998 resultados para ALKALI PROMOTION


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The important role of alkali additives in heterogeneous catalysis is, to a large extent, related to the high promotion effect they have on many fundamental reactions. The wide application of alkali additives in industry does not, however, reflect a thorough understanding of the mechanism of their promotional abilities. To investigate the physical origin of the alkali promotion effect, we have studied CO dissociation on clean Rh(111) and K-covered Rh(111) surfaces using density functional theory. By varying the position of potassium atoms relative to a dissociating CO, we have mapped out the importance of different K effects on the CO dissociation reactions. The K-induced changes in the reaction pathways and reaction barriers have been determined; in particular, a large reduction of the CO dissociation barrier has been identified. A thorough analysis of this promotion effect allows us to rationalize both the electronic and the geometrical factors that govern alkali promotion effect: (i) The extent of barrier reductions depends strongly on how close K is to the dissociating CO. (ii) Direct K-O bonding that is in a very short range plays a crucial role in reducing the barrier. (iii) K can have a rather long-range effect on the TS structure, which could reduce slightly the barriers.

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Transition metals are often introduced to a catalyst as promoters to improve catalytic performance. In this work, we study the promotion effect of transition metals on Co, the preferred catalytic metal for Fischer-Tropsch synthesis because of its good compromise of activity, selectivity and stability, for ethylene chemisorption using density functional theory (DFT) calculations, aiming to provide some insight into improving the alpha-olefin selectivity. In order to obtain the general trend of influence on ethylene chemisorption, twelve transition metals (Zr, Mn, Re, Ru, Rh, It, Ni, Pd, Pt, Cu, Ag and Au) are calculated. We find that the late transition metals (e.g. Pd and Cu) can decrease ethylene chemisorption energy. These results suggest that the addition of the late transition metals may improve alpha-olefin selectivity. Electronic structure analyses (both charge density distributions and density of states) are also performed and the understanding of calculated results is presented. (C) 2009 Elsevier B.V. All rights reserved.

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Mg-Al hydrotalcite coatings have been grown on alumina via a novel alkali- and nitrate-free impregnation route and subsequent calcination and hydrothermal treatment. The resulting Mg-HT/AlO catalysts significantly outperform conventional bulk hydrotalcites prepared via co-precipitation in the transesterification of C-C triglycerides for fatty acid methyl ester (FAME) production, with rate enhancements increasing with alkyl chain length. This promotion is attributed to improved accessibility of bulky triglycerides to active surface base sites over the higher area alumina support compared to conventional hydrotalcites wherein many active sites are confined within the micropores. © 2014 The Royal Society of Chemistry.

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Introduction: Schools provide the opportunity to reach a large number of adolescents in a systematic way however there are increasing demands on curriculum providing challenges for health promotion activities. This paper will describe the research processes and strategies used to design an injury prevention program.----- Methods: A multi-stage process of data collection included: (1) Surveys on injury-risk behaviours to identify targets of change (examining behaviour and risk/ protective factors among more than 4000 adolescents); (2) Focus groups (n= 30 high-risk adolescents) to understand and determine risk situations; (3) Hospital emergency outpatients survey to understand injury types/ situations; (4) Workshop (n= 50 teachers/ administrators) to understand the target curriculum and experiences with injury-risk behaviours; (5) Additional focus groups (students and teachers) regarding draft material and processes.----- Results: Summaries of findings from each stage are presented particularly demonstrating the design process. The baseline data identified target risk and protective factors. The following qualitative study provided detail about content and context and with the hospital findings assisted in developing ways to ensure relevance and meaning (e.g. identifying high risk situations and providing insights into language, culture and development). School staff identified links to school processes with final data providing feedback on curriculum fit, feasibility and appropriateness of resources. The data were integrated into a program which demonstrated reduced injury.----- Conclusions: A comprehensive research process is required to develop an informed and effective intervention. The next stage of a cluster randomised control trial is a major task and justifies the intensive and comprehensive development.

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Sandy soils have low water and nutrient retention capabilities so that zeolite soil amendments are used for high value land uses including turf and horticulture to reduce leaching losses of NH4+ fertilisers. MesoLite is a zeolitic material made by caustic treatment of kaolin at 80-95oC. It has a moderately low surface area (9-12m2/g) and very high cation exchange capacity (494 cmol(+)/kg). Laboratory column experiments showed that an addition of 0.4% MesoLite to a sandy soil greatly (90%) reduced leaching of added NH4+ compared to an unamended soil and MesoLite is 11 times more efficient in retaining NH4+ than natural zeolite. Furthermore, NH4+-MesoLite slowly releases NH4+ to soil solution and is likely to be an effective slow release fertiliser.

