4101 research outputs found
Sort by
Growth of Carbon Nanotubes on Surfaces: The Effects of Catalyst and Substrate
No full textWe report a study of synthesising air-stable, nearly monodispersed bimetallic colloids of Co/Pd and Fe/Mo of varying compositions as active catalysts for the growth of carbon nanotubes. Using these catalysts we have investigated the effects of catalyst and substrate on the carbon nanostructures formed in a plasma-enhanced chemical vapour deposition (PECVD) process. We will show how it is possible to assess the influence of both the catalyst and the support on the controlled growth of carbon nanotube and nanofiber arrays. The importance of the composition of the catalytic nuclei will be put into perspective with other results from the literature. Furthermore, the influence of other synthetic parameters such as the nature of the nanoparticle catalysts will also be analysed and discussed in detail
Analysis of the employer based award scheme
No full textThe employer based award scheme is a facet of the clinical excellence awards that are administered locally. There remains widespread dissatisfaction regarding implementation, fairness, transparency, and the appeal mechanism. This study reflects on the views of consultants and recommends ways to improve the credibility of the scheme
Evaluating the influence of varied fire-retardant surface coatings on post-heat flexural properties of glass/epoxy composites
No full textThis paper investigates the influence of char-forming, flame-inhibiting and intumescent surface coatings on the post-heat flexural behavior of glass fibre-reinforced epoxy composites exposed to one-sided radiant heating. The fire performance of glass/epoxy laminates surface-coated with varied formulations was evaluated using a cone calorimeter under various external heat fluxes (25, 50 and 65 kW/m(2)). Self-sustained ignition was significantly delayed for fire-protected laminates relative to the control. The peak heat release rates and the time to reach this event were significantly reduced in thermally-protected laminates. In addition to the chemical nature of flame retardant chemicals present in the coatings, the time to reach the peak heat release rate and the magnitude of the total heat release were influenced by the quantity and morphology of the char formed by each type of surface coating. The post-heat flexural performance of heat-damaged laminates was determined via three-point bending. There was a significant improvement in the post-heat flexural moduli retention in thermally-protected glass/epoxy laminates. This may be due to the flame retardation efficacy of the coatings and the ability of the charred structures to reduce the heat transfer into the substrate thereby protecting the underlying composite and its mechanical integrity. (C) 2013 Elsevier Ltd. All rights reserved
Starch metabolism and antiflorigenic signals modulate the juvenile-to-adult phase transition in Arabidopsis
No full textThe physiology and genetics underlying juvenility is poorly understood. Here, we exploit Arabidopsis as a system to understand the mechanisms that regulate floral incompetence during juvenility. Using an experimental assay that allows the length of juvenility to be estimated and mutants impaired in different pathways, we show that multiple inputs influence juvenility. Juvenile phase lengths of wild type (WT) accessions Col-0, Ler-0 and Ws-4 are shown to differ, with Col-0 having the shortest and Ws-4 the longest length. Plants defective in sugar signalling [gin1-1, gin2-1, gin6 (abi4)] and floral repressor mutants [hst1, tfl1, tfl2 (lhp1)] showed shortened juvenile phase lengths compared to their respective WTs. Mutants defective in starch anabolism (adg1-1, pgm1) and catabolism (sex1, sex4, bam3) showed prolonged juvenile phase lengths compared to Col-0. Examination of diurnal metabolite changes in adg1-1 and sex1 mutants indicates that their altered juvenile phase length may be due to lack of starch turnover, which influences carbohydrate availability. In this article, we propose a model in which a variety of signals including floral activators and repressors modulate the juvenile-to-adult phase transition. The role of carbohydrates may be in their capacity as nutrients, osmotic regulators, signalling molecules and/ or through their interaction with phytohormonal networks
Leadership: A Question of the Brand
No full textLeadership is at the heart every living organisation, be it human or animal community. Leadership spans the existence of living creatures and or human beings. In trying to understand the phenomenon of leadership various concepts and philosophies have been put forward. Leadership has been described in terms of traits, transformational effects, group norms, etc. The main issue in leadership remains the ability to influence. The leadership of an organisation gives character to that organisation and subsequently projects the image of that organisation. Leadership branding has connotations that impinge on the internal and external dynamics. Internally leadership shapes the organisation values which determine the overall performance. Externally, leadership branding transforms into images that project the organisation to the broader community of stakeholders. Ultimately, the dynamics of leadership need a good understanding of the role played by leaders across a plethora of organisations as they shape the destiny of respective organisations and their outputs. This is a conceptual paper which weighs in on the philosophy behind leadership branding and its implications to organisational performance
