Acceptance limits

Even if the reactor temperature is controlled within acceptable limits, the reactor effluent may need to be cooled rapidly, or quenched, to stop the reaction quickly to prevent excessive byproduct formation. This quench can be accomplished by indirect heat transfer using conventional heat transfer equipment or by direct heat transfer by mixing with another fluid. A commonly encountered situation is... 

The acceptable limits of this kind of analysis are shown in Table 2.2. 

If the spike recovery for Bsf is acceptable, or if the result for sample B is below the method s detection limit or outside the range of 0.1 to 10 times the amount of analyte spiked in Bsf, then the duplicate samples Ai and A2 are analyzed. The results for Ai and A2 are discarded if the difference between their values is excessive. If the difference between the results for Ai and A2 is within the accepted limits, then the results for samples Ai and B are compared. Since samples collected from the same sampling site at the same time should be identical in composition, the results are discarded if the difference between their values is unsatisfactory, and accepted if the difference is satisfactory. 

Environmental intmsion from MHD plants is projected to be not only weU below the mid-1990s acceptable limits, but also low enough to satisfy the more stringent requirements expected in the future. Emissions of SO, particulates can be reduced to levels weU below the 1979 NSPS without... 

Quantification of metamerism is difficult and its avoidance is a principal aim in color technology. The car where body color, upholstery, and plastic parts match in the Ht showroom should not show clashing colors in daylight. The obvious but rarely appHcable solution is to use the same pigments in all parts. Some illuminant metamerism is almost unavoidable, the aim of the color expert being to keep it within acceptable limits, ie, to achieve adequate color consistency. 

In the use of temperature measurement for control of the separation in a distillation column, repeatability is crucial but accuracy is not. Composition control for the overhead product would be based on a measurement of the temperature on one of the trays in the rectifying section. A target would be provided for this temperature. However, at periodic intervals, a sample of the overhead product is analyzed in the laboratory and the information provided to the process operator. Should this analysis be outside acceptable limits, the operator would adjust the set point for the temperature. This procedure effectively compensates for an inaccurate temperature measurement however, the success of this approach requires good repeatability from the temperature measurement. 

Note The speed of the motor ean be varied by vai-ying the frequeney alone but this docs not provide satisfactory performance, A variation in frequeney causes an inverse variation in the flux, for the same system voltage. The strength of magnetic field, p, develops, the torque and moves the rotor, but at lower speeds. / would be reduced, which would raise 0 , and lead the magnetic circuit to saturation. For higher s )ccds, / would be r.nised, but that would reduee which would adversely diminish the torque. Hence frequency variation alone is not recommended practice for speed control. The recommended practiee is to keep V/fas constant, to maintain the motor s vital operatin.c parameters, i.e. its torque and 0 ,. within acceptable limits. 

If there are many large or small consumers that a distribution line is feeding, it is possible that the voltage of the network may be distorted beyond acceptable limits. In this case it is advisable to suppress these harmonics from the system before they damage the loads connected in the system. Preferable locations where the series inductor or the filter-circuits can be installed are ... 

While the former would stress the generator windings, the latter may cause a voltage swing during a load rejection or load fluctuation and result in a line outage. These features, if not controlled, may render the system unstable. Overvoltages must therefore be controlled within an acceptable limit. Table 24..3 prescribes one such limit. 

For the system to remain stable under all conditions of loading, switching, or any other line disturbances it is essential that an uncompensated line is loaded at much below this level. Otherwise disturbances of a minor nature may result in undampened oscillations, and may even swing the receiving-end voltage beyond acceptable limits. It may even cause an outage of the system. It is therefore not practicable to operate an uncompensated line to its optimum level. For this we will analyse this equation for sin 0 and sin S as follows. 

A very close compensation, i.e., a low X - Xcc- may also raise the fault level of the system beyond acceptable limits. 

The important question, then, is not whether a substance is pure but whether a given sample is sufficiently pure for some intended purpose. That is, are the contaminants likely to interfere in the process or measurement that is to be studied. By suitable manipulation it is often possible to reduce levels of impurities to acceptable limits, but absolute purity is an ideal which, no matter how closely approached, can never be attained. A negative physical or chemical test indicates only that the amount of an impurity in a substance lies below a certain sensitivity level no test can demonstrate that a specified impurity is entirely al ent. 

In metals, inelastic deformation occurs at the crack tip, yielding a plastic zone. Smith [34] has argued that the elastic stress intensity factor is adequate to describe the crack tip field condition if the inelastic zone is limited in size compared with the near crack tip field, which is then assumed to dominate the crack tip inelastic response. He suggested that the inelastic zone be 1/5 of the size of the near crack tip elastic field (a/10). This restriction is in accordance with the generally accepted limitation on the maximum size of the plastic zone allowed in a valid fracture toughness test [35,36]. For the case of crack propagation, the minimum crack size for which continuum considerations hold should be at least 50 x (r ,J. 

Vapor space velocities normally should not exceed 100% of critical experience demonstrates that this keeps liquid entrainment into the flare line within acceptable limits. However, a velocity of 175% of critical is permitted when one is applyingthe 1.5 times Design Pressure Rule to remote contingencies,... 

Equipment deficiencies that are outside acceptable limits (defined by the process safety information) are corrected before further use or in a safe and timely manner. 

Sampling and analytical error (SAE) A numerical factor used in analytical methods to account for uncontrollable errors. Its value is taken into consideration in the determination of whether the exposures are within acceptable limits. 

Pre-launch occurs after prototype testing and prior to full production. Additional inspections and tests may be needed until the production processes have been validated and process capability assured. The additional checks serve to contain nonconformities until variation has been brought within acceptable limits for production. 

Toxicologists tend to focus their attention primarily on c.xtrapolations from cancer bioassays. However, tlicrc is also a need to evaluate the risks of lower doses to see how they affect the various organs and systems in the body. Many scientific papers focused on tlic use of a safety factor or uncertainty factor approach, since all adverse effects other than cancer and mutation-based dcvclopmcnUil effects are believed to have a tlu cshold i.e., a dose below which no adverse effect should occur. Several researchers have discussed various approaches to setting acceptable daily intakes or exposure limits for developmental and reproductive toxicants. It is Uiought Uiat an acceptable limit of exposure could be determined using cancer models, but today tliey arc considered inappropriate because of tlircsholds. ... 

To properly handle the changing composition relationships it is almost essential to utilize some electronic computer techniques if good accuracy is to be achieved. Even three component systems become tedious using desk size electronic calculators without significant internal memory. Computers can be well programmed to handle the complexities of trial and check for convergence to a preset acceptable limit. 

Spread Foundations. The purpose of the spread foundation is to distribute loads over a large enough area so that soil can support the loads safely and without excessive settlement. Such foundations are made of steel-reinforced concrete. When concrete is used for a foundation, it should be placed on undisturbed soil. All vegetation should be removed from the surface therefore, the upper few inches of soil should be removed before concrete is laid down. The area of the foundation must be large enough to ensure that the bearing capacity of the soil is not exceeded or that maximum settlement is within acceptable limits. If details are known of the subsurface soil conditions, the foundation must be sized so that differential settlement will not be excessive. For... 

Magnetic Particle Examination. All accessible surfaces of the main load carrying components of the equipment shall be examined by a magnetic particle examination method or technique conforming to the requirements of ASTM E709 Recommended Practice for Magnetic Particle Examination. Acceptance limits shall be as agreed upon by the manufacturer and the purchaser. 

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