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Yakubtsov I.A.,McMaster University | Yakubtsov I.A.,Integrity Testing Laboratory Inc. | Purdy G.R.,McMaster University
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2012

The isothermal transformation kinetics of austenite decomposition in Fe-0.4C-2.78Mn-1.81Si was analyzed by an electrical resistivity technique in the temperature interval 723 K to 418 K (450 °C to 145 °C). The analysis of transformation kinetics of the bainite transformation was performed using the Johnson-Mehl-Avrami-Kolgomorov (JMAK) and Austin-Rickett (AR) approaches. The kinetic parameters, the reaction constant n, rate constant k = k(T), and apparent activation energy Q were evaluated for isothermal transformations below and above the martensite-start temperature M S = 548 K (275 °C), which was determined experimentally. The formation of strain-induced martensite, which starts to accompany the bainite transformation at just above M S, increases the rate of transformation and decreases the apparent activation energy of austenite decomposition. © The Minerals, Metals & Materials Society and ASM International 2011. Source

MacDonald, Dettwiler, Associates and Integrity Testing Laboratory Inc. | Date: 2013-07-03

A method of making a charge dissipative surface of a dielectric polymeric material with tunable (selectable) surface resistivity, comprises the step of controllably carbonizing the surface of the polymeric material in a vacuum environment by bombarding the polymeric surface with an ion beam of rare gas ions, the energy level of the ion source being from 2.5 to 30 keV, in the fluence range 1E16-5E17 ion/cm

Banks B.A.,NASA | Banks B.A.,Alphaport Inc. | Edwards D.L.,NASA | Gouzman I.,Soreq NRC | And 13 more authors.
MRS Bulletin | Year: 2010

To explore higher, farther, and faster, scientists and engineers have developed advanced materials for manned spacecraft and satellites for a range of sophisticated applications in transportation, global positioning, exploration, and communication. Materials used in space are exposed to vacuum, intense ultraviolet radiation from the sun, and ionizing radiation that results in material damage as well as charging (electrostatic discharge effects), micrometeoroids and debris impacts, and thermal cycling (typically from -175 to 160°C). In terms of materials degradation in space, the low Earth orbit (LEO), where LEO is defined as 200-1000 km above the Earth's surface, is a particularly challenging synergistic environment, since atomic oxygen (AO) is present along with all other environmental elements. Hence, this special issue focuses primarily on the materials issues experienced in LEO by space environmental exposure, such as on the exterior of the International Space Station and the Hubble Space Telescope, and the challenges and opportunities of ground-based laboratory sources to mimic LEO. The combination and comparison of both in-flight and ground-based experiments are needed for the development of predictive understanding of the materials degradation and AO passivation mechanisms in LEO. Such insights are essential for the development of advanced materials and coatings to ensure the longterm durability and performance of vehicles employed in space. Source

Zamel N.,University of Waterloo | Litovsky E.,Integrity Testing Laboratory Inc. | Shakhshir S.,University of Waterloo | Li X.,University of Waterloo | Kleiman J.,Integrity Testing Laboratory Inc.
Applied Energy | Year: 2011

Carbon paper is commonly used as the gas diffusion layer (GDL) in polymer electrolyte membrane (PEM) fuel cells as it exhibits high chemical and mechanical durability. This diffusion medium is also anisotropic, which directly affects its transport properties and specifically the thermal conductivity. In this study, the in-plane thermal conductivity of the carbon paper GDL was determined using thermal diffusivity measurements for a temperature range from -20 to +120. °C and four Teflon loadings (0, 5, 20 and 50. wt.%). It is important to understand the effect of temperature on the thermal conductivity since PEM fuel cells are designed to operate under various temperatures depending on the application of use. Further, Teflon is used to change the hydrophobic properties of the carbon paper GDL with 20. wt.% as the most widely used percentage. In this study, the Teflon loadings were chosen to gain a comprehensive understanding of the thermal resistance due to Teflon. In this study, a quasi-steady method was used to measure the thermal properties of the carbon paper; hence, the phase transformation in the presence of PTFE was investigated. The thermal conductivity decreases with an increase in temperature for all samples. The addition of as little as 5. wt.% Teflon resulted in high thermal resistance decreasing the overall thermal conductivity of the sample. Further addition of Teflon did not have major effects on the thermal conductivity. For all treated samples, the thermal conductivity lies in the range of 10.1-14.7. W/mK. Finally, empirical relations for the thermal diffusivity and conductivity with temperature were deduced. © 2011 Elsevier Ltd. Source

Kolich M.,Ford Motor Company | Hoke P.,Ford Motor Company | Dooge D.,ESI North America Inc. | Doroudian M.,ESI North America Inc. | And 2 more authors.
Journal of Elastomers and Plastics | Year: 2014

The thermophysical properties of interior insulation in cars can depend strongly on mechanical compression of the insulation. No data exists presently on such dependence for this insulation. The main aim of this work was to measure the thermal conductivity and specific heat of different car interior parts (seat cushion, back cushion and leather-foam cover) in a temperature range of -20 C to +60 C and at four different compression values of 0%, 20%, 40% and 60%. Due to complicated mechanisms of material's structure deformation under compression, theoretical predictions of these dependencies are very complicated. Therefore, experimental results have both scientific and practical interest. © The Author(s) 2012. Source

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