Part Attributes

It was inevitable that computers will be utilised to exploit the similarity of parts and this led to the Variant Method [4], it became the cornerstone of what is we now call Computer Aided Process Planning (CAPP). Variant Method exploits the similarity of parts as well as the similarity of processes. This similarity can be on the basis of individual process or it can be on the basis of group of processes. The main disadvantage of this procedure is that the quality of process design still depends to a considerable extent on the knowledge of the methods engineer. There are no inference mechanisms in the procedure to fine-tune the process design. This is often required because there are tolerances and various levels of stresses involved in the manufacture of parts and this requires experience to create a feasible process plan. 

Computer-aided automation of process design requires a whole new approach to part manufacture and assembly planning. This centres on the decision logics, formulae, algorithms and data extractions. This approach is labelled as the Generative Method [4]. Examples of such procedures are Decision Trees, Decision Tables, Axiomatic and Expert systems. Regardless of their approach they remain complex in nature and this led to the specific applications, such as those in sheet metal fabrications and electronics manufacture, where parameters are more 

The parametric approach utilises the similarities of variables as for example in the building industry. The cost of building is often related to the square metres of surface involved and this means the amount of work and the cost of materials is known from previous experience. Such similarities are valid in most cases because 

Sackett, P. (2003). Cost engineering The practice and the future. Blue Book Series 2003. USA CASA/SME. 

Groover, M. P. (2002). Fundamentals of modem manufacturing Materials, processes, and systems (2nd ed.). New York Wiley. 

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The resolution of the ZEKE-PE spectmm of 1,4-difluorobenzene can be compared with, for example, that of the ultraviolet photoelectron spectmm of benzene in Figure 8.12. The greatly increased resolution in the ZEKE-PE spectmm is attributable mostly to the fact that only photoelectrons with zero kinetic energy are being detected. It is also partly attributable to the molecules being in a supersonic jet this has the effect of sharpening the bands because of the restricted rotational populations in the ground state of the molecule. 

In poly(ethylene terephthalate) (14—16) and poly(methyl methacrylate) (17—19), the mechanism of action of phosphoms flame retardants is at least partly attributable to a decrease in the amount of combustible volatiles and a corresponding increase in nonvolatile residue (char). In poly(methyl methacrylate), the phosphoms flame retardant appears to cause an initial cross-linking through anhydride linkages (19). 

The rapid increase in computer applications is partly attributable to both the decreasing costs of hardware and software and to the increasing costs of human labor. This shift has given rise to a productivity factor assigned to various tasks performed by computers versus people. One figure recently quoted was a minimum factor of 4 to 5 for CAD (computer aided design), that is, one draftsman with a CAD system can replace 4 to 5 manual draftsmen. 

Evidence exists that the relative solubility of amines and inhibitors in heterogeneous oil-water systems could be decisive in formation of nitrosamines and blocking these reactions, Nitrosopyrrolidine formation in bacon predominates in the adipose tissue despite the fact that its precursor, proline, predominates in the lean tissue (5,6,7). Mottram and Patterson (8) partly attribute this phenomenon to the fact that the adipose tissue furnishes a medium in which nitrosation is favored, Massey, et al, (9) found that the presence of decane in a model heterogeneous system caused a 20-fold increase in rate of nitrosamine formation from lipophilic dihexylamine, but had no effect on nitrosation of hydrophilic pyrrolidine. Ascorbic acid in the presence of decane enhanced the synthesis of nitrosamines from lipophilic amines, but had no effect on nitrosation of pyrrolidine. The oil-soluble inhibitor ascorbyl palmitate had little influence on the formation of nitrosamines in the presence or absence of decane. 

Besides the advantage of recyclability, reactions in ionic liquids are generally faster and are run under milder conditions than reactions with conventional solvents. Further activation may come from ultrasonic agitation.520 Since the majority of ionic liquids used are imidazolium salts, the effect of these solvents can be at least partly attributed to the in situ formation of carbene complexes (Section 9.6.3.4.10).521 Cross-coupling of ArB(OH)2 can also be efficiently performed in ionic liquids based on long-chain tetraalkylphosphonium salts, in which case aryl bromides and some aryl chlorides can be processed in the presence of the trivial ligand PPh3.522... 

Unlike the reaction of alkyl aryl ketoximes with tetrasulfur tetranitride <1996CHEC-II(4)355>, the treatment of alkyl methyl ketoximes 189 with tetrasulfur tetranitride antimony pentachloride complex in either benzene or toluene at 50-80°C gave low yields (3-37%) of 3-alkyl-4-methyl-l,2,5-thiadiazoles 190 (Equation 39) <1999H(50)147>. Compounds 190 were volatile and the low yields are in part attributed to their loss as the solvent was removed in vacuo. Suprisingly, only single regioisomers were obtained. 3-Heptanone oxime 191 did, however, give a mixture of two isomers 192 and 193 (Equation 40). 

As a simple example of non-d coordination, let us consider the hexaammine-zinc(II) cation [Zn(NH3)6]2+, whose optimized structure is shown in Fig. 4.51. Each ammine ligand serves as a formal two-electron sigma donor, and the total electron count atZn therefore corresponds to a 22e system, again violating the 18-electron rule. Each ammine ligand is bound to the Zn2+ cation by about 60.7 kcal mol-1, which is in part attributable to classical electrostatic interactions of ion-dipole type. 

The nitro group, whether attached to aromatic or aliphatic carbon, is probably the most widely studied of the functional groups and this is in part attributed to its use as an explosophore in many energetic materials. The chemistry of the nitro group has been extensively reviewed in several excellent works including in a functional group series. " ... 

The injury caused by chlorine trifluoride is in part attributed to its hydrolysis products, including chlorine, hydrogen fluoride, and chlorine dioxide. Effects in humans have not been reported but may be expected to be very severe inhalation may cause pulmonary edema, and contact with eyes or skin may cause severe burns. 

In the past decade, the use of BZDs for antipanic therapy has declined. This decline is in part attributable to the growing awareness of the disadvantages of BZDs, especially the risk of dependency and abuse. 

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