Artificial intelligent tools like genetic algorithm, artificial neural network (ANN) and fuzzy logic are found to be extremely useful in modeling reliable processes in the field of computer integrated manufacturing (for example, selecting optimal parameters during process planning, design and implementing the adaptive control systems). When knowledge about the relationship among the various parameters of manufacturing are found to be lacking, ANNs are used as process models, because they can handle strong nonlinearities, a large number of parameters and missing information. When the dependencies between parameters become noninvertible, the input and output configurations used in ANN strongly influence the accuracy. However, running of a neural network is found to be time consuming. If genetic algorithm-based ANNs are used to construct models, it can provide more accurate results in less time. This article proposes a genetic algorithm-based ANN model for the turning process in manufacturing Industry. This model is found to be a timesaving model that satisfies all the accuracy requirements.

The migration of the plasticizer, dioctyl adipate (DOA) in the accelerated ageing of composite propellant has been studied. The method is based on the extraction of DOA with carbon tetrachloride and its estimation by gas chromatography. The concentration of DOA in the propellant at different distances from the insulation was determined after a definite ageing period and compared with the initial DOA concentration. The effect of (a) the ageing period, and (b) the ageing temperature on the degree of migration was examined. The present studies confirm the existence of plasticizer migration in the propellant adjacent to the insulation, during ageing.

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Two novel aromatic diamine monomers, Bis-4,4′[(4-aminophenyl-2,2′-isopropylidene phenyloxy)] diphenylsulfone and Bis-4,4′[(4-aminophenyl-2,2′-isopropylidene phenyloxy)] benzophenone were synthesized and characterized by IR and 1H-NMR. A series of processable polyimides were prepared by polycondensation of diamines with aromatic dianhydrides. The polyimides were characterized by infrared, 1H-NMR, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, gel-permeation chromatography, solution viscosity and solubility. Polyimides were soluble in polar approtic solvents and increases in solubility in common organic solvents were observed due to the presence of flexible groups and methyl groups in the chain backbone. The polyimides exhibited good thermal stability, and the temperature at which 10% weight loss occurred ranged from 378 to 465 °C in nitrogen. X-ray diffraction measurements revealed that the polyimides were amorphous.

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Two ether groups containing bisnitrophthalimide monomers 4,4'-Bis(4-nitrophthalimido phenoxy)diphenyl sulfone and 4,4 0 -bis (4-nitrophthalimido phenoxy)benzophenone were synthesized. The monomers were characterized by Fourier transform infrared (IR) spectroscopy and 1 H-NMR. The polyetherimides were prepared from bisnitrophthalimides by nucleophilic displacement of nitro group by bisphenolate ion. The polyetherimides were characterized by IR, 1 H-NMR, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, dielectric constants, solution viscosity and solubility. Polyetherimides were soluble in polar approtic solvents and improved solubility in common organic solvents is due to the presence of flexible groups in the polymer backbone. Polyetherimides exhibited good thermal stability and the temperature at which 10% weight loss occurs in the range 357-453 C in a nitrogen atmosphere. X-ray diffraction measurements revealed that these polyetherimides are amorphous.

New aromatic diimide-diol monomers were prepared by the aromatic nucleophilic substitution reaction of aromatic dianhydrides and 4-aminophenol/(4-aminophenyl)-2'-(4-hydroxy phenyl)propane. The monomers were characterized by IR and 1H-NMR spectroscopy. A series of poly(esterimide)s was prepared from diimide-diols and aromatic diacid chlorides by solution polycondensation reaction in N-methyl-2-pyrrolidone. The poly(esterimide)s were characterized by IR and 1H-NMR spectroscopy, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, gel-permeation chromatography, solution viscosity and solubility behaviour. The poly(esterimide)s with flexible groups, methyl groups and 1,3-disubstituted phenyl rings in the chain were expected to disturb the symmetry, and their effects on the property were studied. Most of the poly(esterimide)s exhibited good solubility in common organic solvents. The poly(esterimide)s displayed good thermal stability, and the 10% weight loss under nitrogen atmosphere ranged from 361 to 439 °C respectively.

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