998 resultados para ALUMINOXANE CATALYSTS


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Neutral Ni(II) salicylaldiminato complexes activated with modified methylaluminoxane as catalysts were used for the vinylic polymerization of norbornene. Catalyst activities of up to 7.08 x 10(4) kg(pol)/(mol(Ni) (.) h) and viscosity-average molecular weights of polymer up to 1.5 x 10(6) g/mol were observed at optimum conditions. Polynorbornenes are amorphous, soluble in organic solvents, highly stable, and show glass-transition temperatures around 390 degreesC. Catalyst activity, polymer yield, and polymer molecular weight can be controlled over a wide range by the variation of the reaction parameters such as the Al/Ni ratio, monomer/catalyst ratio, monomer concentration, polymerization reaction temperature, and time.

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A series of nickel(II) complexes bearing two nonsymmetric bidentate beta-ketoiminato chelate ligands have been prepared, and the structures of complexes [(2,6-Me2C6H3)NC(CH3)C(H)C(Ph)O](2)Ni (4a) and [(2,6-Me2C6H3)NC(CH3)C(H)C(CF3)O](2)Ni (4c) have been confirmed by X-ray crystallographic analysis. These nickel(II) complexes were investigated as catalysts for the vinylic polymerization of norbornene. Using modified methylaluminoxane (MMAO) as a cocatalyst, these complexes display very high activities and produce high molecular weight polymers. Catalytic activity of up to 1.16 x 10(4) kg/mol(Ni) .h and the viscosity-average molecular 9 weight of polymer of up to 870 kg/mol were observed. Catalyst activity, polymer yield, and polymer molecular weight could be controlled over a wide range by the variation of the reaction parameters such as Al/Ni molar ratio, norbornene/catalyst molar ratio, monomer concentration, polymerization reaction temperature and time.

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A series of neutral palladium(II) complexes bearing non-symmetric bidentate pyrrole-iminato or salicylaldiminato chelate ligands have been synthesized, and the structure of representative complexes (3a, 4a, and 5a) have been confirmed by X-ray crystallographic analysis. These palladium complexes have been investigated as catalysts for the polymerization of norbornene. Using modified methylaluminoxane (MMAO) as a cocatalyst, these complexes display high activities and produce vinyl-addition polynorborenes. Catalytic activity of up to 8.52 x 10(3) kg/mol(Pd) h has been observed. Wide-angle X-ray diffraction (WAXD) has been used to investigate the polymer microstructure and it has been found that they are non-crystalline.

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New neutral nickel(II) complexes bearing nonsymmetric bidentate pyrrole-imine chelate ligands (4a-d), [2-(ArNCH)C4H3N]Ni(PPh3)Ph [Ar=2,6-diisopropylphenyl (a), 2-methyl-6-isopropylphenyl (b), 2,6-diethylphenyl (c), 2-tert-butylphenyl (d)], have been prepared in good yields from the sodium salts of the corresponding ligands and trans-Ni(PPh3)(2)(Ph)Cl, and the structure of complex 4a has been confirmed by X-ray crystallographic analysis. These neutral Ni(II) complexes were investigated as catalysts for the vinylic polymerization of norbornene. Using modified methylaluminoxane (MMAO) as a cocatalyst, these complexes display very high activities and produce great mass polymers. Catalyst activity of up to 4.2 x 10(7) g (mol Ni h)(-1) and the viscosity-average molecular weight of polymer of up to 9.2 x 10(5) g mol(-1) were observed. Catalyst activity, polymer yield, and polymer molecular weight can be controlled over a wide range by the variation of reaction parameters such as Al-Ni ratio, norbornene-catalyst ratio, monomer concentration, polymerization reaction temperature and time.

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Collaborative networks have come to form a large part of the public sector’s strategy to address ongoing and often complex social problems. The relational power of networks, with its emphasis on trust, reciprocity and mutuality provides the mechanism to integrate previously dispersed and even competitive entities into a collective venture(Agranoff 2003; Agranoff and McGuire 2003; Mandell 1994; Mandell and Harrington 1999). It is argued that the refocusing of a single body of effort to a collective contributes to reducing duplication and overlap of services, maximizes increasingly scarce resources and contributes to solving intractable or 'wicked’problems (Clarke and Stewart 1997). Given the current proliferation of collaborative networks and the fact that they are likely to continue for some time, concerns with the management and leadership of such arrangements for optimal outcomes are increasingly relevant. This is especially important for public sector managers who are used to working in a top-down, hierarchical manner. While the management of networks (Agranoff and McGuire 2001, 2003), including collaborative or complex networks (Kickert et al. 1997; Koppenjan and Klijn 2004), has been the subject of considerable attention, there has been much less explicit discussion on leadership approaches in this context. It is argued in this chapter that the traditional use of the terms ‘leader’ or ‘leadership’ does not apply to collaborative networks. There are no ‘followers’ in collaborative networks or supervisor-subordinate relations. Instead there are equal, horizontal relationships that are focused on delivering systems change. In this way the emergent organizational forms such as collaborative networks challenge older models of leadership. However despite the questionable relevance of old leadership styles to the contemporary work environment, no clear alternative has come along to take its place.

