234 resultados para black metal
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This paper seeks to investigate the link between the objective regional opportunity structure (captured by regional data) and individuals’ engagement in different stages in the venture creation process (intention to start a business and engagement in nascent entrepreneurship). We further investigate pathways through which a favourable regional environment could affect entrepreneurial intentions and the propensity to be a nascent entrepreneur. We combine individual level GEM-data for Western Germany with regional level data from the statistical office and use multi-level analysis to test our hypotheses. We find support for our contention that a favourable regional opportunity structure affects entrepreneurial intentions and engagement. As pathways between the region and individual behaviour serve the individual perception of founding opportunities and the individual social capital.
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One of the greatest challenges for the study of photocatalysts is to devise new catalysts that possess high activity under visible light illumination. This would allow the use of an abundant and green energy source, sunlight, to drive chemical reactions. Gold nanoparticles strongly absorb both visible light and UV light. It is therefore possible to drive chemical reactions utilising a significant fraction of full sunlight spectrum. Here we prepared gold nanoparticles supported on various oxide powders, and reported a new finding that gold nanoparticles on oxide supports exhibit significant activity for the oxidation of formaldehyde and methanol in the air at ambient temperature, when illuminated with visible light. We suggested that visible light can greatly enhance local electromagnetic fields and heat gold nanoparticles due to surface plasmon resonance effect which provides activation energy for the oxidation of organic molecules. Moreover, the nature of the oxide support has an important influence on the activity of the gold nanoparticles. The finding reveals the possibility to drive chemical reactions with sunlight on gold nanoparticles at ambient temperature, highlighting a new direction for research on visible light photocatalysts. Gold nanoparticles supported on oxides also exhibit significant dye oxidation activity under visible light irradiation in aqueous solution at ambient temperature. Turnover frequencies of the supported gold nanoparticles for the dye degradation are much higher than titania based photocatalysts under both visible and UV light. These gold photocatalysts can also catalyse phenol degradation as well as selective oxidation of benzyl alcohol under UV light. The reaction mechanism for these photocatalytic oxidations was studied. Gold nanoparticles exhibit photocatalytic activity due to visible light heating gold electrons in 6sp band, while the UV absorption results in electron holes in gold 5d band to oxidise organic molecules. Silver nanoparticles also exhibit considerable visible light and UV light absorption due to surface plasmon resonance effect and the interband transition of 4d electrons to the 5sp band, respectively. Therefore, silver nanoparticles are potentially photocatalysts that utilise the solar spectrum effectively. Here we reported that silver nanoparticles at room temperature can be used to drive chemical reactions when illuminated with light throughout the solar spectrum. The significant activities for dye degradation by silver nanoparticles on oxide supports are even better than those by semiconductor photocatalysts. Moreover, silver photocatalysts also can degrade phenol and drive the oxidation of benzyl alcohol to benzaldehyde under UV light. We suggested that surface plasmon resonance effect and interband transition of silver nanoparticles can activate organic molecule oxidations under light illumination.
