989 resultados para Word formation


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In this paper, two ideal formation models of serrated chips, the symmetric formation model and the unilateral right-angle formation model, have been established for the first time. Based on the ideal models and related adiabatic shear theory of serrated chip formation, the theoretical relationship among average tooth pitch, average tooth height and chip thickness are obtained. Further, the theoretical relation of the passivation coefficient of chip's sawtooth and the chip thickness compression ratio is deduced as well. The comparison between these theoretical prediction curves and experimental data shows good agreement, which well validates the robustness of the ideal chip formation models and the correctness of the theoretical deducing analysis. The proposed ideal models may have provided a simple but effective theoretical basis for succeeding research on serrated chip morphology. Finally, the influences of most principal cutting factors on serrated chip formation are discussed on the basis of a series of finite element simulation results for practical advices of controlling serrated chips in engineering application.

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A review of Barrie Kosky's essay, On Ecstasy : Most of us describe the E word as a pleasant, out of this world experience—a type of boundless, artificial joy, deliberately induced by some kind of technicoloured drug. For others, it is that “lovey dovey” feeling. A spinning ceiling. Anything Lindt. For sensualist and soup connoisseur Barrie Kosky, it is easier than this. Being On Ecstasy involves, quite simply, his grandmother's chicken specialty—something warm and golden, surrendered with vegetables and a side of transcendental bliss. “A soup that took you to the beginning and end of time itself. A dazzling, pure, clear rhapsody” (7).

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Early this year the Australian Department of Environment and Heritage commissioned a desktop literature review with a focus on ultrafine particles including analysis of health impacts of the particles as well as the impact of sulphur content of diesel fuel on ultrafine particle emission. This paper summarizes the findings of the report on the link between the sulphur content of diesel fuels and the number of ultrafine particles in diesel emissions. The literature search on this topic resulted in over 150 publications. The majority of these publications, although investigating different aspects of the influence of fuel sulphur level on diesel vehicle emissions, were not directly concerned with ultrafine particle emissions. A specific focus of the paper is on: ----- ----- summary of state of knowledge established by the review, and ----- ----- summary of recommendations on the research priorities for Australia to address the information gaps for this issue, and on the appropriate management responses.

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The self-assembling behavior and microscopic structure of zinc oxide nanoparticle Langmuir-Blodgett monolayer films were investigated for the case of zinc oxide nanoparticles coated with a hydrophobic layer of dodecanethiol. Evolution of nanoparticle film structure as a function of surface pressure (π) at the air-water interface was monitored in situ using Brewster’s angle microscopy, where it was determined that π=16 mN/m produced near-defect-free monolayer films. Transmission electron micrographs of drop-cast and Langmuir-Schaefer deposited films of the dodecanethiol-coated zinc oxide nanoparticles revealed that the nanoparticle preparation method yielded a microscopic structure that consisted of one-dimensional rodlike assemblies of nanoparticles with typical dimensions of 25 x 400 nm, encased in the organic dodecanethiol layer. These nanoparticle-containing rodlike micelles were aligned into ordered arrangements of parallel rods using the Langmuir-Blodgett technique.

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Objectives: The periosteum plays an indispensable role in both bone formation and bone defect healing. The aim of this project is to produce tissue engineered periosteum for bone defect treatment. Methods: In this study we constructed an artificial in vitro periosteum by incorporating osteogenic differentiated bone marrow stromal cells (BMSCs) and cobalt chloride (CoCl2)-treated BMSCs. The engineered periostea were implanted both subcutaneously and into skull bone defects in SCID mice to investigate ectopic and orthotopic osteogenesis and vascularisation. After two weeks in subcutaneous and four weeks in bone defect areas, the implanted constructs were assessed for ectopic and orthotopic osteogenesis and vascularisation by micro-CT, histomorphometrical and immunohistochemical methods. Results: The results showed that CoCl2 pre-treated BMSCs induced higher degree of vascularisation and enhanced osteogenesis within the implants in both ectopic and orthotopic areas. Conclusion: This study provided a novel approach using BMSCs sourced from the same patient for both osteogenic and pro-angiogenic purposes in constructing tissue engineered periosteum to enhance vascularized osteogenesis.

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This paper presents the findings of a research project that was set up to establish haw well Gibber, a street magazine set up in Perth in 1994, effectively provides a 'voice' for its canstituency -'young people marginalised by society'.

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The seawater neutralisation process is currently used in the Alumina industry to reduce the pH and dissolved metal concentrations in bauxite refinery residues, through the precipitation of Mg, Al, and Ca hydroxide and carbonate minerals. This neutralisation method is very similar to the co-precipitation method used to synthesise hydrotalcite (Mg6Al2(OH)16CO3•4H2O). This study looks at the effect of temperature on the type of precipitates that form from the seawater neutralisation process of Bayer liquor. The Bayer precipitates have been characterised by a variety of techniques, including X-ray diffraction, Raman spectroscopy and infrared spectroscopy. The mineralogical composition of Bayer precipitates largely includes hydrotalcite, hydromagnesite, and calcium carbonate species. XRD determined that Bayer hydrotalcites that are synthesised at 55 °C have a larger interlayer distance, indicating more anions are removed from Bayer liquor. Vibrational spectroscopic techniques have identified an increase in hydrogen bond strength for precipitates formed at 55 °C, suggesting the formation of a more stable Bayer hydrotalcite. Raman spectroscopy identified the intercalation of sulfate and carbonate anions into Bayer hydrotalcites using these synthesis conditions.

