Process specification

Both PSI and PSII are necessary for photosynthesis, but the systems do not operate in the implied temporal sequence. There is also considerable pooling of electrons in intermediates between the two photosystems, and the indicated photoacts seldom occur in unison. The terms PSI and PSII have come to represent two distinct, but interacting reaction centers in photosynthetic membranes (36,37) the two centers are considered in combination with the proteins and electron-transfer processes specific to the separate centers. 

N. E. Promisel and co-workers. Materials and Process Specifications and Standards, NMAB Report 33, Washington, D.C., 1977. 

PMA requirements differ between preamendment and post-amendment devices. Preamendment devices are those in commercial distribution before May 28, 1976 post-amendment devices are those first commercially distributed after the date. Class III post-amendment devices that are not substantially equivalent to preamendment Class III devices are considered new devices. Manufacturers of such devices are required to obtain PMA appHcation approval before marketing these. If the post-amendment device is substantially equivalent to a preamendment device and PDA has not initiated a regulatory process specifically requiring the submission of a PMA for the device category, a 510(k) submission can be made. 

Exhaust emissions of CO, unbumed hydrocarbons, and nitrogen oxides reflect combustion conditions rather than fuel properties. The only fuel component that degrades exhaust is sulfur the SO2 concentrations ia emissions are directly proportional to the content of bound sulfur ia the fuel. Sulfur concentrations ia fuel are determined by cmde type and desulfurization processes. Specifications for aircraft fuels impose limits of 3000 —4000 ppm total sulfur but the average is half of these values. Sulfur content ia heavier fuels is determined by legal limits on stack emissions. 

Process simulators stop generally at the process specifications for the equipment. For the detailed mechanical design of the equipment, such as heat exchangers and distillation columns, stand-alone programs are often used. They make process calculations, size the equipment, calculate thermal and mechanical stresses, design mechanical support of the parts of the equipment, design inlet and outlet nozzles, etc. 

The design chosen in step 5 is evaluated, or rated, as to its ability to meet the process specifications with respect to both heat transfer and pressure drop. 

Process trouble shooting. Analysis or separation system operation and malfunc tion, examination of composition profiles, and tracking of trace impurities with implications for corrosion and process specifications. 

In any event, the users of the mixer can issue a mechanical specification aud determine the speed, diameter of an impeller, aud power with in-house expertise. Or they may issue a processes specification which describes the engineering purpose of the mixing operation and the vendor will supply a description of the mixer process performance as well as prepare a mechanical design. 

Direct-Liquefaction Kinetics All direct-liquefac tion processes consist of three basic steps (1) coal slurrying in a vehicle solvent, (2) coal dissolution under high pressure and temperature, and (3) transfer of hydrogen to the dissolved coal. However, the specific reac tion pathways and associated kinetics are not known in detail. Overall reaction schemes and semiempirical relationships have been generated by the individual process developers, but apphcations are process specific and limited to the range of the specific data bases. More extensive research into liquefaction kinetics has been conducted on the laboratory scale, and these results are discussed below. 

Process-specific training prior to each compaign for existing processes... 

Process specifications will typically be set forth in the process technology package. However, a process hazard analysis (PHA) in preparation for startup may reveal additional useful measurements or sample points. These may be analyses or measurements for the startup period or for the life of the toll. 

The accuracy of QRA results is also dependent on the analysis resources. Obviously, more complete QRA models can produce more accurate results. But even the best model is worthless if the input data are speculative or erroneous. Fortunately, the scarcity of process-specific data for some applications may not be an insurmountable problem. There exist a few industrywide databases, such as those in Table 2, that... 

In addition to being useful for side studies, the process specification sheets can be used as a file to capture the latest thinking for each individual unit of major material for cost estimation and final design. Vendor quotes are expedited if data is provided to them on standard-type process specification sheets. 

This discussion of offsites is subdivided into Utilities and Other Offsites. The utility portion interacts with the process area, while the other offsites have minor interaction w ith the process area, if any. In addition, the process area may have utility generation, such as waste heat boilers. It is convenient to discuss all utility generation as one package pointing out special considerations for the process area units along the way. The goal for this study phase is the same as for battery limits specification complete major material list and process specification sheets. 

Boeing Process Specification, BAC 5555 Issue M. Phosphoric acid anodizing of aluminum for structural bonding. Boeing Airplane Company, 1995. 

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