Design basic approach

There are two basic approaches to heat-exchanger design for low temperatures (1) the effec tiveness-NTU approach and (2) the log-mean-temperature-difference (LMTD) approach. The LMTD approach is used most frequently when all the required mass flows are known and the area of the exchanger is to be determined. The effec-... 

The above example is only for the outdoor part of the bus system. The indoor part, in any case, would be cooler than the outdoor one and will also provide a heat sink to the hotter enclosure and the conductor constructed outdoors. No separate exercise is therefore carried out for the indoor part of the bus system, for the sake of brevity. For a realistic design that would be essential. The above example provides a basic approach to the design of an IPB system. With some permutations and combinations, a more realistic and economical design can be achieved. A computer is necessary for this exercise. 

For an existing process plant, the designer has the opportunity to take measurements of the fume or plume flow rates in the field. There are two basic approaches which can be adopted. For the first approach, the fume source can be totally enclosed, and a temporary duct and fan system installed to capture the contaminant. For this approach, standard techniques can be used to measure gas flow rates, gas compositions, gas temperatures, and fume loadings. From the collected fume samples, the physical and chemical characteristics can be established using standard techniques. For most applications, this approach is not practical and not very cost effec tive. For the second approach, one of three field measurement techniques, described next, can be used to evaluate plume flow rates and source heat fl uxes. 

From the traditional HF/E perspective, error is seen as a consequence of a mismatch between the demands of a task and the physical and mental capabilities of an individual or an operating team. An extended version of this perspective was described in Chapter 1, Section 1.7. The basic approach of HF/E is to reduce the likelihood of error by the application of design principles and standards to match human capabilities and task demands. These encompass the physical environment (e.g., heat, lighting, vibration), and the design of the workplace together with display and control elements of the human-machine interface. Examples of the approach are given in Wilson and Corlett (1990) and Salvendy (1987). 

The basic approach in designing any product made from any material (steel, aluminum, wood, plastic, etc.) involves knowing the behaviors and characteristics of the materials and manufacturing influences on the materials. In turn this knowledge is to be correctly applied such as using, when required, the processed material s static and/or dynamic properties. Should a need arise for data at conditions different from those at which test data are available, with few exceptions, it would not be too difficult or costly to obtain. 

To obtain the equipment needed a simple basic approach can be used. Design the product determining the plastic material to... 

Some authors argue that the basic approach underlying emission reduction credit systems like the Kyoto Clean Development Mechanism (CDM) can be extended to create linkage opportunities in diverse emission control systems in ways that do not necessarily suffer from the shortfalls of the current CDM. Moreover, while emission reduction credit systems are designed to work with MB systems like tradable permits, they describe ways in which it can interact with tax systems as well as certain regulatory systems [22]. 

There are two basic approaches to foundation design equivalent static and dynamic. The equivalent static approach is almost always selected because of its simplicity. However, sometimes an overly conservative design could result. The dynamic approach involves a very complex analysis, although it should result in a more realistic design. 

Pilot plant work is essential as a basis for full scale design. It may be directed to finding suitable velocities, temperatures and drying times, or it may employ more basic approaches. The data provided for Example 9.8, for instance, are of particle size distribution, partial pressure of water in the solution, and heat and mass transfer coefficients. These data are sufficient for the... 

Sheet die design equations were first developed by Carley (59) for T-shaped dies using Newtonian fluids. Pearson (60), whose basic approach we now elucidate, extended the design equations to Power Law fluids. The proper die design delivers a given polymer melt under specified conditions through a constant die opening at a constant rate and temperature (cross-machine direction uniformity). Here, we trace the development of a die... 

A variation of the same basic approach, which has been employed [123], is to examine the total amount of decomposition of a molecular ion at different sample temperatures. The experiments were performed using a specially designed source [122], the whole of which could be heated to 900 K so that the temperature of the neutral sample was reliably known. One finding of these studies was that, if only the emitter itself was heated and the rest of the source kept at ambient, the sample did not fully accommodate to the temperature of the emitter [122]. 

In this chapter, we present an overview of the detailed kinetic analysis of the oxidation of NADH at a poly(aniline) modified electrode, both to demonstrate the basic approach which can be used, and to illustate the type of information which can be extracted. In many ways the design of... 

Steam power plants produce electricity with rather low thermal efficiency. An increase in efficiency leads to savings in fuel costs and minimizes environmental effects. The two basic approaches in increasing the thermal efficiency of a cycle are (i) design a process that transfers heat to the working fluid at high temperature in the boiler and (ii) design a process that transfers heat to the working fluid at low temperature in the condenser. These may decrease the temperature differences, and hence the level of irreversibility. 

Some approaches to design with uncertainty are reviewed in order to identify the appropriate basic approach and relevant techniques from previous work. A new algorithm is then presented which builds on previous work and attempts to exploit the characteristics of the design problems. 

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