Finite-element simulation of the hot pressing process has been performed using ABAQUS. The viscoelastic polymer (polymethyl methacrylate) used in this study has mechanical properties that depend on the temperature and working pressure. Based on the nonlinear viscoelastic model, the polymer material behaviour is simulated successfully with the data obtained from material tests. Simulation result...

The effect of excitation and emission wavelengths on fluorescence decay times of Chlorophyll a were measured in four solutions (C approximately 10(-5) mol X 1(-1] and in polymethyl methacrylate films. The decay times observed were corrected with respect to self-absorption and re-emission effects. The fluorescence decay times of Chlorophyll a was found to depend on both the excitation and the em...

High-throughput few-layered BN nanosheets have been synthesized through a facile chemical blowing route. They possess large lateral dimensions and high surface area, which are beneficial to fabricate effectively reinforced polymeric composites. The demonstrated composites made of polymethyl methacrylate and BN nanosheets revealed excellent thermal stability, 2.5-fold improved dielectric constan...

This paper describes an experiment that determined the position, and its associated uncertainty, of a proton at three different depths inside of a polymethyl-methacrylate (PMMA) absorber. These observed positions prove the fact that one can predict the most likely path (MLP) of a proton moving through a uniform medium, as long as the displacement and angle of that proton are known at the absorb...

An experimental method is presented for the rapid evaluation of structured solids with microelastic degrees of freedom associated with the microstructure. By contrast with earlier methods based on size effect studies, the present method makes use of a single specimen subjected to holographic interferometry. Results are presented for polymethyl methacrylate and for a dense polyurethane foam, whi...

background and aims. polymethyl methacrylate, pmma, is widely used in prosthodontics for fabrication of removable prostheses. this study was undertaken to investigate the effect of adding silver nanoparticles (agnps) to pmma at 2% and 0.2% concentrations on compressive and tensile strengths of pmma. materials and methods. the silver nanoparticles were mixed with heat-cured acrylic resin in an a...