7,140 research outputs found

    Using HCMM Thermal Data to Improve Classification of MSS Data

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    Spectral overlap between urban and rural land use/land cover categories can lead to unacceptable map accuracy levels in the classification of LANDSAT multispectral scanner (MSS) data. The four MSS bands used alone are not always adequate to distinguish among various land uses and cover types having similar spectral responses. The use of thermal data from the Heat Capacity Mapping Mission (HCMM) satellite as a means of improving MSS land cover classification accuracies for urban versus rural categories was investigated. The approaches used to integrate the HCMM data are described

    Use of steepest descent and various approximations for efficient computation of minimum noise aircraft landing trajectories

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    The following areas related to landing trajectory optimization research were discussed: (1) programming and modifying the steepest descent optimization procedure, (2) successfully iterating toward the optimum for a four-mile trajectory, (3) beginning optimization runs for a twenty-mile trajectory, and (4) adapt wind tunnel data for computer usage. Other related areas were discussed in detail in the two previous annual reports

    Ion composition in a noctilucent cloud

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    Ion composition at mesospheric altitudes was measured and compared between high and mid-latitude sites under summer daytime conditions. Rocket-borne measurements were made with pumped quadrupole ion mass spectrometers. The mid-latitude data were obtained at Wallops Island, Virginia on June 30, 1973, at 1510 LMT. Large quantities of hydronium cluster ions were observed through 109+, with maximum concentrations at 55+ and 73+. Also, cluster ions of nitric oxide were observed through 84+. The high latitude launch occurred at Kiruna, Sweden on August 2, 1973, at 0700 LMT following visual sighting of a noctilucent cloud on the prior evening. The data near mesopause shows cluster ions, but also a preponderance of heavy ions between 90 and 145 AMU, with groupings 18 AMU apart but unrelated to the more typical cluster ions. One possible set of consistent identifications leads to iron and iron oxide hydrates. These results may suggest the presence of metallic particulates and ions which form hydrated clusters ions

    Optimization and sensitivity studies of flight-path trajectories

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    The optimization of landing trajectories of the Boeing 737 is presented. The primary factor considered was the noise delivered to the population residing near an air terminal but passenger comfort, fuel consumption and time elapsed during the maneuver were also considered. A digital simulation of the aircraft, a noise model and a passenger comfort model, was completed. The digital simulation was made more efficient time-wise. A population model for an urban area was developed and the noise model was integrated into the population model. A steepest descent optimization algorithm was programmed. Some constant glide slope trajectories into an urban Airport were simulated and evaluated with respect to the performance index, and their ground track plotted

    Monitoring strip mining and reclamation with LANDSAT data in Belmont County, Ohio

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    The utility of LANDSAT digital data for mapping and monitoring surface mines in Belmont County, Ohio was investigated. Two data sets from 1976 and 1979 were processed to classify level 1 land covers and three strip mine categories in order to examine change over time and assess reclamation efforts. The two classifications were compared with aerial photographs. Results of the accuracy assessment show that both classifications are approximately 86 per cent correct, and that surface mine change detection (date-to-date comparison) is facilitated by the digital format of LANDSAT data

    Accurate, rapid, temperature and liquid-level sensor for cryogenic tanks

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    Thermopiles measure ullage gas temperatures to within plus or minus 1.65 deg K between 20 and 300 deg K, and also serve as point liquid-level sensors. Thermopile technique measures smaller temperature differences by keeping the reference junctions inside the tank and near the temperature range of the measuring junction

    On the Explanatory Power of Generalized Darwinism: Missing Items on the Research Agenda

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    In a recent article in this journal, Geoffrey Hodgson points out that the notion of 'evolution' is widely used in organization science without authors being sufficiently clear on what exactly they mean by this term. In his article, Hodgson cleans up the terminological and conceptual confusion on evolution in organization science and positions so-called 'generalized Darwinism' as the only well-elaborated evolutionary framework available in social science. We doubt, however, whether in its present form generalized Darwinism itself constitutes a viable approach. In this article we argue that Hodgson and collaborators so far have failed to show that generalized Darwinism is actually capable of serving as a basis for the construction of evolutionary explanations of social and organizational phenomena. We suggest a few items that should be put on generalized Darwinism's research agenda in order to develop it towards a viable option. © The Author(s) 2013

    Silicon nanoparticles and interstellar extinction

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    To examine a recently proposed hypothesis that silicon nanoparticles are the source of extended red emission (ERE) in the interstellar medium, we performed a detailed modeling of the mean Galactic extinction in the presence of silicon nanoparticles. For this goal we used the appropriate optical constants of nanosized Si, essentially different from those of bulk Si due to quantum confinement. It was found that a dust mixture of silicon nanoparticles, bare graphite grains, silicate core-organic refractory mantle grains and three-layer silicate-water ice-organic refractory grains works well in explaining the extinction and, in addition, results in the acceptable fractions of UV/visible photons absorbed by silicon nanoparticles: 0.071-0.081. Since these fractions barely agree with the fraction of UV/visible photons needed to excite the observed ERE, we conclude that the intrinsic photon conversion efficiency of the photoluminescence by silicon nanoparticles must be near 100%, if they are the source of the ERE.Comment: Latex2e, uses emulateapj.sty (included), multicol.sty, epsf.sty, 6 pages, 3 figures (8 Postscript files), accepted for publication in ApJ Letters, complete Postscript file is also available at http://physics.technion.ac.il/~zubko/eb.html#SNP

    The Existence of Einstein Static Universes and their Stability in Fourth order Theories of Gravity

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    We investigate whether or not an Einstein Static universe is a solution to the cosmological equations in f(R)f(R) gravity. It is found that only one class of f(R)f(R) theories admits an Einstein Static model, and that this class is neutrally stable with respect to vector and tensor perturbations for all equations of state on all scales. Scalar perturbations are only stable on all scales if the matter fluid equation of state satisfies cs2>5−16≈0.21c_s^2>\frac{\sqrt{5}-1}{6}\approx 0.21. This result is remarkably similar to the GR case, where it was found that the Einstein Static model is stable for cs2>1/5c_s^2>{1/5}.Comment: Minor changes, To appear in PR

    Second Eastern Regional Remote Sensing Applications Conference

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    Participants from state and local governments share experiences in remote sensing applications with one another and with users in the Federal government, universities, and the private sector during technical sessions and forums covering agriculture and forestry; land cover analysis and planning; surface mining and energy; data processing; water quality and the coastal zone; geographic information systems; and user development programs
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