13,515 research outputs found
Grid enabling legacy applications for scalability – Experiences of a production application on the UK NGS
Impact of remote sensing upon the planning, management, and development of water resources
A survey of the principal water resource users was conducted to determine the impact of new remote data streams on hydrologic computer models. The analysis of the responses and direct contact demonstrated that: (1) the majority of water resource effort of the type suitable to remote sensing inputs is conducted by major federal water resources agencies or through federally stimulated research, (2) the federal government develops most of the hydrologic models used in this effort; and (3) federal computer power is extensive. The computers, computer power, and hydrologic models in current use were determined
On the Nature of Precursors in the Radio Pulsar Profiles
In the average profiles of several radio pulsars, the main pulse is
accompanied by the preceding component. This so called precursor is known for
its distinctive polarization, spectral, and fluctuation properties. Recent
single-pulse observations hint that the sporadic activity at the extreme
leading edge of the pulse may be prevalent in pulsars. We for the first time
propose a physical mechanism of this phenomenon. It is based on the induced
scattering of the main pulse radiation into the background. We show that the
scattered component is directed approximately along the ambient magnetic field
and, because of rotational aberration in the scattering region, appears in the
pulse profile as a precursor to the main pulse. Our model naturally explains
high linear polarization of the precursor emission, its spectral and
fluctuation peculiarities as well as suggests a specific connection between the
precursor and the main pulse at widely spaced frequencies. This is believed to
stimulate multifrequency single-pulse studies of intensity modulation in
different pulsars.Comment: 5 pages, no figures. Accepted for publication in MNRAS Letter
The Equilibrium Distribution of Gas Molecules Adsorbed on an Active Surface
We evaluate the exact equilibrium distribution of gas molecules adsorbed on
an active surface with an infinite number of attachment sites. Our result is a
Poisson distribution having mean , with the
mean gas density, the sticking probability, the evaporation
probability in a time interval , and Smoluchowski's exit probability
in time interval for the surface in question. We then solve for the case
of a finite number of attachment sites using the mean field approximation,
recovering in this case the Langmuir isotherm.Comment: 14 pages done in late
Impact of remote sensing upon the planning, management and development of water resources, appendix
Lists are presented of water resource agencies from the federal, state, Water Resources Research Institute, university, local, and private sectors. Information is provided on their water resource activities, computers, and models used. For Basic doc., see N75-25263
Impact of remote sensing upon the planning, management, and development of water resources
Principal water resources users were surveyed to determine the impact of remote data streams on hydrologic computer models. Analysis of responses demonstrated that: most water resources effort suitable to remote sensing inputs is conducted through federal agencies or through federally stimulated research; and, most hydrologic models suitable to remote sensing data are federally developed. Computer usage by major water resources users was analyzed to determine the trends of usage and costs for the principal hydrologic users/models. The laws and empirical relationships governing the growth of the data processing loads were described and applied to project the future data loads. Data loads for ERTS CCT image processing were computed and projected through the 1985 era
The application of remote sensing to the development and formulation of hydrologic planning models
A hydrologic planning model is developed based on remotely sensed inputs. Data from LANDSAT 1 are used to supply the model's quantitative parameters and coefficients. The use of LANDSAT data as information input to all categories of hydrologic models requiring quantitative surface parameters for their effects functioning is also investigated
The application of remote sensing to the development and formulation of hydrologic planning models
For abstract, see N76-18632
The application of remote sensing to the development and formulation of hydrologic planning models
For abstract, see N76-14576
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