Microstructural features, such as defects, crystal morphology, and crystal size distribution, can significantly affect the ignition sensitivity, performance, and mechanical properties of energetic materials. To evaluate the influence of pressing parameters on microstructure, three cylinders of PBX 9501 were pressed at 5,000, 15,000, and 30,000 psi, using a 100 ton heated steel die press. Polarized light microscopy images taken at 144 locations within each cylinder show differences in porosity, crystal size, and crystal size distribution between cylinders and at different locations within the same cylinder. Scanning electron microscopy further verifies increased fracture and pulverization of HMX crystals during pressing.

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We analyzed the metacarpophalangeal pattern profile (MCPP) on 18 male individuals from 16 families with fragile X-fra (X), or Martin-Bell-syndrome and calculated a mean syndrome profile. Fourteen of 18 individuals with fra (X) syndrome had significant positive correlations which indicated clinical homogeneity. Discriminant analysis of individuals with fra (X) syndrome compared with a sample of normal individuals produced a correct classification rate of 88% based on a function of 3 MCPP variables that may provide a useful tool in screening individuals for the fra (X) syndrome. Discriminant and correlation analyses of individuals with Sotos sequence and individuals with fra (X) syndrome did not identify MCPP similarities. Therefore, there was no MCPP evidence in our study of patients with Sotos sequence and fra (X) chromosome expression.

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Factor analysis has been performed on gel permeation chromatography (GPC)-Fourier transform infrared (FT-IR) spectroscopic data sets for one control and two artificially aged, multicomponent polymer systems. This approach was utilized to provide insight into degradation chemistry and to obtain component spectra (factors) and their concentration profiles (scores). The results are evaluated in terms of the infrared spectra of the chemical species present, their concentration profiles, and the different aging environments. For the formulation of a poly(ester urethane) with added plasticizer, and stabilizer, the results demonstrate that chain scission and nitration of the poly(ester urethane) are dominant degradation pathways under radiolytic aging conditions. Thermal aging conditions induce some chain scission. In both aging studies, branching is shown not to be a dominant degradation pathway. However, because branching processes produce insoluble cross-linked material, this possibility was not further investigated in this study.