The skeletal system of bones and cartilage forms a framework that supports and protects soft tissues. It also provides surfaces to which muscles, ligaments and tendons attach and coordinate movement of bones. Since such musculoskeletal system serves as a “structural” element of the body it is easy to see that its functional capabilities are closely related to it mechanical strength. Consequently, there have been numerous attempts to characterize the properties of bones. Currently, several sophisticated diagnostic procedures and radiographic imaging techniques are available for quantitative purposes. Virtually all the available methods are based on the measurement of mineral content of the bone. It is well known that it is the combination of the organic and the inorganic components that determine the strength of the bones. Thus, in principle, the traditional methods can provide only part of the information about the bone tissues. With this shortcoming in view an effective case can be made for the development of a technique that measures both the components. Many researchers have looked at ultrasonic energy to fulfill this role. The rationale for the choice of this energy is that ultrasound is a “mechanical radiation” and its propagating properties provide a direct measure of mechanical strength or related property of the medium.

This paper presents a new, three-dimensional (3-D) nuclear magnetic resonance (NMR) imaging technique for spatially mapping proton distributions in green-state ceramic composites. The technique is based on a 3-D back-projection protocol for data acquisition, and a reconstruction technique based on 3-D Radon transform inversion. In principle, the 3-D methodology provides higher spatial resolution of solid materials than is possible with conventional slice-selection protocols. The applicability of 3-D NMR imaging has been demonstrated by mapping the organic additive distribution (2.5 wt.%) in cold-pressed Si34 whisker-reinforced Si34 ceramic composites. Three-dimensional X-ray computed tomography (CT) also has been employed for mapping voids and inclusions within the composite specimen. Combining information from both imaging modalities provides an extremely powerful nondestructive evaluation tool for materials characterization.

We have applied NMR Imaging and X_Ray Computerized Tomography to the study of the structural properties of rocks. Samples from different porous rocks; sandstones, granites, limestones have been successively examined by both techniques. NMR images have been obtained on water saturated samples. The spatial distribution of liquid indicates the effective porosity. By constrast, X_Ray images display the mineral content of rocks. Standard tomographs do not have the required resolution to see pores smaller than 100 μm. We used water as a constrast agent to localize porosities by “differential” CT. Comparative results are shown.

In this work the wavelet transform is used to process high- and medium resolution electron micrographs from small particles and their substrates. It is concluded that the edge sensitivity of the technique and its contrast enhancement capabilities are most useful in the processing of electron micrographs.

A survey is given of recent developments in selected areas of neutron tomography, within the context of several applications Argonne is involved in, including high penetration of reactor-fuel bundles in thick containers (involving TREAT and NRAD facilities), dual-energy hydrogen imaging (performed at IPNS), dynamic coarse-resolution emission tomography of reactor fuel under test (a proposed modification to the TREAT hodoscope), and an associated-particle system that uses neutron flight-time to electronically collimate transmitted neutrons and to tomographically image nuclides identified by reaction gamma-rays.

Two NDT techniques were used to characterize low-density, microcellular, carbon foams fabricated from a salt replica process. The two techniques are x-ray computed tomography (CT) and ion microtomography (IMT); data are presented on carbon foams that contain high-density regions. The data show that densities which differ by <10% are easily observable for these low density (<100 mg/cm3) materials. The data reveal that the carbon foams produced by this replica process have small density variations; the density being ∼30% greater at the outer edges than when compared to the interior of the foam. In addition, the density gradient is found to be rather sharp, that is the density drops-off rapidly from the outer edges to a uniform one in the interior of the foam. This edge build-up in carbon density was explained in terms of polymer concentrating on the foam exterior during drying which immediately followed a polymer infusion processing step. Supporting analytical data from other techniques show the foam material to be >99.9 % carbon