In order to partially or totally replace defective hard tissues, biomaterial scientists have been looking for synthetic ceramic-polymer composites to match the composition, microstructure and properties of natural hard tissues.This work aims at the study of using alumina (Al2O3) nanoparticles as a reinforcing agent for a polymeric matrix based on ultrahigh molecular weight polyethylene (UHMWPE). Groups of alumina nanoparticles (Al2O3) dispersed UHMWPE samples were prepared using injection molding technique at different nanofiller concentrations. The mechanical and thermal properties of the injection molded samples were measured to investigate the impact of alumina nanoparticles concentration on the characteristics of the produced composites. Different characterization techniques have been used. Among these tensile testing, thermo-gravermetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscope (SEM).
Light weight cores are widely used in composite sandwich structures due to their unique ability to provide low weight and high stiffness to weight ratios. These unique properties stem from cores' highly porous structure, which also renders them inherently weak. Accordingly, cores used in sandwich structures are susceptible to sustain damage due to inadvertent loading. Since the honeycomb is sandwiched between two sheets, nondestructive methods are much more appealing. However, common nondestructive techniques have limited effectiveness in inspecting light weight cores as their porous structure renders them dispersive to ultrasound waves, while inspecting them using sub-ultrasound frequencies has been introduced lately as a promising alternative to ultrasound inspection. However, this approach requires a priori knowledge of the wave propagation characteristics in the inspected material. Accordingly, this work relies on finite element computations to quantify the phase velocities and dispersive properties of low frequency elastic wave propagating in aluminum honeycombs.
Pollution is one of the main problems that today's world is facing. It can be of different types such as air and soil pollution. This research aims to reduce these kinds of pollution by reducing the space cooling, energy consumption and recycling tire rubber waste. While polystyrene (PS) was used as a matrix in this research, Devulcanized rubber (DVR) was used as a filler in the matrix. The measured thermal conductivity of 30 % DVR composite is lower than that of scrape rubber-polyester composite, crumb rubber-concrete panel and plaster-rubber board, by 46.5 %, 73.34 % and 54.11%, respectively. This makes DVR-PS developed composites good alternatives to be used in building insulation industries. In addition the developed DVR-PS has good thermal properties, if they were compared with the available commercial thermal insulators.
