Analysis of Pt/SnO(sub x) during catalysis of CO oxidation

Temperature-programmed reduction using 6kPaH2 suggests that a sample consisting of 3 percent Pt supported directly on SnO2 is, under conditions of catalysis of CO oxidation used here, best represented as 3 percent Pt/SnO sub x, since the support is likely to partially reduced, probably in the vicinity of the metal/oxide interface. Catalytic measurements at 421 to 424 K show that this 3 percent Pt/SnO sub x is significantly more active per unit area of Pt than 6 percent Pt/SiO2 in catalyzing the oxidation of CO. In situ micro-FTIR reveals that while the latter has predominantly linearly bound CO on the surface under reaction conditions, the Pt/SnO sub x also has a species absorbing at 2168 cm(exp -1) which may be CO upon Pt in a positive oxidation state or weakly chemisorbed CO on zero-valent Pt. This may be directly involved in the low temperature oxidation of CO on the Pt/SnO sub x, since being weakly held the activation energy for its surface diffusion to the metal/oxide interface will be low; such mobile species could allow the high rates of surface transport and an increase in the fraction of the surface over which the CO oxidation occurs. FTIR also reveals carbonate-type species on the P/SnO sub c surface

Vascular Plants of the Truelove Inlet Region, Devon Island

Ninety-three species of vascular plants are recorded from a 16 sq. mile coastal lowland on the northern coast of Devon Island, Northwest Territories. The following taxa are apparently new records for Devon Island: Cystopteris fragilis, Woodsia alpina, Equisetum variegatum, Poa alpigena, Carex amblyorhyncha, Draba oblongata, Saxifraga tenuis, Epilobium arcticum, Hippuris vulgaris, Pedicularis lanata, Puccinellia vaginata var. paradoxa. These additions bring the total known flora of Devon Island to 115 species. The Truelove flora is part of the High Arctic biogeographic element of the Canadian Arctic Archipelago. However, a distinct element of species of more southerly distribution is present probably due to the moderating influence of the lowland environment

V3885 Sagittarius: a Comparison with a Range of Standard Model Accretion Disks

A $\widetilde{\chi}^2$ analysis of standard model accretion disk synthetic spectrum fits to combined $FUSE$ and STIS spectra of V3885 Sagittarius, on an absolute flux basis, selects a model that accurately represents the observed SED. Calculation of the synthetic spectrum requires the following system parameters. The cataclysmic variable secondary star period-mass relation calibrated by Knigge in 2007 sets the secondary component mass. A mean white dwarf (WD) mass from the same study, that is consistent with an observationally-determined mass ratio, sets the adopted WD mass of $0.7M_{\odot}$, and the WD radius follows from standard theoretical models. The adopted inclination, i=65{\arcdeg}, is a literature consensus, and is subsequently supported by $\widetilde{\chi}^2$ analysis. The mass transfer rate is the remaining parameter to set the accretion disk $T_{\rm eff}$ profile, and the $Hipparcos$ parallax constrains that parameter to $\dot{M}=5.0{\pm}2.0{\times}10^{-9} M_{\odot} {\rm yr}^{-1}$ by a comparison with observed spectra. The fit to the observed spectra adopts the contribution of a $57,000{\pm}5000$K WD. The model thus provides realistic constraints on $\dot{M}$ and $T_{\rm eff}$ for a large $\dot{M}$ system above the period gap.Comment: 41 pages, 7 figures, 9 tables. Astrophysical Journal (accepted

Devon Island Programs, 1968

Four field parties, studying glaciology, botany and ornithology, used the Arctic Institute's facilities on Devon Island during the summer of 1968. The botanical and ornithological studies were carried out from the Base Camp near Cape Sparbo, while the glaciological work was pursued from field camps on the ice cap and the Sverdrup Glacier. ..

Far Ultraviolet Spectroscopic Explorer Spectroscopy of the Nova-like BB Doradus

We present an analysis of the Far Ultraviolet Spectroscopic Explorer ({\it{FUSE}}) spectra of the little-known southern nova-like BB Doradus. The spectrum was obtained as part of our Cycle 8 {\it FUSE} survey of high declination nova-like stars. The FUSE spectrum of BB Dor, observed in a high state, is modeled with an accretion disk with a very low inclination (possibly lower than 10deg). Assuming an average WD mass of 0.8 solar leads to a mass accretion rate of 1.E-9 Solar mass/year and a distance of the order of 650 pc, consistent with the extremely low galactic reddening in its direction. The spectrum presents some broad and deep silicon and sulfur absorption lines, indicating that these elements are over-abundant by 3 and 20 times solar, respectively

Perspectives of distance learning : a study of administrators instructors and students of the public college system of Newfoundland and Labrador

The purpose of this study was to examine the direction of distance learning in the public college system of Newfoundland and Labrador as perceived by administrators, instructors, and students. -- Data were collected using three methods: (a) interviews, (b) student survey, and (c) Delphi panel. Interviews were conducted with ten persons who had some special knowledge about the direction of distance in the public college system. A random sample of 282 students was selected from the distance learning population of 955 for the 1995-96 academic year. Of these 228 students were surveyed, for a response rate of approximately 81%. The survey presented an opportunity for students to voice their opinions and provide feedback concerning distance learning courses in the public college system. In the Delphi process, a sample of 14 campus administrators was administered a structured questionnaire in two rounds, with results from the first round being used to help achieve convergence in perceptions of the future directions in distance learning. -- The data indicated that administrators, instructors, and students all concurred that distance learning has a place in the public college system. However, with distance learning in the early stages, it is not at all clear what directions this will take in the future. Administrators and instructors were cautious in their views about distance learning. The student survey indicated that students would avail of courses offered through distance learning. However, students indicated very strongly that the college should offer only some courses through distance. The Delphi panel members echoed the views of the administrators and instructors. A cautionary approach of building one block at a time is required. -- The recommendations reflect the research findings about distance learning in the public college system. These recommendations include: (a) continue to provide accessibility to distance courses throughout the scattered campuses across the province but at a moderate pace; since both technological change and the cost-effectiveness question were in a transitional phase, (b) monitor and review technological advancements to determine the need to merge with existing college technology; implementing a combination of methods for distance courses provides students with a choice, (c) further study on the cost-effectiveness of distance learning; the actual cost-effectiveness of distance learning requires study relative to the traditional approach and other methods, (d) monitoring of distance courses to determine the needs of students and employers; the college should contact employers to determine the assistance that can be provided - offering courses requested by employers and students sets the stage for increased participation rates, and (e) provide an enhanced communication system between instructors and students; this system should include direct phone numbers, e-mail, fax, and an on-line help service via the world wide web

Devon Island Programs, 1967

The Arctic Institute's facilities on Devon Island were again used during the summer of 1967 by field parties studying glaciology, glacio-isostatic geomorphology, periglacial geomorphology, ornithology, and botany. In addition, an expedition photographer recorded the summer's activities with still photographs and on 16 mm. colour film. Field camps were established at various locations and the studies were pursued from these as well as from the Base Camp close to Cape Sparbo. ..