928 resultados para Open circuit potential
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The Time magazine ‘Person of theYear’ award is a venerable institution. Established by Time’s founder Henry Luce in 1927 as ‘Man of the Year’, it is an annual award given to ‘a person, couple, group, idea, place, or machine that ‘for better or for worse ... has done the most to influence the events of the year’ (Time 2002, p. 1). In 2010, the award was given to Mark Zuckerberg, the founder and CEO of the social networking site Facebook.There was, however, a strong campaign for the ‘People’s Choice’ award to be given to Julian Assange, the founder and editor-in-chief of Wikileaks, the online whistleblowing site. Earlier in the year Wikileaks had released more than 250 000 US government diplomatic cables through the internet, and the subsequent controver- sies around the actions of Wikileaks and Assange came to be known worldwide as ‘Cablegate’. The focus of this chapter is not on the implications of ‘Cablegate’ for international diplomacy, which continue to have great significance, but rather upon what the emergence of Wikileaks has meant for journalism, and whether it provides insights into the future of journalism. Both Facebook and Wikileaks, as well as social media platforms such as Twitter and YouTube, and independent media practices such as blogging, citizen journalism and crowdsourcing, are manifestations of the rise of social media, or what has also been termed web 2.0.The term ‘web 2.0’ was coined by Tim O’Reilly, and captures the rise of online social media platforms and services, that better realise the collaborative potential of digitally networked media. They do this by moving from the relatively static, top-down notions of interactivity that informed early internet development, towards more open and evolutionary models that better harness collective intelligence by enabling users to become the creators and collaborators in the development of online media content (Musser and O’Reilly 2007; Bruns 2008).
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A novel concept of producing high dc voltage for pulsed-power applications is proposed in this paper. The topology consists of an LC resonant circuit supplied through a tuned alternating waveform that is produced by an inverter. The control scheme is based on the detection of variations in the resonant frequency and adjustment of the switching signal patterns for the inverter to produce a square waveform with exactly the same frequencies. Therefore the capacitor voltage oscillates divergently with an increasing amplitude. A simple one-stage capacitor-diode voltage multiplier (CDVM) connected to the resonant capacitor then rectifies the alternating voltage and gives a dc level equal to twice the input voltage amplitude. The produced high voltage appears then in the form of high-voltage pulses across the load. A basic model is simulated by Simulink platform of MATLAB and the results are included in the paper.
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In this report we take a look at what separates high potential emerging and young start-ups from others. We compare the characteristics, intentions and behaviours of start-ups that we judge to be 'high potential' with other start-ups. We utilise the first two years of data from the CAUSEE study. We also compare Australian start-ups with a similar study conduced in the US.
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Product innovation is an important contributor to the performance of infrastructure projects in the construction industry. Maximizing the potential for innovative product adoption is a challenging task due to the complexities of the construction innovation system. A qualitative methodology involving interviews with major construction project stakeholders is employed to address the research question: ‘What are the main obstacles to the adoption of innovative products in the road industry?’ The characteristics of six key product innovation obstacles in Australian road projects are described. The six key obstacles are: project goal misalignment, client pressures, weak contractual relations, lack of product trialling, inflexible product specifications and product liability concerns. A snapshot of the dynamics underlying these obstacles is provided. There are few such assessments in the literature, despite the imperative to improve construction innovation rates globally in order to deliver road infrastructure projects of increasing size and complexity. Key obstacles are interpreted through an open innovation construct, providing direction for policy to enhance the uptake of innovation across the construction product supply network. Early evidence suggests the usefulness of an open innovation construct that integrates three conceptual lenses: network governance, absorptive capacity and knowledge intermediation, in order to interpret product adoption obstacles in the context of Australian road infrastructure projects. The paper also provides practical advice and direction for government and industry organizations that wish to promote the flow of innovative product knowledge across the construction supply network.
