Identification of the principal elements governing the wettability characteristics of ordinary Portland cement following high power diode laser surface treatment

The elements governing modifications to the wettability characteristics of ordinary Portland cement (OPC) following high power diode laser (HPDL) surface treatment have been identified. Changes in the contact angle, , and hence the wettability characteristics of the OPC after HPDL treatment were attributed to: reductions in the surface roughness of the OPC; the increase in the surface O2 content of the ceramic and the increase in the polar component of the surface energy, . What is more, the degree of influence exerted by each element has been qualitatively ascertained and was found to differ markedly. Surface energy, by way of microstructural changes, was found to be by far the most predominant element governing the wetting characteristics of the OPC. To a much lesser extent, surface O2 content, by way of process gas, was also seen to influence to a changes in the wettability characteristics of the OPC, whilst surface roughness was found to play a minor role in inducing changes in the wettability characteristics

The influence of a high power diode laser (HPDL) generated glaze on the wetting characteristics and the subsequent HPDL enamelling of ordinary Portland cement

High power diode laser (HPDL) surface glazing of the ordinary Portland cement (OPC) surface of concrete was found to effect significant changes in the wettability characteristics of the OPC. This behaviour was identified as being primarily due to: (i) the polar component of the OPC surface energy increasing after HPDL glazing from 3.46 to 15.56 mJm-2, (ii) the surface roughness of the OPC decreasing from an Ra value of 21.91 to 2.88 m after HPDL glazing and (iii) the relative surface O2 content of the OPC increasing by 4.5at% after HPDL glazing. HPDL glazing was consequently identified as occasioning a decrease in the enamel contact angle from an initial value of 1090 to 310, thus allowing the vitreous enamel to wet the OPC surface

Surface glazing of concrete using a 2.5 kW high power diode laser and the effects of large beam geometry

Interaction of a 2.5 kW high power diode laser (HPDL) beam with the ordinary Portland cement (OPC) surface of concrete has been investigated, resulting in the generation of a tough, inexpensive amorphous glaze. Life assessment testing revealed that the OPC glaze had an increase in wear life of 1.3 to 14.8 times over an untreated OPC surface, depending upon the corrosive environment. Also, variations in the width of the HPDL beam were seen to have a considerable affect on the melt depth. Furthermore, the maximum coverage rate that it may be possible to achieve using the HPDL was calculated as being 1.94 m2/h. It is a distinct possibility that the economic and material benefits to be gained from the deployment of such an effective and efficient large area coating on OPC could be significant

Spectral methods for the wave equation in second-order form

Current spectral simulations of Einstein's equations require writing the equations in first-order form, potentially introducing instabilities and inefficiencies. We present a new penalty method for pseudo-spectral evolutions of second order in space wave equations. The penalties are constructed as functions of Legendre polynomials and are added to the equations of motion everywhere, not only on the boundaries. Using energy methods, we prove semi-discrete stability of the new method for the scalar wave equation in flat space and show how it can be applied to the scalar wave on a curved background. Numerical results demonstrating stability and convergence for multi-domain second-order scalar wave evolutions are also presented. This work provides a foundation for treating Einstein's equations directly in second-order form by spectral methods.Comment: 16 pages, 5 figure

Reframing e-assessment: building professional nursing and academic attributes in a first year nursing course

This paper documents the relationships between pedagogy and e-assessment in two nursing courses offered at the University of Southern Queensland, Australia. The courses are designed to build the academic, numeracy and technological attributes student nurses need if they are to succeed at university and in the nursing profession. The paper first outlines the management systems supporting the two courses and how they intersect with the e-learning and e-assessment components of course design. These pedagogical choices are then reviewed. While there are lessons to be learnt and improvements to be made, preliminary results suggest students and staff are extremely supportive of the courses. The e-assessment is very positively received with students reporting increased confidence and competency in numeracy, as well as IT, academic, research and communication skills

A portable high power diode laser-based single-stage ceramic tile grout sealing system

