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Wyszukujesz frazę "atmospheric air" wg kryterium: Wszystkie pola


Wyświetlanie 1-4 z 4
Tytuł:
The correlation between the meteorological conditions and the concentration of radionuclides in the ground layer of atmospheric air
Autorzy:
Krajny, E.
Ośródka, L.
Wojtylak, M.
Michalik, B.
Skowronek, J.
Powiązania:
https://bibliotekanauki.pl/articles/148116.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
atmospheric air
meteorology
neural network
radionuclides
Opis:
The main goal of this work was to find correlation between the concentrations of radionuclides in outdoor air and the meteorological conditions like: air temperature, atmospheric pressure, wind velocity and amount of precipitation. Because the sampling period of radionuclides concentrations in air was relatively long (7 days), the average levels of meteorological parameters have been calculated within the same time. Data of radionuclide concentrations and meteorological data have been analyzed in order to find statistical correlation. The regression analysis and one of the AI methods, known as neural network, were applied. In general, analysis of the gathered data does not show any strong correlation between the meteorological conditions and the concentrations of radionuclides in air. A slightly stronger correlation we found for radionuclides with relatively short half-lives. The only positive correlation has been found between the Be-7 concentration and air temperature (at the significance level á=0.05). In our opinion, the lack of correlation was caused by a too long sampling time in measurements of radionuclides in outdoor air (a whole week). Results of the analysis received by means of the artificial neuron network are better. We were able to find certain groups of meteorological conditions, related with the corresponding concentrations of particular radionuclides in air. Preliminary measurements of radon progeny concentration support the thesis that the link between changes of meteorological parameters and concentrations of radionuclides in ambient air must exist.
Źródło:
Nukleonika; 2001, 46, 4; 189-194
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Natural and artificial radionuclides in the tropospheric and lower stratospheric air over Poland
Autorzy:
Kownacka, L.
Powiązania:
https://bibliotekanauki.pl/articles/148112.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
atmospheric radioactivity
Chernobyl
nuclear tests
stratosphere
transport in the atmosphere
troposphere
Opis:
The high altitude aircraft sampling of aerosols have been carried out at four to seven levels up to 15 km over Poland from 1973 to 1998, and 117 vertical concentration profiles of natural radionuclides and fission products were determined. It was found that the atmospheric concentrations of 226Ra increased after large volcanic eruptions. The vertical concentrations profile of 226Ra had a characteristic quasi-parabolic distribution, with the highest concentrations near the ground level and in the stratosphere. Concentrations of 210Pb had a more homogeneous vertical distribution, due to the quiescent ascent of its gaseous 222Rn precursor from the ground. Vertical concentrations of fission products revealed different types of profiles. After nuclear explosions, the highest concentrations were observed in the stratosphere. The Chernobyl accident reversed the aerial vertical profiles; the main source was near the ground level, but part of the radioactive debris entered also the lower stratosphere. Because of resuspension, the stratospheric residence time of radiocesium from the Chernobyl accident was about three times longer than that of the fallout from nuclear explosions. The resuspension effects and the atmospheric mass transport in the boundary layers are also responsible for the increased concentrations of radiocesium at 1 km altitude observed since 1987 in the situations of atmospheric mass advection from the highly contaminated Chernobyl region.
Źródło:
Nukleonika; 2001, 46, 4; 175-177
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fluctuation of radiocaesium concentrations in the near-surface atmospheric layer in Białystok in the period 1992-1999
Autorzy:
Kapała, J.
Zalewski, M.
Tomczak, M.
Mnich, Z.
Karpińska, M.
Powiązania:
https://bibliotekanauki.pl/articles/147161.pdf
Data publikacji:
2002
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
air contamination
Chernobyl accident
Cs-137
Opis:
Air samples were collected at an early-warning sampling and monitoring radioactive contamination station ASS-500. The results of the measurements are presented for radioactive aerosols collected on filters each week between 1992 and 1999. The large variations in activity concentration were observed in annual cycles. The maximum values exceeded the mean annual values by a factor of 2.8 to 7.3. Over the period of eight years the mean values of activity in air was found to decrease from 5.3 mi Bq m-3 in 1992 to 2.2 mi Bq m-3 in 1999. A good correlation between the Cs-137 activity and dust content in the air indicates that in the observed period the main source of Cs-137 activity is the dust with soil and vegetation particles. The effect of radiation from inhalation is negligible (626 pSv).
Źródło:
Nukleonika; 2002, 47, 2; 69-73
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vertical distributions of beryllium-7 and lead-210 in the tropospheric and lower stratospheric air
Autorzy:
Kownacka, L.
Powiązania:
https://bibliotekanauki.pl/articles/147188.pdf
Data publikacji:
2002
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
atmospheric radioactivity
7Be in the atmosphere
210Pb in the atmosphere
stratosphere
transport in the atmosphere
troposphere
Opis:
Vertical distributions of 7Be and 210Pb were observed in the troposphere and lower stratosphere over Poland at several altitudes between 0 and 15 km in the period 1987-1998. These two natural radionuclides are formed from gases in the atmosphere by nuclear processes. They are associated with similar size distributions aerosol particles and are removed from the atmosphere with similar efficiencies by scavenging processes of washout and deposition, however, they have various types of sources in the atmosphere. Vertical profiles of 7Be (cosmogenic origin), characterized by small concentrations near the ground level, increase in the tropospheric levels and at 15 km altitude the concentrations are the highest. The highest concentrations of 210Pb (terrestrial origin) are observed near the ground level, the lowest are below the tropopause, and in the stratosphere the concentration increases slightly. The dependence of the vertical distributions of both radionuclides in the situation of various levels of tropopause are discussed in this work.
Źródło:
Nukleonika; 2002, 47, 2; 79-82
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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