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Appearance-based loop closure techniques, which leverage the high information content of visual images and can be used independently of pose, are now widely used in robotic applications. The current state-of-the-art in the field is Fast Appearance-Based Mapping (FAB-MAP) having been demonstrated in several seminal robotic mapping experiments. In this paper, we describe OpenFABMAP, a fully open source implementation of the original FAB-MAP algorithm. Beyond the benefits of full user access to the source code, OpenFABMAP provides a number of configurable options including rapid codebook training and interest point feature tuning. We demonstrate the performance of OpenFABMAP on a number of published datasets and demonstrate the advantages of quick algorithm customisation. We present results from OpenFABMAP’s application in a highly varied range of robotics research scenarios.
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Purpose: The purpose of this research is to understand reflective journalling in a first year Public Health practice unit. Design/methodology/approach: This research uses pure phenomenography to interpret students descriptions of reflective journalling. Data was collected from thirty-two students enrolled in PUB215 Public Health Practice in the School of Public Health, Queensland University of Technology. Participants completed a brief open-ended questionnaire to evaluate the first assessment item in this unit, a Reflective Journal. Questionnaire responses were analysed through Dahlgren and Fallsberg’s (1991) seven phases of data analysis. Findings: The Reflective Journal required students to reflect on lecture content from five of seven guest speakers. Participants responses were categorised into four conceptions - 1) engagement in learning, 2) depth of knowledge, 3) understanding the process and 4) doing the task. Participants describe reflective journalling as a conduit to think critically about the content of the guest speakers presentations. Other participants think journalling is a vehicle to think deeply about their potential career pathways. Some define journalling as a pragmatic operation where practical issues are difficult to navigate. The Reflective Journal successfully a) engaged students learning, b) increased students depth of knowledge and c) deepened students understanding of the journalling process. Originality/value: This research gives an insight into how first year public health students understand reflective journalling, supports educators in reflective journalling assessments and confirms a Reflective Journal assessment can move student reflection towards higher order thinking about practice.
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The presence of colour in raw sugar plays a key role in the marketing strategy of the Australian raw sugar industry. Some sugars are relatively difficult to decolourise during refining and develop colour during storage. A new approach that might result in efficient and cost-effective colour removal during the sugar manufacturing process is the use of an advanced oxidation process (AOP), known as Fenton oxidation, that is, catalytic production of hydroxyl radicals from the decomposition of hydrogen peroxide using ferrous iron. As a first step towards developing this technology, this study determined the composition of colour precursors present in the juice of cane harvested by three different methods. The methods were harvesting cane after burning, harvesting the whole crop with half of the trash extracted and harvesting the whole crop with no trash extracted. The study also investigated the degradation at pH 3, 4 and 5 of a phenolic compound, caffeic acid (3,4–dihydroxycinnamic acid), which is present in sugar cane juice, using both hydrogen peroxide and Fenton’s reagent. The results show that juice expressed from whole crop cane has significantly higher colour than juices expressed from burnt cane. However, the concentrations of phenolic acids were lower in the juices expressed from whole crop cane. The main phenolic acids present in these juices were p-coumaric, vanillic, 2,3–dihydroxybenzoic, gallic and 3,4–dihydroxybenzoic acids. The degradation of caffeic acid significantly improved using Fenton’s reagent in comparison to hydrogen peroxide alone. The Fenton oxidation was optimum at pH 5 when up to ~86 % of caffeic acid degraded within 5 min.
