For each monitoring event, carbon tetrafluoride
(CF4) was introduced into the spectrometer's flow-through cell from a cylinder traceable to the National Institute of Standards and Technology (NIST) and measured for precision.
And although there are some hazardous materials used, such as silane gas, cadmium, carbon tetrafluoride
, and lead, he says, "if you look at the quantities in relation to their use in other industries, they are very, very small." But these risks will become more significant as the industry grows, he adds.
Study Species Plasma treatment 1 Radish (n = 31) & two Pea Cultivars Carbon tetrafluoride (n = 16/cv.) 2 Soybean & Corn (n = 200/species) Octadecafluorodecalin 3 Corn & Bean (n = 400/species) Octadecafluorodecalin 4 Soybean & Corn (n = 200/species) Aniline 5 Corn (n = 200) Hydrazine 6 Soybean & Corn (n = 300/species) Cyclohexane Pressure Time mT min 1 200 5 2 300 10 3 200 2 5 20 4 200 20 5 200 20 6 70 10 150 Seeds of corn (Zea mays) (n = 200) and soybean [Glycine max (L.) Merr.] (n = 200) were also treated with ODFD, a hydrophobic compound, for 10 min under 300 mT.
Germination Species Treatment [T.sub.50] -- h -- Raphanus sativus control 2a carbon tetrafluoride 38b Pisum sativum cv.
Carbon tetrafluoride is a non-depositing gas under common cold-plasma conditions.
Argon, which is inert, is also used for plasma cleaning--it may be compared to "molecular sandblasting." Other gases like oxygen or carbon tetrafluoride
clean chemically as well as physically.