Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 3

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
w słowach kluczowych:  gaz szlachetny
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
Temat gazów szlachetnych, którymi napełniana jest przestrzeń międzyszybowa szyby zespolonej dla polepszenia jej parametrów technicznych, jest faktem dosyć dobrze znanym producentom szyb zespolonych oraz wykonawcom stolarki okiennej i fasadowej. Warto przyjrzeć się temu zagadnieniu z trochę większą uwagą, ponieważ w projektach i dokumentacji wykonawczej, szczególnie w odniesieniu do różnych rodzajów fasad, można znaleźć wiele przykładów określania parametrów dla przeszkleń, które mając łączyć kilka funkcji mogą się nawzajem wykluczać.
Content available remote Nanodiamonds in meteorites: properties and astrophysical context
Purpose: This contribution provides an overview on properties and origin of nanodiamonds in primitive meteorites. Nanodiamond are a type of stardust, i.e. “pre-solar” grains that formed in the outflows or ejecta of stars. Design/methodology/approach: We summarize previously obtained results and include our results dealing with recoil loss from nanoparticles during radioactive decay of trace elements within them. Findings: Nanodiamonds in primitive meteorites have a mean size of ~2.6 nm and an abundance reaching up to ~0.15 % by weight. They contain trace noble gases, notably xenon, with an unusual isotopic composition. The latter is reminiscent of the p- and r-processes of nucleosynthesis that are thought to occur during supernova explosions. Our new results show that recoil loss during â decay of implanted 22Na does not exceed what is expected from energy distribution and range-energy relations in matter. While a CVD origin for the diamonds appears likely (but is not assured), the noble gases were probably introduced by ion implantation. Research limitations/implications: The isotopic pattern of Xe contained in nanodiamonds indicates some unconventional types of element synthesis in stars or modification by secondary processes. Recoil loss from nanometer-sized grains during decay of unstable precursor nuclides has been suggested as an explanation, but our experiments do not support this idea. Originality/value: Other processes must be invoked for explanation of the isotopically unusual xenon trapped in meteoritic nanodiamonds. Ion implantation experiments suggest of “trapped” cosmic ray 3He for deriving an age for the diamonds.
The detailed research of a gas mixture released from the thermal water, which is extracted from borehole KT-1 at Karpniki, showed the predominance of nitrogen (98.08% by volume) with subordinate Ar (1.52%) and He (0.32%) and trace amounts of CO2 (0.07%) and CH4 (0.01%). The 222Rn radionuclide is also dissolved in this water, showing an activity concentration of 245 Bq/dm3 at the outflow and 256 Bq/dm3 in the aquifer. A small value of the gas exponent (0.014), and also a value of the δ coefficient close to 1 (0.93) were calculated based on the dissolved Ar and N2 content in the water examined, as well as on concentrations of argon and nitrogen in water, assuming that atmospheric air is present above the water surface with a contemporary composition and under normal pressure. The data obtained indicate that these gases and additionally CO2 and CH4 are of atmospheric origin. These gases were either dissolved in rainwater, which infiltrated deep into the Karkonosze granite massif, orformed within the organic layer covering this exposed intrusion. This is evidenced by concentrations of these gases that can be comparable to their atmospheric equivalents. Helium is a radiogenic gas formed as a result of nuclear transformation of isotopes assigned to natural radioactive series. The radiogenic and also radioactive gas is represented by the 222Rn radioisotope which is released from reservoir rocks, in an amount of 5% of the atom poolforming in the reservoir rock, into thermal water that subsequently reaches borehole KT-1 from a distance of 34 m at most. The thermal paleoinfiltration water has been heated up as a result of the conduction, and the source of heat is the temperature of the rocks resulting from an average geothermal gradient of 2.96°C per 100 m. The results of the authors’research indicate that there are no traces of inflow of hotfluids (especially water) from the deeper layers of the crust or from the mantle. If the examined thermal water is considered as paleoinfiltration water, its static resources may be limited, non-renewable.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.