The design process

Whatever the type of quality or cost characteristic, the transformations are such that the S/N ratio is always interpreted in the same way, the larger the S/N ratio the better (Bryne and Taguchi (1986)). 

To better understand the background of RPV design, it is useful to review the general design practices that were used by the major US vendors. For 

Irradiation Embrittlement of Reactor Pressure Vessels (RPVs) 

Core support columns Instrumentation thimble guides 

Closure head assembly Hold-down spring 

2 Typical pressurized water reactor (PWR) pressure vessel. 

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Most of these methods are commonly employed in the downstream processing of the desired ceU culture technology product. Hence, most of the time it is only necessary to demonstrate that the designed process is reducing the putative risk factors to acceptable levels. Validation methods employed for risk reduction are discussed in the Hterature (25). 

Whereas process simulation includes quantitative analysis of a design given the stmcture of the design, process synthesis involves determining the stmcture that will meet the requirements of the design as well as finding the best stmcture for the requirements. For example, if components A, B, C, and D whose relative volatOities were in the order D, C, B, and A were to be separated by distillation for which each column produced a top and a bottom fraction, five schemes of three columns arise as possible stmctures (53) (Fig. 8). 

Much of the experience and data from wastewater treatment has been gained from municipal treatment plants. Industrial liquid wastes are similar to wastewater but differ in significant ways. Thus, typical design parameters and standards developed for municipal wastewater operations must not be blindly utilized for industrial wastewater. It is best to run laboratory and small pilot tests with the specific industrial wastewater as part of the design process. It is most important to understand the temporal variations in industrial wastewater strength, flow, and waste components and their effect on the performance of various treatment processes. Industry personnel in an effort to reduce cost often neglect laboratory and pilot studies and depend on waste characteristics from similar plants. This strategy often results in failure, delay, and increased costs. Careful studies on the actual waste at a plant site cannot be overemphasized. 

AC Good, R Lewis. New methodology for profiling combinatorial libraries and screening sets Cleaning up the design process with HARPick. I Med Chem 40 3926-3936, 1997. 

Reliability targets are typically set based on previous product failures or existing design practice (Ditlevsen, 1997) however, from the above arguments, an approach based on FMEA results would be useful in setting reliability targets early in the design process. 

Klit, P., Jensen, F. and Ellevang, P. 1993 Reliable Design Methodology - the use and misuse of reliability data in the design process. In Proceedings ICED 93, The Hague, 1156-1164. 

Today, one has many choices in the area of controller-integrated circuits. One must decide early in the design process how much functionality and integration... 

The following examples, though tedious, should provide a good insight into the design process of a PWM switching power supply. 

Let us examine how one determines the values of the inductor and capacitor. Several assumptions have to be made at the beginning of the design process since several of the tank circuit s characteristics are variable within the application. The first is to assume a value for the Q of the tank circuit. In the application, the Q varies greatly with the amount of load placed on the output of the supply. So, a good value to start with is... 

To begin the design process, the inherent dc gain of the control-to-output gain function (Gdc and is found using equations B.6 and B.7. 

In a similar manner to the design process for packed columns, the physical characteristics and the performance specifications can be calculated theoretically for open tubular columns. The same protocol will be observed and again, the procedure involves the use of a number of equations that have been previously derived and/or discussed. However, it will be seen that as a result of the geometric simplicity of the open tubular column, there are no packing factors and no multi-path term and so the equations that result are far less complex and easier to manipulate and to understand. 

The design process for open tubular columns is similar to that for packed columns, and the physical characteristics and performance specifications can be calculated... 

Defence in depth. The design process should ensure that multiple levels of protection are provided and the necessity of human intervention is minimized. 

In heterogeneous systems AP must be critically reviewed, especially if the reaction involves a two-phase mixture of liquid and gas, or if the gas flows through a deep bed of catalyst particles as in the FCC systems. AP should be checked early in the design process to assess its influence on the overall plant integrity. 

This chapter is written as a general introduction to design with plastics. It outlines the range of plastics available, describes the type of behaviour which they exhibit and illustrates the design process involved in selecting the best plastic for a particular application. 

The first and most important steps in the design process are to define clearly the purpose and function of the proposed product and to identify the service environment. Then one has to assess the suitability of a range of candidate materials. The following are generally regarded as the most important characteristics requiring consideration for most engineering components. 

A key part of the CANDU 9 design program was the review by the AECB that explored and resolved issues during design. PSA in the design process ensures that safety related requirements are addressed early to reduce retrofits as well as its role in safety assessment and licensing. 

Identify and collect data that depend only on the site location and that do not change during the design process, such as outdoor conditions. 

The target level assessment process for paper machine halls is the result of long historical development. The performances of installed paper machine hall ventilation systems are measured very often and the results are compared with input data used as the basis for design. As a result of these comparisons corrections are made to the design process as necessary. 

The factory scenario must be updated with new information as the design process evolves. 

The different steps of the flow and batch processes of the industrial production must be roughly described early in the design process. A more detailed description may be needed in regions w here heat and contaminants are released. Production design engineers are likely to provide the information needed. 

The definition of the breathing zone and of the zone of occupancy must be revised at each stage in the design process to make the climatization design effective and efficient. 

Utilization of natural ventilation for air conditioning will normally interact with the architectural design, and it should be considered early in the design process. 

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