Thermo-oxidative stability of graphite fiber/PMR-15 polyimide composites at 350 deg C

A series of graphite fiber/PMR-15 polyimide composites were subjected to isothermal aging at 350 C in flowing air (100 cc/min and 1000 cc/min) over a 520 hr time period. The graphite fibers were analyzed by ISS/SIMS techniques before composite fabrication. Fibers exposed at the surface of the composite due to the isothermal aging process were also analyzed by the ISS/SIMS method. Component and composite weight less studies were also conducted for similarly exposed materials. Optical micrograph investigations of composites to follow the progress of the thermo-oxidative process were also conducted. Flexural and interlaminar shear strengths of the imaged and aged composites were measured. The relationship of component and composite properties as they relate to the thermo-oxidative behavior of the materials was discussed

Imide modified epoxy matrix resins

High char yield epoxy using novel bisimide amines (BIA's) as curing agents with a state of the art epoxy resin was developed. Stoichiometric quantities of the epoxy resin and the BIA's were studied to determine the cure cycle required for preparation of resin specimens. The bisimide cured epoxies were designated IME's (imide modified epoxy). The physical, thermal and mechanical properties of these novel resins were determined. The levels of moisture absorption exhibited by the bisimide amine cured expoxies (IME's) were considerably lower than the state of the art epoxies. The strain-to-failure of the control resin system was improved 25% by replacement of DDS with 6F-DDS. Each BIA containing resin exhibited twice the char yield of the control resin MY 720/DDS. Graphite fiber reinforced control (C) and IME resins were fabricated and characterized. Two of the composite systems showed superior properties compared to the other Celion 6000/IME composite systems and state of the art graphite epoxy systems. The two systems exhibited excellent wet shear and flexural strengths and moduli at 300 and 350 F

Narrow-band noise due to the moving vortex lattice in superconducting niobium

We report measurements of voltage noise due to vortex motion in Niobium, a conventional low-Tc superconductor. A coherent oscillation leading to narrow band noise (NBN) is evidenced. Its characteristic frequency is a linear function of the overcritical transport current in the flux-flow regime, and hence scales as the main velocity of the vortex flow. The associated length scale is not the intervortex distance but the width of the sample, indicating temporal coherence at a large scale. NBN is also observed in the non linear part of the V(I) at the onset of depinning, in apparent disagreement with a stochastic creep motion of flux bundles. NBN exists in the peak effect region, showing that long range temporal correlations are preserved in this regime.Comment: accepted for publication in Phys Rev

Report on Experiential Learning: Stratford Festival Internship and Private Art Collection Management

In her report, Natalie Scola discusses her two experiential-learning opportunities: her internship in the Stratford Festival archives cataloguing costumes and her work cataloguing and preserving a private art collection

SASAH Experiential Learning: Stratford Festival Archives and Collections Management

Natalie Scola discusses her two experiential-learning opportunities: her internship in the Stratford Festival archives cataloguing costumes and her work cataloguing and preserving a private art collection

Planning for Changing Suburbs: Vaughan's Urban Growth Centre

Suburban development, in the last half century, has been the dominant style of urban expansion in Southern Ontario. The Greater Golden Horseshoe, which consists of Ontario's largest and most heavily populated regions, has experienced growth through urban sprawl over the last few decades. There are certain issues associated with this style of growth that are reflected in the environmental, economic and the social well-being of cities. There has been a shift in the way suburbs are being planned and the Province of Ontario has taken steps in recent years towards curbing sprawl through the implementation of policy that encourages compact growth. The policy document that sets out these growth initiatives is called the Places to Grow Act: Growth Plan for the Greater Golden Horseshoe (2006). This document "sets out policies and guidelines that direct municipalities how and where to grow". The same document also identifies the Vaughan Metropolitan Centre as an Urban Growth Centre with growth targets that the area must meet by the year 2031. This major paper looks at the process of suburbanization and intensification, as well as the land use policy framework that governs the City of Vaughan and asks the question: is Vaughan developing and growing in the right direction? By looking at the works of Pierre Filion and the Expo City Development the paper argues that the City of Vaughan, while working successfully towards meeting the province's growth targets, lacks certain elements within their growth centre such as affordable housing and a civic centre/city hall (which was recently built away from the site). In the paper I apply Filion's criteria of what makes suburban town centres successful and apply them to the Vaughan Metropolitan Centre to distinguish if Vaughan's downtown centre is headed towards being successful