Object-oriented construction of a multigrid electronic-structure code with Fortran 90

We describe the object-oriented implementation of a higher-order finite-difference density-functional code in Fortran 90. Object-oriented models of grid and related objects are constructed and employed for the implementation of an efficient one-way multigrid method we have recently proposed for the density-functional electronic-structure calculations. Detailed analysis of performance and strategy of the one-way multigrid scheme will be presented.Comment: 24 pages, 6 figures, to appear in Comput. Phys. Com

Copolymerization of ε-caprolactone and morpholine-2,5-dione derivatives

Novel biodegradable poly(ester-amide)s were prepared by ring-opening copolymerization of -caprolactone and 3- and/or 6-alkyl-substituted morpholine-2,5-dione derivatives. The copolymerizations were carried out in the bulk using stannous octoate as an initiator. Molecular weights of the copolymers ranged from 1,0 · 104 to 8,3 · 104 and decreased with increasing mole fractions of morpholine-2,5-dione derivatives in the feed. 13C NMR sequence analysis indicated that the copolymers had a random distribution of -oxycaproyl and depsipeptide units, which resulted from the occurrence of transesterification reactions during copolymerization. The results of the DSC measurements and 13C NMR sequence analysis showed a close relationship between the crystallinity and average length of ε-oxycaproyl blocks. Copolymers with a mole fraction of depsipeptide units smaller than 0,20 were semi-crystalline, whereas incorporation of larger amounts of depsipeptide units resulted in amorphous copolymers. The melting point depression as a function of the molar composition of the semi-crystalline copolymers was in good agreement with the melting point depression predicted by the Baur equation, which indicated the rejection of depsipeptide units from crystals consisting of ε-oxycaproyl units

Educational Philosophy of John Dewey and its relevance to current dilemmas in Education

Peer reviewedPublisher PD

Consequences of fast ion driven modes in MAST

As we enter the era of burning plasmas in next step devices such as ITER, the confinement of fusion born a-particles for sufficient duration that they impart their energy to the bulk fuel ions in order to maintain the thermonuclear burn is an important challenge in magnetically confined fusion. Fast ion driven plasma instabilities can cause significant redistribution and loss of the suprathermal energetic particle (EP) population, degrading performance. With dimensionless parameters such as the ratio of fast ion to thermal ion beta (Bfi/Bth ~50%) and the relative fast ion velocity to the Alfvén velocity (vfi/vA ~2) similar to those anticipated in ITER, the Mega Ampere Spherical Tokamak (MAST) provides the ideal place to study such instabilities. During periods of Neutral Beam Injection (NBI) heating, 'fishbone' instabilities are observed that coincide with a reduction to the fusion rate measured by drops in the neutron emission. Via experimental observations, fishbones are identified to be low frequency internal kink modes that burst in amplitude and chirp downwards in frequency and are synonymous with high power tokamak discharges on a wide range of devices around the world. This thesis provides a detailed analysis of what occurs during a single fishbone event. Experiments have been performed on MAST that have been interpreted using fast ion plasma physics codes. Modelling of the instability shows a resulting flux of fast ions away from the core, providing evidence at a fundamental level that they drive sufficient levels of anomalous fast ion transport to explain experimental observations. The diffusivity is shown to scale with mode amplitude, and the effect of altering other fishbone parameters within the scope of the experimental observations have been explained by identifying the extent of the fast ion population that is resonant with the mode. Resonant surfaces that sweep through phase space during the chirp are presented that coincide with populous domains of the EP distribution function; it is the gradients in this distribution function that define the drive and or damping of the instability. Via the use of synthetic diagnostics, changes to the radial profiles of neutron emissivity caused by a fishbone are shown to match those measured experimentally

Competitors and Cooperators: A Micro‐Level Analysis of Regional Economic Development Collaboration Networks

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90044/1/j.1540-6210.2011.02501.x.pd

The effect of learning on climate policy under fat-tailed risk

The effect of learning on climate policy is not straightforward when climate policy is concerned. It depends not only on the ways that climate feedbacks, preferences, and economic impacts are considered, but also on the ways that uncertainty and learning are introduced. Deep (or fat-tailed) uncertainty does matter for the optimal climate policy in that it requires more stringent efforts to reduce carbon emissions. However, learning may reveal thin-tailed uncertainty, weakening the case for emission abatement: learning reduces the stringency of the optimal abatement efforts relative to the no learning case even when we account for deep uncertainty. In order to investigate this hypothesis, we construct an endogenous (Bayesian) learning model with fat-tailed uncertainty on climate change and solve the model with stochastic dynamic programming. In our model a decision maker updates her belief on the total feedback factors through temperature observations each period and takes a course of action (carbon reductions) based on her belief. With various scenarios, we find that the uncertainty is partially resolved over time, although the rate of learning is relatively slow, and this materially affects the optimal decision: the decision maker with a possibility of learning lowers the effort to reduce carbon emissions relative to the no learning case. This is because the decision maker fully utilizes the information revealed to reduce uncertainty, and thus she can make a decision contingent on the updated information. In addition, with incorrect belief scenarios, we find 2 that learning enables the economic agent to have less regrets (in economic terms, sunk benefits or sunk costs) for her past decisions after the true value of the uncertain variable is revealed to be different from the initial belief

Financial regulation of public limited companies in the UK: A way forward post-Enron

Argues that the collapse of Enron Corp. provides an opportunity for regulators to consider fundamental issues associated with the regulatory framework for financial reporting, auditing and corporate governance in Great Britain. Details of the changes that have been introduced to the regulatory framework of financial reporting and auditing in Great Britain from 1991 to 1992; Patterns of behavior among non-executive directors who influence the effectiveness of corporate governance