5,786 research outputs found

    Online learning : towards enabling choice

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    Education is rapidly evolving from an opportunity that was provided mainly for an elite to one that is available to a mass markets and as such is prone to the forces generated by this environment. Where, in the established pattern, commercial interest was limited mainly to the use of skills developed during the educational process, the future model of educational provision will involve extensive commercial activity in the production, delivery and marketing of material. Already there are a number of commercial companies offering framework products enabling "off the shelf solutions" for the construction and delivery of web based courses in any subject area. The commercialisation of education is underway and it is inevitable that it will be viewed, by entrepreneurs and customers alike, as any other commercial product. It would seem reasonable that the consumer should be able to evaluate the performance of these new modes of working in a similar manner to other commercial products. This paper draws together current thinking on the problems associated with evaluating computer and communication based learning

    Alien Registration- Ferguson, John S. (Dover-Foxcroft, Piscataquis County)

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    https://digitalmaine.com/alien_docs/10371/thumbnail.jp

    A layered approach to technology transfer of AVIRIS between Earth Search Sciences, Inc. and the Idaho National Engineering Laboratory

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    Since initial contact between Earth Search Sciences, Inc. (ESSI) and the Idaho National Engineering Laboratory (INEL) in February, 1994, at least seven proposals have been submitted in response to a variety of solicitations to commercialize and improve the AVIRIS instrument. These proposals, matching ESSI's unique position with respect to agreements with the National Aeronautics and Space Administration (NASA) and the Jet Propulsion Laboratory (JPL) to utilize, miniaturize, and commercialize the AVIRIS instrument and platform, are combined with the applied engineering of the INEL. Teaming ESSI, NASA/JPL, and INEL with diverse industrial partners has strengthened the respective proposals. These efforts carefully structure the overall project plans to ensure the development, demonstration, and deployment of this concept to the national and international arenas. The objectives of these efforts include: (1) developing a miniaturized commercial, real-time, cost effective version of the AVIRIS instrument; (2) identifying multiple users for AVIRIS; (3) integrating the AVIRIS technology with other technologies; (4) gaining the confidence/acceptance of other government agencies and private industry in AVIRIS; and (5) increasing the technology base of U.S. industry

    (1'-Benzoylferrocenyl)diphenylmethanol; a Centrosymmetric R⁴₄(16) Dimer Generated by C-H...O Hydrogen Bonding

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    In (1'-benzoylferrocenyl)diphenylmethanol, [(PhCOC₅H₄)Fe(C₅H₄)]CPh₂OH, (C₃₀H₂₄FeO₂), there is an intramolecular O-H...O hydrogen bond with O...O 2.891 (2) Å: the ferrocenyl unit adopts an eclipsed conformation and the molecules are linked into centrosymmetric dimers by C-H...O hydrogen bonds with C...O 3.357 (3) Å, to generate a cyclic R⁴₄(16) motif

    Initial Flight Test Evaluation of the F-15 ACTIVE Axisymmetric Vectoring Nozzle Performance

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    A full envelope database of a thrust-vectoring axisymmetric nozzle performance for the Pratt & Whitney Pitch/Yaw Balance Beam Nozzle (P/YBBN) is being developed using the F-15 Advanced Control Technology for Integrated Vehicles (ACTIVE) aircraft. At this time, flight research has been completed for steady-state pitch vector angles up to 20' at an altitude of 30,000 ft from low power settings to maximum afterburner power. The nozzle performance database includes vector forces, internal nozzle pressures, and temperatures all of which can be used for regression analysis modeling. The database was used to substantiate a set of nozzle performance data from wind tunnel testing and computational fluid dynamic analyses. Findings from initial flight research at Mach 0.9 and 1.2 are presented in this paper. The results show that vector efficiency is strongly influenced by power setting. A significant discrepancy in nozzle performance has been discovered between predicted and measured results during vectoring

    Simulated Dynamical Weakening and Abelian Avalanches in Mean-Field Driven Threshold Models

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    Mean-field coupled lattice maps are used to approximate the physics of driven threshold systems with long range interactions. However, they are incapable of modeling specific features of the dynamic instability responsible for generating avalanches. Here we present a method of simulating specific frictional weakening effects in a mean field slider block model. This provides a means of exploring dynamical effects previously inaccessible to discrete time simulations. This formulation also results in Abelian avalanches, where rupture propagation is independent of the failure sequence. The resulting event size distribution is shown to be generated by the boundary crossings of a stochastic process. This is applied to typical models to explain some commonly observed features.Comment: 27 pages, 9 figure

    Accurate Redeterminations of 1,1'-Dibenzoylferrocene and (4-Nitrophenyl)ferrocene

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    In the solid state, molecules of 1,1'-dibenzoylferrocene, [Fe(C₁₂H₉O)₂], (I), are linked to form infinite chains in the [100] direction via (cyclopentadienyl)C-H...O hydrogen bonds [C...O 3.354 (4) Å]. In the structure of (4-nitrophenyl)ferrocene, [Fe(C₅H₅)(C₁₁H₈NO₂)], (II), there are no C-H...O hydrogen bonds and molecules are separated by normal van der Waals distances. For earlier determinations see Struchkov [Dokl. Akad. Nauk SSSR (1956), 110, 67-70] for (I) and Roberts et al. [J. Chem. Soc. Dalton Trans. (1988), pp. 1549-1556] for (II)

    Extensive spontaneous plasticity of corticospinal projections after primate spinal cord injury.

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    Although axonal regeneration after CNS injury is limited, partial injury is frequently accompanied by extensive functional recovery. To investigate mechanisms underlying spontaneous recovery after incomplete spinal cord injury, we administered C7 spinal cord hemisections to adult rhesus monkeys and analyzed behavioral, electrophysiological and anatomical adaptations. We found marked spontaneous plasticity of corticospinal projections, with reconstitution of fully 60% of pre-lesion axon density arising from sprouting of spinal cord midline-crossing axons. This extensive anatomical recovery was associated with improvement in coordinated muscle recruitment, hand function and locomotion. These findings identify what may be the most extensive natural recovery of mammalian axonal projections after nervous system injury observed to date, highlighting an important role for primate models in translational disease research

    Oxygen Vacancies in LiAlO\u3csub\u3e2\u3c/sub\u3e Crystals

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    Singly ionized oxygen vacancies are produced in LiAlO2 crystals by direct displacement events during a neutron irradiation. These vacancies, with one trapped electron, are referred to as V+O centers. They are identified and characterized using electron paramagnetic resonance (EPR) and optical absorption. The EPR spectrum from the V+O centers is best monitored near 100 K with low microwave power. When the magnetic field is along the [001] direction, this spectrum has a g value of 2.0030 and well-resolved hyperfine interactions of 310 and 240 MHz with the two 27Al nuclei that are adjacent to the oxygen vacancy. A second EPR spectrum, also showing hyperfine interactions with two 27Al nuclei, is attributed to a metastable state of the V+O center. An optical absorption band peaking near 238 nm is assigned to V+O centers. Bleaching light from a Hg lamp converts a portion of the V+O centers to V0O centers (these latter centers are oxygen vacancies with two trapped electrons). The V0O centers have an absorption band peaking near 272 nm, a photoluminescence band peaking near 416 nm, and a photoluminescence excitation band peaking near 277 nm. Besides the oxygen-vacancy EPR spectra, a holelike spectrum with a resolved, but smaller, hyperfine interaction with one 27Al nucleus is present in LiAlO2 after the neutron irradiation. This spectrum is tentatively assigned to doubly ionized aluminum vacancies
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