3,735 research outputs found

    Determination of cobalt in seawater

    Get PDF
    Cobalt has been isolated from seawater by cocrystallization with α-nitroso-β-naphthol. Quantitative determination by a nitroso-R-salt method for each of two sea.water samples has indicated the cobalt content to be 0.038 µg/l after radiometric correction for losses incurred in the isolation process

    Are You Ready to Provide Instruction Via Interactive Satellite Delivery Technology

    Get PDF
    A difficulty for faculty new to teaching at a distance is being able to visualize the scope of needed skills and tasks that will be required of them. The purpose of this project was to provide an empirically-based, self-administered skill enhancement guide for new distance education faculty teaching via interactive satellite broadcast. A modified Delphi approach was used to survey 18 faculty members experienced in distance education from the 6 colleges at a major eastern university. Respondents created a validated task list in phase 1 and determined task criticality and sequencing of task learning in phase 2

    Development of a Prototype Simulation Executive with Zooming in the Numerical Propulsion System Simulation

    Get PDF
    A major difficulty in designing aeropropulsion systems is that of identifying and understanding the interactions between the separate engine components and disciplines (e.g., fluid mechanics, structural mechanics, heat transfer, material properties, etc.). The traditional analysis approach is to decompose the system into separate components with the interaction between components being evaluated by the application of each of the single disciplines in a sequential manner. Here, one discipline uses information from the calculation of another discipline to determine the effects of component coupling. This approach, however, may not properly identify the consequences of these effects during the design phase, leaving the interactions to be discovered and evaluated during engine testing. This contributes to the time and cost of developing new propulsion systems as, typically, several design-build-test cycles are needed to fully identify multidisciplinary effects and reach the desired system performance. The alternative to sequential isolated component analysis is to use multidisciplinary coupling at a more fundamental level. This approach has been made more plausible due to recent advancements in computation simulation along with application of concurrent engineering concepts. Computer simulation systems designed to provide an environment which is capable of integrating the various disciplines into a single simulation system have been proposed and are currently being developed. One such system is being developed by the Numerical Propulsion System Simulation (NPSS) project. The NPSS project, being developed at the Interdisciplinary Technology Office at the NASA Lewis Research Center is a 'numerical test cell' designed to provide for comprehensive computational design and analysis of aerospace propulsion systems. It will provide multi-disciplinary analyses on a variety of computational platforms, and a user-interface consisting of expert systems, data base management and visualization tools, to allow the designer to investigate the complex interactions inherent in these systems. An interactive programming software system, known as the Application Visualization System (AVS), was utilized for the development of the propulsion system simulation. The modularity of this system provides the ability to couple propulsion system components, as well as disciplines, and provides for the ability to integrate existing, well established analysis codes into the overall system simulation. This feature allows the user to customize the simulation model by inserting desired analysis codes. The prototypical simulation environment for multidisciplinary analysis, called Turbofan Engine System Simulation (TESS), which incorporates many of the characteristics of the simulation environment proposed herein, is detailed

    A Comparative Study of High and Low Fidelity Fan Models for Turbofan Engine System Simulation

    Get PDF
    In this paper, a heterogeneous propulsion system simulation method is presented. The method is based on the formulation of a cycle model of a gas turbine engine. The model includes the nonlinear characteristics of the engine components via use of empirical data. The potential to simulate the entire engine operation on a computer without the aid of data is demonstrated by numerically generating "performance maps" for a fan component using two flow models of varying fidelity. The suitability of the fan models were evaluated by comparing the computed performance with experimental data. A discussion of the potential benefits and/or difficulties in connecting simulations solutions of differing fidelity is given

    Robo-AO Discovery and Basic Characterization of Wide Multiple Star Systems in the Pleiades, Praesepe, and NGC 2264 Clusters