By means of a 60 W high power diode laser (HPDL) and a specially developed grout material the void between adjoining ceramic tiles has been successfully sealed. A single-stage process has been developed which uses a crushed ceramic tile mix to act as a tough, inexpensive bulk substrate and a glazed enamel surface to provide an impervious surface glaze. The single-stage ceramic tile grout sealing process yielded seals produced in normal atmospheric conditions that displayed no discernible cracks and porosities. The single-stage grout is simple to formulate and easy to apply. Tiles were successfully sealed with power densities as low as 200 kW/mm2 and at rates of up to 600 mm/min. Bonding of the enamel to the crushed ceramic tile mix was identified as being primarily due to van der Waals forces and, on a very small scale, some of the crushed ceramic tile mix material dissolving into the glaze. In terms of mechanical, physical and chemical characteristics, the single-stage ceramic tile grout was found to be far superior to the conventional epoxy tile grout and, in many instances, matched and occasionally surpassed that of the ceramic tiles themselves. What is more, the development of a hand-held HPDL beam delivery unit and the related procedures necessary to lead to the commercialisation of the single-stage ceramic tile grout sealing process are presented. Further, an appraisal of the potential hazards associated with the use of the HPDL in an industrial environment and the solutions implemented to ensure that the system complies with the relevant safety standards are given

The languages of belief : nineteenth-century religious discourse in Southwest Donegal

This short narrative was one of hundreds of legends gathered in the 1930s and 1940s from men and women then in their seventies and eighties living in southwest Donegal. Many of the stories related individual and social dramas with religious themes and actors - saints, holy wells, and powerful priests. All such figures or places displayed power, by punishing of enemies, as in the preceding case, or by rewarding the believer with a cure. Gathered by a native-born folklorist and now stores in the National Folklore Archive, this corpus of texts constitutes and rare and potentially fertile resource for a historical ethnography of the region in the late nineteenth century

“Man the fisher”: salmon fishing and the expression of community in a rural Irish settlement

This paper analyzes the significance of the summer salmon fishery of Teelin, a small coastal settlement in county Donegal, Ireland. Although not of great economic importance to most Teelin families, the salmon pursuit is the subject of considerable cultural attention, providing a source of communal and personal identity. An explanation for the disproportionate cultural strength of the fishery is sought in its contribution to the maintenance of the local community as a bounded social entity in a region where historical disincorporations have made the existence and nature of such communities problematic. The ways in which the interactional and experiential aspects of this fishery contribute to Teelin’s “local culture” are examined as a sample case of the relation between any such socially definitive activity and the structure of a local system of social relations or ideology

Stories of Power, Powerful Stories: The Drunken Priest in Donegal

This story is one of twenty-three “priest stories” collected in one notebook by folklorist Sean Ó’hEochaidh from his natal community of Teelin in Donegal, Ireland. The notebook containing these Gaelic tales is dated 1945, but there are also dozens of other priest stories scattered through the more than seventy volumes of oral lore recorded by Ó’hEochaidh in his nearly half century (beginning in the early 1930s) of folklore collecting in the area. The stories relate the exploits of local curates and parish priests – many of them named – in the late nineteenth and early twentieth centuries. The narratives fall very neatly into two categories. In one, priests whom I will call “heroic”, battle the evil forces of the Protestant ascendancy in their local incarnations: landlords, agents, bailiffs, Protestant farmers and the rare Catholic collaborator (see Lawrence Taylor 1985). Such clerics are typically armed with the paraphernalia of the church, such as the priest who dons his stole and recites from his book in order to bring a Protestant up from Hell as an object lesson to his unregenerate family. The other category, which includes the story related above, features clerics who “have a taste for the wee drop” or, to translate the Irish euphemism, “drunken priests”. These protagonists perform their magic, whether to help or harm, usually unaided by anything but their inherent charisma

The Merchant in Peripheral Ireland: A Case from Donegal

The place of the local merchant or shopkeeper in rural Ireland is a point of some contention among the ethnographers of that island (1). Arensberg and Kimball describe the credit-debt relation of shopkeeper and countryman as an “extension of the sentiments surrounding the reciprocal familial relations” (Arensberg and Kimball 1968:395). Although dealing in money, the local shopkeeper is thus depicted as operating within the idiom and values of “traditional” social relations. Differences of income and cultural orientation seem not to separate the shopkeeper from his clientele, with whom he may be anxious to establish affinal relations. This sort of merchant is as dependent on his customer as they are on him, so that the relationship naturally follows the same egalitarian rules operating between small farmers. Peter Gibbon (1973), on the other hand, notes that rural shopkeepers in the west of Ireland are, and have long been, “gombeenmen”: usurious exploiters of a dependent peasantry. This essay presents a description and analysis of the historical emergence of a particular group of rural merchants in western Ireland, but is further aimed as explaining the apparent discrepancy in described merchant-peasant relations with a model applicable to other, structurally similar, cases elsewhere