High resolution electron microscopy study of a high Cu variant of Weldalite (tm) 049 and a high strength Al-Cu-Ag-Mg-Zr alloy

Weldalite (trademark) 049 is an Al-Cu-Li-Ag-Mg alloy that is strengthened in artificially aged tempers primarily by very thin plate-like precipitates lying on the set of (111) matrix planes. This precipitate might be expected to be the T(sub 1) phase, Al2CuLi, which has been observed in Al-Cu-Li alloys. However, in several ways this precipitate is similar to the omega phase which also appears as the set of (111) planes plates and is found in Al-Cu-Ag-Mg alloys. The study was undertaken to identify the set of (111) planes precipitate or precipitates in Weldalite (trademark) 049 in the T8 (stretched and artificially aged) temper, and to determine whether T(sub 1), omega, or some other phase is primarily responsible for the high strength (i.e., 700 MPa tensile strength) in this Al-Cu-Li-Ag-Mg alloy

Research on boron filaments and boron reinforced composites

Boron filaments for use as reinforcing phase in composite materials for aerospace structure

Infrared ground-based astronomy with the Hughes 256 X 256 PtSi array

It is shown that large format PtSi Schottky diode infrared arrays, the Hughes 256 X 256 hybrid Schottky array in particular, are competitive alternatives to the smaller format photovoltaic arrays for ground-based astronomy. The modest quantum efficiency of the PtSi compared to the photovoltaic devices is more than compensated for by the larger format. The use of hybrid technology yields effective fill factors of nearly 100 percent, and the low dark current, noise, excellent imaging characteristics, cost, and solid nitrogen operating temperature add to the effectiveness of this array for ground-based imaging. In addition to discussing the characteristics of this array, researchers present laboratory test data and astronomical results achieved at Kitt Peak

The Alcohol Health Alliance: the emergence of an advocacy coalition to stimulate policy change

This paper provides an account of the emergence and early development of the Alcohol Health Alliance (AHA), a coalition of organizations including medical bodies, charities and alcohol health campaigners. Launched in 2007, the AHA aimed to re-frame awareness of alcohol consumption and related harms, to gain greater policy saliency for health compared to criminal justice priorities, and to shift policy towards adopting a population approach as compared to a targeted approach to intervention. The strategies used by the AHA to mobilize support and re-frame understanding of the alcohol problem, were successful in the short term. The alliance benefited from their links with established powerful institutions that helped them secure a strong presence within the policy arena and in the media, not least by forging relationships with political allies. However, in the longer term, it may be difficult to maintain a position of strength and to combat pre-existing entrenched relationships that favour competing alternative perceptions of the alcohol problem and the appropriate policy response

Designing a Regulatory and Supervisory Framework for Integrated Financial Markets

The financial crisis that started in 2007 casts doubt about the ability of national laws and competent authorities to manage the stability of the financial system and to protect investors. This is due to the relevant evolving features of financial intermediation, like the cross-border strategies in banking, with many M&A undertaken, especially in Europe, and more in general the globalization of finance, also through the many recent operations among exchanges. The associated regulatory and supervisory challenges have proved to be difficult to tackle. An international perspective is needed on single banking regulatory instruments, even if it is impossible at this stage to imagine unique rules and single international authorities managing capital ratios, deposit insurance, reserve requirements and lending of last resort, as well as other tools for providing financial markets stability. However, some common principles on regulation and the structure of supervision may be stated both in US and in Europe: we suggest a “four peak” approach to the matter.The financial crisis that started in 2007 casts doubt about the ability of national laws and competent authorities to manage the stability of the financial system and to protect investors. This is due to the relevant evolving features of financial intermediation, like the cross-border strategies in banking, with many M&A undertaken, especially in Europe, and more in general the globalization of finance, also through the many recent operations among exchanges. The associated regulatory and supervisory challenges have proved to be difficult to tackle. An international perspective is needed on single banking regulatory instruments, even if it is impossible at this stage to imagine unique rules and single international authorities managing capital ratios, deposit insurance, reserve requirements and lending of last resort, as well as other tools for providing financial markets stability. However, some common principles on regulation and the structure of supervision may be stated both in US and in Europe: we suggest a “four peak” approach to the matter.Refereed Working Papers / of international relevanc