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Partition of heavy metals between particulate and dissolve fraction of stormwater primarily depends on the adsorption characteristics of solids particles. Moreover, the bioavailability of heavy metals is also influenced by the adsorption behaviour of solids. However, due to the lack of fundamental knowledge in relation to the heavy metals adsorption processes of road deposited solids, the effectiveness of stormwater management strategies can be limited. The research study focused on the investigation of the physical and chemical parameters of solids on urban road surfaces and, more specifically, on heavy metal adsorption to solids. Due to the complex nature of heavy metal interaction with solids, a substantial database was generated through a series of field investigations and laboratory experiments. The study sites for the build-up pollutant sample collection were selected from four urbanised suburbs located in a major river catchment. Sixteen road sites were selected from these suburbs and represented typical industrial, commercial and residential land uses. Build-up pollutants were collected using a wet and dry vacuum collection technique which was specially designed to improve fine particle collection. Roadside soil samples were also collected from each suburb for comparison with the road surface solids. The collected build-up solids samples were separated into four particle size ranges and tested for a range of physical and chemical parameters. The solids build-up on road surfaces contained a high fraction (70%) of particles smaller than 150ìm, which are favourable for heavy metal adsorption. These solids particles predominantly consist of soil derived minerals which included quartz, albite, microcline, muscovite and chlorite. Additionally, a high percentage of amorphous content was also identified in road deposited solids. In comparing the mineralogical data of surrounding soil and road deposited solids, it was found that about 30% of the solids consisted of particles generated from traffic related activities on road surfaces. Significant difference in mineralogical composition was noted in different particle sizes of build-up solids. Fine solids particles (<150ìm) consisted of a clayey matrix and high amorphous content (in the region of 40%) while coarse particles (>150ìm) consisted of a sandy matrix at all study sites, with about 60% quartz content. Due to these differences in mineralogical components, particles larger than and smaller than 150ìm had significant differences in their specific surface area (SSA) and effective cation exchange capacity (ECEC). These parameters, in turn, exert a significant influence on heavy metal adsorption. Consequently, heavy metal content in >150ìm particles was lower than in the case of fine particles. The particle size range <75ìm had the highest heavy metal content, corresponding with its high clay forming minerals, high organic matter and low quartz content which increased the SSA, ECEC and the presence of Fe, Al and Mn oxides. The clay forming minerals, high organic matter and Fe, Al and Mn oxides create distinct groups of charge sites on solids surfaces and exhibit different adsorption mechanisms and bond strength, between heavy metal elements and charge sites. Therefore, the predominance of these factors in different particle sizes leads to different heavy metal adsorption characteristics. Heavy metals show preference for association with clay forming minerals in fine solids particles, whilst in coarse particles heavy metals preferentially associate with organic matter. Although heavy metal adsorption to amorphous material is very low, the heavy metals embedded in traffic related materials have a potential impact on stormwater quality.Adsorption of heavy metals is not confined to an individual type of charge site in solids, whereas specific heavy metal elements show preference for adsorption to several different types of charge sites in solids. This is attributed to the dearth of preferred binding sites and the inability to reach the preferred binding sites due to competition between different heavy metal species. This confirms that heavy metal adsorption is significantly influenced by the physical and chemical parameters of solids that lead to a heterogeneity of surface charge sites. The research study highlighted the importance of removal of solids particles from stormwater runoff before they enter into receiving waters to reduce the potential risk posed by the bioavailability of heavy metals. The bioavailability of heavy metals not only results from the easily mobile fraction bound to the solids particles, but can also occur as a result of the dissolution of other forms of bonds by chemical changes in stormwater or microbial activity. Due to the diversity in the composition of the different particle sizes of solids and the characteristics and amount of charge sites on the particle surfaces, investigations using bulk solids are not adequate to gain an understanding of the heavy metal adsorption processes of solids particles. Therefore, the investigation of different particle size ranges is recommended for enhancing stormwater quality management practices.
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There is an intimate interconnectivity between policy guidelines defining reform and the delineation of what research methods would be subsequently applied to determine reform success. Research is guided as much by the metaphors describing it as by the ensuing empirical definition of actions of results obtained from it. In a call for different reform policy metaphors Lumby and English (2010) note, “The primary responsibility for the parlous state of education... lies with the policy makers that have racked our schools with reductive and dehumanizing processes, following the metaphors of market efficiency, and leadership models based on accounting and the characteristics of machine bureaucracy” (p. 127)
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Contends that South African universities must find admissions criteria, other than high school grades, that are both fair and valid for Black applicants severely disadvantaged by an inferior school education. The use of traditional intellectual assessments and aptitude tests for disadvantaged and minority students remains controversial as a fair assessment; they do not take account of potential for change. In this study, therefore, a measure of students' cognitive modifiability, assessed by means of an interactive assessment model, was added as a moderator of traditional intellectual assessment in predicting 1st-yr university success. Cognitive modifiability significantly moderated the predictive validity of the traditional intellectual assessment for 52 disadvantaged Black students. The higher the level of cognitive modifiability, the less effective were traditional methods for predicting academic success and vice versa.
