Observations of directional gamma prime coarsening during engine operation

Two alloys with negative mismatch parameters, NASAIR 100 and a modified NASAIR 100 called Alloy 3 were run as turbine blades in an experimental ground based Garret TFE731 engine for up to 200 hr. The directional coarsening of gamma prime (rafting) that developed during engine testing was analyzed and compared to previous research from laboratory tests. The blades were found to be rafted normal to the centrifugal stress axis over much of the span, but near the surfaces, the blades were found to be rafted parallel to the centrifugal stress axis for certain cycles. Representative photomicrographs of the blades and the effects of stress and temperature on raft formation are shown

Energy potential of a tidal fence deployed near a coastal headland

Enhanced tidal streams close to coastal headlands appear to present ideal locations for the deployment of tidal energy devices. In this paper, the power potential of tidal streams near an idealized coastal headland with a sloping seabed is investigated using a near-field approximation to represent a tidal fence, i.e. a row of tidal devices, in a two-dimensional depth-averaged numerical model. Simulations indicate that the power extracted by the tidal fence is limited because the flow will bypass the fence, predominantly on the ocean side, as the thrust applied by the devices increases. For the dynamic conditions, fence placements and headland aspect ratios considered, the maximum power extracted at the fence is not related in any obvious way to the local undisturbed kinetic flux or the natural rate of energy dissipation due to bed friction (although both of these have been used in the past to predict the amount of power that may be extracted). The available power (equal to the extracted power net of vertical mixing losses in the immediate wake of devices) is optimized for devices with large area and small centre-to-centre spacing within the fence. The influence of energy extraction on the natural flow field is assessed relative to changes in the M2 component of elevation and velocity, and residual bed shear stress and tidal dispersion

Modelling tidal energy extraction in a depth-averaged coastal domain

An extension of actuator disc theory is used to describe the properties of a tidal energy device, or row of tidal energy devices, within a depth-averaged numerical model. This approach allows a direct link to be made between an actual tidal device and its equivalent momentum sink in a depth-averaged domain. Extended actuator disc theory also leads to a measure of efficiency for an energy device in a tidal stream of finite Froude number, where efficiency is defined as the ratio of power extracted by one or more tidal devices to the total power removed from the tidal stream. To demonstrate the use of actuator disc theory in a depth-averaged model, tidal flow in a simple channel is approximated using the shallow water equations and the results are compared with the published analytical solutions. © 2010 © The Institution of Engineering and Technology

A People's Religion: P. W. Philpott and the Hamilton Christian Workers' Church

When P. W. Philpott left the Salvation Army and founded the Christian Workers’ Church in 1892, he was followed by many former Salvation Army adherents who, like Philpott, were dissatisfied with the Army’s hierarchical structure and its centralized management of funds. While the Christian Workers had no political or social agenda and did not foster a class consciousness, much of Philpott’s critique of the Army paralleled the language and concerns of class struggle. The Christian Workers dissociated themselves from what they portrayed as a concern for social propriety and economic advancement that had distanced the “denominational” churches from the working people. The lack of a political agenda could be interpreted as a failure of the Christian Workers to respond to the social realities of the early twentieth century, especially in rapidly industrializing Hamilton, where Philpott was pastor for over 20 years. However, the discourse and practices of the Christian Workers provided what Michel Foucault has called “technologies of the self” that could be employed individually by men and women to make sense of their lives and thereby transform themselves and their condition.Quand P. W. Philpott quitta l’Armée du Salut pour aller fonder l’Église des travailleurs chrétiens en 1892, le suivirent de nombreux anciens adhérents de l’Armée du Salut qui, comme lui, étaient insatisfaits de la structure hiérarchique de l’Armée et de sa gestion centralisée des fonds. Tandis que les Travailleurs chrétiens n’avaient pas de programme politique ou social et ne prônaient pas de conscience de classe, une bonne partie de la critique que faisait Philpott de l’Armée trouvait écho dans le langage et les préoccupations de la lutte des classes. Les Travailleurs chrétiens se dissocièrent de ce qu’ils dépeignaient comme le souci de la propriété sociale et de l’avancement économique qui avait éloigné les églises « confessionnelles » des travailleurs. L’absence de programme politique pourrait être interprétée comme un échec de la part des Travailleurs chrétiens à réagir aux réalités sociales du début du XXe siècle, surtout dans la ville en industrialisation rapide de Hamilton, où Philpott fut pasteur pendant 20 ans. Cependant, le discours et les pratiques des Travailleurs chrétiens fournissaient ce que Michel Foucault qualifiait de « technologies du soi », que les hommes et les femmes pouvaient utiliser individuellement pour tenter de comprendre leur vie et, par le fait même, se transformer eux-mêmes et changer leur condition