Serendipity elements

Figure 5.27 shows a finite element model of the joint. The members are modelled by 8-node Serendipity elements under the assumption of plane stress conditions. The two steel plates of thickness h are modelled by one steel plate of thickness 2h for an accurate overall stiffness representation. The fasteners and holes are represented by Unite spring elements which are connected to node points on the members. The stiffness constants of the spring elements (Kffe) are determined according to the procedure described in section 5.2.2.4 of the EUROCOMP Handbook. 

A viscous problem, based on the u-v-p formulation, would require 22 dof per element (9u, 9v, and 4p variables). If the flow problem is also coupled with the thermal problem, then we have 31 dof/element (9T variables). A serendipity element is cheaper as it has only 8 nodes (it lacks the centroid node), thus giving 20(28) dof/ element (flow/ + thermal problem). 

Our laboratory started to work on circadian rhythms by serendipity, while studying the liver-specific transcription of the serum albumin gene. We isolated a cDN A copy for a transcription factor that we dubbed DBP (for albumin promoter D-element Binding Protein). DBP, a basic leucine zipper (bZip) transcription factor, is the founding member of the PAR (proline-acidic amino acid rich)-domain bZip transcription factors, a small subfamily of bZip proteins consisting of DBP, TEF and HLF. It turned out that DBP protein and mRNA accumulation undergo circadian cycles with amplitudes in excess of one hundred-fold (Wuarin Schibler 1990). 

Figure 9.26 illustrates two types of three-dimensional elements, the prisms and the tetrahe-drals. The prisms shown are of the serendipity family and the coordinates for these elements are normalized the same way as the rectangular two-dimensional elements and the shape functions are just simple extensions of the 2D elements. The tetrahedral elements have volume normalized coordinates, which again are an extension of the 2D area normalized coordinates. 

While there appears to be an element of serendipity in the success of Pt-Re formulations, the invention of Pt-Ir catalysts is an example of engineering desirable properties by rational scientific design.8... 

This chapter has focused particularly on the mechanistic aspects of catalytic methanol carbonylation and how the underlying organometallic chemistry has an impact on process considerations. Although there is often an element of serendipity in catalyst discovery, a thorough fundamental understanding of reaction mechanisms will play a crucial role in developing the next generation of catalysts. 

The cases we have examined so far all demonstrate that an element of chance is sometimes involved in scientific discoveries. But is it really correct to call it serendipity The three princes of Serendip in Horace Walpole s play certainly made fortuitous discoveries, but more than that, they were in no way looking for what they eventually found. On the contrary, they were pursuing entirely different goals and their successes bear no relation to what they originally set out to do. The difference between the cases discussed above and the heroes of Walpole s play is obvious. Pare, Auenbrugger and Laennec were one way or another favored by chance, but on the other hand they were clearly engaged in activities that were directly related to their discoveries. Could one possibly think of another case, even more similar to the princes of Serendip ... 

A survey of major historical signifcance has been presented by F. W. Lichtenthaler on Emil Fischer s monumental work on the proof of the configuration of the sugars. A century on, it gives an in-depth insight into the story in which the reasoning and creative processes as well as elements of serendipity involved in the work are featured. ... 

The era of fluoropolymers began with the discovery of polytetrafluoroethylene in 1938. The history of fluoropolymers, as will be seen in this book, is steeped in both scientific curiosity and serendipity— the seemingly indispensable elements of most major discoveries and inventions. There has been an explosion of fiuoropolymer applications in all facets of human affairs. Old and new technological advances have been made possible by their unique properties. From the Manhattan project in the early 1940 s, to the Apollo missions in the 1970 s, to integrated manufacturing in the late 1980 s, industries have relied on fluoropolymers for their inertness and durability. New applications are being developed everyday after more than six decades since the discovery of this plastic family. Few materials have impacted the lives of peoples as extensively as fluoropolymers. 

The program PERMAS [19] is used for the computations. The three- dimensional modelling was performed with HEXEC20 (20 nodal points per element) and HEXEC15 (15 nodal points per element) elements of Serendipity type. 

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