Design Paradox

Before discussing available methods for safety and health assessment in biofuel production systems, it would be so much valuable to comprehend the idea behind design paradox. This section aims to bridge the understanding on the concept of inherent safety introduced earlier with the current and potential assessment approaches to be covered in the next 

R D design Process predesign Basic engineering Detailed engineering 

First process concept Process block All in R D stage Flow sheet (simple or detailed) All in R D and predesign stages All in R D, predesign, and basic engineering stages 

Diagram PI diagram Detailed equipment, piping, and instrumentation 

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Dorst, K. (2006). Design problems and design paradoxes. Design Issues, 22(3), 4—17. 

Figure 14.1 The design paradox and inherently safer design. Reproduced from Hurme and...

The ultimate goal of protein engineering is to design an amino acid sequence that will fold into a protein with a predetermined structure and function. Paradoxically, this goal may be easier to achieve than its inverse, the solution of the folding problem. It seems to be simpler to start with a three-dimensional structure and find one of the numerous amino acid sequences that will fold into that structure than to start from an amino acid sequence and predict its three-dimensional structure. We will illustrate this by the design of a stable zinc finger domain that does not require stabilization by zinc. 

It is paradoxically in the most urban of settings that one becomes powerfully aware of the enduring beauty and utility of nature. It is the reshaping of nature that has made civilized urban life possible. Nature has a social and cultural history that has enriched countless dimensions of the urban experience. The design, use, and meaning of urban space involves the transformation of nature into a new synthesis. ... 

A somewhat paradoxical situation has arisen in more recent years because of the increased interest in comparative data and databases. Some of the pressure for better design data and the criticism of the standardised methods has been turned to a demand for very tightly standardised data. To be comparable, data in a database needs to be all produced in exactly the same way and the development of standards to offer a choice of method and several choices of conditions for the same property is not compatible with this need. Consequently, there has been a lobby for what might be termed extreme standards which are specifically intended to yield completely comparable data very efficiently, but possibly at the expense of other attributes. 

Another instructive scenario may be found when considering the metalation of arenes. There are two distinct mechanisms for the metalation of aromatic C-H bonds - electrophilic substitution and concerted oxidative addition (Box2). The classical arene mercuration, known for more than a century, serves to illustrate the electrophilic pathway whereas the metal hydride-catalyzed deuterium labeling of arenes document the concerted oxidative addition mechanism [8, 17]. These two processes differ both in kinetic behavior and regioselectivity and thus we may appreciate the need to differentiate these two types of process. However, the choice of C-H bond activation to designate only one, the oxidative addition pathway, creates a similar linguistic paradox. Indeed, it is hard to argue that the C-H bond in the cationic cr-complex is not activated. 

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