Flame retarding ceramic fibres
No full textIn contrast to organic fibres, ceramic, i.e. inorganic, fibres, are not flammable and can maintain their physical strength and thus structure at very high temperatures. They find applications as materials used in very high temperature (> 1000o ) environments. This chapter provides an account of the range of these applications as well as the developments in ceramic fibre production techniques which enhance their high temperature properties.Ceramic fibres are increasingly used as reinforcements in organic resin matrices for high performance structural ceramic matrix composites and metals required for aerospace and marine applications. Since organic resins are potentially flammable, it is important that the whole composite system be fire resistant. The current status of this topic is reviewed together with a discussion of the potential for future improvements
Enhancement of microfluidic efficiency with nanocrystalline diamond interlayer in the ZnO-based surface acoustic wave device
No full textUltra-smooth nanocrystalline diamond (UNCD) films with high-acoustic wave velocity were introduced into ZnO-based surface acoustic wave (SAW) devices to enhance their microfluidic efficiency by reducing the acoustic energy dissipation into the silicon substrate and improving the acoustic properties of the SAW devices. Microfluidic efficiency of the ZnO-based SAW devices with and without UNCD inter layers was investigated and compared. Results showed that the pumping velocities increase with the input power and those of the ZnO/UNCD/Si devices are much larger than those of the ZnO/Si devices at the same power. The jetting efficiency of the droplet was improved by introducing the UNCD interlayer into the ZnO/Si SAW device. Improvement in the microfluidic efficiency is mainly attributed to the diamond layer, which restrains the acoustic wave to propagate in the top layer rather than dissipating into the substrate
Poetry in action [research]. An innovative means to a reflective learner in higher education (HE)
No full textThis research investigated the use of poems for reflection. Participants (n = 16) were enrolled upon a Foundation Degree in Sports Coaching. Part modular assessment saw the students create an action plan that provided key indicators as to their ability within a range of study skills. The entire cohort failed to implement the plan. Whilst there exists a prevailing wind of poetic embrace within the social sciences, limitations are evident within the domain of sport and physical activity. The research questions whether poems may be implemented as a means to initial reflection and reorientation and as a consolidation of prior learning. Findings suggest poetry may aid initial reflection and reorientation and a consolidation of prior learning, that the writings were enjoyable, at times frustrating, developmental and that such creativity might be advocated elsewhere across the HE curriculum. Implications for the learner are discussed and I suggest a framework for practitioners (‘Reflective Facilitation’), which considers how we may assist our learners in a process of guided discovery in which their reflections may become critical and self-governed. The paper then considers the limitations of the research process and offers considerations for future practice
Numerical study of metal oxide hetero-junction solar cells with defects and interface states
No full textFurther to our previous work on ideal metal oxide (MO) hetero-junction solar cells, a systematic simulation has been carried out to investigate the effects of defects and interface states on the cells. Two structures of the window/absorber (WA) and window/absorber/voltage-enhancer (WAV) were modelled with defect concentration, defect energy level, interface state (ISt) density and ISt energy level as parameters. The simulation showed that the defects in the window layer and the voltage-enhancer layer have very limited effects on the performance of the cells, but those in the absorption layer have profound effects on the cell performance. The interface states at the W/A interface have a limited effect on the performance even for a density up to 1013 cm−2, while those at the A/V interface cause the solar cell to deteriorate severely even at a low density of lower than 1 × 1011 cm−2. It also showed that the back surface field (BSF) induced by band gap off-set in the WAV structure loses its function when defects with a modest concentration exist in the absorption layer and does not improve the open voltage at all