Phosphorite is a sedimentary rock with a high enough content of phosphate minerals to bo of economic Interest. Most phosphorites are composed predominantly of m1crocrystall1no to cryptocrystalline carbonate fluorapatlte thenceforth In this report referred to simply by the mineral group name apatite). Florida produces roughly 1/3 of the world's supply of phosphate rock, most of which is used 1n the fe rtiliz e r Industry.

Long term continuation of phosphorite mining In Florida will require exploitation of the extensive hlgh-magneslum phosphorite deposits south of the present mining d istrict 1n central Florida, and this will require new technology In order to produce beneficlated concentrates with less than 1% MgO, a limit Imposed by fe r tiliz e r processing technology. In order to develop benefication methods applicable to these ores, it is essential to know how Mg occurs in phosphorites. Dolomite, CaMg(C03)2, is the chief host of Mg In phosphorites from Florida. Magnesium may also be present, however, as a substituent In apatite (the chief phosphate.mineral in these deposits), as a minor substituent 1n calcite (CaCO3), in certain clay minerals (particularly palygorskite and to a lesser extent in some smectites), and/or in organic matter within the apatite particles.

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.

Digitized data acquisition and subsequent peak-profile fitting are used in aligning and maintaining the Guinier diffraction system in this laboratory. Utilization of a stepping motor driven goniometer along with profile analysis allows rapid and reproducible alignment while providing a means to investigate the types and magnitudes of errors introduced by various misalignments of the optical system.

The combination of an improved resolution, gas proportional detector with advanced microprocessor technology provides a new and unique solution to the problem of alloy analysis.

A field portable, microprocessor controlled, fully user-programmable x-ray analyser is described for fast, reliable, on-site, positive alloy identification and assay. The radio-isotope based analyser employs a modified Lueas-Tooth and Price model of intensity corrections for quantitative, multielement analysis. Applications are reviewed and include examples to show the superior performance of the instrument in such difficult eases as sulfur in carbon steels, and titanium and nickel in stainless steels.

Discussion of the unique alloy identification scheme and its underlying principles is followed by examples of applications illustrating the capabilities of the instrument in distinguishing, in 5 seconds, alloys of closely similar compositions such as stainless steels 303, 304 and 321, and 410 and 416.

X-ray microscopy is a field that has developed rapidly in recent years. Two different approaches have been used. Zone plates have been employed to produce focussed beams with sizes as low as 0.07 pm for x-ray energies below 1 keV. Images of biological materials and elemental maps for major and minor low Z have been produced using above and below absorption edge differences. At higher energies collimators and focussing mirrors have been used to make small diameter beams for excitation of characteristic K— or L-x rays of all elements in the periodic table.

Urea complexes consist of a channel made up of hydrogen-bonded urea host molecules into which a variety of guest molecules can fit to form a crystalline complex. The urea host can accommodate, one at a time, a variety of guests having the requisite size and shape. The stability of the resulting complex is a function of the properties of the guest molecule. A procedure has been devised which produces pure complex free of any uncomplexed urea or host molecules in solution. The insoluble crystalline complexes formed from the solution of urea and guest molecule in methanol established a dynamic equilibrium. When the crystals of complex are removed from the solution, dissociation to urea and guest occurs to an extent, depending upon the dissociation constant of the complex. If the dissociation constant, KD, is very low, undetectable quantities of uncomplexed urea form along with complex. If the dlissoclation constant is high, extensive amounts of urea form in the presence of complex. Characteristic interplanar spacing s are obtained for a urea complex irrespective of the guest molecule present. The pattern obtained for the hexagonal complex is completely different from the pattern obtained for tetragonal urea. X-ray examination of a homologous series of compounds gives, for each partially dissociated complex, spacings for both urea and complex. The relative intensities of urea and complex spacings permit the estimation of the stability of such a complex compared to that of other homologues.

The ability to prcbe the structure of a polymer during deformation is of considerable technological interest as it lends an insight into the mechanisms involved in polymer processing. The behaviour of Liquid Crystalline Polymers (LCP's) during shear flow has generated much experimental interest by virtue of their unusual behaviour compared to that of simpler polymeric melts. The theory developed by Doi attempts to explain the observed phenomena in terms of considering interactions of rigid-rods Exact solutions to the Doi theory have been compared to experimental procedures using lyotropic LCP systems. Although much of the available data relates to mechanical measurements, the comparisons with quantitative structural data can provide useful insight.

A detailed analysis of the high angle diffuse scattering from small platelets is given. A large number of statistically centrosymmetric platelets is considered, and it is shown that, in this cage, the positive square root of the diffuse intensity from the platelets is proportional to the amplitude of the scattered radiation over particular regions in reciprocal space. The measured amplitude distribution is truncated from the true amplitude distribution by the limits of measurement and the influence of Bragg scattering. A truncation function is introduced to describe this truncated amplitude distribution in terms of the true amplitude distribution. This truncation introduces modulations on the measured electron density distribution. The measured electron density distribution is described in terms of the convolution of the true electron density distribution and the transform of the truncation function. The transform of the truncation function is knowi analytically, so the true electron density distribution can be found by a relaxation method. The true electron density distribution is given in terms of composition and strain parameters which are independently adjusted during the relaxation procedure to fit the measured values. Examples of the influence of the truncation function arc given and the technique is applied to G–P 1 zones in an aluminum - 1.67 at % copper alloy.