    Get PDF
    We identify and roughly characterize 66 candidate binary star systems in the Pleiades, Praesepe, and NGC 2264 star clusters based on robotic adaptive optics imaging data obtained using Robo-AO at the Palomar 60" telescope. Only ∼\sim10% of our imaged pairs were previously known. We detect companions at red optical wavelengths having physical separations ranging from a few tens to a few thousand AU. A 3-sigma contrast curve generated for each final image provides upper limits to the brightness ratios for any undetected putative companions. The observations are sensitive to companions with maximum contrast ∼\sim6m^m at larger separations. At smaller separations, the mean (best) raw contrast at 2 arcsec is 3.8m^m (6m^m), at 1 arcsec is 3.0m^m (4.5m^m), and at 0.5 arcsec is 1.9m^m (3m^m). PSF subtraction can recover close to the full contrast in to the closer separations. For detected candidate binary pairs, we report separations, position angles, and relative magnitudes. Theoretical isochrones appropriate to the Pleiades and Praesepe clusters are then used to determine the corresponding binary mass ratios, which range from 0.2-0.9 in q=m2/m1q=m_2/m_1. For our sample of roughly solar-mass (FGK type) stars in NGC 2264 and sub-solar-mass (K and early M-type) primaries in the Pleiades and Praesepe, the overall binary frequency is measured at ∼\sim15.5% ±\pm 2%. However, this value should be considered a lower limit to the true binary fraction within the specified separation and mass ratio ranges in these clusters, given that complex and uncertain corrections for sensitivity and completeness have not been applied.Comment: Accepted to A

    Who is Jesus? Supplementary materials for Religious Education in the upper secondary school

    Get PDF
    This is the final version. Freely available onlineWho is Jesus? provides an innovative examination of the figure of Jesus through a variety of different cultural, religious and disciplinary lenses. A team of fictional scholars, each with a different set of interpretations, methodologies and methods, guide students in their encounters with artistic, visually-impaired, Muslim, feminist and cross-cultural perspectives of Jesus. The aim is not to inculcate any particular view of Jesus or to promote a particular approach to studying him, but to introduce students to some of the diverse ways in which the title question – Who is Jesus? – can be answered

    Depredation of Common Eider, Somateria mollissima, Nests on a Central Beaufort Sea Barrier Island: A Case Where No One Wins

    Get PDF
    Along the central Beaufort Sea, Pacific Common Eiders (Somateria mollissima v-nigra) nest on unvegetated, barrier islands; often near nesting Glaucous Gulls (Larus hyperboreus). Nest-site choice likely reflects a strategy of predator avoidance: nesting on islands to avoid mammalian predators and near territorial gulls to avoid other avian predators. We observed a nesting colony of Common Eiders from first nest initiation through nesting termination on Egg Island near Prudhoe Bay, Alaska (2002 – 2003). Resident gulls depredated many eider nests, mostly during initiation. All nests failed when an Arctic Fox (Alopex lagopus) visited the island and flushed hens from their nests, exposing the eggs to depredation by the fox and gulls (resident and non-resident). Common Eiders actively defended nests from gulls, but not from foxes. Likely all three species (i.e., eiders, gulls, and foxes) ultimately achieved negligible benefit from their nest-site selection or predatory activity: (a) island nesting provided no safety from mammalian predators for eiders or gulls, (b) for Common Eiders, nesting near gulls increased egg loss, (c) for Glaucous Gulls, nesting near colonial eiders may have reduced nest success by attracting the fox, and (d) for Arctic Foxes, the depredation was of questionable value, as most eggs were cached and probably not recoverable (due to damage from fall storms). Thus, the predator-prey interactions we observed appear to be a case where little or no fitness advantage was realized by any of the species involved

    Jurassic Redbeds of the Connecticut Valley: (1) Brownstones of the Portland Formation; and (2) Playa-Playa Lake-Oligomictic Lake Model for Parts of the East Berlin, Shuttle Meadow, and Portland Formations

    Get PDF
    Guidebook for field trips in Connecticut and south central Massachusetts: New England Intercollegiate Geological Conference 74th annual meeting, University of Connecticut, Storrs Connecticut , October 2 and 3, 1982: Trip M-
    • …
    corecore