A study of the performance of diamond wire in hard natural stone

Includes bibliographical references.Diamond wire has been developed as a flexible cutting tool and is used by the natural stone industry for the quarrying of blocks and for subsequent squaring, slabbing and shaping operations in the stone yard. The performance of diamond wire depends on how its beads wear and the optimum life is achieved when the diamond particles are consumed in a desired manner from the periphery of each bead. This thesis covers diamond related aspects which influence the performance of diamond wire. An investigation is made of the wear of diamond particles in the bead matrix and a comparison is made with diamond particle wear found in other diamond tools. Bead matrix wear progressions are described, pertaining to diamond wire sawing operating conditions. An equation of chip thickness in relation to the cutting action of a diamond segment is derived and chip thicknesses are determined for wire sawing operating parameters used in different stone types. The sawability and abrasivity properties of stone are evaluated and are compared with corresponding results of diamond wire life. Formulae are derived for the approximation of the length of cut and area sawn in quarrying and stationary wire sawing applications and for the forces acting on a bead over a constant cutting radius. A method of testing single diamond beads is used for comparative assessments of different diamond grades and the effects of applied load, cutting velocity and cutting rate are examined in relation to bead wear. High speed video imaging is used to analyse the dynamics of diamond wire in operation and the problems associated with uneven bead wear

Making asset investment decisions for wastewater systems that include sustainability

Effective integrated water management is a key component of the World Water Vision and the way in which aspirations for water equity may be realized. Part of the vision includes the promotion of sustainability of water systems and full accountability for their interaction with other urban systems. One major problem is that “sustainability” remains an elusive concept, although those involved with the provision of urban wastewater systems now recognize that decisions involving asset investment should use the “triple bottom line” approach to society, the economy, and the environment. The Sustainable Water Industry Asset Resource Decisions project has devised a flexible and adaptable framework of decision support processes that can be used to include the principles of sustainability more effectively. Decision mapping conducted at the outset of the project has shown that only a narrow range of criteria currently influence the outcome of asset investment decisions. This paper addresses the concepts of sustainability assessment and presents two case studies that illustrate how multicriteria decision support systems can enhance the assessment of the relative sustainability of a range of options when decisions are being made about wastewater asset investment

An integrated measurement method for complex micro-scale geometries

Micro-scale geometries are becoming commonplace in many high-precision manufacturing applications. Micro-drilling processes, for example, are being employed for producing holes in demanding applications involving fluid transfer, atomisers and micro-mechanics. This paper explores the measurement and characterisation of a high aspect-ratio micro-hole (nominal diameter approximately 1000 pm, aspect-ratio 1:10), produced using abrasive waterjet in Ti6AI4V. X-ray computed tomography, contact micro-coordinate metrology and focus-variation microscopy are used for measuring the hole surfaces, and dedicated computational geometry algorithms are applied to obtain critical hole dimensions, such as radius as a function of depth. The comparison of the measurement and characterisation results obtained by means of the different solutions explored hints at new approaches for multisensor data fusion that can help reduce bias in the measurement of high aspect-ratio micro-scale features

A comparison of uterine contractile responsiveness to arginine vasopressin in oviparous and viviparous lizards

Nonapeptides and their receptors regulate a diverse range of physiological processes. We assessed the contractile responsiveness of uteri from the squamate viviparous-oviparous species pair, Pseudemoia entrecasteauxii and Lampropholis guichenoti, as well as the bimodally reproductive species, Saiphos equalis, to arginine vasopressin (AVP). We assessed the resulting uterine contractility as a function of pregnancy status, species and parity mode. We also measured mRNA abundance for the nonapeptide receptor, oxytocin receptor (oxtr), in uteri from P. entrecasteauxii and L. guichenoti and compared expression across pregnancy status and parity mode. We found that pregnant uteri exhibited a significantly greater contractile response to AVP than non-pregnant uteri in all three lizard species studied. Cross-species comparisons revealed that uteri from viviparous P. entrecasteauxii were significantly more responsive to AVP than uteri from oviparous L. guichenoti during both pregnant and non-pregnant states. Conversely, for non-pregnant S. equalis, uteri from viviparous individuals were significantly less responsive to AVP than uteri from oviparous individuals, while during pregnancy, there was no difference in AVP contractile responsiveness. There was no difference in expression of oxtr between L. guichenoti and P. entrecasteauxii, or between pregnant and non-pregnant individuals within each species. We found no significant correlation between oxtr expression and AVP contractile responsiveness. These findings indicate that there are differences in nonapeptide signalling across parity mode and suggest that in these lizards, labour may be triggered either by an increase in plasma nonapeptide concentration, or by an increase in expression of a different nonapeptide receptor from the vasopressin-like receptor family

On the anisotropy in the dry-sliding behaviour of a self-lubricating PTFE composite and the effects from surface texturing

In self-lubricating sliding contact facilitated with polytetrafluoroethylene (PTFE) composites, the anisotropy in tribological performance was often attributed to the oriented structures of the polymer. However, in this research, it is found that the non-homogeneity introduced by the hard fibres or stiffeners may be the main contributor to the anisotropic tribological performance of the polymeric composites. The interaction between the non-uniformly arranged hard fibres/stiffeners and the metallic counterface was found to be the leading phenomenon of this tribological behaviour. Moreover, the effects from a surface texturing scheme was found capable of establishing intervention to this interaction and reducing the anisotropy. The mechanism of the texturing effects was found related with back-transfer of PTFE and trapping of wear debris

