Construction sequence

Although often land reclamation works precede the civil works, occasionally another construction sequence may be preferable. This may, in particular, relate to structures such as quay walls that have to retain the fill or structures that have to be buried in the fill (e.g., submerged tunnels). The construction sequence may have significant effects on the planning and costs. 

Benefits and drawbacks of three different construction sequences can be described as follows  

Preference for the sequence to be adopted during the execution cannot be deduced from a straightforward procedure. The sequence depends on a diversity of aspects, varying from specific project conditions to contract philosophy, and should, on an individual basis, be evaluated during the design stage of each project. 

---

However, by constructing a nested sequence of successively larger discrete spaces and approximations therein we hope to end up with some approximation of a unique invariant measure, which is then implicitly defined via the constructed sequence of subspaces. An expression of this mathematical consideration is the multilevel structure of the suggested algorithm - details see below (Section 3.2). In physical terms, we hope that the perturbations introduced by discretization induce a unique and smooth invariant measure but are so weak that they do not destroy the essential physical structure of the problem. 

A comprehensive list of behavioral phenomena and physical attributes affecting the strength and stability of steel frames is compiled in White 1991. Some of the items listed include initial imperfections, residual stresses, initial strains, construction sequence, effects of simultaneous axial force, shear and moment on section capacities, P-dclta effect, local buckling and spread of inelastic zones in members. A similar list of items could be compiled for reinforced concrete and other structural materials. It is clear that a comprehensive advanced analysts can become quite... 

The technique for developing causal factor charts share a number of fundamental principles with MES and STEP. Basic principles for constructing sequence diagrams ) are given below. 

DNA expression construct Sequence Expression vector Regulatory Elements Method of Production Purification Purity standards Same Same... 

Nonselective attacks at the carbon combined with a nitro group and carbon combined with the N(O) atom of the azoxy group were observed in the reaction of 4,4 -dinitroazoxyfurazan with bases and nucleophiles [468], The preparation of dinitro polyfurazans shows the great synthetic potential of the construction sequence. The simplicity and availability of the starting substances (compounds) makes this strategy a powerful method for high energetic material construction. 

The masterlist of individual half-reactions in Table 3 may now be used to derive all possible pairs of two successive, self-consistent half-reactions for each of the three two-construction patterns in Fig, 3. The products of these pairs will in turn constitute substrates for a third successive self-consistent half-reaction to give sequence lists for each of the derived three-construction patterns. In this way general sequence lists for each of the 13 patterns wiU be obtained, containing all possible self-consistent sequences. The generation of these lists is now simply a mechanical mathematical exercise, unprejudiced by chemical preconceptions. Like the masterlist itself they will include sequences of dubious practicality and even presently unknown chemical detail, but they must include all possible sequences derived from the masterlist reactions 2). These lists can also serve to stimulate study of potentially useful construction sequences which are not currently practical. 

The three-construction sequences are derived from two-construction sequences by accepting the product /-list of two constructions as the substrate for a third. 

The derived patterns are assembled in Fig. 7 at the right. From (aa), (aaa) fully overlaps but (aa/ ) will have no overlap for the third reaction if si=S2=l. As with the non-overlap case in (afi) these must be separately generated by adding to these (aa) products (with FS = 1) all possible jS-fimctionalities to make nonoverlap substrates for the third half-reaction, (aay) is similarly parallel to (ay) and non-overlap cases must be created by adding all possible y- or /l,y-functionality to the parent (oa) sequences of FS = 1 or 2. In extending (ay) to its three derived patterns, (ayo), (ay/ ) and (ayy), all non-overlaps have already been included in (ay) and no added functionalities are required. All six of these derived three-construction sequences will have FS=3, their functionality fitting onto the a,/, y strand in all cases the reactive strand for the third half-reaction also lies on this strand. 

There are only 237 sequences (substrates and two successive half-reactions) for the (aa) pattern which emerge from application of the criteria and lead to only 30 different product /-lists. This represents a selection of 237/14,400 or 1.65%. The other two-construction sequence patterns list 396 sequences (2.75%) for (afi) and 503 (3.49%) lor (ay) with less overlap. Indeed the latter two contain a large proportion of non-overlap sequences, as noted above, which rapidly swells the total the non-overlaps for (afi), for example, are the si =S2 = 1 sequences,... 

The product functionality may be either exactly that of the target or may differ from it in a way which is still deemed acceptable to refunctionalize after the self-consistent construction sequence is complete. In many syntheses a target secondary alcohol existed as a ketone at an earlier stage, etc. 

Statistical test plarmiag can be carried out advantageously by expert systems which design the test plan, evaluate the results, and optimize the process in a single logically constructed sequence. An example is the program APO (Analysis Process Optimization) [30]. 

Penicillins are cheap chiral sources of thioesters 128, but in the process, only the azetidinone ring and, sometimes, the sulfur atom is retained this structural waste is particularly palpable when 128 are obtained by cleavage of the N-oxalo compounds 129. Woodward realized the inelegance of this destruction-re-construction sequence, mentioning the possibility of reducing oxoamides 129 to carbinolamides 203 (B2H5 in THF), but yields were unsatisfactory and no useful penem ester was prepared by this route. 

The construction sequences are illustrated in Figure 6.4. Figure 6.5 shows a drill rig. 

Hyperplanes are moved into the current polytope Pjt with the purpose of cutting away unattainable space from the region. The resulting polytope P +i is defined by the collection of all hyperplanes and smaller than the original polytope Pjj, and thus it provides a closer approximation to the tme AR. In the limit of infinitely many elimination steps, the remaining set of points is an approximation to the AR. Figure 8.21 shows a schematic of the construction sequence for the method. 

---