Testing design changes

Precipitation of trinitrobenzene or other sensitive energetic materials in the energetics slurry handling and SILVER II system was identified as a concern during Demo II testing. Design changes identified in the final EDP and demonstrated in EDS II 12-kW tests appear to adequately prevent precipitation. 

The final recommended configuration for improving dust capture is shown in Fig. 10.46. The design change was rather simple and the model test showed a significant reduction in visible fugitive emissions. 

The configuration of the product in terms of its design standard, deviations, nonconformities, and design changes to be recorded prior to and subsequent to the tests... 

By employing accurate test-design procedures (Pan and Wypych, 1992a), it is possible to model and design each pipe branch separately so that the system ultimately is well balanced. However, such a system may not be reliable over time due to uneven wear in the pipes/bends, changes in material property and/or on-site conditions. 

The committee believes that further testing during systemization of a full-scale facility would reveal a need for more than the usual number of design changes. Some aspects of the current design that point to the likelihood of further change are the following ... 

Figure 5.5 shows a three level full factorial design for the HPLC example which tests three factors, centred around the method conditions. This design allows the testing of changes from the method conditions to extremes on either side. 

The burden of proof for such an unprecedented effect should be high, and the foregoing experiments with willows and tent caterpillars cannot be considered to constitute such proof. However, at the very least, they show that the results of experiments designed to test for changes in leaf quality of attacked plants should be Interpreted with caution, particularly if control plants are near attacked ones. 

Three demonstration models were made for the Office of Saline Water. Figures 3, 4, and 5 give the basic elements of these models. The most obvious design change was the use of cellophane sheets for the capillary surface instead of the porous ceramic plates. The use of cellophane with its high entry pressure permitted tests on sea water as well as dilute sodium chloride solutions. Other evolutionary changes had to do with better techniques of gap fabrication and pressure control. 

Test-frequency changes to shorten or lengthen the test cycle at PPG are based upon evaluations of prooftest results, performance of the components in the loop, or changes in equipment or service. When the desired test pass rate (100-percent pass rate for Class 1 loops) is not met, causes of failure are evaluated. If warranted, a corrective action (such as a design change, test frequency change or request for further study) is initiated. 

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