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The presence of colour in raw sugar plays a key role in the marketing strategy of the Australian raw sugar industry. Some sugars are relatively difficult to decolourise during refining and develop colour during storage. A new approach that might result in efficient and cost-effective colour removal during the sugar manufacturing process is the use of an advanced oxidation process (AOP), known as Fenton oxidation, that is, catalytic production of hydroxyl radicals from the decomposition of hydrogen peroxide using ferrous iron. As a first step towards developing this technology, this study determined the composition of colour precursors present in the juice of cane harvested by three different methods. The methods were harvesting cane after burning, harvesting the whole crop with half of the trash extracted and harvesting the whole crop with no trash extracted. The study also investigated the degradation at pH 3, 4 and 5 of a phenolic compound, caffeic acid (3,4–dihydroxycinnamic acid), which is present in sugar cane juice, using both hydrogen peroxide and Fenton’s reagent. The results show that juice expressed from whole crop cane has significantly higher colour than juices expressed from burnt cane. However, the concentrations of phenolic acids were lower in the juices expressed from whole crop cane. The main phenolic acids present in these juices were p-coumaric, vanillic, 2,3–dihydroxybenzoic, gallic and 3,4–dihydroxybenzoic acids. The degradation of caffeic acid significantly improved using Fenton’s reagent in comparison to hydrogen peroxide alone. The Fenton oxidation was optimum at pH 5 when up to ~86% of caffeic acid degraded within 5 min.
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Compound pelvic fractures are deemed to be one of the most severe orthopaedic injuries with an extremely high morbidity and mortality. After the initial resuscitation phase the prevention of pelvic sepsis is one of the main treatment goals for patients with an open pelvic fracture. If there is a suspicion of a rectal injury or if the wounds are in the perineal area, The Princess Alexandra Hospital's management plan includes early faecal diversion combined with vigorous soft tissue debridement, VAC(®) therapy and (if indicated) external fixation of the pelvic fracture. We present our flowchart for the treatment of trauma patients with compound pelvic fractures illustrated by a case report describing a 32 year old patient who sustained an open pelvic ring injury in a workplace accident. The aim of this paper is to underline the importance of a safe, straightforward approach to compound pelvic fractures.
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Collaborative user-led content creation by online communities, or produsage (Bruns 2008), has generated a variety of useful and important resources and other valuable outcomes, from open source software through the Wikipedia to a variety of smaller-scale, specialist projects. These are often seen as standing in an inherent opposition to commercial interests, and attempts to develop collaborations between community content creators and commercial partners have had mixed success rates to date. However, such tension between community and commerce is not inevitable, and there is substantial potential for more fruitful exchanges and collaboration. This article contributes to the development of this understanding by outlining the key underlying principles of such participatory community processes and exploring the potential tensions which could arise between these communities and their potential external partners. It also sketches out potential approaches to resolving them.
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Background Evolutionary biologists are often misled by convergence of morphology and this has been common in the study of bird evolution. However, the use of molecular data sets have their own problems and phylogenies based on short DNA sequences have the potential to mislead us too. The relationships among clades and timing of the evolution of modern birds (Neoaves) has not yet been well resolved. Evidence of convergence of morphology remain controversial. With six new bird mitochondrial genomes (hummingbird, swift, kagu, rail, flamingo and grebe) we test the proposed Metaves/Coronaves division within Neoaves and the parallel radiations in this primary avian clade. Results Our mitochondrial trees did not return the Metaves clade that had been proposed based on one nuclear intron sequence. We suggest that the high number of indels within the seventh intron of the β-fibrinogen gene at this phylogenetic level, which left a dataset with not a single site across the alignment shared by all taxa, resulted in artifacts during analysis. With respect to the overall avian tree, we find the flamingo and grebe are sister taxa and basal to the shorebirds (Charadriiformes). Using a novel site-stripping technique for noise-reduction we found this relationship to be stable. The hummingbird/swift clade is outside the large and very diverse group of raptors, shore and sea birds. Unexpectedly the kagu is not closely related to the rail in our analysis, but because neither the kagu nor the rail have close affinity to any taxa within this dataset of 41 birds, their placement is not yet resolved. Conclusion Our phylogenetic hypothesis based on 41 avian mitochondrial genomes (13,229 bp) rejects monophyly of seven Metaves species and we therefore conclude that the members of Metaves do not share a common evolutionary history within the Neoaves.
