17 resultados para Vertical pull-out failure

em Deakin Research Online - Australia


Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper draws on the findings of a recent and extensive literature review to examine the efficacy of pull-out education programs (alternative programs) in schools in relation to student learning, well-being, and pathways. It synthesises the research on alternative education programs and their contribution to student outcomes using three main conceptual categories: how sustainable these programs are their stickability; how effective these programs are in achieving their stated purpose of improving and enhancing vulnerable students’ learning, well-being, and pathways, their transformability; and how these programs may be used successfully in other locations and contexts— their transmittability. It concludes with recommendations for future practice, suggesting that school systems should prioritise prevention and early intervention in providing support to vulnerable students in ways that take account of students’ own reasons for why they are disengaged from schooling.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Research report for Department of Education and Early Childhood Development, Frankston Mornington Peninsula Youth Partnerships & Frankston Mornington Peninsula Local Learning Employment Network. The focus of this review is on programs organised for schools by providers external to the education system for students who are at risk of not completing both compulsory and the non‐compulsory years of schooling and/or who are at risk of low academic achievement. The nature of such risks faced by students and the responses of education institutions to them—and the efficacy of such programs—are also considered.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The silence around overpopulation prevents the global health community from making the necessary link between the planner's limited ability to support its people and health and development crises. The author describes how popular thinking on population control has been shaped over the last 200 years and how out failure to address the population explosion may be one cause of recent epidemics and social unrest.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper examines the perspectives of primary school teachers, administrators and personnel working in eastern suburban Melbourne as they consider the rationale for, and the purposes of, gifted education within the broader landscape of teachers' work. The data for this presentation are drawn from a single case qualitative case study where semi-structured interviews were held four years after the school participated in the Bright Futures gifted professional development. The school proudly proclaims a tradition of scholarship and excellence within a friendly, caring, cooperative and democratic ethos. Teachers welcomed the opportunity to express their thoughts, sentiments and opinions on curriculum, assessment and reporting practices, their attitudes to the aims of gifted education, the selection of children for pull-out programs, and their views to school management and to parents in relation tho these matters. Using a Foucoultian framework, I analyse how teachers juggle many goals within the complex reality of daily classroom teaching, and how they are wedged between the power of formal school rhetoric and educational policy working to improve learning outcomes for all students. This, in turn, has significant repercussions for addressing the needs of gifted students and generates considerable ambivalence about the implementation of gifted programs. I propose that such responses are important elements in the contemporary landscape of teacher's work

Relevância:

100.00% 100.00%

Publicador:

Resumo:

To compare the effectiveness of pulse-lavage brushing followed by hydrogen peroxide-gauze packing with either technique alone or normal-saline irrigation in bone-bed preparation for cemented total hip arthroplasty. 44 fresh-frozen ox femoral canals were prepared for cemented total hip arthroplasty using 4 techniques: normal-saline irrigation, pulse-lavage brushing, hydrogen peroxide-soaked gauze packing, and a combination of the latter 2 techniques. The maximum tensile pull-out force required to separate the prosthesis from the femoral canal was measured as an indicator of the strength of the cement-bone interface. The mean pull-out force to separate the prosthesis from the femoral canal was significantly higher in specimens prepared with pulse-lavage brushing followed by hydrogen peroxide-soaked gauze packing or pulse-lavage brushing alone than those prepared with normal-saline irrigation or hydrogen peroxide-soaked gauze packing alone 300(p<0.001). Pulse-lavage brushing is more effective at cleansing the femoral canal and increasing mechanical strength at the cement-bone interface than preparation with normal-saline irrigation or hydrogen peroxide-soaked gauze packing.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We determined the inter-day variability in elite-standard women's artistic gymnastics competition scores. National (50 gymnasts for up to three days) and Olympic (24 gymnasts for up to five days) competition scores published in the public domain (‘Giant poster pull-out’, 2010; Gymnastics Australia, 2008) were evaluated using three statistical measures. Analyses of the inter-day differences in the mean scores as a percentage (MDiff%), coefficient of variation percentages for the mean score across both days (CV%), and Pearson correlation coefficients for the inter-day score (r) were interpreted using thresholds from trivial to large. National-class gymnasts' two-day performance variation was trivial for vault, small for floor and beam, and moderate for bars. When senior gymnasts competed for a third day the performance variation increased to moderate for vault. Across five days of Olympic competition there were trivial (e.g. CV%: vault = 0.8) to small (e.g. CV%: bars = 2.0) variations in performances between days on all apparatus. Olympians' performance score consistency is superior to senior, national-class competitors. The performance score consistency required for gymnasts who aspire to participate at the Olympics as a top-24 competitor is better than 3%.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Abstract Novel magnetite-carbon nanofiber hybrids (denoted by Fe3O4@CNFs) have been developed by coating carbon nanofibers (CNFs) with magnetite nanoparticles in order to align CNFs in epoxy using a relatively weak magnetic field. Experimental results have shown that a weak magnetic field (∼mT) can align these newly-developed nanofiber hybrids to form a chain-like structure in the epoxy resin. Upon curing, the epoxy nanocomposites containing the aligned Fe3O4@CNFs show (i) greatly improved electrical conductivity in the alignment direction and (ii) significantly higher fracture toughness when the Fe3O4@CNFs are aligned normal to the crack surface, compared to the nanocomposites containing randomly-oriented Fe3O4@CNFs. The mechanisms underpinning the significant improvements in the fracture toughness have been identified, including interfacial debonding, pull-out, crack bridging and rupture of the Fe3O4@CNFs, and plastic void growth in the polymer matrix.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

