Differences, performance

The initial uses of colorants in plastics were as extenders and additives. Carbon black and titanium dioxide were and are stiU used as fillers (qv) because of their low cost. Almost from plastics inception the limitation of black and white did not offer sufficient color choices for end users looking to differentiate their products. The increase in aesthetic requirements along with different performance requirements and resin compatibiUties led to a great expansion in the number of different chemical classes of colorants and forms in which these colorants are available in today s market. 

The operators have been given instructions on unit operation. Most of these are written and should have been studied prior to the meeting. Others may be verbal or implied. While this is not optimal, verbal instruc tions and operating experience are still part of every unit. It is not unusual that different shifts will have different operation methods. While none of the shift operations may be incorrect, they do lead to variability in operation and different performance. What-if ques-... 

In many cases, two identical reaction systems (e.g., a pilot plant scale and a full-scale commercial plant) exhibit different performances. This difference in performance may result from different flow patterns in the reactors, kinetics of the process, catalyst performance, and other extraneous factors. 

Aircraft and land-based turbines have different performance criteria. Aircraft turbine engine performance is measured in terms of output, efficiency, and... 

Plastic films represent the largest worldwide market for plastics with practically all extruded (6). They are used to meet different performance requirements particularly for its major packaging market. Worldwide just for biaxial oriented (Chapter 8) polypropylene consumption is about 5 /2 billion lb. Their use includes tape, food, tobacco, and confectionery. Thermoforming film (and extruded sheets) is a major processing technique producing all kinds of products. 

Plastics provide different performance requirement in providing protective liners in many different applications such as building foundations, pipe and tank liners containing corrosive liquids, etc. As an example Fig. 4-13 shows an RP stack liner being inspected prior to installation in a 682 ft. high reinforced concrete chimney (background) of the 1,500-megawatt Intermountain Power Project near Delta, Utah (1985). 

Plastic also refers to a material that has a physical characteristic such as plasticity and toughness. The general term commodity plastic, engineering plastic, advanced plastic, advanced reinforced plastic, or advanced plastic composite is used to indicate different performance materials. These terms and others will be reviewed latter in this chapter. Plastics are made into specialty products that have developed into major markets. An example is plastic foams that can provide flexibility to rigidity as well as other desired properties (heat and electrical insulation, toughness, filtration, etc.). 

With RPs different performance capabilities can be obtained. Reason for this capability is because the designer can combine different materials in different proportions. Examples of properties, including other materials of construction, are shown in Figs. 5-9, 6-18a to c and Table 6-22. 

Tables 7-5 to 7-7 show that there are different orders of magnitude between plastics and metals. Depending on the application, plastics may be formulated and processed to exhibit a single property or a designed combination of electrical, mechanical, chemical, thermal, optical, aging properties, and others. The chemical structure of polymers and the various additives they incorporate provide compounds to meet many different performance requirements.

Finally, it should be added that the conventional problem statement and pointwise solution format can be interpreted as a particular degenerate case of our more general formulations. As the minimum acceptable size for zones in the decision space decreases, the different performance criteria converge to each other and X gets closer and closer to x. Both approaches become exactly identical in the extreme limiting case where Ax = 0, m = 1,..., M, which is the particular degenerate case adopted in traditional formulations. 

Let II II denote the Euclidean norm and define = gk+i gk- Table I provides a chronological list of some choices for the CG update parameter. If the objective function is a strongly convex quadratic, then in theory, with an exact line search, all seven choices for the update parameter in Table I are equivalent. For a nonquadratic objective functional J (the ordinary situation in optimal control calculations), each choice for the update parameter leads to a different performance. A detailed discussion of the various CG methods is beyond the scope of this chapter. The reader is referred to Ref. [194] for a survey of CG methods. Here we only mention briefly that despite the strong convergence theory that has been developed for the Fletcher-Reeves, [195],... 

The present study focuses on the comparison of the behaviour of three catalysts with different performance, viz. Co-, Cu- and Fe-ZSM-5, with emphasis on the kinetics and mechanism of the reaction. 

During the training session the performance of the network must be monitored. Different performance criteria are possible, but usually the normalized standard error, NSE, is used. 

To facilitate the maintenance of equipment with different performance criteria, written procedures are needed that serve as a record of the process used to evaluate the system s performance. Maintenance by appropriately trained personnel should be performed at regular intervals before equipment parts fail. 

When comparing these three voltammetric electrodes they show different performance with respect to the purpose of their use. 

As a consequence of the optimization of performance, different performing instruments were first designed for one specific task. However, the best instruments from the latest generation correspond to universal instruments that make it possible to run several types of experiments such as fluorimetry, luminometry, and densitometry for instance. This has interesting consequences for users who work in different domains of luminescence for research and development purposes and do not have to buy a whole range of instruments. 

There are a number of different performance scoring systems used in proficiency testing schemes. The most commonly used system is the z-score, which... 

In this case, the results for /A2 are different, and this is typical for nonlinear processes. The lower result is for case (ii) in which earlier mixing occurs that is, when the CSTR precedes the PFR. Thus, although the kinetics, RTD, and degree of segregation (microfluid) are the same, a different mixing pattern in terms of location of mixing may result in a different performance. 

Many RTD curves of quite different shapes may have the same variance and may result in quite different performances as chemical reactors. Several such cases are in the problem section. 

Carbon electrodes are commercially available in many forms. These include plates, foams, felts, cloths, fibers, spherical and other particles suitable for beds or powders. Graphite or amorphous carbons exhibit quite different performances. Porosity, surface area and pretreatment are important variables to be considered in designing carbon electrodes. 

Figure 18 Cross section of an exposed AF paint analysed by an optical microscope (e.g. x200). Schematic illustrations of the different performance parameters obtained from this analysis. (Yebra et al., 2005b).

Though different performance criteria may be defined, many of the OQ and PQ tests will overlap however, one should try to keep such redundancy to a minimum. Exactly what is tested and what the particular validation criteria are is dependent on both the capabilities of the system and the operating intentions of the user. Throughout, for the entire validation process to be implemented most successfully, it is important for there to be clear communication between the user and the vendor, to know what is expected, who is responsible for each task and to be committed to the details of the process. 

The models used can be either fixed or adaptive and parametric or non-parametric models. These methods have different performances depending on the kind of fault to be treated i.e., additive or multiplicative faults). Analytical model-based approaches require knowledge to be expressed in terms of input-output models or first principles quantitative models based on mass and energy balance equations. These methodologies give a consistent base to perform fault detection and isolation. The cost of these advantages relies on the modeling and computational efforts and on the restriction that one places on the class of acceptable models. 

Validation is the process of proving that a method is acceptable for its intended purpose. It is important to note that it is the method, not the results, that are validated (Chapter 10). The most important aspect of any analytical method is the quality of the data it ultimately produces. The development and validation of a new analytical method may therefore be an iterative process. Results of validation studies may indicate that a change in the procedure is necessary, which may then require revalidation. Before a method is routinely used, it must be validated. There are a number of criteria for validating an analytical method, as different performance characteristics will require different validation criteria. 

Considering the variety of analytical methods, it becomes obvious that different test methods require different validation schemes. ICH distinguishes mainly four different cases shown in Table 3. It is the responsibility of the applicants to choose the validation procedure and protocol most suitable for their method because different performance characteristics will require different validation criteria. 

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