Common use of Rationale Clause in Contracts

Rationale. The foregoing procedure is designed to produce a standard humic-containing solution that is pH controlled, and sufficiently aged that its photobleaching first-order rate con- stant is not time dependent. It has been demonstrated that after 7 days of winter sunlight exposure, SHW solu- tions photobleached with a nearly con- stant rate constant (Mill et al. (1983) under paragraph (f)(11) of this section). (c) Phase 2—Screening test— (1) Intro- duction and purpose. (i) Phase 2 meas- urements provide approximate solar photolysis rate constants and half-lives of test chemicals in PW and SHW. If the photoreaction rate in SHW is sig- nificantly larger than in PW (factor of >2X) then the test chemical is subject to indirect photoreaction and Phase 3 is necessary. Phase 2 data are needed for more accurate Phase 3 measure- ments, which require parallel solar ir- radiation of actinometer and test chemical solutions. The actinometer composition is adjusted according to the results of Phase 2 for each chem- ical, to equalize as much as possible photoreaction rate constants of chem- ical in SHW and actinometer. (ii) In Phase 2, sunlight photoreaction rate constants are meas- ured in round tubes containing SHW and then mathematically corrected to a flat water surface geometry. These rate constants are not corrected to clear-sky conditions.

Rationale. The foregoing procedure is designed to produce a standard humic-containing solution that is pH controlled, and sufficiently aged that its photobleaching first-order rate con- stant is not time dependent. It has been demonstrated that after 7 days of winter sunlight exposure, SHW solu- tions photobleached with a nearly con- stant rate constant (Mill et al. (1983) under paragraph (f)(11) of this section). (c) Phase 2—Screening test— (1) Intro- duction and purpose. (i) Phase 2 meas- urements provide approximate solar photolysis rate constants and half-lives of test chemicals in PW and SHW. If the photoreaction rate in SHW is sig- nificantly larger than in PW (factor of >> 2X) then the test chemical is subject to indirect photoreaction and Phase 3 is necessary. Phase 2 data are needed for more accurate Phase 3 measure- ments, which require parallel solar ir- radiation of actinometer and test chemical solutions. The actinometer composition is adjusted according to the results of Phase 2 for each chem- ical, to equalize as much as possible photoreaction rate constants of chem- ical in SHW and actinometer. (ii) In Phase 2, sunlight photoreaction photo- reaction rate constants are meas- ured measured in round tubes containing SHW and then mathematically corrected to a flat water surface geometry. These rate constants are not corrected to clear-clear- sky conditions.