There is an increasing demand for high performance composites with enhanced mechanical and electrical properties. Carbon nanofibres offer a promising solution but their effectiveness has been limited by difficulty in achieving directional alignment. Here we report the use of an alternating current (AC) electric field to align carbon nanofibres in an epoxy. During the cure process of an epoxy resin, carbon nanofibres (CNFs) are observed to rotate and align with the applied electric field, forming a chain-like structure. The fracture energies of the resultant epoxy nanocomposites containing different concentrations of CNFs (up to 1.6wt%) are measured using double cantilever beam specimens. The results show that the addition of 1.6wt% of aligned CNFs increases the electrical conductivity of such nanocomposites by about seven orders of magnitudes to 10<sup>-2</sup>S/m and increases the fracture energy, G<inf>Ic</inf>, by about 1600% from 134 to 2345J/m<sup>2</sup>. A modelling technique is presented to quantify this major increase in the fracture energy with aligned CNFs. The results of this research open up new opportunities to create multi-scale composites with greatly enhanced multifunctional properties.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Carbon fibre reinforced polymer (CFRP) sheet has gained its popularity to retrofit civil structures which is bonded externally, typically on the soffit of a beam. In this study, the bond between carbon fibre reinforced polymer (CFRP) and concrete is improved by modifying the property of commercial epoxy and compared against normal epoxy. The deterioration in bond strength was produced by placing the beam into salt water under wet dry cycles. Also, a model is proposed to determine the bond strength from flexural test and compared against the available bond strength models which are typically obtained from pull out test. This proposed model shows promising results in terms of predicting the bond strength from flexural test. In addition, a strength reduction factor is introduced to incorporate the effect of wet dry cycles to predict the long term behaviour. It is found that the modified epoxy enhance the ductile property and bond strength.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The present paper compares improvements to the fracture energy and electrical conductivity of epoxy nanocomposites reinforced by one-dimensional carbon nanofibres (CNFs) or two-dimensional graphene nanoplatelets (GNPs). The focus of this investigation is on the effects of the shape, orientation and concentration (i.e. 0.5, 1.0, 1.5 and 2.0 wt%) of nanoscale carbon reinforcements on the property improvements. Alignment of the nano-reinforcements in the epoxy nanocomposites was achieved through the application of an alternating current (AC) electric-field before gelation and curing of the epoxy resin. Alignment of the nano-reinforcements increased the electrical conductivity and simultaneously lowered the percolation threshold necessary to form a conductive network in the nanocomposites. Nano-reinforcement alignment also increased greatly the fracture energy of the epoxy due to a higher fraction of the nano-reinforcement participating in multiple intrinsic (e.g. interfacial debonding and void growth) and extrinsic (e.g. pull-out and bridging) toughening mechanisms. A mechanistic model is presented to quantify the contributions from the different toughening mechanisms induced by CNFs and GNPs to the large improvements in fracture toughness. The model results show that one-dimensional CNFs are more effective than GNPs at increasing the intrinsic toughness of epoxy via void growth, whereas two-dimensional GNPs are more effective than CNFs at improving the extrinsic toughness via crack bridging and pull-out.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Carbon nanotube (CNT) deposition onto carbon fibre resulting in hybrid surface structures with various morphologies were successfully carried out using electrospray technique. In terms of tensile testing and Weibull analysis this process did not degrade fibre mechanical properties. When incorporated into composites, the interfacial shear strength (IFSS), as measured by single fibre fragmentation testing, increased by up to 124%. Experimental work was carried out to develop a deeper understanding of the interfacial reinforcing mechanism. Contact angle measurements demonstrated that the CNT deposition resulted in good wettability by the resin. Significant increases in roughness, friction and surface area were also found after CNT deposition, especially for the sample prepared using the parameter of 20 kV/10 cm at 100 °C. Surface energy analysis revealed that an increase in the dispersive surface energy due to the CNTs likely contributed to the improvement of interaction between fibre and matrix. Fractographic analysis revealed that the length of fibre pull-out and the size of cracks between the fibre and matrix were markedly decreased in the hybrid CNT surface structure, indicating that the stress transfer and interfacial shear strength have been improved. Finally, the potential for further improvement in interfacial composite properties by this approach was assessed.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Much of the research that has been carried out into outsourcing is based on relatively successful case studies. Yet drawing inferences from case studies when those with largely negative outcomes rarely see the light of day represents a significant problem. When negative cases are systematically unrepresented, there is less opportunity to subject theory to scrutiny. This chapter goes some way towards redressing this trend, by reporting on a large scale “selective” outsourcing arrangement that has been publicly described as a failure — the Australian Federal Government’s “whole of government” IT infrastructure outsourcing initiative. This initiative, originally promoted as likely to lead to a billion dollar saving, was abandoned early in 2001, after a damning public report by the Australian Auditor General. However, a detailed study of the initiative suggests that the “failure” occurred despite the project adhering to many of the recommended guidelines for successful