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The aim of this study is to develop a new intra-canal disinfectant-carrier for infected canal treatment. To achieve this purpose, a new porous Ca-Si (CS)-based nanosphere was synthesized and characterized. Results showed that the nanospheres can infiltrate into dentinal tubules and released the ampicillin over one week time in a sustained manner. The release of ampicillin from spheres has significantly antibacterial property. Extensive and well-organized in vitro mineralization and crystallization of apatite were induced on the surface of dentin slices covered by CS nanospheres. All these features indicate that the porous CS nanospheres may be developed into a new intra-canal disinfectant-carrier for infected canal treatment.
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Ion channels are membrane proteins that open and close at random and play a vital role in the electrical dynamics of excitable cells. The stochastic nature of the conformational changes these proteins undergo can be significant, however current stochastic modeling methodologies limit the ability to study such systems. Discrete-state Markov chain models are seen as the "gold standard," but are computationally intensive, restricting investigation of stochastic effects to the single-cell level. Continuous stochastic methods that use stochastic differential equations (SDEs) to model the system are more efficient but can lead to simulations that have no biological meaning. In this paper we show that modeling the behavior of ion channel dynamics by a reflected SDE ensures biologically realistic simulations, and we argue that this model follows from the continuous approximation of the discrete-state Markov chain model. Open channel and action potential statistics from simulations of ion channel dynamics using the reflected SDE are compared with those of a discrete-state Markov chain method. Results show that the reflected SDE simulations are in good agreement with the discrete-state approach. The reflected SDE model therefore provides a computationally efficient method to simulate ion channel dynamics while preserving the distributional properties of the discrete-state Markov chain model and also ensuring biologically realistic solutions. This framework could easily be extended to other biochemical reaction networks. © 2012 American Physical Society.
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Numerical simulations for mixed convection of micropolar fluid in an open ended arc-shape cavity have been carried out in this study. Computation is performed using the Alternate Direct Implicit (ADI) method together with the Successive Over Relaxation (SOR) technique for the solution of governing partial differential equations. The flow phenomenon is examined for a range of values of Rayleigh number, 102 ≤ Ra ≤ 106, Prandtl number, 7 ≤ Pr ≤ 50, and Reynolds number, 10 ≤ Re ≤ 100. The study is mainly focused on how the micropolar fluid parameters affect the fluid properties in the flow domain. It was found that despite the reduction of flow in the core region, the heat transfer rate increases, whereas the skin friction and microrotation decrease with the increase in the vortex viscosity parameter, Δ.
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The structures of the cyclic imides cis-2-(2-fluorophenyl)-3a,4,5,6,7,7a-hexahydroisoindole-1,3-dione, C14H14FNO2, (I), and cis-2-(4-fluorophenyl)-3a,4,5,6,7,7a-hexahydroisoindoline-1,3-dione, C14H14FNO2, (III), and the open-chain amide acid rac-cis-2-[(3-fluorophenyl)carbamoyl]cyclohexane-1-carboxylic acid, C14H16FNO3, (II), are reported. Cyclic imides (I) and (III) are conformationally similar, with comparable ring rotations about the imide N-Car bond [the dihedral angles between the benzene ring and the five-membered isoindole ring are 55.40 (8)° for (I) and 51.83 (7)° for (III)]. There are no formal intermolecular hydrogen bonds involved in the crystal packing of either (I) or (III). With the acid (II), in which the meta-related F-atom substituent is rotationally disordered (0.784:0.216), the amide group lies slightly out of the benzene plane [the interplanar dihedral angle is 39.7 (1)°]. Intermolecular amide-carboxyl N-HO hydrogen-bonding interactions between centrosymmetrically related molecules form stacks extending down b, and these are linked across c by carboxyl-amide O-HO hydrogen bonds, giving two-dimensional layered structures which lie in the (011) plane. The structures reported here represent examples of compounds analogous to the phthalimides or phthalanilic acids and have little precedence in the crystallographic literature.