8,209 research outputs found
Current research on aviation weather (bibliography)
This bibliography of 326 readily usable references of basic and applied research programs related to the various areas of aviation meteorology was assembled. A literature search was conducted which surveyed the major abstract publications such as the International Aerospace Abstracts, the Meteorological and Geoastrophysical Abstracts, and the Scientific and Technical Aerospace Reports. In addition, NASA and DOT computer literature searches were run; and NASA, NOAA, and FAA research project managers were requested to provide writeups on their ongoing research
Internal Migration and Regional Population Dynamics in Europe: Romanian Case Study
The report analyses population migration and change in Romania over the period 1984-1994. The analysis of population change is conducted for 2948 communes and towns, the finest administrative division for which population data are available. The lack of migration data on the level of communes and towns makes in-depth analysis of the migration for small spatial units impossible. For that reason analysis of the patterns of migration is conducted for 40 Judete (also referred to as counties or regions) and the capital city of Bucharest, i.e. 41 units altogether.
Council of Europe Publishing,
F-67075 Strasbourg - Cedex,
France
Proceedings of the 2nd Annual Workshop on Meteorological and Environmental Inputs to Aviation Systems
The proceedings of a workshop held at the University of Tennessee Space Institute, Tullahoma, Tennessee, March 28-30, 1978, are reported. The workshop was jointly sponsored by NASA, NOAA, FAA, and brought together many disciplines of the aviation communities in round table discussions. The major objectives of the workshop are to satisfy such needs of the sponsoring agencies as the expansion of our understanding and knowledge of the interactions of the atmosphere with aviation systems, as the better definition and implementation of services to operators, and as the collection and interpretation of data for establishing operational criteria, relating the total meteorological inputs from the atmospheric sciences to the needs of aviation communities
Internal Migration and Regional Population Dynamics in Europe: Finland Case Study
Both natural increase and internal migration have played roles in the shaping of population distribution of Finland since 1900. Far reaching recent changes in the economy have brought about massive shift of jobs from agriculture to manufacturing and services. As a result people have relocated from rural to urban areas. Both natural change and net migration have distinct geographical patterns, resulting in serious depopulation in remote areas in the east and north of the country. Internal migration benefits the south, the west, coastal areas, urban agglomerations and suburban areas. International migration is a marginal phenomenon in Finland and has little impact on population dynamics. Net migration losses in the past were offset by high natural increase and in recent decades Finnish emigrants have returned.
Urban concentration is a dominant feature of the Finnish migration system. At the subregional level, suburbanisation is visible, but is not as strong as in the overcrowded metropolises of Western Europe. The relationships between migration and size of municipality, migration and population density and migration and urban/rural class of municipalities show that the process of concentration is the strongest force at work in shifting people to urban agglomerations and their suburban rings.
Regional patterns of migration show strong transfers of population from north and east to south and to lesser extent to west of the country. The Baltic Sea coast has a strong attraction to migrants. Migration is sex-selective, with a much higher propensity of females to leave remote and rural areas and migrate to urban centres and the southern part of the country. The result is a significant gender imbalance: a deficiency of females in rural areas and in the north and east of the country and a surplus in urban and semi-urban areas. However, the economic indicator unemployment has a rather weak and imprecise effect on migrants
Are There Local Analogs of Lyman Break Galaxies?
To make direct comparisons in the rest-far-ultraviolet between LBGs at z~3
and more local star-forming galaxies, we use HST/STIS to image a set of 12
nearby (z<0.05) HII galaxies in the FUV and a set of 14 luminous compact blue
galaxies (LCBGs) at moderate redshift (z~0.5) in the NUV, corresponding to the
rest-FUV. We then subject both sets of galaxy images and those of LBGs at z~3
to the same morphological and structural analysis. We find many qualitative and
quantitative similarities between the rest-FUV characteristics of distant LBGs
and of the more nearby starburst samples, including general morphologies,
sizes, asymmetries, and concentrations. Along with some kinematic similarities,
this implies that nearby HII galaxies and LCBGs may be reasonable local analogs
of distant Lyman break galaxies.Comment: 4 pages, 4 figures. To appear in "Starbursts: from 30 Doradus to
Lyman Break Galaxies" 2005, eds. R. de Grijs and R. M. Gonzalez Delgado
(Kluwer
Cosmic ray muon computed tomography of spent nuclear fuel in dry storage casks
Radiography with cosmic ray muon scattering has proven to be a successful
method of imaging nuclear material through heavy shielding. Of particular
interest is monitoring dry storage casks for diversion of plutonium contained
in spent reactor fuel. Using muon tracking detectors that surround a
cylindrical cask, cosmic ray muon scattering can be simultaneously measured
from all azimuthal angles, giving complete tomographic coverage of the cask
interior. This paper describes the first application of filtered back
projection algorithms, typically used in medical imaging, to cosmic ray muon
imaging. The specific application to monitoring spent nuclear fuel in dry
storage casks is investigated via GEANT4 simulations. With a cylindrical muon
tracking detector surrounding a typical spent fuel cask, the cask contents can
be confirmed with high confidence in less than two days exposure. Similar
results can be obtained by moving a smaller detector to view the cask from
multiple angles.Comment: 12 pages, 8 figure
Plasmonic lenses for tunable ultrafast electron emitters at the nanoscale
Simultaneous spatiotemporal confinement of energetic electron pulses to femtosecond and nanometer scales is a topic of great interest in the scientific community, given the potential impact of such developments across a wide spectrum of scientific and industrial applications. For example, in ultrafast electron scattering, nanoscale probes would enable accurate maps of structural dynamics in materials with nanoscale heterogeneity, thereby leading to an understanding of the role of boundaries and defects on macroscopic properties. On the other hand, advances in this field are mostly limited by the brightness and size of the electron source. We present the design, fabrication, and optical characterization of bullseye plasmonic lenses for next-generation ultrafast electron sources. Using electromagnetic simulations, we examine how the interplay between light-plasmon coupling, plasmon propagation, dispersion, and resonance governs the properties of the photoemitted electron pulse. We also illustrate how the pulse duration and strength can be tuned by geometric design and predict that sub-10-fs pulses with nanoscale diameter can be achieved. We then fabricate lenses in gold films and characterize their plasmonic properties using cathodoluminescence spectromicroscopy, demonstrating suitable plasmonic behavior for ultrafast nanoscale photoemission
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