810 research outputs found
Serviceability response of a bench-mark cable-stayed footbridge: comparison of available methods
In previous Footbridge Conferences, the focus of researchers has been on the representation of pedestrian actions (vertical and lateral) to design footbridges, on the proposal of methodologies for the analysis in service of these structures and on the description of the serviceability response of particular footbridges. Nonetheless, none of these research works have been focused on the magnitude of the serviceability response of footbridges according to its structural type. This paper characterises the response of footbridges with stayed cables as main structural type. Based on a compiled dataset of cable-stayed footbridges (developed for this research work), the paper presents the geometrical and structural characteristics of a footbridge that can be regarded as representative of this structural type. Considering the best methodologies available for the assessment of its response in vertical and lateral direction, the paper describes the magnitude of the serviceability performance of this bridge under a wide range of pedestrian scenarios. This description familiarises designers at early stages of their design with the order of magnitude of the serviceability response of cable-stayed footbridges with an arrangement similar to that commonly used for this structural type
Symphony of Lights: An Exploration of the Stained Glass Windows in St. John the Evangelist Anglican Church, London, Ontario. February 9-18, 2021. Artlab Gallery
This catalogue developed out of the exhibition, Symphony of Lights: An Exploration of Stained Glass Windows in St. John the Evangelist Anglican Church, London, ON, hosted at the Artlab Gallery on the campus of The University of Western Ontario from February 8-19, 2021. The exhibition focused on the visual and aural effects of the art of St. John’s. In the exhibition, we attempted to reimagine the grandeur of St. John’s artistic features by acknowledging their religious and historical settings, but more importantly, highlighting their artistic merit through a multisensorial experience that furthers those Londoners have enjoyed for over 130 years.https://ir.lib.uwo.ca/visualartsebooks/1004/thumbnail.jp
Tailoring magnetic anisotropy in epitaxial half metallic La0.7Sr0.3MnO3 thin films
We present a detailed study on the magnetic properties, including anisotropy,
reversal fields, and magnetization reversal processes, of well characterized
half-metallic epitaxial La0.7Sr0.3MnO3 (LSMO) thin films grown onto SrTiO3
(STO) substrates with three different surface orientations, i.e. (001), (110)
and (1-18). The latter shows step edges oriented parallel to the [110]
(in-plane) crystallographic direction. Room temperature high resolution
vectorial Kerr magnetometry measurements have been performed at different
applied magnetic field directions in the whole angular range. In general, the
magnetic properties of the LSMO films can be interpreted with just the uniaxial
term with the anisotropy axis given by the film morphology, whereas the
strength of this anisotropy depends on both structure and film thickness. In
particular, LSMO films grown on nominally flat (110)-oriented STO substrates
presents a well defined uniaxial anisotropy originated from the existence of
elongated in-plane [001]-oriented structures, whereas LSMO films grown on
nominally flat (001)-oriented STO substrates show a weak uniaxial magnetic
anisotropy with the easy axis direction aligned parallel to residual substrate
step edges. Elongated structures are also found for LSMO films grown on vicinal
STO(001) substrates. These films present a well-defined uniaxial magnetic
anisotropy with the easy axis lying along the step edges and its strength
increases with the LSMO thickness. It is remarkable that this step-induced
uniaxial anisotropy has been found for LSMO films up to 120 nm thickness. Our
results are promising for engineering novel half-metallic magnetic devices that
exploit tailored magnetic anisotropy.Comment: 10 pages, 10 figures, 1 tabl
Paternity allocation in a mutant Heliothis virescens colony
Tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), females can copulate multiple times creating the possibility for sperm competition. We used a colony lacking wild pigmentation on the wings (albino-type) for an experiment in which females double mated. Females copulated 2 days apart with two, 2-day-old males, one albino-type and one wild-type, or in the opposite sequence. A third of the females produced offspring from the first mate, and this group was significantly biased toward producing albino-type compared to wild-type progeny. A fourth of the females produced offspring from the second male exclusively and within this group was a significant bias toward wild-type compared to albino-type progeny. Almost half of the females produced offspring sired in equal proportions by both males simultaneously or in alternated paternities throughout all the reproductive life. These results suggest that regardless of the order in which moths mated, wild-type sperm had potential superior competitiveness. Therefore, sperm precedence is not the main driving force behind the paternity allocation mechanism in this strain of tobacco budworm
Research achievements in under-deck and combined cable-stayed bridges
Under-deck cable-stayed bridges and combined cable-stayed bridges constitute two
innovative bridge types that have been designed and built on only a few occasions over the last thirty
years by outstanding structural engineers, such as Leonhardt, Schlaich, Menn, Virlogeux, Manterola,
and Cremer. In these bridge types, the stay cables have unconventional layouts: below the deck, in the
case of under-deck cable-stayed bridges, and above and below the deck, in the case of combined
cable-stayed bridges. Over the last few years, major research advances related to these bridge types
have been made to the point that now research dictates the development of these new bridge
typologies. In this communication, a general overview of the current state-of-art will be set out;
addressing issues related to built bridges, research developments, structural behaviour, design criteria
and potential applications for these innovative bridge types. Major attention will be paid to their
highly-efficient structural behaviour, that allows a significant reduction in the amounts of materials in
comparison with conventional bridges, leading to sustainable design. Other advantages of these
structural types, such as the numerous construction possibilities, aesthetical properties, and broad
range of potential applications, will also be stressed
Hartman-Grobman Theorems along Hyperbolic Stationary Trajectories
We extend the Hartman-Grobman theorems on discrete random dynamical systems (RDS), proved in [7], in two directions: For continuous RDS and for hyperbolic stationary trajectories. In this last case there exists a conjugacy between traveling neighbourhoods of trajectories and neighbourhoods of the origin in the corresponding tangent bundle. We present applications to deterministic dynamical systems
- …