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A number of studies in relation to the place, impact and purpose of Wellness curricula provide insight into the perceived benefits of Wellness education in university environments. Of particular note is the recommendation by many authors that curriculum design fosters personal experiences, reflective practice and active self-managed learning approaches in order to legitimise (give permission for) the adoption of wellness as a personal lifestyle approach in the frenetic pace of student life. From a broader educational perspective, Wellness education provides opportunities for students to engage in learning self regulation skills both within and beyond the context of the Wellness construct.To realise the suggested potential of Wellness education in higher learning, it is necessary that curricula overlay the principles from the domains of both self-regulation and Wellness, to highlight authentic learning as a means to lifelong approaches. Currently, however, systematic development and empirical examination of the Wellness construct have received limited academic investigation. Despite having a multitude of intended purposes from the educative to the therapy oriented goals of the original authors, most wellness models appear to be limited to the “what” of Wellness. Investigations of the “how” and “why” aspects of Wellness may serve to enhance currently existing models by incorporating behaviour modification and learning approaches in order to create more comprehensive frameworks for health education and promotion.It is also important to note that none of the current Wellness models actually address the educative framework necessary for an individual to learn and thus become aware or understand and make choices about their own Wellness.The literature reviewed within this paper would suggest that learner success is optimised by giving learners authentic opportunities to develop and practice self regulation strategies. Such opportunities include learning experiences that: provide options for self determined outcomes; require skills development; recognise principles of successful learning as outlined by the APA; and are scaffolded according to learner needs rather than in generic ways. Thus, configuring a learner centred curriculum in Wellness Education would potentially benefit from overlaying principles from the domains of both SRL and Wellness to highlight authentic learning as a means to lifelong approaches, triggered by undergraduate experiences.Student perceptions are a rich and significant data base for the measurement of their experiences, activities, practices and behaviours. Wellness undergraduate education, such as the “Fitness, Health and Wellness” unit offered by Queensland University of Technology, offers a context in which to confirm possibilities suggested by the literature reviewed in this paper in a practical, Australian context.

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Globality generates increasingly diffuse networks of human and non-human innovators, carriers and icons of exotic, polyethnic cosmopolitan difference; and this diffusion is increasingly hard to ignore or police (Latour 1993). In fact, such global networks of material-symbolic exchange can frequently have the unintended consequence of promoting status systems and cultural relationships founded on uncosmopolitan values such as cultural appropriation and status-based social exclusion. Moreover, this materialsymbolic engagement with cosmopolitan difference could also be rather mundane, engaged in routinely without any great reflexive consciousness or capacity to destabilise current relations of cultural power, or interpreted unproblematically as just one component of a person’s social environment. Indeed, Beck’s (2006) argument is that cosmopolitanism, in an age of global risk, is being forced upon us unwillingly, so there should be no surprise if it is a bitter pill for some to swallow. Within these emergent cosmopolitan networks, which we call ‘cosmoscapes’, there is no certainty about the development of ethical or behavioural stances consistent with claims foundational to the current literature on cosmopolitanism. Reviewing historical and contemporary studies of globality and its dynamic generative capacity, this paper considers such literatures in the context of studies of cultural consumption and social status. When one positions these diverse bodies of literature against one another, it becomes clear that the possibility of widespread cosmopolitan cultural formations is largely unpromising.

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Legislation regulating advance directives exists in six Australian jurisdictions. In all of these jurisdictions, legislation was enacted to enshrine the common law right of a competent adult to refuse treatment in advance, even if that treatment was required to sustain life. It was thought that enshrining the common law would also enshrine the principle of autonomy on which the common law was based. This article explores whether this is the case by examining the legislative restrictions that are imposed on a competent adult who wishes to complete an advance directive refusing treatment. The article reviews the legislation in all Australian jurisdictions and concludes that, while many of the legislative restrictions can be justified, many cannot as they effectively erode rather than promote the right of a competent adult to refuse treatment.

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The Victorian Aboriginal Community Controlled Health Organisation’s (VACCHO) Public Health and Research Unit delivered an Aboriginal Health Promotion Short Course in Mildura in 2009. ----- The VACCHO delivered Aboriginal Health Promotion Short Course included current health promotion theory and practice as it specifically relates to Aboriginal people within Victoria. As Aboriginal people have a higher risk of cardiovascular disease and type 2 diabetes, the course specifically addressed risk factors for chronic disease including smoking, physical activity, nutrition and mental health and well-being. Hence, a key part of the course involved participants working in groups to plan a health promotion program for one of the key health issues- smoking, physical activity and nutrition, or spiritual health and wellbeing. The aim is for participants to use these programs in their daily work with Aboriginal clients.