Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1995-1999  (3)
  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 36 (1995), S. 3704-3721 
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: Light cone cuts are the intersection of the light cones of space–time events with an initial data surface which is usually taken to be null infinity. These are determined by a "cut function,'' a function of the space–time coordinates and the sphere of generators of null infinity. The Bach equations and the conformal vacuum equations are shown to lead to a single scalar "main'' equation on the cut function. In simplified cases, i.e., when the Weyl curvature is either small or self-dual, this equation can be integrated to give a simple scalar conformally invariant elliptic equation on the sphere of null directions. It has the remarkable property that the general solution of the Einstein vacuum equations in these cases can be derived from the solution to this auxiliary equation in two dimensions. In general, it will not be possible to reduce it to an auxilliary equation on the sphere. Nevertheless, the main equation is still a necessary condition and it is conjectured that it is also sufficient to imply the Bach equations in general and supporting arguments are given. It is also shown how to extend the Kozameh–Newman framework to the case of light cone cuts of a spacelike Cauchy hypersurface. The analogous procedures for Yang–Mills are also discussed. A conformally invariant formalism for calculations on null infinity is described in an Appendix. This is used for all the calculations which are only described in brief form in the main text. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 235 (1998), S. 71-75 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Anthropogenic radioactivity is being measured in near-real time by an international monitoring system designed to verify the Comprehensive Nuclear Test Ban Treaty. Airborne radioactivity measurements are conducted in-situ by stations that are linked to a central data processing and analysis facility. Aerosols are separated by high-volume air sampling with high-efficiency particulate filters. Radio-xenon is separated from other gases through cryogenic methods. Gamma-spectrometry is performed by high purity germanium detectors and the raw spectral data is immediately transmitted to the central facility via Internet, satellite, or modem. These highly sensitive sensors, combined with the automated data processing at the central facility, result in a system capable of measuring environmental radioactivity on the microbeequerel scale where the data is available to scientists within minutes of the field measurement. During the past year, anthropogenic radioactivity has been measured at approximately half of the stations in the current network. Sources of these measured radionuclides include nuclear power plant emissions, Chernobyl resuspension, and isotope production facilities. The ability to thoroughly characterize site-specific radionuclides, which contribute to the radioactivity of the ambient environment, will be necessary to reduce the number of false positive events. This is especially true of anthropogenic radionuclides that could lead to ambiguous analysis.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 235 (1998), S. 65-69 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A global radionuclide monitoring system is being engineered as part of a multi-technology verification system for the Comprehensive Nuclear Test Ban Treaty. The system detects airborne radioactive aerosols and gases that can indicate nuclear weapons test debris. The backbone of the system is a network of 80 remote detection stations that utilize high-volume air sampling and high-resolution gamma spectrometry to provide in-situ assay and near-real time reporting. These stations are linked to the International Data Centre, which is a central data processing hub where raw spectral data is automatically processed, analyzed, and disseminated to the states parties. Measurements are categorized based on spectral content to determine which contain anomalous anthropogenic radionuclides that require intensive radiochemical analysis at a certified laboratory. The resulting system has the capability to measure microbecquerel concentrations of radionuclides and provide accessible data products within minutes of field measurements. During the past year of international operations, the minimum detectable concentrations and spectroscopy processing statistics were recorded as a function of geographical location and time. The results show that this system is an effective tool for nuclear test monitoring, as well as other applications such as radiological emergency response, public health monitoring, and scientific research.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...