Marginal designs

If we exclude marginal designs, such as the use of an unusually large Eulerian cradle able to internally hold a two-stage cryocooler (T. F. Koetzle and J. L. Henriques, unpublished, 1976) or the use of a very small full-circle Eulerian cradle mounted completely inside the sample room of a helium cryostat [82], the LT device must fit a commercial Eulerian cradle. At present, x shafts with inner diameters in the range 250 to 400 mm in diameter are common the plane of the x circle may either contain the axis of the circle or be offset. 

Note This represents a marginal design since H is slightly higher than 0.5 ft. 

In preliminary process design it mig] it be necessary to use marginal costs for steam, but the designer should keep in mind the dangers of using such costs. 

Once a substance is designated by EPA as a ha2ardous air pollutant (HAP), EPA has to promulgate a NESHAP (National Emission Standard for Ha2ardous Air Pollutants), designed to protect pubHc health with an ample margin of safety. 

Design Margins. The heat-transfer surface area determined usiag the siting or rating methods is considered the minimum required area. 

There are additional surface-area requirements for design margins ia the final siting of a heat exchanger. 

Amalgam restorations are prepared by mixing a powdered alloy with mercury to form a plastic moldable mass that is packed or condensed iato the prepared cavity. The cavity is designed to provide mechanical retention, maximum marginal mass, support to absorb the functional stresses transmitted through the restoration, and maximum protection to the remaining tooth stmcture. The restoration reestabUshes the normal tooth anatomical form and function. 

Breakeven charts can be plotted in any of the three forms shown in Figs. 9-2, 9-3, and 9-4. The abscissa shown as annual sales volume R is also frequently plotted as a percentage of the designed production or sales capacity Rq. In the case of ships, aircraft, etc., it is then called the percentage utilization. The percentage margin of safety is defined as... 

Plate-Column Capacity The maximum allowable capacity of a plate for handling gas and liquid flow is of primaiy importance because it fixes the minimum possible diameter of the column. For a constant hquid rate, increasing the gas rate results eventually in excessive entrainment and flooding. At the flood point it is difficult to obtain net downward flow of hquid, and any liquid fed to the column is carried out with the overheaa gas. Furthermore, the column inven-toiy of hquid increases, pressure drop across the column becomes quite large, and control becomes difficult. Rational design caUs for operation at a safe margin below this maximum aUowable condition. 

For design, the slip velocity is derated to 70-80 percent of the calculated value to give some margin of safety this sets the design value of the continuous phase velocity (V ). The column cross sectional area (and therefore diameter) is set by QJVc- With the diameter set, the other dimensions can be set using the ratios given above. 

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