Messung der Krypton-85-und Xenon-133-Aktivität der atmosphärischen Luft / A Method for Measurement of the Krypton-85 and Xenon-133-content in the Atmosphere

1977 ◽  
Vol 32 (11) ◽  
pp. 1249-1253 ◽  
Author(s):  
H. Stockburger ◽  
H. Sartorius
Keyword(s):  
Activated Carbon ◽  
Proportional Counter ◽  
Molecular Sieve ◽  
Room Temperature ◽  
Sampling Time ◽  
Rare Gas ◽  
Activity Levels ◽  
Separation And Purification ◽  
Rare Gases ◽  
Xenon 133

AbstractTo measure the 85Kr and 133Xe content in the atmosphere approximately 60 m3 of dried and CO2-removed air are pumped through activated carbon (pressure 300 torr, temperature 77 K) during one week. When sampling time is over, the carbon is heated to 570 K. This gives a gas sample of 41 with more than 90% of the atmospherical krypton and xenon within two hours. With a further step of enrichment, the volume of sample is reduced to 100 ml. The final separation and purification of the rare gases from O2, N2, CO and CO2 is made chromatographically. First the xenon is sepa­rated in a column filled with molecular sieve (5A) at 390 K, after that the krypton is separated in a column with activated charcoal at room temperature with methane as a "carrier gas" and is simultaneously transported to a proportional counter (230 ml). In the first half-year of 1977 the activity levels of 85Kr and 133Xe ran to 17.7 respectively 0.19 pCi/m3 air. The variations of the rare gas-activities are indeed rather high. The xenon-activities are not correlated with the krypton-activities. In a preliminary discussion we try to find reasons for these variations.

Messung der Krypton-85-Aktivität der atmosphärischen Luft / A Method for Measurement of the Krypton-85-content in the Atmosphere

1975 ◽  
Vol 30 (8) ◽  
pp. 959-961 ◽  
Author(s):  
H. Stockburger ◽  
A. Sittkus
Keyword(s):  
Activated Carbon ◽  
Proportional Counter ◽  
Room Temperature ◽  
Sampling Time ◽  
Simple Method

AbstractTo measure the Kr-85 content in the atmosphere we developed a simple method. Within a time internal of five to ten days (depending on the moisture of the air) five to ten m 3 of air (NTP) are pumped through activated carbon (pressure 300 torr, temperature 77 °K). When sampling time is over, the carbon is heated to 470 °K. This gives a gas sample of 4 1 with more than 90% of the atmospherical krypton in 3 hours. With a further step of enrichment, the volume of the sample is reduced to 100 ml. The final separation of krypton from O2 , N2 , CO, CO2 and Xe is made by gaschromatography at room temperature with methane as eluent gas (duration 25 min). The Kr-fraction is transported to a proportional counter (200 ml). The overall yield is 90%. The overall error of the Kr-85 content is near 1%. Data are given for the time of 15. 6. 1973 to 29. 12. 1974.

Collision-induced microwave absorption in gaseous mixtures of various rare gases at 2.3 cm−1

1980 ◽  
Vol 58 (5) ◽  
pp. 633-641 ◽  
Author(s):  
I. R. Dagg ◽  
W. D. Leckie ◽  
L. A. A. Read
Keyword(s):  
Microwave Absorption ◽  
Room Temperature ◽  
Infrared Region ◽  
Exponential Model ◽  
Rare Gas ◽  
Rare Gases ◽  
Gaseous Mixtures ◽  
Induced Dipole ◽  
Upper Limits ◽  
Density Ratios

Collision-induced microwave absorption has been observed at 2.3 cm−1 for the rare gas mixtures Ne–Kr, Ar–Kr, Ar–Xe, and Kr–Xe. The absorption coefficient has been measured at room temperature for density products up to 8000 amagat2 and for various density ratios. These results have been used in conjunction with those of the infrared region to determine more accurately the zeroth moment for each of the spectra and hence have allowed improved values for the induced dipole moment parameters for the exponential model. Upper limits to the absorption in He–Xe and He–Ar mixtures in the microwave region have also been established.

