60,555 research outputs found
To PB or not PB: making wikis work for your library
Library staff at Leeds Metropolitan University have recently launched a wiki to help them with the organisation of the information they need for their day-to-day enquiry and circulation duties. Here we outline the development of the project and the reasons behind choosing a wiki as the best format for this information
Fractal Droplets in Two Dimensional Spin Glasses
The two-dimensional Edwards-Anderson model with Gaussian bond distribution is
investigated at T=0 with a numerical method. Droplet excitations are directly
observed. It turns out that the averaged volume of droplets is proportional to
l^D with D = 1.80(2) where l is the spanning length of droplets, revealing
their fractal nature. The exponent characterizing the l dependence of the
droplet excitation energy is estimated to be -0.42(4), clearly different from
the stiffness exponent for domain wall excitations.Comment: 4 pages 4 figure
Stability of Elastic Glass Phases in Random Field XY Magnets and Vortex Lattices in Type II Superconductors
A description of a dislocation-free elastic glass phase in terms of domain
walls is developed and used as the basis of a renormalization group analysis of
the energetics of dislocation loops added to the system. It is found that even
after optimizing over possible paths of large dislocation loops, their energy
is still very likely to be positive when the dislocation core energy is large.
This implies the existence of an equilibrium elastic glass phase in three
dimensional random field X-Y magnets, and a dislocation free,
bond-orientationally ordered ``Bragg glass'' phase of vortices in dirty Type II
superconductors.Comment: 12 pages, Revtex, no figures, submitted to Phys Rev Letter
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Research impact evaluation, a wider context: Findings from a research impact pilot
In the face of increasing pressure to demonstrate the socio-economic impact of funded research, whether it is funded directly by research councils or indirectly by governmental research block grants, institutions have to tackle the complexity of understanding, tracking, collecting, and analysing the impact of all their research activities. This paper attempts to encapsulate the wider context of research impact by delineating a broad definition of what might be classified as impact. It also suggests a number of different dimensions that can help in the development of a systematic research impact assessment
framework. The paper then proceeds to indicate how boundaries and criteria around the definition of impact and these dimensions can be used to refine the impact assessment framework in order to focus on the objectives of the assessor. A pilot project, run at Brunel University, was used to test the validity of the approach and
possible consequences. A tool specifically developed for the pilot, the Brunel Research
Impact Device for Evaluation (BRIDE), is used for the analysis of research impact collected during the pilot. The paper reports on the findings of the analysis produced by BRIDE and confirms how a number of areas might be greatly affected by the boundaries set on definition and dimensions of research impact. The pilot project shows that useful information on impacts can be generated and it also provides a way to identify areas of work from each unit of assessment for which it would be worth developing narrative case studies. The pilot project has illustrated that it is feasible to make progress in terms of assessing impact, but that there are many difficulties to be addressed before impact assessment can be incorporated into a system of assessing the impact from the university sector as a whole. The paper concludes with an institutional perspective of the value of the approach and highlights possible applications. It also confirms the intention to expand the pilot and introduce new lines of investigation
Observation of fine one-dimensionally disordered layers in silicon carbide
The improved resolution of synchrotron edge-topography is enabling thinner (less than 100 microns), silicon carbide crystals to be studied, and is providing a more detailed and wider database on polytype depth profiles. Fine long-period and one-dimensionally-disordered layers, 5-25 microns thick, can now be confidently resolved and are found to be very common features, often in association with high-defect density bands. These features are illustrated in this paper using three examples. A new long period polytype LPP (152H/456R) has been discovered and reported here for the first time
Can crack front waves explain the roughness of cracks ?
We review recent theoretical progress on the dynamics of brittle crack fronts
and its relationship to the roughness of fracture surfaces. We discuss the
possibility that the intermediate scale roughness of cracks, which is
characterized by a roughness exponent approximately equal to 0.5, could be
caused by the generation, during local instabilities by depinning, of
diffusively broadened corrugation waves, which have recently been observed to
propagate elastically along moving crack fronts. We find that the theory agrees
plausibly with the orders of magnitude observed. Various consequences and
limitations, as well as alternative explanations, are discussed. We argue that
another mechanism, possibly related to damage cavity coalescence, is needed to
account for the observed large scale roughness of cracks that is characterized
by a roughness exponent approximately equal to 0.8Comment: 26 pages, 3 .eps figure. Submitted to J. Mech. Phys. Solid
Party finance reform as constitutional engineering? The effectiveness and unintended consequences of party finance reform in France and Britain
In both Britain and France, party funding was traditionally characterized by a laissez faire approach and a conspicuous lack of regulation. In France, this was tantamount to a 'legislative vacuum'. In the last two decades, however, both countries have sought to fundamentally reform their political finance regulation regimes. This prompted, in Britain, the Political Parties, Elections and Referendums Act 2000, and in France a bout of 'legislative incontinence' — profoundly transforming the political finance regime between 1988 and 1995. This article seeks to explore and compare the impacts of the reforms in each country in a bid to explain the unintended consequences of the alternative paths taken and the effectiveness of the new party finance regime in each country. It finds that constitutional engineering through party finance reform is a singularly inexact science, largely due to the imperfect nature of information, the limited predictability of cause and effect, and the constraining influence of non-party actors, such as the Constitutional Council in France, and the Electoral Commission in Britain
Monitoring crack extension in fracture toughness tests by ultrasonics
An ultrasonic method was used to observe the onset of crack extension and to monitor continued crack growth in fracture toughness specimens during three point bend tests. A 20 MHz transducer was used with commercially available equipment to detect average crack extension less than 0.09 mm. The material tested was a 300-grade maraging steel in the annealed condition. A crack extension resistance curve was developed to demonstrate the usefulness of the ultrasonic method for minimizing the number of tests required to generate such curves
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