Failed Runs

The data from all failed validation runs should be maintained with the rest of the validation data and reported in 

Here processed and unprocessed data refer to control matrix spiked with arralytical standard before and after extraction, respectively. Note that the ratios of the two peak areas represent a combination of extraction efficiency plus differences in matrix effects (if any). 

A = Analyte (post process), Internal Standard (post process) 

D = Analyte (solution only). Internal Standard (solution only) 

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Future investigations would be necessary to determine the precision of bootstrap and how best to deal with failed runs. The reader is referred to Chapter 15 for more on implementation issues with the bootstrap. 

Cumulative standard curve and quality control (QC) data tables containing appropriate statistical parameters should be generated and included with the study sample values in the final study report. Additional documentation with respect to the failed runs, dates of these mns, and the reason for failure should be documented. All deviations, impact to the study results, and supporting data should also be included in the final report. 

Validation runs may not be re-injected simply on the basis of failure to meet the method targets for precision and accuracy. Data for an entire validation run may be rejected only if there is an assignable cause. Rejection of data due to assignable cause includes documented sample processing errors or for other documented reasons, e.g., the data were lost or corrupted during acquisition or data processing or there was a documented hardware failure. Complete documentation of the failed run and the reasons for the failure should be maintained in the study file. 

For study sample analysis the calibration curve and QC samples are evaluated separately, and run acceptance is based upon criteria estabhshed for both curves and QCs. For validation runs, however, only the standard curve and other factors such as carryover are considered for run acceptance and aU of the results for the various types of validation QCs, e.g., precision and accuracy, stability, etc., are reported and used for statistical analysis. It is important at this time to emphasize the distinction between a failed and rejected validation run. Runs may be rejected for specific assignable cause such as documented evidence that the method was run incorrectly or hardware failure (Section 10.5.2c). Data from failed runs on the other hand, such as those where an excessive number of calibrators are considered to be outhers or QCs used to assess precision and accuracy do not meet the... 

Reporting requirements for validation runs are addressed in Section 10.3.4. For runs that fail due to an excessive number of calibrator outliers, a reference to the failed run should be provided in the report along with a description of underlying cause for the failure. For validation QCs, accuracy and precision calculations should include all data although additional tables with outhers excluded can be provided also. Poor precision and accuracy for a particular experiment e.g. stability, may indicate the need to repeat that study in a subsequent validation run. If poor results are observed for the QCs used for intra-day and inter-day precision and accuracy, it may be necessary to repeat the entire vahdation run. In these instances, a reference to the failed run must be included in the final vahdation report. 

Failed Run Identify runs, assay dates and reason for failure (Section 10.5.2c)... 

Air release Apply water spray to minimize vapor dispersion if careful leak elimination measures have failed. Run off should be diked since solution is corrosive. Keep eombustible away from dispersing gas. 

In an effort to reduce the Bronsted acidity and increase the Lewis acidity, water was removed from the catalyst at 150 C. This catalyst also did not promote formylation (Run 3). These results raised the question whether the material used showed any catalytic activity. A literature procedure for acylation using benzoic acid anhydride failed (Run 5), which suggests that it may still contain small amounts of moisture, not removed during the activation step. Since good acylation yields with calcined sulphated zirconiumoxide were reported the same activating conditions were applied to the... 

The failure mode of an equipment item describes the reason for the failure, and is often determined by analysing what causes historic failures in the particular item. This is another good reason for keeping records of the performance of equipment. For example, if it is recognised that a pump typically fails due to worn bearings after 8,000 hours in operation, a maintenance strategy may be adopted which replaces the bearings after 7,000 hours if that pump is a critical item. If a spare pump is available as a back-up, then the policy may be to allow the pump to run to failure, but keep a stock of spare parts to allow a quick repair. 

The ah initio module can run HF, MP2 (single point), and CIS calculations. A number of common basis sets are included. Some results, such as population analysis, are only written to the log file. One test calculation failed to achieve SCF convergence, but no messages indicating that fact were given. Thus, it is advisable to examine the iteration energies in the log file. 

The calculation setup screens list a good selection of the options that are most widely used. However, it is not a complete list. The user also chooses which queue to use on the remote machine and can set queue resource limits. All of this is turned into a script with queue commands and the job input file. The user can edit this script manually before it is run. Once the job is submitted, the inputs are transferred to the server machine, the job is run and the results can be sent back to the local machine. The server can be configured to work with an NQS queue system. The system administrator and users have a reasonable amount of control in configuring how the jobs are run and where files are stored. The administrator should look carefully at this configuration and must consider where results will be sent in the case of a failed job or network outage. 

Deflagration Arresters The two types of deflagration arrester normally considered are the end-of-line arrester (Figs. 26-23 and 26-24) and the tank vent deflagration arrester Neither type of arrester is designed to stop detonations. If mounted sufficiently far from the atmospheric outlet of a piping system, which constitutes the unpro-tec tea side of the arrester, the flame can accelerate sufficiently to cause these arresters to fail. Failure can occur at high flame speeds even without a run-up to detonation. 

BuMgBr, benzene, 80°, 69%. MeMgl fails in this reaction. In general, benzyl ethers are quite stable to Grignard reagents because these reactions are rarely run at such high temperatures. 

Some tolled products can be reworked if they fail quality assurance tests. In these cases the production cost may go up, but the product is not a complete loss. However, other tolled products, some pharmaceuticals for example, could be completely ruined by similar processing mishaps. Losses in these cases can be quite extensive. Test runs and approved rework procedures for such products may help avoid these losses. 

First, the pressure vessel must be safe from plastic collapse that is, the stresses must everywhere be below general yield. Second, it must not fail by fast fracture if the largest cracks it could contain have length 2a (Fig. 16.4), then the stress intensity K CTV must everywhere be less than K. Finally, it must not fail by fatigue the slow growth of a crack to the critical size at which it runs. 

A bent shaft is physically bent and distorted. Placing the shaft into a lathe or dynamic balancer and rotating it will reveal the distortion. If a bent shaft is installed into a pump and run, it will fail prematurely, leaving evidence and specific signs on the eircumferenee of close tolerance stationary parts around the pump s volute circle. The shaft will exhibit a wear spot on its surface where the elo.se tolerance parts were rubbing. 

Maybe you ve heard your auto mechanic say on installing a new radiator watera or alternator onto your car. .. that if it runs for 5 minutes, then it will run for i i years. If It s going to fail, it will do so within the first five minutes. 

It is interesting to note that some pump users literally know that their pumps will fail after a specific time period. They understand that the running time of the pump should be maximized to have an acceptable yield in the process. This type of strategy is expensive since it raises a doubt of the continuity of the pump performance. To compensate, some plants install back up or redundant pumps. 

Trial runs demonstrated that one mole of benzalaceto-phenone required at least two moles of anhydrous aluminum chloride to complete the reaction at room temperature. When less aluminum chloride was used the yeUow addition product failed to dissolve entirely even after stirring for twenty-four hours, and the yield was decreased. 

Channeling. Cleavage and furrowing of the resin bed ean be eaused by faulty operational proeedures or a elogged bed or underdrain. This ean mean that the solution being treated follows the path of least resistanee, runs through these furrows, and fails to eontaet aetive groups in other parts of the bed. 

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