Unnecessary risks start with risk

From the preliminary study to actual implementation, the assistance of plant engineers and operators is essential for the success of the project. In many cases, process engineers who design DWC columns are unaware of the site-specific concerns. Thorough and clear communication with them reduces unnecessary time loss and risks during implementation. The concepts and operation modes of the DWC and new devices as well as the start-up and shutdown procedures were explained to the plant engineers and operators. Their questions were clarified with 3-D models and simulation results. 

When no hazard exists, continued operation of the process is generally preferable to initiating an unnecessary shutdown. Shutdown can cause additional hazards, such as large flaring events or cascade shutdowns of other process units, and does result in the need to restart the process unit with all of its potential hazards. The decision to shut down versus continued operation is made by balancing the risk posed by the potential process hazard if a process demand occurs and the risk associated with shutdown and start-up. This decision is greatly influenced by the relative robustness of the SIS architecture and system utilities. The path can be selected at the channel, sub card, card, or CPU level of the system. The device safety manual may contain specific requirements that should be followed, unless a detailed analysis of the final system architecture demonstrates that deviation from the safety manual is acceptable. 

Vitamin C levels can be determined in stored blood or blood components such as serum, plasma, or leukocytes if particular preservation steps are performed during preparation. The concentration of vitamin C is stable in whole blood for several hours with negligible decay. If whole blood is centrifuged and serum or plasma obtained, vitamin C starts to disappear immediately. Therefore, the stabilization of vitamin C by metaphosphoric acid or other substances is required if such aliquots are to be used to determine vitamin C concentration in future analyses. The need for preserving aliquots is unnecessary in the determination of other antioxidant substances such as vitamin E or carotenoids. The preservation issue may also be a reason that blood determinations of antioxidants, such as (3-carotene or vitamin E, and their relation to disease risk are found more frequently than vitamin C (Comstock a/., 1992). 

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