Worcester Polytechnic Institute

About: Worcester Polytechnic Institute is a education organization based out in Worcester, Massachusetts, United States. It is known for research contribution in the topics: Computer science & Population. The organization has 6270 authors who have published 12704 publications receiving 332081 citations. The organization is also known as: WPI.

Room Temperature Self-Healing Thermoset Based on the Diels–Alder Reaction

Abstract: A self-healing epoxy-amine thermoset based on the compatible functionalization of the thermoset and encapsulated healing agent has been successfully developed. Healing of the thermoset resulted from the reaction of furans in the thermoset and multimaleimides (MMIs) in the healing agent solution. The healing agent, MMI dissolved in phenyl acetate, was encapsulated using a urea-formaldehyde encapsulation method. Autonomic healing of the thermoset was achieved by incorporating microcapsules filled with the healing agent solution within a furan-functionalized epoxy-amine thermoset. The resulting self-healing thermoset recovered 71% of its initial load after fracture.

A study of coarsening, recrystallization, and morphology of microstructure in Al-Sc-(Zr)-(Mg) alloys

Abstract: Minor additions of Sc are effective in controlling the recrystallization resistance of 5xxx, 2xxx, and 7xxx aluminum. The addition of Sc to aluminum results in the rapid precipitation of homogeneously distributed Al3Sc dispersoids, which are coherent with the matrix and have the L12 structure. The presence of Al3Sc dispersoids increases the recrystallization resistance of wrought alloys. The higher coarsening rate of Al3Sc compared to that of Al3Zr may limit its applications as a single ancillary addition. When both scandium and zirconium are used in the same alloy, Al3(Sc1-x , Zr x ) dispersoids form. These dispersoids are more effective recrystallization inhibitors than either Al3Sc or Al3Zr. The Al3(Sc1-x , Zr x ) dispersoids precipitate more rapidly than Al3Zr but have a slower coarsening rate than Al3Sc. Furthermore, the distribution of Al3(Sc1-x , Zr x ) is significantly more homogeneous than Al3Zr. It was also established that alloys containing up to 3.5Mg showed improvement in recrystallization resistance when both Sc and Zr were present. Several morphologies of Al3Sc and Al3(Sc1-x , Zr x ) were also observed.

Effect of Stenosis Asymmetry on Blood Flow and Artery Compression: A Three-Dimensional Fluid-Structure Interaction Model

Abstract: A nonlinear three-dimensional thick-wall model with fluid-structure interactions is introduced to simulate blood flow in carotid arteries with an asymmetric stenosis to quantify the effects of stenosis severity, eccentricity, and pressure conditions on blood flow and artery compression (compressive stress in the wall). Mechanical properties of the tube wall are measured using a thick-wall stenosis model made of polyvinyl alcohal hydrogel whose mechanical properties are close to that of carotid arteries. A hyperelastic Mooney–Rivlin model is used to implement the experimentally measured nonlinear elastic properties of the tube wall. A 36.5% pre-axial stretch is applied to make the simulation physiological. The Navier–Stokes equations in curvilinear form are used for the fluid model. Our results indicate that severe stenosis causes critical flow conditions, high tensile stress, and considerable compressive stress in the stenosis plaque which may be related to artery compression and plaque cap rupture. Stenosis asymmetry leads to higher artery compression, higher shear stress and a larger flow separation region. Computational results are verified by available experimental data. © 2003 Biomedical Engineering Society. PAC2003: 8719Uv, 8710+e

Characterization of Intermetallic Diffusion Barrier and Alloy Formation for Pd/Cu and Pd/Ag Porous Stainless Steel Composite Membranes

Abstract: The formation of the intermetallic diffusion barrier layer by the controlled in-situ oxidation method for Pd and Pd/alloy porous stainless steel composite membranes was investigated. SEM and EDS results showed the existence of an oxide layer as the intermetallic diffusion barrier for oxidation temperatures higher than 600 °C. At oxidation temperatures lower than 600 °C, there might still be an oxide layer at the membrane-substrate interface although it was too thin to be detected by SEM and EDS. The alloy formation study showed that annealing at 500 °C under helium atmosphere did not produce alloys with uniform compositions either for Pd/Ag or Pd/Cu membranes. However, annealing at 600 °C gave a uniform Pd/Cu-porous stainless steel (PSS) composite membrane, with no detectable presence of elements from the PSS substrate, further demonstrating the oxide layer as an effective intermetallic diffusion barrier.