Engineering Commons^™

The Transcriptional Response Of Phanerochaete Chrysosporium And Trametes Versicolor To Growth On Stems Of Helianthus Argophyllus (Silverleaf Sunflower), Nadh Hamoud Alsubaie

Masters Theses

Traditional physicochemical and physicomechanical pretreatment technologies have improved the deconstruction of lignocellulose, but often require high energy inputs and added chemical reagents. Recent studies have demonstrated the use of white-rot fungi as alternative biological pretreatment agents that can mitigate these concerns. Although, white-rot fungi have been shown to grow on a variety of non-woody substrates, they have not been explored with respect to sunflower, which has the potential to provide raw materials for both biodiesel and bioethanol. In the present study, Silverleaf sunflower stems (Helianthus argophyllus) were used as substrates for the white-rot fungi Phanerochaete chrysosporium and Trametes …

Effects Of Compression Processing Parameters And Antioxidants On Molecular Degradation Of Biodegradable Poly-L-Lactide (Plla), Thomas J. Hannan Jr.

Masters Theses

The purpose of this research was to find a combination of poly (L-lactic acid), also known as poly-L-lactide or (PLLA) and antioxidants that would, together, produce a product whose degradation rate would be advantageous for use in biodegradable medical implants. Intrinsic viscosity tests were conducted on compression molded samples of PLLA that were molded at various processing parameters in order to find optimal parameters. The optimal processing parameters were found to be time 10 minutes, temperature 220°C, and pressure 1000 psi.

The molecular weight of PLLA sample was taken while pressure, time, and temperature were varied. As pressure increased, no …

The Effects Of Machining On Structure And Tribological Properties Of Ultra High Molecular Weight Polyethylene For Artificial Joint Prostheses, Jinshan Song

Masters Theses

Understanding the effect of machining on the structure and property of subsurface layer of ultra high molecular weight polyethylene (UHMWPE) can significantly facilitate the increase in longevity of artificial joints. This study was performed to investigate the machining effects on the polymeric structure and tribological properties. Machining parameters include cutting speed, tool feed rate and depth of cut. Temperature rise was studied during machining to assess the extent of thermal degradation due to machining. Polymeric structure of the semicrystalline polymer was characterized using differential scanning calorimetry (DSC) in terms of melting enthalpy, crystallinity and melting temperature. Surface texture and hardness …