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The notion of pedagogy for anyone in the teaching profession is innocuous. The term itself, is steeped in history but the details of the practice can be elusive. What does it mean for an academic to be embracing pedagogy? The problem is not limited to academics; most teachers baulk at the introduction of a pedagogic agenda and resist attempts to have them reflect on their classroom teaching practice, where ever that classroom might be constituted. This paper explores the application of a pedagogic model (Education Queensland, 2001) which was developed in the context of primary and secondary teaching and was part of a schooling agenda to improve pedagogy. As a teacher educator I introduced the model to classroom teachers (Hill, 2002) using an Appreciative Inquiry (Cooperrider and Srivastva 1987) model and at the same time applied the model to my own pedagogy as an academic. Despite being instigated as a model for classroom teachers, I found through my own practitioner investigation that the model was useful for exploring my own pedagogy as a university academic (Hill, 2007, 2008). Cooperrider, D.L. and Srivastva, S. (1987) Appreciative inquiry in organisational life, in Passmore, W. and Woodman, R. (Eds) Research in Organisational Changes and Development (Vol 1) Greenwich, CT: JAI Press. Pp 129-69 Education Queensland (2001) School Reform Longitudinal Study (QSRLS), Brisbane, Queensland Government. Hill, G. (2002, December ) Reflecting on professional practice with a cracked mirror: Productive Pedagogy experiences. Australian Association for Research in Education Conference. Brisbane, Australia. Hill, G. (2007) Making the assessment criteria explicit through writing feedback: A pedagogical approach to developing academic writing. International Journal of Pedagogies and Learning 3(1), 59-66. Hill, G. (2008) Supervising Practice Based Research. Studies in Learning, Evaluation, Innovation and Development, 5(4), 78-87

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The concept of sustainable urban development has been pushed to the forefront of policy-making and politics as the world wakes up to the impacts of climate change and the effects of modern urban lifestyles. Today, sustainable development has become a very prominent element in the day-to-day debate on urban policy and the expression of that policy in urban planning and development decisions. As a result of this, during the last few years, sustainable development automation applications such as sustainable urban development decision support systems have become popular tools as they offer new opportunities for local governments to realise their sustainable development agendas. This chapter explores a range of issues associated with the application of information and communication technologies and decision support systems in the process of underpinning sustainable urban development. The chapter considers how information and communication technologies can be applied to enhance urban planning, raise environmental awareness, share decisions and improve public participation. It introduces and explores three web-based geographical information systems projects as best practice. These systems are developed as support tools to include public opinion in the urban planning and development processes, and to provide planners with comprehensive tools for the analysis of sustainable urban development variants in order to prepare the best plans for constructing sustainable urban communities and futures.

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Women are substantially under-represented in the professoriate in Australia with a ratio of one female professor to every three male professors. This gender imbalance has been an ongoing concern with various affirmative action programs implemented in universities but to limited effect. Hence, there is a need to investigate the catalysts for and inhibitors to women’s ascent to the professoriate. This investigation focussed on women appointed to the professoriate between 2005, when a research quality assessment was first proposed, and 2008. Henceforth, these women are referred to as “New Women Professors”. The catalysts and inhibitors in these women’s careers were investigated through an electronic survey and focus group interviews. The survey was administered to new women professors (n=255) and new men professors (n=240) to enable a comparison of responses. However, only women participated in focus group discussions (n=21). An analysis of the survey and interview data revealed that the most critical catalysts for women’s advancement to the professoriate were equal employment opportunities and mentoring. Equal opportunity initiatives provided women with access to traditionally male-dominated forums. Mentoring gave women an insider perspective on the complexity of academia and the politics of the academy. The key inhibitors to women’s career advancement were negative discrimination, the culture of the boys’ club, the tension between personal and professional life, and isolation. Negative discrimination and the boys’ club are problematic because they favour men and marginalise women. The tension between personal and professional life is a particular concern for women who bear children and typically assume the major role in a family for child rearing. Isolation was a concern for both women and men with isolation appearing to increase after ascent to the professoriate. Knowledge of the significant catalysts and inhibitors provides a pragmatic way to orient universities towards redressing the gender balance in the professoriate.

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Women are substantially under-represented in the professoriate in Australia with a ratio of one female professor to every three male professors. This gender imbalance has been an ongoing concern with various affirmative action programs implemented in universities but to limited effect. Hence, there is a need to investigate the catalysts for and inhibitors to women’s ascent to the professoriate. This investigation focussed on women appointed to the professoriate between 2005, when a research quality assessment was first proposed, and 2008. Henceforth, these women are referred to as “New Women Professors”. The catalysts and inhibitors in these women’s careers were investigated through an electronic survey and focus group interviews. The survey was administered to new women professors (n=255) and new men professors (n=240) to enable a comparison of responses. However, only women participated in focus group discussions (n=21). An analysis of the survey and interview data revealed that the most critical catalysts for women’s advancement to the professoriate were equal employment opportunities and mentoring. Equal opportunity initiatives provided women with access to traditionally male-dominated forums. Mentoring gave women an insider perspective on the complexity of academia and the politics of the academy. The key inhibitors to women’s career advancement were negative discrimination, the culture of the boys’ club, the tension between personal and professional life, and isolation. Negative discrimination and the boys’ club are problematic because they favour men and marginalise women. The tension between personal and professional life is a particular concern for women who bear children and typically assume the major role in a family for child rearing. Isolation was a concern for both women and men with isolation appearing to increase after ascent to the professoriate. Knowledge of the significant catalysts and inhibitors provides a pragmatic way to orient universities towards redressing the gender balance in the professoriate.