RESUMO
A simple, repeatable method for determination of the degree of grain refinement in irradiated Uranium-Molybdenum fuels has been developed. This method involves mechanical potting and polishing of samples along with examination using a scanning electron microscope located outside of a hot cell. The commercially available software package Mathematica was used to determine the degree of grain refinement by way of a built-in iterative active contour method of image segmentation. Baseline methods for degree of grain refinement assessment are suggested for consideration and further development.
RESUMO
This article discusses the unique material manufacturing process of self-propagating high temperature synthesis (SHS) as applied to the making of porous biomaterials. Porous materials have long been considered as the first step toward in-vivo bone tissue engineering and the creation of patient life-time implants. The authors have approached this challenge by utilizing combustion synthesis, to create novel materials such as NiTi + TiC as well as porous forms of materials that are commonly accepted for biomedical applications such as tricalcium phosphate and hydroxyapatite. In the SHS product, physico-chemical properties are controlled by, but not limited to, reactant stoichiometry; green density; particle size of the reactant mix; use or presence of a gasifying agent; heating rate of the reactants and gravity. By balancing these parameters, the energy of the reaction is controlled to create the desired product stoichiometry, porosity, and mechanical properties. SHS provides a means to rapidly manufacture materials, saving time and production costs as well as enabling the synthesis of custom devices through the use of individual molds. Mold materials can range from graphite to paper or paper machete. Combustion synthesis offers a method for the rapid manufacture of affordable, individual biomedical devices that will reduce patient recovery time.
