Small-angle x-ray scattering (SAXS) and wide-angle x-ray diffraction (WAXD) data are used to establish relationships among the degree of crystallinity, melting temperature and lamellar thickness for random copolymers of poly(β-hydroxybutyrate-co-β-hydroxyvaierate) (PHB/V). The morphology of this isodimorphic system is best described by a two phase model consisting of crystalline and amorphous domains having density fluctuations within each domain. The Sanchez-Eby inclusion model is used to predict melting point depression in these materials and, combined with SAXS data, to gain insight into the degree of inclusion of hydroxy valerate units within the polyhydroxybutyrate crystalline domains.

The analysis of crystalline organic phases by X-ray powder diffraction presents special problems, beyond those typically associated with inorganic materials. The large unit cells often associated with organic compounds, combined with the low symmetry of the structures, give rather complicated diffraction patterns which contain many low angle lines. The Bragg-Brentano geometric arrangement employed in most commercial diffractometers gives maximum d-spacing error at low diffraction angles. This, in turn, means that not only can the large d-spacing data be of poor quality, but also that much of the low angle data required for the indexing of the pattern is subject to large errors.

An integrated XRD-XRF system for the on-stream analysis of slurries was configured to the requirements of industry for process control. The slurry-handling system includes a multiplexer, header tank, de-aerator and a windowless sample presenter. The XRD part of the system is composed of a molybdenum anode X-ray tube, a pyrolytic graphite primarybeam monochromator, a vertical fixed-geometry goniometer, and a simultaneous detector system. The X-ray beam is transmitted through the slurry curtain so that the diffracted intensities are measured in the forward diffracted mode. The energy-dispersive XRF spectrometer measures the reflected fluorescence intensities. Examples and data from the onstream XRD analysis of fluorspar and apatite are presented. Mention is made of the application of an integrated XRD-XRF system in the heavy-minerals and base-metal industries.

All intensity data in a powder XRD pattern can be used to provide useful results for the interpretation of the mineralogical variability of geological samples. Simple statistical methods using Bonferroni's theorem permit the recognition of areas usually associated with mineral peaks where sample patterns are different at a predetermined level of confidence. Intensity/frequency histograms reveal subtle differences in low intensity regions of the XRD patterns that are also indicative of sample variability. These procedures facilitate the comparison of samples and may reduce the total analytical error because the weight percent determination can be eliminated.

Nonlinear equations are given for determining the crystallographic orientation of surfaces of single crystals. The equations are solved by an iterative method in several variables. The angle ϕ between the surface plane and the lattice plane in question is decomposed into two components α and β. These two components are obtained from the solution of a non-linear system of equations using two measurements and the Bragg angle. The diffractometric system considered is the well known θ/2θ with a sufficiently large area of x-ray detection and the capability of holding single crystal samples. The results obtained are discussed from experimental and theoretical points of view.

Two-dimensional geometry information contained in SAED spot patterns augmented with EDS elemental data is employed in a computerized phase identification of microcrystalline particles. The initial chemistry screening of a laboratory managed database using the 'bitmap' concept is followed by a geometry search/match treating of the spot patterns as planar sections through the reciprocal lattice of a candidate phase. The identification is selective, fast, and yields to a complete automatization,