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Thermogravimetry combined with evolved gas mass spectrometry has been used to ascertain the stability of the ‘cave’ mineral brushite. X-ray diffraction shows that brushite from the Jenolan Caves is very pure. Thermogravimetric analysis coupled with ion current mass spectrometry shows a mass loss at 111°C due to loss of water of hydration. A further decomposition step occurs at 190°C with the conversion of hydrogen phosphate to a mixture of calcium ortho-phosphate and calcium pyrophosphate. TG-DTG shows the mineral is not stable above 111°C. A mechanism for the formation of brushite on calcite surfaces is proposed, and this mechanism has relevance to the formation of brushite in urinary tracts.

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The last two decades have seen a significant restructuring of work across Australia and other industrialised economies, a critical part of which has been the appearance of competency based education and assessment. The competency movement is about creating a more flexible and mobile labour force to increase productivity and it does so by redefining work as a set of transferable or ‘soft’ generic skills that are transportable and are the possession of the individual. This article sought to develop an analysis of competency based clinical assessment of nursing students across a bachelor of nursing degree course. This involved an examination of a total of 406 clinical assessment tools that covered the years 1992-2009 and the three years of a bachelor degree. Data analysis generated three analytical findings: the existence of a hierarchy of competencies that prioritises soft skills over intellectual and technical skills; the appearance of skills as personal qualities or individual attributes; and the absence of context in assessment. The article argues that the convergence in nursing of soft skills and the professionalisation project reform has seen the former give legitimacy to the enduring invisibility and devaluation of nursing work.

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Despite the challenges that giftedness can add to self-formation during early adolescence, gifted young adolescents seldom are asked about their lives outside of counselling and educational contexts. The study considers the complexities that face gifted young adolescents in the process of self-discovery and self-representation, thereby building a case for seeking their own viewpoints. A guiding assumption for the study was that gifted young adolescents may respond positively to the opportunity to share their own perspectives and their own versions of “who they are”. The theoretical underpinnings for this study drew from Dialogical Self Theory. The study resides within an interactive view of self as a dynamic construction rather than a static state, where “who we are” is formed in everyday exchanges with self and others. Self-making as a process among gifted young adolescents is presented as an interactive network of “I” voices interpreted to reflect internal and external dialogue. In this way, self is understood within dialogical concepts of voices as multiple expressions. The study invited twelve gifted young adolescents to write freely about themselves over a six month period in an email journal project. Participants were recruited online and by word-of-mouth and they were able to negotiate their own levels of involvement. Access to the lives of individual young adolescents was sought in an out-of-school setting using narrative methods of personal writing in the form of journals sent as emails to the researcher. The role of the researcher was to act as a supportive listener who responded to participant-led emails and thereby facilitated the process of authoring that occurred across the data-gathering phase. The listening process involved responses that were affirming and designed to build trust. Data in the form of email texts were analysed using a close listening method that uncovered patterns of voices that were explicitly or subtly expressed by participants. The interpretation of voices highlighted the tensions and contradictions involved in the process of participants forming a “self” that emerged as multiple “I” voices. There were three key findings of the study. First, the gifted young adolescent participants each constructed a self around four key voices of Author, Achiever, Resistor/Co-operator and Self-Innovator. These voices were dialogical selfconstructions that showed multiplicity as a normal way of being. Second, the selfmaking processes of the gifted young adolescent participants were guided by a hierarchy of voices that were directed through self-awareness. Third, authoring in association with a responsive adult listener emerged as a dialogic space for promoting self-awareness and a language of self-expression among gifted young adolescents. The findings of the study contribute to knowledge about gifted young adolescents by presenting their own versions of “who” they are, perspectives that might differ from mainstream perceptions. Participants were shown to have highly diverse, complex and individual expressions that have implications for how well they are understood and supported by others. The use of email journals helped to create a synergy for self-disclosure and a safe space for self-expression where participants’ abilities to be themselves were encouraged. Increased self-awareness and selfknowledge among gifted young adolescents is vital to their self-formation and their management of self and others’ expectations. This study makes an original contribution to the field of self-study by highlighting the processes and complexities of young adolescents’ self-constructions. Through the innovative use of narrative methods and an inter-disciplinary approach, the voices of gifted young adolescents were privileged. At a practical level, the study can inform educators, policy-makers, parents and all those who seek to contribute to the well-being of gifted young adolescents.

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Stimulated by the efficacy of copper (I) catalysed Huisgen-type 1,3-dipolar cycloaddition of terminal alkynes and organic azides to generate 1,4-disubstituted 1,2,3-triazole derivatives, the importance of ‘click’ chemistry in the synthesis of organic and biological molecular systems is ever increasing.[1] The mild reaction conditions have also led to this reaction gaining favour in the construction of interlocked molecular architectures.[2-4] In the majority of cases however, the triazole group simply serves as a covalent linkage with no function in the resulting organic molecular framework. More recently a renewed interest has been shown in the transition metal coordination chemistry of triazole ligands.[3, 5, 6] In addition novel aryl macrocyclic and acyclic triazole based oligomers have been shown to recognise halide anions via cooperative triazole C5-H….anion hydrogen bonds.[7] In light of this it is surprising the potential anion binding affinity of the positively charged triazolium motif has not, with one notable exception,[8] been investigated. With the objective of manipulating the unique topological cavities of mechanically bonded molecules for anion recognition purposes, we have developed general methods of using anions to template the formation of interpenetrated and interlocked structures.[9-13] Herein we report the first examples of exploiting the 1,2,3-triazolium group in the anion templated formation of pseudorotaxane and rotaxane assemblies. In an unprecedented discovery the bromide anion is shown to be a superior templating reagent to chloride in the synthesis of a novel triazolium axle containing [2]rotaxane. Furthermore the resulting rotaxane interlocked host system exhibits the rare selectivity preference for bromide over chloride...