Identifying promising approaches and initiatives to reducing alcohol related harm

This study aimed to identify promising approaches that could be included in multi-component programmes (MCPs) to reduce alcohol related harm at local level in the UK. MCPs involve the identification of alcohol related problems at the local level and implementation of a programme of co-ordinated projects to tackle a problem. They are based on an integrative design where singular interventions run in combination with each other and/or are sequenced together over time; the identification, coordination and mobilisation of local agencies, stakeholders and community are key elements (Thom and Bayley, 2007). This study was underpinned by the recognition that the voices of practitioners are often marginalised in the debates about ‘what works’ and it set out to include their views. So whilst acknowledging the importance of the international research literature, care was taken not to privilege it over other ‘softer’ sources e.g. knowledge and experience of practitioners

Low temperature shape relaxation of 2-d islands by edge diffusion

We present a precise microscopic description of the limiting step for low temperature shape relaxation of two dimensional islands in which activated diffusion of particles along the boundary is the only mechanism of transport allowed. In particular, we are able to explain why the system is driven irreversibly towards equilibrium. Based on this description, we present a scheme for calculating the duration of the limiting step at each stage of the relaxation process. Finally, we calculate numerically the total relaxation time as predicted by our results and compare it with simulations of the relaxation process.Comment: 11 pages, 5 figures, to appear in Phys. Rev.

Statics, Dynamics and Manipulations of Bright Matter-Wave Solitons in Optical Lattices

Motivated by recent experimental achievement in the work with Bose-Einstein condensates (BECs), we consider bright matter-wave solitons, in the presence of a parabolic magnetic trap and a spatially periodic optical lattice (OL), in the attractive BEC. We examine pinned states of the soliton and their stability by means of perturbation theory. The analytical predictions are found to be in good agreement with numerical simulations. We then explore possibilities to use a time-modulated OL as a means of stopping and trapping a moving soliton, and of transferring an initially stationary soliton to a prescribed position by a moving OL. We also study the emission of radiation from the soliton moving across the combined magnetic trap and OL. We find that the soliton moves freely (without radiation) across a weak lattice, but suffers strong loss for stronger OLs.Comment: 7 pages, 5 figs, Phys Rev A in Press (2005

Non-collinear coupling between magnetic adatoms in carbon nanotubes

The long range character of the exchange coupling between localized magnetic moments indirectly mediated by the conduction electrons of metallic hosts often plays a significant role in determining the magnetic order of low-dimensional structures. In addition to this indirect coupling, here we show that the direct exchange interaction that arises when the moments are not too far apart may induce a non-collinear magnetic order that cannot be characterized by a Heisenberg-like interaction between the magnetic moments. We argue that this effect can be manipulated to control the magnetization alignment of magnetic dimers adsorbed to the walls of carbon nanotubes.Comment: 13 pages, 5 figures, submitted to PR

Kramers degeneracy in a magnetic field and Zeeman spin-orbit coupling in antiferromagnets

In this article, I analyze the symmetries and degeneracies of electron eigenstates in a commensurate collinear antiferromagnet. In a magnetic field transverse to the staggered magnetization, a hidden anti-unitary symmetry protects double degeneracy of the Bloch eigenstates at a special set of momenta. In addition to this `Kramers degeneracy' subset, the manifold of momenta, labeling the doubly degenerate Bloch states in the Brillouin zone, may also contain an `accidental degeneracy' subset, that is not protected by symmetry and that may change its shape under perturbation. These degeneracies give rise to a substantial momentum dependence of the transverse g-factor in the Zeeman coupling, turning the latter into a spin-orbit interaction. I discuss a number of materials, where Zeeman spin-orbit coupling is likely to be present, and outline the simplest properties and experimental consequences of this interaction, that may be relevant to systems from chromium to borocarbides, cuprates, hexaborides, iron pnictides, as well as organic and heavy fermion conductors.Comment: 16+ pages, extended version of arXiv:0805.0378; revised versio