After evaluating the results, we determined that the most likely place for the rotational axis is on the median-sagittal plane, in the anterior portion of the spinal canal.

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Monolithic silica aerogels are nanostructured solids characterized with exceptionally high porosity and specific surface area. Although their strength can be improved by surface treatment with polymers, none of them has been tested yet as a filler in biocompatible polymer composites. The new aerogel-poly(methyl methacrylate) composites were prepared by free radical bulk polymerization of neat methyl methacrylate in the presence of natural and functionalized silica aerogels at 60 °C, using cumene hydroperoxide initiator and 4,N,N-trimethylaniline redox pair. Synthetic conditions were set to be most similar to the setting of orthopedic bone cements.Structures, compositions, and molecular weight distributions were determined by scanning electron microscopy, combustion analysis and gel permeation chromatography, respectively. Compressive strength, Shore D hardness and Gardner's impact strength were measured, and the fracture properties were compared to the matrices. All four aerogel fillers resulted in significant enhancement in compressive strength, reaching a maximum value of 123 MPa. Dissolution of H103PC-1 natural and H106PB-1 C16 modified aerogel containing specimens in simulated body fluid occurred in twenty days, leaving porous surfaces behind, which may give rise to higher tissue adhesion potential in bone cements. Heat treated silica aerogel in H112PA-1 showed no leaching out, and its composites might be usefull in high-load technical applications.3

The development of an efficient procedure for 3d modeling and finite element simulation of metal foams is one of the greatest challenges for engineer researchers nowadays. Creating 3d CAD model is alone a demanding engineering task due to its extremely complex geometry, and the proper finite element analysis process is still in the center of the research. The increasingly widespread application of the metal foams, e.g. in vehicle and medical industry, requires this knowledge in the design phase. A closed-cell metal foam is studied using different analyzing methods where the aim is to collect information about the composition and geometry (structure) that is satisfactory for the later research. Using statistical methods microscopic, X-ray and surface analyzing studies on the specimens produced according to the concerning standard are evaluated. The main goal of this part of the project is to obtain structural information and to determine the homogeneity or the in-homogeneity property of the metal foam specimens taken from different locations.

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