6 resultados para 1137

em Aston University Research Archive


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Recent studies of new institutional spaces typically underplay the uneven and contested process of institutional change by undervaluing the role of inherited institutions and discourses. This is a critical issue as neoliberal networked forms of governance interact with inherited institutional arrangements, characterised by important path dependencies that guide actors. Contradiction and tensions can emerge, culminating in crisis tendencies, and producing both discursive and material contestation between actors. It is with an understanding of path dependencies, ideas (structured into discourses), and (perceived and actual) crisis tendencies that this paper examines contested institutional change through a case-study analysis of one city, and a critical engagement with neoinstitutionalism. The purpose is to examine, firstly, the significance of inherited path-dependent arrangements in fostering conflict and crisis tendencies during interaction with emergent state action; secondly, the extent to which crisis is evident in processes of institutional change and the form that this takes; and, thirdly, the importance of ideas in producing institutional transformation. It is found that institutional conflict is evident between inherited institutions and emergent state action, and stems both from the way agents are organised by the state and from certain path dependencies, but that this does not lead to an actual material crisis. Rather, the nation-state, in partnership with senior city government actors, use ideational/discursive ‘crisis talk’ as a means by which to induce institutional change. The role of ideas has been in critical in this process as the nation-state frames problems and solutions in line with its existing policy paradigm and institutional arrangements, and with discourses further reinforcing existing material power relations.

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We present the first experimental demonstration of a resolvable mode structure with spacing c/2nL in the RF spectra of ultralong Raman fiber lasers. The longest ever demonstrated laser cavity (L=84km), RF peaks of ∼100 Hz width and spacing ∼1 kHz have been observed at low intracavity powers. The width of the peaks increases linearly with growing intracavity power and is almost independent of fiber length. © 2007 Optical Society of America.

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The utilization of solar energy by photovoltaic (PV) systems have received much research and development (R&D) attention across the globe. In the past decades, a large number of PV array have been installed. Since the installed PV arrays often operate in harsh environments, non-uniform aging can occur and impact adversely on the performance of PV systems, especially in the middle and late periods of their service life. Due to the high cost of replacing aged PV modules by new modules, it is appealing to improve energy efficiency of aged PV systems. For this purpose, this paper presents a PV module reconfiguration strategy to achieve the maximum power generation from non-uniformly aged PV arrays without significant investment. The proposed reconfiguration strategy is based on the cell-unit structure of PV modules, the operating voltage limit of gird-connected converter, and the resulted bucket-effect of the maximum short circuit current. The objectives are to analyze all the potential reorganization options of the PV modules, find the maximum power point and express it in a proposition. This proposition is further developed into a novel implementable algorithm to calculate the maximum power generation and the corresponding reconfiguration of the PV modules. The immediate benefits from this reconfiguration are the increased total power output and maximum power point voltage information for global maximum power point tracking (MPPT). A PV array simulation model is used to illustrate the proposed method under three different cases. Furthermore, an experimental rig is built to verify the effectiveness of the proposed method. The proposed method will open an effective approach for condition-based maintenance of emerging aging PV arrays.

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It is well known that many medicines are a mixture of two enantiomers, or mirror-image molecules. Two enantiomers occur when a molecule has a single chiral centre and the two mirror images, called S or L (left handed) and R or D (right handed), are usually found in equal amounts in the parent (racemic) mixture. While for many compounds used in clinical practice the active moiety is found in one of the two enantiomers with the other being seen as an unnecessary and redundant component of the racemic mixture, the difference between enantiomers can mean a difference between therapeutic and adverse effects, as well as in beneficial pharmacological effect and potency. © 2010 The Author(s).

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We developed and tested a team level contingency model of innovation, integrating theories regarding work demands, team reflexivity - the extent to which teams collectively reflect upon their working methods and functioning -, and team innovation. We argued that highly reflexive teams will be more innovative than teams low in reflexivity when facing a demanding work environment. The relationships between team reflexivity, a demanding work environment (i.e. quality of the physical work environment and work load) and team innovation was examined among 98 primary health care teams (PHCTs) in the UK, comprised of 1137 individuals. Results showed that team reflexivity is positively related to team innovation, and that there is an interaction between team reflexivity, team level workload, and team innovation, such that when team level workload is high, combined with a high level of team reflexivity, team innovation is also higher. The complementary interaction between team reflexivity, quality of physical work environment, and team innovation, showed that when the quality of the work environment is low, combined with a high level of team reflexivity, team innovation was also higher. These results are discussed in the context of the need for team reflexivity and team innovation among teams at work facing high work demands.