Wake hydrodynamics downstream from a horizontal axis turbine under current flow and waves

Due to concerns over the potential impacts of climate change on the environment, there is a growing interest in developing renewable forms of energy. Tidal streams are a potential source of renewable energy that can be harnessed for electricity generation using tidal stream turbines. However, due to the technology being a relatively new development, with limited testing and commercial applications, the flow dynamics and environmental impact of such devices is still poorly understood.This research investigates the flow dynamics downstream from a horizontal axis tidal stream turbine device using a physical modelling experiment in the Total Environment Simulator laboratory flume, using a channel which measured 11m long, 1.6m wide and 0.6m deep. Detailed flow measurements were collected using a two-camera submersible Particle Image Velocimetry (PIV) system to quantify the three-dimensional flow velocities and turbulence downstream from the model tidal turbine device. A wide range of rotor positions and flow conditions were tested, including current flow and combined wave-current flows. The data collected will be used to validate numerical models developed by project partners, which will assist with developing full-scale operational tidal stream turbines.The presence of the tidal stream turbine within the channel had a significant impact on the flow downstream. A significant velocity deficit was observed in the wake of the turbine. This was particularly skewed, owing to the turbine rotation, to the right hand side of the centreline, where the deficit was greater than the left hand side. Subjecting the turbine to wave-current flow reduced this deficit considerably, with the shortest wake length occurring under the troughs of waves. Positioning the turbine closer to the bed resulted in a substantial increase in shear stress, with vertical and horizontal asymmetry observed in the wake of the turbine and horizontal asymmetry observed in the resulting scour below the turbine.The work outlines the impact of these variables on seafloor scour and integrity, and highlights and discusses the optimisation of turbine efficiency with minimal wake and seafloor scour impacts

Les travailleurs au sein de la Nouvelle Chanson Chilienne: la représentation du mineur et l’incarnation du travail musical

The article begins by considering the New Chilean Song movement, which has traditionally been conceptualized through the connection that its musicians established with Salvador Allende and the Popular Unity Coallition's 'government of the workers.' "Popular subjects" pervaded the movement's repertory, particularly the figure of the miner, who was considered to be the revolutionary proletarian par excellence. The article then discusses how music groups embodied musical labour by promoting the redistribution of roles, multi-instrumentalism and collective creation. Finally, it explores how these musicians, who attempted to include "the people" in their creation, discursively developed a 'double rapport' between musicians and workers.L'article s'intéresse d'abord à la valeur accordée à la Nouvelle Chanson Chilienne, laquelle réside habituellement dans le lien que ses musiciens établirent avec le « gouvernement des travailleurs » de Salvador Allende et l'Unité Populaire. Dans leur répertoire, les représentations des « sujets populaires » sont nombreuses, particulièrement celles du mineur, prolétaire révolutionnaire par excellence. Il discute ensuite l'incarnation du travail musical par les ensembles qui promurent la redistribution des rôles, le multi-instrumentisme et la création collective. Enfin, il met de l'avant la conceptualisation d'un « double rapport » entre musiciens et travailleurs qui émerge à partir des discours des musiciens qui cherchèrent à inclure « le peuple » dans la création

CO2 reduction with protons and electrons at a boron-based reaction center.

Borohydrides are widely used reducing agents in chemical synthesis and have emerging energy applications as hydrogen storage materials and reagents for the reduction of CO2. Unfortunately, the high energy cost associated with the multistep preparation of borohydrides starting from alkali metals precludes large scale implementation of these latter uses. One potential solution to this issue is the direct synthesis of borohydrides from the protonation of reduced boron compounds. We herein report reactions of the redox series [Au(B2P2)] n (n = +1, 0, -1) (B2P2, 9,10-bis(2-(diisopropylphosphino)phenyl)-9,10-dihydroboranthrene) and their conversion into corresponding mono- and diborohydride complexes. Crucially, the monoborohydride can be accessed via protonation of [Au(B2P2)]-, a masked borane dianion equivalent accessible at relatively mild potentials (-2.05 V vs. Fc/Fc+). This species reduces CO2 to produce the corresponding formate complex. Cleavage of the formate complex can be achieved by reduction (ca. -1.7 V vs. Fc/Fc+) or by the addition of electrophiles including H+. Additionally, direct reaction of [Au(B2P2)]- with CO2 results in reductive disproportion to release CO and generate a carbonate complex. Together, these reactions constitute a synthetic cycle for CO2 reduction at a boron-based reaction center that proceeds through a B-H unit generated via protonation of a reduced borane with weak organic acids

La musique des Chiliens exilés à Montréal pendant la dictature (1973-1989) : la création de musiques de la résistance politique et la réception des auditeurs dans l’exil

