Derating coefficients

Finally, the reader should note that neither Fqn (7.8) nor (7.9) includes derating coefficients for factors such as temperature, service life, cychc loading, or other factors such as pipe geometry. These factors are now applied in Fqn (7.10) to generate an expression for the final design repair thickness. 

The derating coefficients can have a pronounced effect on the required number of layers to attain the desired repair performance over the speeified life of the repair. The design engineer should closely examine the derating factor testing from a materials supplier to understand how the factors were arrived at... 

A summary of the report follows The problem is to separate proteins. Furthermore, SpinPro should pay particular attention to the purity of the separation. The sample is not negatively affected by sucrose, has a sedimentation coefficient of 16 Svedbergs, and is in liquid form of 3 mL and a concentration of 1% w/w. The protein of interest should be placed 45% from the top of the gradient at the end of the run. Of the gradient concentrations 10-40% and 5-20%, the 10-40% is preferred by the investigator. There are no solvents in the sample that are harmful to the tubes. Finally, from the lab, SpinPro should use the L2-75B ultracentrifuge and the SW 41 Ti rotor, which does not require a speed derating due to its age. 

Flow-through relief valves have traditionally been analyzed by treating the valve as a convergent noz-2ie [i 29.30] discharge coefficient (kactual mass flow rate to the theoretical ideal mass flow rate through a one-dimensional convergent nozzle of exit area equal to the nominal bore of the tested valve. Measured discharge coefficients are derated by 10% (Aidr) to specify valve capacity. 

According to [4] a certified derated discharge coefficient, Kdischarge coefficient only applies to the specific type of safety valve or bursting disc within defined ranges of pressures and temperamres. 

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