Hanson R.,McMaster University |
Ziada S.,Technological and Nuclear Institute of Portugal |
Journal of Fluids and Structures | Year: 2011
The effect of acoustic resonance on the dynamic lift force acting on the central tube in square and normal triangle tube arrays is investigated experimentally. For each array pattern three different tube spacing ratios, corresponding to small, intermediate and large spacing ratios, are tested. The resonant sound field in the tube array is found to cause two main effects. First, it generates a "sound-induced" dynamic lift due to the resonant acoustic pressure distribution on the surface of the tube, and secondly, it synchronizes vorticity shedding from the tubes and thereby enhances the hydrodynamic lift force due to vortex shedding. The combined effect of these two unsteady lift forces depends on the phase shift between them, which is dictated by the frequency ratio of the acoustic mode to the natural vortex shedding frequencies. When the flow velocity is increased during the coincidence resonance range, the phase shift increases rapidly and therefore the effects of the two lift components change from reinforcing to counteracting each other. For the pre-coincidence lock-on range, the frequency ratio remains larger than unity and the two lift components always reinforce each other. Numerical simulations are also performed to compute the sound-induced lift force, and sound-enhancement coefficients are developed to estimate the effect of sound on the vortex shedding forces. The simulation and experimental results are implemented in a simplified design guide, which can be used to evaluate the dynamic lift forces acting on the tubes during acoustic resonances. © 2011 Elsevier Ltd.
Academic Psychiatry | Year: 2013
Objective: This article provides a brief overview of the history of psychiatry residency training in Canada, and outlines the rationale for the current training requirements, changes to the final certification examination, and factors influencing future trends in psychiatry education and training. Method: The author compiled findings and reports on residency education in Canada from current and historical sources. Results: Residency training in psychiatry in Canada has undergone significant change in the past 5 years, moving from an "apprenticeship" model to a competency-based curriculum with explicit expectations for the acquisition of key, defined competencies. Conclusion: Continuous evaluation of teaching methodologies, increasing use of innovative and creative medical education techniques, flexible curricula, and increasingly rigorous standards of accreditation are some of the factors likely to continue to shape the future. Copyright © 2013 Academic Psychiatry.
Karp D.D.,University of Houston |
Lee S.J.,Dana-Farber Cancer Institute |
Keller S.M.,Montefiore Medical Center |
Wright G.S.,Florida Cancer Specialists |
And 15 more authors.
Journal of Clinical Oncology | Year: 2013
Purpose Selenium has been reported to have chemopreventive benefits in lung cancer. We conducted a double-blind, placebo-controlled trial to evaluate the incidence of second primary tumors (SPTs) in patients with resected non-small-cell lung cancer (NSCLC) receiving selenium supplementation. Patients and Methods Patients with completely resected stage I NSCLC were randomly assigned to take selenized yeast 200
Fakhr A.,McMaster University |
Haddara Y.M.,McMaster University |
Nanotechnology | Year: 2010
InGaP nanowires (NWs) were grown by the Au-assisted method in a gas source molecular beam epitaxy system. The dependence of InGaP composition, morphology and stacking fault density was studied with respect to groupIII andV impingement rate and size of the Au particle. Compositional analysis showed that the NWs had an In-rich core and a Ga-rich shell structure. The In incorporation within the NW became limited as the Au seed particle size diminished or the groupIII andV flux decreased. The NWs had wurtzite (WZ) crystal structure with zinc blende (ZB) segments (stacking faults). The density of the stacking faults decreased as the groupIII flux decreased and the groupV flux increased. © 2010 IOP Publishing Ltd.
Jarvis V.,sterUniversity |
Jarvis V.,McMaster University |
Britten J.F.,sterUniversity |
Britten J.F.,McMaster University |
Lapierre R.R.,McMaster University
Semiconductor Science and Technology | Year: 2011
The technique of texture analysis by x-ray diffraction is demonstrated for GaAs nanowires grown by the vapor-liquid-solid process in a gas source molecular beam epitaxy system. This technique allows simultaneous and facile determination of nanowire growth direction and crystal structure over large sample areas and with improved statistics relative to scanning electron microscopy. © 2011 IOP Publishing Ltd Printed in the UK & the USA.