The study of condensed matter by deep inelastic neutron scattering

This thesis describes the technique of electron-volt neutron spectroscopy at the pulsed spallation neutron source ISIS at the Rutherford Appleton Laboratory. A number of systems were studied, with the emphasis on the validity of the impulse approximation in each case. Assuming a Gaussian momentum distribution, the mean kinetic ener­gies of ZrHj, ZrD2, NbH and NbD and lithium metal between 20 K and 300 K were measured. By numerical calculation, it is shown that anharmonicity in metal hydride systems can be dealt with in terms of a Gaussian momentum distribution, as for har­monic systems. The vibrational density of states of H in ZrH2 was determined from inelastic neutron scattering measurements of the dynamic structure factor made on the MARI spectrometer, and used to perform exact numerical simulations of eVS mea­sured neutron Compton profiles for a range of momentum transfers. The deviations of these simulated data from the impulse approximation due to final state effects were compared to deviations from the impulse approximation of data measured on eVS. It is shown that these deviations are small enough to be treated by a straightforward correction procedure

Does short termism affect the quality of urban design in the UK?

This paper follows the report on the “Quality of Urban Design: Study of the Influence of Private Property Decision Maker in Urban Design” (RICS 1996). It focuses on one of the findings in the report, namely that decisions made in development, investment and occupation seemed overly influenced by short term considerations. In this paper, the authors review the Report and examine the concept of short termism as it affects urban design decisions. The paper concludes that although it is difficult to establish whether or not short termism exists in many decisions, there are grounds for believing that a priori short termism might particularly influence property orientated decisions. The paper ends with some implications for policy both at the economy and local level

“Regulatory Daubert”: A Proposal to Enhance Judicial Review of Agency Science by Incorporating Daubert Principles into Administrative Law

In Daubert v. Merrell Dow Pharmaceuticals Inc, the US Supreme Court empowered federal judges to reject irrelevant or unreliable scientific evidence. Daubert provides a suitable framework for reviewing the quality of agency science and the soundness of agency decisions consistent with the standards established for review of agency rulemakings under the Administrative Procedure Act

“Regulatory Daubert”: A Proposal to Enhance Judicial Review of Agency Science by Incorporating Daubert Principles into Administrative Law

In Daubert v. Merrell Dow Pharmaceuticals Inc, the US Supreme Court empowered federal judges to reject irrelevant or unreliable scientific evidence. Daubert provides a suitable framework for reviewing the quality of agency science and the soundness of agency decisions consistent with the standards established for review of agency rulemakings under the Administrative Procedure Act

Mirror symmetry, Tyurin degenerations and fibrations on Calabi-Yau manifolds

We investigate a potential relationship between mirror symmetry for Calabi-Yau manifolds and the mirror duality between quasi-Fano varieties and Landau-Ginzburg models. More precisely, we show that if a Calabi-Yau admits a so-called Tyurin degeneration to a union of two Fano varieties, then one should be able to construct a mirror to that Calabi-Yau by gluing together the Landau-Ginzburg models of those two Fano varieties. We provide evidence for this correspondence in a number of different settings, including Batyrev-Borisov mirror symmetry for K3 surfaces and Calabi-Yau threefolds, Dolgachev-Nikulin mirror symmetry for K3 surfaces, and an explicit family of threefolds that are not realized as complete intersections in toric varieties.Comment: v2: Section 5 has been completely rewritten to accommodate results removed from Section 5 of arxiv:1501.04019. v3: Final version, to appear in String-Math 2015, forthcoming volume in the Proceedings of Symposia in Pure Mathematics serie

Synthetic approaches to tryptophan based dipeptide alkaloids

Imperial Users onl

Improving Canada's Immigration Policy

As labour markets change, the question arises whether Canada’s immigration policy – and our “point system” in particular – is doing a good job of identifying potential immigrants who will fare well on arrival in Canada.economic growth and innovation, immigration point system, Canadian immigration policy

Development of a Multi-Objective Optimization Capability for Heterogeneous Light Water Reactor Fuel Assemblies

As pressure grows on developed nations to move away from fossil fuel-based energy sources, so does the potential for nuclear energy to make its resurgence. However, the complex nature of the design process in nuclear engineering and a regulatory culture of ever-increasing safety standards create unique challenges to the nuclear industry. As in many engineering disciplines, the question is one of trade-offs between safety, performance, cost, and time required to develop the design from paper to real life operation. The possibilities facing a designer are virtually unlimited, with fuel choice, layout and operating conditions just three of the many categories which interact with one another in a highly non-linear manner, making it difficult to quantitatively define these trade-offs. Deciding upon an ‘optimal’ design is therefore traditionally done through expert judgement and an iterative design process. Mathematical optimization methods offer a more formal way to optimize designs by employing algorithms to explore the myriad of possibilities in a methodical manner which can yield increased performance over expert designs. In this thesis, an extensive review of the literature revealed gaps which present opportunities for novel research. Two new algorithms are created with the ability to solve optimization problems with multiple objectives simultaneously without requiring weighting or bias from the designer. They are then applied to a series of problems drawn from both the literature and real world designs. The results demonstrate the algorithms’ effectiveness and robustness as well as their ability to handle complex multi-physics problems with reasonably low computational requirements. This research offers an original and effective tool for performing optimization on nuclear fuel assembly design problems and has advanced the state of the art in both multi-objective optimization and its application to the nuclear engineering industry