outsourcing that had been derived from earlier case analysis. The findings have important implications for decision makers confronted with outsourcing choices. The study suggests that the risks of outsourcing are often downplayed, or ignored in the rush to reap the expected benefits. The study also suggests that expectations of savings from outsourcing IT are often substantially higher than those that have been empirically confirmed in the field. Decision makers are advised that key assumptions about costs, savings, managerial effort, and the effects of outsourcing on operational performance might be incorrect, and to plan for their outsourcing activity accordingly. They should pay particular attention to coordination and transaction costs, as these tend to be overlooked in the business case. These costs will be magnified if “best in breed” multiple-vendor outsourcing is chosen, and if contracts are kept short. Decision-makers are also warned of the difficulties they are likely to have at the end of an outsourcing contract if there is not a large and robust pool of alternative vendors willing to bid against the incumbent.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This thesis is involved with changes that have occurred to small mammal populations following a major disturbance in the Anglesea region as a result of the 1983 Ash Wednesday fires. Fire, with its effects on spatial and temporal heterogeneity, was found to be an important factor in the maintenance of vegetation and small mammal community structure and diversity in the region. Successional changes in vegetation and small mammal communities were described by multivariate analyses, using data collected annually from 22 study sites. The use of factor analysis techniques, in reducing the annual capture data content, enabled long-term changes in the structure of mammal communities to be interpreted. The small mammal communities in the coastal heath and forest vegetation in the Anglesea region show evidence of a general resilience, (the degree and speed of recovery), to disturbance. Two phases of successional response to fire by mammal species have been proposed; a ‘re-establishment’ phase which occurs in the initial 5-6 years post-fire and is accompanied by rapid increase in species’ abundance, and a subsequent ‘maintenance’ phase accompanied by relatively minor changes in abundance. Habitat Suitability Indices were produced relating to these phases. Vertical density measures of understorey shrubs and herb layers showed significant relationships with small mammal species abundance at the study sites. Long term studies following major disturbances are needed to distinguish between short term recovery of plant and animal species and long term changes in these species. Studies extending over a number of years enable a better directional view of changes in small mammal communities than can be determined from . observations made over a short period. As a part of the investigation into temporal change, it was proposed to undertake trial reintroductions of the Swamp antechinus, Ant echinus minimus, a marsupial dasyurid species which was trapped in the area prior to the 1983 fire, but rarely subsequently. Other more commonly observed native small mammal species (e.g. Rattus fuscipes,R. lutreolus, Antechinus stuartii, Sminthopsis leucopus) had re-invaded the proposed reintroduction site after this fire. Failure of A. minimus to re-establish may have been due to spatial separation of the pre-fire populations coupled with the extensive area burnt in 1983, A source population of the species was located about 100km to the west and habitat utilization and interspecific and niche relationships between the species making the small mammal community explored. Discriminant analysis revealed some spatial separation of species within a habitat based on structural vegetation factors rather than floristic factors. Temporal separation of species was observed, asA. minimus were more active than Rattus species during daylight periods. There was evidence of micro-habitat selection by species, and structural vegetation factors were most commonly identified in statistical analyses as contributing towards selection by small mammal species. Following a theoretical modelling study three reintroduction trials were carried out near Anglesea during 1992-94. Individuals were subsequently radio tracked, and habitat relationships between the species in the small mammal community investigated. Although successful breeding of A, minimus occurred during the latter two trials, the subsequent fate of offspring was not determined. Invasive techniques required to adequately monitor young animals were considered potentially too damaging. Telemetry studies indicated a preference of A. minimus for short, wet heath vegetation. Structural vegetation factors were identified as being significant in discriminating between capture locations of species. Small scale and inexpensive trial reintroductions have yielded valuable additional data on this species and may be viewed as a useful tool in the conservation of other small native mammals.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This paper introduces and analyses three broad discourses of academic achievement and failure, specifically those that speak of students' deficits, disadvantages and differences. It draws on interview data collected from teachers working in Australian primary (elementary) and secondary (high) schools and on academic literature that speaks to the field. The paper argues that 'deficit', 'disadvantage' and 'difference' represent discourses of considerable influence in determining how teachers, students and parents define what constitutes success or failure in schools, which respective approaches educators employ, and the beliefs we hold about students who fail and those who succeed. In this respect, the paper is concerned with matters of inclusion and exclusion in schooling. In particular, we seek to tease out the stories that these discourses tell about student diversity, as a way of unmasking how students are differently represented and how these representations serve to include some and exclude others from the benefits of schooling and society more broadly.