Diffusion in multicomponent gaseous mixtures. Part 3

1967 ◽  
Vol 45 (16) ◽  
pp. 1825-1828 ◽  
Author(s):  
Harry Watts
Keyword(s):  
Kinetic Theory ◽  
Multicomponent Mixture ◽  
Equimolar Mixture ◽  
Rare Gas ◽  
Rare Gases ◽  
Binary Diffusion ◽  
Gaseous Mixtures ◽  
Diffusion Systems ◽  
Theory Equation ◽  
Xenon 133

Diffusion of one rare gas into an equimolar mixture of two other rare gases has been followed using krypton-85 or xenon-133 tracer. The systems behave as pseudo-binary diffusion systems. A kinetic theory equation, valid for diffusion of a trace in a multicomponent mixture, is not a good approximation for diffusion of a major component.

Rare gas bubbles in muscovite mica implanted with xenon and krypton

1994 ◽  
Vol 9 (12) ◽  
pp. 3095-3107 ◽  
Author(s):  
G.A. Hishmeh ◽  
L. Cartz ◽  
F. Desage ◽  
C. Templier ◽  
J.C. Desoyer ◽  
...  
Keyword(s):  
Room Temperature ◽  
Liquid Nitrogen Temperature ◽  
Amorphous Structure ◽  
Dark Field ◽  
Rare Gas ◽  
Rare Gases ◽  
Transmission Electron ◽  
Dark Field Microscopy ◽  
Muscovite Mica ◽  
Gas Pressures

Xenon and krypton have been implanted into muscovite mica at room temperature and at liquid nitrogen temperature. The behavior of the implanted Xe and Kr was followed by low-temperature transmission electron microscopy and energy dispersive x-ray analysis. An electron diffraction pattern of diffuse bands is observed at room temperature due to the presence of fluid rare gas and to noncrystalline mica. Visible cavities with diameters 10–300 nm formed in the Xe-implanted mica. Visible cavities in room-temperature Kr-implanted mica ranged from 5–50 nm in diameter. The gas pressures at room temperature in the cavities are estimated, assuming all of the implanted gas precipitated in cavities to be ∼10 MPa for Xe and ∼20 MPa for Kr. These pressures are considerably lower than found for rare gases implanted in metals and ceramics, but sufficient to liquefy the rare gases at room temperature. The Xe and Kr were observed by dark-field microscopy to form fcc crystalline solids within the cavities at temperatures below their triple points, with lattice parameters of a(xe) = 0.630 ± 0.0015 nm and a(Kr) = 0.565 ± 0.005 nm. The solid Xe within bubbles was unstable under the electron beam of the transmission electron microscope at temperatures above 80 K, while the solid Kr within bubbles was unstable at temperatures as low as 35 K. The crystalline mica matrix undergoes a transformation from a crystalline structure to an amorphous structure as a result of implantation.

Fibrillin molecules aggregate to form an extendible beaded structure which is a major component of “Elastin Associated” microfibrils

1989 ◽  
Vol 47 ◽  
pp. 246-247
Author(s):  
Douglas R. Keene ◽  
B. Kerry Maddox ◽  
Marie B. Spurgin ◽  
Lynn Y. Sakai ◽  
Robert W. Glanville
Keyword(s):  
Molecular Sieve ◽  
Room Temperature ◽  
Culture Medium ◽  
Weight Fraction ◽  
Ammonium Bicarbonate ◽  
High Molecular Weight Fraction ◽  
Bicarbonate Buffer ◽  
Human Amnion ◽  
Gold Conjugate ◽  
Ammonium Bicarbonate Buffer

A mouse monoclonal antibody was used to identify beaded aggregates found in guanidine extracts of human amnion as assemblies of fibrillin molecules. These aggregates were also shown to be a major component of extracellular matrix microfibrils. We further demonstrated that the periodicity of these aggregates can be increased when subjected to mechanical stress.Human amnion was extracted with guanidine and the extracted material purified using ion exchange and molecular sieve chromatography. A high molecular weight fraction was precipitated by dialyzing against dilute acetic acid. Part of the precipitate was suspended in 0.2 M ammonium bicarbonate buffer and rotary shadowed. A second portion was resuspended in culture medium containing antibody which recognizes matrix microfibrils, diluted 1:5 in ammonium bicarbonate and reacted for 120 minutes at room temperature. Antibody labeled precipitate was washed by repeated pelleting and resuspension in buffer and then incubated in Janssen GAM 5 nm gold conjugate for 60 minutes at room temperature.

scholarly journals The effect of storage conditions on samples for the evaluation of copper status in blesbok (Damaliscus pygargus phillipsi)