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This chapter discusses an action research project into the lived experience of the workplace mobbing phenomenon. The action research methodology is based on the exemplarian model (Coenen & Khonraad, 2003) from the Netherlands Group. This model requires positive outcomes for those immersed in the problem to reduce the adversity of their circumstances. The findings challenge the psychological perspective of the existing bullying literature that tends to focus on individual behaviour. This research, undertaken over a three year period with 212 participants, identified the dysfunctional nature of public sector bureaucracies and the power gained through gossip and rumour as some of the key emergent themes to explain the workplace mobbing problem. In addition, resistance, conscientisation, and agency were identified as the key to transformation for those targeted. The discussion focuses on the crystallisation phase of the exemplarian model where the participants identified themselves as the Black Sheep and adopted the motto that “a black sheep is a biting beast” (Bastard, 1565 or 6-1618, p. 90), reflecting a sense of empowerment, individual agency, and a sense of humour in dealing with the serious yet seemingly absurd reality of their situations. The identity of the Black Sheep was consolidated when the group organised a 2 day conference with over 200 attendees to discuss how best to prevent workplace mobbing. This self-affirming action was a proactive step towards metaphorically “biting back” at the problem. A number of positive outcomes were achieved including the conference with over 200 attending leading to national media coverage across Australia and additional interviews with magazines, newspapers, and radio.
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Determining the optimal of black-start strategies is very important for speeding the restoration speed of a power system after a global blackout. Most existing black-start decision-making methods are based on the assumption that all indexes are independent of each other, and little attention has been paid to the group decision-making method which is more reliable. Given this background, the intuitionistic fuzzy set and further intuitionistic fuzzy Choquet integral operator are presented, and a black-start decision-making method based on this integral operator is presented. Compared to existing methods, the proposed algorithm cannot only deal with the relevance among the indexes, but also overcome some shortcomings of the existing methods. Finally, an example is used to demonstrate the proposed method. © 2012 The Institution of Engineering and Technology.
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Food modelling systems such as the Core Foods and the Australian Guide to Healthy Eating are frequently used as nutritional assessment tools for menus in ‘well’ groups (such as boarding schools, prisons and mental health facilities), with the draft Foundation and Total Diets (FATD) the latest revision. The aim of this paper is to apply the FATD to an assessment of food provision in a long stay, ‘well’, group setting to determine its usefulness as a tool. A detailed menu review was conducted in a 1000 bed male prison, including verification of all recipes. Full diet histories were collected on 106 prisoners which included foods consumed from the menu and self funded snacks. Both the menu and diet histories were analysed according to core foods, with recipes used to assist in quantification of mixed dishes. Comparison was made of average core foods with Foundation Diet recommendations (FDR) for males. Results showed that the standard menu provided sufficient quantity for 8 of 13 FDRs, however was low in nuts, legumes, refined cereals and marginally low in fruits and orange vegetables. The average prisoner diet achieved 9 of 13 FDRs, notably with margarines and oils less than half and legumes one seventh of recommended. Overall, although the menu and prisoner diets could easily be assessed using the FDRs, it was not consistent with recommendations. In long stay settings other Nutrient Reference Values not modelled in the FATDS need consideration, in particular, Suggested Dietary Targets and professional judgement is required in interpretation.
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This paper investigates theoretically and numerically local heating effects in plasmon nanofocusing structures with a particular focus on the sharp free-standing metal wedges. The developed model separates plasmon propagation in the wedge from the resultant heating effects. Therefore, this model is only applicable where the temperature increments in a nanofocusing structure are sufficiently small not to result in significant variations of the metal permittivity in the wedge. The problem is reduced to a one-dimensional heating model with a distributed heat source resulting from plasmon dissipation in the metal wedge. A simple heat conduction equation governing the local heating effects in a nanofocusing structure is derived and solved numerically for plasmonic pulses of different lengths and reasonable energies. Both the possibility of achieving substantial local temperature increments in the wedge (with a significant self-influence of the heating plasmonic pulses), and the possibility of relatively weak heating (to ensure the validity of the previously developed nanofocusing theory) are demonstrated and discussed, including the future applications of the obtained results. Applicability conditions for the developed model are also derived and discussed.