La version intégrale de ce mémoire est disponible uniquement pour consultation individuelle à la Bibliothèque de musique de l’Université de Montréal (http://www.bib.umontreal.ca/MU).Cette étude musicologique aborde la musique pratiquée et écoutée par les Chiliens exilés à Montréal pendant la dictature (1973-1989), se concentrant sur l’histoire de la musique du point de vue des auditeurs. Quelles musiques participent à l’expérience d’exil et quel rôle accomplissent-elles? Comment les musiques accompagnent-elles le processus d’adaptation au pays d’accueil et comment aident-elles à construire un lien avec le pays d’origine? Ce sont quelques unes des questions qui ont guidé le développement de la recherche, dont la méthodologie est mixte et se concentre sur l’entrevue. Trois dimensions de l’histoire musicale y sont examinées. Premièrement, la contribution de la pratique musicale au mouvement de solidarité envers le peuple du Chili, notamment à travers la formation d’ensembles musicaux et l’organisation des peñas et des concerts. Deuxièmement, le rôle des musiques dans la construction d’une communauté culturelle chilienne, où différents discours sur l’identité nationale et politique sont négociés. Troisièmement, la présence des musiques dans les expériences individuelles d’exil, de déracinement et d’adaptation. Les genres de musique populaire les plus présents, soit la Nueva Canción Chilena et la Proyección Folclórica, ainsi que leurs enjeux des significations identitaires et politiques, font partie de la problématique du présent texte. La cueca, considérée la danse nationale, occupe aussi une place privilégiée de la discussion, due à la place importante qu'elle occupe dans la communauté chilienne de Montréal.This musicological study examines the music created, performed and listened to by Chilean exiles in Montreal during the 1973-1989 dictatorship, focusing mainly on the history of music, as told from the perspective of the listeners. The main questions guiding the research process – which took on a varied methodological approach consisting primarily of interviews – were based on the types of music that participated in their experience of exile and the role it accomplished, as well as how this music contributed to the adaptation to their host country and helped to maintain a link with their country of origin. The first of the three historical dimensions that are examined in the study is the contribution of music in solidarity movements with the people of Chile, especially, via the formation of musical ensembles and the organizing of peñas and concerts. Secondly, the ways in which the role of music in the construction of a Chilean cultural community interacted with different discourses on politics and national identity, furthermore, with the individual experiences of exile, uprooting, and adaptation as the third dimension. The most present popular music genres, the Nueva Canción Chilena and Proyección Folclórica, as well as their significance in identity and politics, are integral parts of the text’s main issues. The cueca, considered the Chilean national dance, will also be given considerable attention throughout the discussion, due to its vast importance in the Chilean community of Montreal

Assessment worlds colliding? Negotiating between discourses of assessment on an online open course

Using the badged open course, Taking your first steps into Higher Education, this case study examines how assessment on online open courses draws on concepts of assessment used within formal and informal learning. Our experience was that assessment used within open courses, such as massive open online courses, is primarily determined by the requirements of quality assurance processes to award a digital badge or statement of participation as well as what is technologically possible. However, this disregards much recent work in universities that use assessment in support of learning. We suggest that designers of online open courses should pay greater attention to the relationship of assessment and learning to improve participant course completion

Arts Alive!: 2001-2002 Project Report

Embracing HAI's mission of Hope and Inspiration through the Arts, Arts Alive! targeted New York City youths from schools and districts most affected by the September 11th attacks. Between January and June 2002, Arts Alive! arranged for more than 10,500 New York City schoolchildren to attend cultural events with classmates, parents and teachers. Arts Alive! engaged children who had lost a family member, children from schools with a direct view of the WTC, children from schools in lower Manhattan forced to relocate, children in schools that absorbed relocated students, and children from schools in the lower Manhattan and New Jersey areas

A spatially distributed model for the dynamic prediction of sediment erosion and transport in mountainous forested watersheds

Erosion and sediment transport in a temperate forested watershed are predicted with a new sediment model that represents the main sources of sediment generation in forested environments (mass wasting, hillslope erosion, and road surface erosion) within the distributed hydrology-soil-vegetation model (DHSVM) environment. The model produces slope failures on the basis of a factor-of-safety analysis with the infinite slope model through use of stochastically generated soil and vegetation parameters. Failed material is routed downslope with a rule-based scheme that determines sediment delivery to streams. Sediment from hillslopes and road surfaces is also transported to the channel network. A simple channel routing scheme is implemented to predict basin sediment yield. We demonstrate through an initial application of this model to the Rainy Creek catchment, a tributary of the Wenatchee River, which drains the east slopes of the Cascade Mountains, that the model produces plausible sediment yield and ratios of landsliding and surface erosion when compared to published rates for similar catchments in the Pacific Northwest. A road removal scenario and a basin-wide fire scenario are both evaluated with the model