2002 ◽  
Vol 73 (3) ◽  
Author(s):  
M. Quan ◽  
M.S. Mulders ◽  
D.G.A. Meltzer
Keyword(s):  
Superoxide Dismutase ◽  
Liquid Nitrogen ◽  
Liver Tissue ◽  
Room Temperature ◽  
Storage Conditions ◽  
Superoxide Dismutase Activity ◽  
Activity Levels ◽  
Sample Storage ◽  
Live Animal ◽  
Jersey Cows

Investigaltions to determine the effect of sample storage on the concentration of copper in liver tissue and on the activity of erythrocyte superoxide dismutase were undertaken in preparation for a study of blesbok (Damaliscus pygargus phillipsi) that were suspected to be suffering from copper deficiency. Two liver samples were collected from each of 20 culled blesbok in a manner that simulated the collection of biopsies from the live animal. These samples were stored either in 10 % formalin or frozen at -20 °C until analysed 4 1/2 months later. The effect of different methods of sample storage on superoxide dismutase activity was determined. Erythrocytes collected from 3 Jersey cows and 5 culled blesbok were washed and divided into 0.5m portions, stored at room temperature (~20 °C), in a refrigerator (4 °C), frozen at -20 °C in a freezer, and in liquid nitrogen (-200 °C). An analysis of superoxide dismutase activity was undertaken using a commercial assay kit at intervals of 2-4 days until the levels of activity had fallen significantly. The copper concentration in formalin-preserved liver samples was significantly lower than that measured in frozen liver tissue apparently as a result of leaching. The activity of superoxide dismutase in cattle blood was unchanged for 4 days at room temperature but fell appreciably after 2 days at 4 °C and -20 °C. Enzyme activity remained unchanged for 200 days in erythrocytes stored in liquid nitrogen. Superoxide dismutase activity levels in healthy blesbok were considerably lower than those measured in Jersey cows and remained unaffected for up to 6 days in samples stored at 4 °C and 20 °C. The level of activity fell significantly thereafter. Samples stored in liquid nitrogen were unchanged after 40 days.

Pressure Isotherms of Hydrogen Adsorption in Carbon Nanostructures

2001 ◽  
Vol 706 ◽  
Author(s):  
Xiaohong Chen ◽  
Urszula Dettlaff-Weglikowska ◽  
Miroslav Haluska ◽  
Martin Hulman ◽  
Siegmar Roth ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Activated Carbon ◽  
Hydrogen Storage ◽  
Carbon Nanostructures ◽  
Room Temperature ◽  
Storage Capacity ◽  
Hydrogen Adsorption ◽  
Single Wall Carbon Nanotubes ◽  
Hydrogen Storage Capacity ◽  
Carbon And Graphite

AbstractThe hydrogen adsorption capacity of various carbon nanostructures including single-wall carbon nanotubes, graphitic nanofibers, activated carbon, and graphite has been measured as a function of pressure and temperature. Our results show that at room temperature and a pressure of 80 bar the hydrogen storage capacity is less than 1 wt.% for all samples. Upon cooling, the capacity of hydrogen adsorption increases with decreasing temperature and the highest value was observed to be 2.9 wt. % at 50 bar and 77 K. The correlation between hydrogen storage capacity and specific surface area is discussed.

Ozone yields from the Febetron radiolysis of oxygen – rare gas mixtures

1977 ◽  
Vol 55 (2) ◽  
pp. 203-209 ◽  
Author(s):  
A. W. Boyd ◽  
O. A. Miller ◽  
E. B. Selkirk
Keyword(s):  
Excited State ◽  
Gas Mixtures ◽  
Rare Gas ◽  
Rare Gases

Ozone yields have been measured from the Febetron irradiation of mixtures containing 1–50 mol% oxygen and each of the five rare gases. The maximum values of G(O3) calculated using the energy absorbed only in the rare gas are obtained with the addition of less than 10% oxygen and are for: He, 16; Ne, 14; Ar, 11; Kr, 10; Xe, 12; each with an uncertainty of less than ±10%. On the addition of 0.2 mol% SF6 these yields are reduced to 6,5,1,2, and 2.5 respectively.These values are compared with those derived from ion and excited state yields and the contributions of subexcitation electrons.

Sign in / Sign up

Export Citation Format

Share Document