Part-count reduction

Before setting about the task of developing such a model, the product development process requires definition along with an indication of its key stages, this is so the appropriate tools and techniques can be applied (Booker et al., 1997). In the approach presented here in Figure 5.11, the product development phases are activities generally defined in the automotive industry (Clark and Fujimoto, 1991). QFD Phase 1 is used to understand and quantify the importance of customer needs and requirements, and to support the definition of product and process requirements. The FMEA process is used to explore any potential failure modes, their likely Occurrence, Severity and Detectability. DFA/DFM techniques are used to minimize part count, facilitate ease of assembly and project component manufacturing and assembly costs, and are primarily aimed at cost reduction. 

Often, the manufacturing processes involved for composite structures fabrication are greatly simplified as compared to those for metal structures. Reduced part count results in a much lower assembly cost and overall reduction in the factory labor hours. 

Reduction in parts count - a metal blocker door requires more than 20 parts whereas using RTM this was reduced to less than ten... 

Figure 7.6b illustrates a single-electrode variation of the photoelectrode system comprising anode and cathode surfaces at opposite faces of a single monolithically integrated device. In this configuration, electron transfer is readily achieved through the body of the electrode, but pathways for ionic transfer in the electrolyte need to be provided around the electrode body to minimize solution conductivity losses. Electron transmission loss is reduced, as is system part count. This offers potential cost reduction. 

The inclusion of assembly is very conscious, in that assembly issues are often neglected in product engineering. Through consideration of assembly, many strategically important issues can be addressed. For example, DFA impacts much more than assembly itself. In addition to reducing component assembly and handling costs, DFA encourages part-count optimization, variety reduction and standardization. 

We have seen that the evaluation of the generalized Fock matrix according to (10.8.23) is an expensive process, with an operation count of n(/. Let us now consider the construction of the generalized Fock matrix from the inactive and active Fock matrices and the Q matrix as discussed in Section 10.8.4. The construction of the inactive Fock matrix (10.8.28) is a third-order process which scales as n I since, for each of the elements of the inactive Fock matrix, we must sum over I terms in the two-electron part. Further reductions arise since the inactive Fock matrix is symmetric, leaving us with only n I/2 operations. However, constant factors such as 1/2 are usually less important and more difficult to keep track of than the overall scaling of the opmtion count and are often disregarded in discussions of computational cost. 

A common cause of inaccuracy in SPC-based time domain detection is pulse-pileup, that is, the arrival of photons during the dead-time of the detection system. Because the higher probability of emission (and detection) in the earlier part of the decay, pulse-pileup is more probable in this part of the decay. Consequently, the decay will be distorted and the lifetime will be biased towards higher values. Moreover, pulse-pileup will also result in a reduction of the detection efficiency (see Fig. 3.7 and Eq. (3.4)). Therefore, care should be taken to avoid excitation rates too close to the efficacy count rate (i.e., the inverse of the dead-time) in order to minimize these effects. 

In more recent studies the use of HPLC allowed isolation and counting of individual sterols after administration of labelled precursors. The sterols isolated from mantles and viscera of the nudibranch Doris verrucosa were identified as cholestanol, cholesterol, 24-dehydrocholesterol and 7-dehydrocholesterol [103]. After injection of dl-[2-14C]-mevalonic acid DBED salt, cholesterol (57) and 7-dehydrocholesterol (58) were isolated as the acetates by reversed phase HPLC. Both sterols were found significantly labelled specific radioactivity associated with 7-dehydrocholesterol was higher by one order of magnitude than that associated with cholesterol. This fact would indicate either that the reduction of the A1 double bond of 7-dehydrocholesterol to afford cholesterol occurs at a low rate, or that the cholesterol found in D. verrucosa comes partly from a dietary source. 

Whether this condition can be fulfiUed depends on the electron count of the metal, and the stereochemistry of the elimination. For instance, in m-elimination from octahedral d , or square planar d , systems, metal ndipP -y ) acts as acceptor, and this should be a facile process ( e Fip. 1, 2). For /rans-elimination, on tiie other hand, the lowest empty orbital of correct symmetry is (n + l)p. Such elimination Kerns energetically less Ukely, unless a non-concerted pathway (such as successive anionic and cationic loss) is available. The same arguments apply, of course, to oxidative additions. It foUows that the many known cases of traits oxidative addition to square planar t/ systems are unlikely to take place by a concerted mechanism, and this conclusion is now generally accepted There are special complexities in reductive elimination from trigonal systems, and these are discussed furdier in Part III. 

Reduction of background radiation owing to natural radioactivity in the metal parts of the detector chamber and shielding can be reduced as shown by using electrolytic quality metals. In addition, backscatter can be reduced significantly by improvements in the counting geometry. These improvements are worthy of consideration. 

Evident shortcomings of the process were that the number of shortterm irradiations per week was apparently limited by the available analyzer counting time and the manpower needed for data reduction. These two parts of the scheme were studied to improve efficiency by increasing the number of short-term irradiations and counting in an 8-hr shift as well as significantly reducing the man-hours for data reduction. 

Turner et al. [114] described an ICP-MS with a hexapole transfer lens (Fig. 3.12a) in a tube that allows the pressure to be maintained. The cell was initially reported to contain He, although it is likely that H2 or H20 vapor was also in the cell and is now purposely added to the cell [115]. Ar2+, ArCl+, ArO+, and Ar+ signals were reduced relative to Se+, As+, Fe+, and Ca+, respectively. Detection limits for Fe, Ca, K, Se, and As near 10 parts per trillion (ppt) have been reported [115]. Recently, Beaty and Liezers [116] also described a collision-reaction cell at a pressure of 30 mtorr that reduced the ion kinetic energy spread as well as continuum ICP-MS background to less than 1 count/sec. Previously, Douglas and French had described the use of an rf-only quadrupole for collisional focusing and reduction of the ion kinetic energy spread [117]. 

Similar reaction conditions for manganese, iron and cobalt complexes lead to more stable arene systems, presumably due in part to a higher valence electron count for these metal centres. Reduction of [3,5- Pr2-2,6-Trip2C6HMX]ra (M = Mn, X = I, n= 1 M = Fe, X = C1, n= 1 M = Co, X = C1, n — 2) gives rise to the Mn(I) inverted sandwich complex [3,5- Pr2-... 

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