issues involved with developing systems, and procedures for interfacing transport aircraft with air traffic control systems planned for 1985 to 2000. Crew system needs of NASA, the U.S. Air Force, and industry were investigated and reported. A matrix of these is included, as are recommended functional requirements and design criteria for simulation facilities in which to conduct this research. Methods of exploiting the commonality and similarity in facilities are identified, and plans for exploiting this in order to reduce implementation costs and allow efficient transfer of experiments from one facility to another are presented

    Modelling gravity on a hyper-cubic lattice

    Full text link
    We present an elegant and simple dynamical model of symmetric, non-degenerate (n x n) matrices of fixed signature defined on a n-dimensional hyper-cubic lattice with nearest-neighbor interactions. We show how this model is related to General Relativity, and discuss multiple ways in which it can be useful for studying gravity, both classical and quantum. In particular, we show that the dynamics of the model when all matrices are close to the identity corresponds exactly to a finite-difference discretization of weak-field gravity in harmonic gauge. We also show that the action which defines the full dynamics of the model corresponds to the Einstein-Hilbert action to leading order in the lattice spacing, and use this observation to define a lattice analogue of the Ricci scalar and Einstein tensor. Finally, we perform a mean-field analysis of the statistical mechanics of this model.Comment: 5 page

    Xenoestrogens from Household Plastics Bind Estrogen Receptors and Affect Cell Proliferation

    Get PDF
    Xenoestrogens are “foreign” chemicals or compounds that interact with estrogen receptors as either agonists or antagonists to interfere with endocrine system function. Xenoestrogens include phytoestrogens, pesticides, industrial by- products and synthetic estrogens. In this study, consumer plasticware, including baby bottles and food storage containers, were found to release xenoestrogenic compounds that bound to ERα and ERβ and affected cell proliferation

    Composites Materials and Manufacturing Technologies for Space Applications

    Get PDF
    Composite materials offer significant advantages in space applications. Weight reduction is imperative for deep space systems. However, the pathway to deployment of composites alternatives is problematic. Improvements in the materials and processes are needed, and extensive testing is required to validate the performance, qualify the materials and processes, and certify components. Addressing these challenges could lead to the confident adoption of composites in space applications and provide spin-off technical capabilities for the aerospace and other industries. To address the issues associated with composites applications in space systems, NASA sponsored a Technical Interchange Meeting (TIM) entitled, "Composites Materials and Manufacturing Technologies for Space Applications," the proceedings of which are summarized in this Conference Publication. The NASA Space Technology Mission Directorate and the Game Changing Program chartered the meeting. The meeting was hosted by the National Center for Advanced Manufacturing (NCAM)-a public/private partnership between NASA, the State of Louisiana, Louisiana State University, industry, and academia, in association with the American Composites Manufacturers Association. The Louisiana Center for Manufacturing Sciences served as the coordinator for the TIM

    The Anatomy of Memory Politics: A Formalist Analysis of Tate Britain’s ‘Artist and Empire’ and the Struggle over Britain’s Imperial Past

    Get PDF
    In this paper, I propose a new approach for understanding the meaning of memory politics, which draws upon the archetypal literary criticism of Northrop Frye. I suggest that the four archetypes elaborated by Frye—comedy, romance, tragedy, and satire—can be used as a heuristic device for interpreting the contested historical narratives that are associated with the politics of memory. I illustrate this approach through a case-study of Artists and Empire: Facing Britain’s Imperial Past, an exhibition held at Tate Britain in 2016, amidst increasing contestation over the meaning of the British Empire. In sum, I find that the exhibit narrated Britain’s imperial past as a comedy, in which a key theme was the progressive cultural mixing of the British and the people they colonized. To conclude, I discuss the implications of such a narrative for constructing an inclusive, postcolonial British identity. As an alternative, I draw on Aristotle to suggest that a tragic narrative would have been more propitious

    Rotating Superconductors and the London Moment: Thermodynamics versus Microscopics

    Full text link
    Comparing various microscopic theories of rotating superconductors to the conclusions of thermodynamic considerations, we traced their marked difference to the question of how some thermodynamic quantities (the electrostatic and chemical potentials) are related to more microscopic ones: The electron's the work function, mean-field potential and Fermi energy -- certainly a question of general import. After the correct identification is established, the relativistic correction for the London Moment is shown to vanish, with the obvious contribution from the Fermi velocity being compensated by other contributions such as electrostatics and interactions.Comment: 23 pages 4 fi

    Modelling Nitrous Oxide Emissions from Grazed Grasslands in New Zealand

    Get PDF
    Spatial and temporal variability are major difficulties when quantifying annual N2O fluxes at the field scale. New Zealand currently relies on the IPCC default methodology (National Inventory Report, 2004). This methodology is too simplistic and generalised as it ignores all site-specific controls, but is also not sufficiently flexible to allow mitigation options to be assessed. Therefore, a more robust, process-based approach is required to quantify N2O emissions more accurately at the field level. Denitrification-decomposition (DNDC) is a process-based model originally developed (Li et al., 1992) to quantify agricultural nitrous oxide (N2O) emissions across climatic zones, soil types, and management regimes. This has been modified to represent New Zealand grazed grassland systems (Saggar et al., 2004). More recent modifications include measured biomass C and N parameters in perennial pasture and compaction impacts on the soil water dynamics. Further validation tests have been conducted against observed soil moisture and gas fluxes. Here we i) assess the ability of a modified DNDC model NZ-DNDC to simulate N2O emissions; ii) compare the measured, modelled and IPCCestimated N2O emissions from dairy- and sheep-grazed pastures; and iii) give preliminary results for upscaling the model to provide preliminary regional emissions estimates
    corecore