Papers by Author: Mufit Akinc

Abstract: Use of environmentally friendly processing additives for nanometric powders has tremendous technological implications. In this study, the rheology of aqueous nanometric alumina powdersuspensions and variation of viscosity with solids content and with fructose concentration were studied by rheometry. The mechanism of dramatic viscosity reduction by fructose addition is studied by differential scanning calorimetry (DSC) and thermogravimetry (TGA). The interparticle forces between the particles were investigated by colloidal probe-atomic force microscopy (CP-AFM). DSC indicates that the significant fraction of water is bound on the surface hence does not contribute to flow of the particles. It also indicates that the fructose displaces water from the particle surface and reducing the interparticle forces. The interactions between the nanometric alumina particles in water can be explained by the DLVO theory. The interaction forces (amplitude and range) between nanometric alumina particles decrease with increasing fructose concentration.

Abstract: Tricalcium phosphate modified by silicon and zinc was synthesized as a candidate for resorbable temporal bone implant having a controlled solubility and improved biocompatibility. Since Si and Zn are essential trace elements with stimulatory effects on bone formation, Si,Znmodified tricalcium phosphate can also promote bone formation. From XRD and ICP analyses, it was shown that up to 10 mol% Si and Zn can be incorporated in the tricalcium phosphate lattice without formation of a second phase. Changes in lattice parameters and unit volume of TCP as calculated by Rietveld refinement analysis indicate that Si and Zn substitute for P and Ca respectively.