Reference

The vertical distribution of halocarbons in the stratosphere

The vertical distribution of halocarbons in the stratosphere. Fabian, Peter; Goemer, Dagmar (Max-Planck-Inst. Aeron., Katlenburg-Lindau D-3411, Fed. Rep. Ger.). Fresenius' Z. Anal. Chem., 319(8), 890-7 (English) 1984. CODEN: ZACFAU. ISSN: 0016-1152. DOCUMENT TYPE: Journal CA Section: 59 (Air Pollution and Industrial Hygiene) Section cross-reference(s): 53 By means of cryogenic sampling and subsequent gas-chromatog. anal., vertical profiles of CCl4 [56-23-5], CCl3F [75-69-4], CCl2F2 [75-71-8], CClF3 [75-72-9], CF4 [75-73-0], C2Cl3F3 [26523-64-8], C2Cl2F4 [1320-37-2], C2ClF5 [63938-10-3], C2F6 [76-16-4], MeCl [74-87-3], and MeCCl3 [71-55-6] were derived for stratospheric heights of ￡35 km. Vertical profiles of halocarbons computed by means of 1-dimensional and 2-dimensional models fall off less rapidly in the stratosphere than the measured profiles, this systematic discrepancy being due to deficiencies in the radiation and transport schemes of present models. It is shown that measured profiles of fully halogenated hydrocarbons provide a tool for systematically studying these deficiencies and thus improving the models. Sources and sinks of halocarbons are discussed, and an assessment of past and future sources of organically bound Cl in the atm. is made.

Group-contribution method used in the estimation of viscosity of oil saturated with Freons

Group-contribution method used in the estimation of viscosity of oil saturated with Freons. Lu, Ping; Liu, Zhigang (School of Energy and Power Eng., Xi'an Jiaotong Univ., Xi'an 710049, Peop. Rep. China). Gongcheng Rewuli Xuebao, 17(3), 269-272 (Chinese) 1996 Kexue. CODEN: KCJPDF. ISSN: 0253-231X. DOCUMENT TYPE: Journal CA Section: 51 (Fossil Fuels, Derivatives, and Related Products) Section cross-reference(s): 48 A group-contribution method was developed to calc. viscosity of oil satd.Several substances with their cas registry numbers 63938-10-3 and 359-35-3 may be metioned in this study. with Freons. In this method, a Freon mol. is treated as a combination of groups (-CH3, -CH2F, -CH2Cl, -CHF2, -CHCl2, etc.), and it relates the satd. liq. viscosity to the contribution of each of the constituting groups. The deviation of the method is within ±5%. .