Embodied Discourses of Literacy in the Lives of Two Preservice Teachers

This study examines the emerging teacher literacy identities of Ian and A.J., two preservice teachers in a graduate teacher education program in the United States. Using a poststructural feminisms theoretical framework, the study illustrates the embodiment of literacy pedagogy discourses in relation to the literacy courses’ discourse of comprehensive literacy and the literacy biographical discourses of Ian and A.J. The results of this study indicate the need to deconstruct how the discourse of comprehensive literacy limits how we, as literacy teacher educators, position, hear and respond to our preservice teachers and suggests the need for differentiation in our teacher education literacy courses

Towards the coordinated and fit-for-purpose deployment of Unmanned Aerial Systems (UASs) for flood risk management in England

Preparedness for flood emergency response is crucial for effective flood management. The need for advanced flood decision support tools that aid flood management has been recognized by several authors. This work examines the variability that currently exists across England with regard to the Unmanned Aerial System (UAS) data collection and processing strategy in flood emergency events. Expert elicitation was carried out using a tailored questionnaire about UAS deployment in three flood emergency scenarios. The survey highlighted that reduced equipment assembly time, a national network of appropriately qualified UAS pilots and the effective UAS deployment when on-site, can reduce the response time to flood emergency. For improved comparability and reduced bias in data collection and interpretation, clear guidelines on which data products are most beneficial for particular purposes, processing time required, platform and sensor selection may also be necessary. We consider that releasing a comprehensive documentation pack, which includes guidelines, standards and protocols that detail the methods, tools, technology, quantity and quality of data, to UAS pilots on a flood emergency call, will enhance the timely response

Multi-province epidemiological research using administrative data in Canada: Challenges and opportunities

Introduction Canada has a publicly-funded universal health care system with information systems managed by 13 provinces and territories. This context creates inconsistencies in data collection and challenges for epidemiological research conducted at the national or multi-jurisdictional level. Objectives and Approach Using a recent five-province research project as a case study (BC, AB, MB, ON, QC), we will discuss the strengths and challenges of using Canadian administrative health data in a multi-jurisdictional context. Our goal is to contribute to a better understanding of these challenges and the development of a more integrated and harmonized approach to conducting multi-jurisdictional research. Results Multi-jurisdictional data work is feasible but requires detailed coordination and extensive cooperation from all involved. There were noteable variations across provinces in this multi-province study. For example, time required to access the data varied greatly across the five provinces (from 4 to 9 months), and thus there were sequencing challenges, with some provinces being well into the analysis stage while others were still waiting for data. Access to human resources varied across provinces and in some cases led to delays in data abstraction. Cost of data (or analytic support) also varied across provinces, from $12,000 –$15,000. Critical to the success of the project was a coordinating group with expertise in both administrative health data and cross-provincial project coordination. Conclusion/Implications This project demonstrated the value of comparable data infrastructure with equitable access policies. Many of the disadvantages to multi-province projects using health care administrative data, such as potential coding errors and inconsistencies, can be managed by developing national standards and protocols, and tools that are shared for data cleaning and validation

Seahorse brood pouch morphology and control of male parturition in Hippocampus abdominalis

Introduction Syngnathids (seahorses, pipefishes and seadragons) are among the few vertebrates that display male pregnancy. During seahorse pregnancy, males incubate developing embryos embedded in a placenta within a fleshy brood pouch, before expelling fully developed neonates at parturition. The mechanisms underpinning seahorse parturition are poorly understood. Methods We examined the morphology of the brood pouch using microcomputed tomography and histological techniques, in combination with physiological assays, to examine how male pot-bellied seahorses (Hippocampus abdominalis) control labour. In female-pregnant vertebrates, nonapeptide hormones (such as vasopressin- and oxytocin-like hormones) produce contractions of gestational smooth muscle to produce labour. Results Histological analysis of the seahorse brood pouch reveals only scattered small smooth muscle bundles in the brood pouch, and in-vitro application of isotocin (a teleost nonapeptide hormone) to the brood pouch do not produce measurable muscle contractions. Micro-computed tomography shows differences in size and orientation of the anal fin assembly between male and female pot-bellied seahorses, and histological analysis reveals large skeletal muscle bundles attached to the anal fin bones at the male brood pouch opening. Discussion We conclude that seahorse parturition may be facilitated by contraction of these muscles, which, in combination with body movements, serves to gape open the pouch and expel the neonates. Future biomechanical studies are needed to test this hypothesis

Sexualisation, or the queer feminist provocations of Miley Cyrus

Miley Cyrus has increasingly occupied debates at the centre of feminist engagements with popular culture. Evoking concerns around young women and ‘sexualisation’, Cyrus emerges as a convergent signifier of sexualised media content and the girl-at-risk. As Cyrus is repeatedly invoked in these debates, she comes to function as the bad object of young femininity. Arguing, however, that Cyrus troubles the sexualisation thesis in the provocations of her creative practice, I suggest that this contested media figure exceeds the frames through which she is read. Thus, I ask: what kinds of insights might be possible if we were to transform the terms on which we approach this figure? Considering a selection of the images and performances that constitute the Cyrus archive, this article proposes a reading of Cyrus as performative provocation. Mobilising an existing sensibility of queer feminist struggle, Cyrus emerges as a disruptive, albeit contradictory, figure. Questions of privilege, limit and possibility emerge in this discussion, as well as what constitutes feminist struggle