Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events

The $B^0$-$\bar B^0$ oscillation frequency has been measured with a sample of 23 million \B\bar B pairs collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we select events in which both B mesons decay semileptonically and use the charge of the leptons to identify the flavor of each B meson. A simultaneous fit to the decay time difference distributions for opposite- and same-sign dilepton events gives $\Delta m_d = 0.493 \pm 0.012{(stat)}\pm 0.009{(syst)}$ ps$^{-1}$.Comment: 7 pages, 1 figure, submitted to Physical Review Letter

Perioperative medicine and UK plc.

No abstract available

Grain refinement of magnesium alloys: a review of recent research, theoretical developments and their application

This paper builds on the ‘‘Grain Refinement of Mg Alloys’’ published in 2005 and reviews the grain refinement research onMg alloys that has been undertaken since then with an emphasis on the theoretical and analytical methods that have been developed. Consideration of recent research results and current theoretical knowledge has highlighted two important factors that affect an alloy’s as-cast grain size. The first factor applies to commercial Mg-Al alloys where it is concluded that impurity and minor elements such as Fe and Mn have a substantially negative impact on grain size because, in combination with Al, intermetallic phases can be formed that tend to poison the more potent native or deliberately added nucleant particles present in the melt. This factor appears to explain the contradictory experimental outcomes reported in the literature and suggests that the search for a more potent and reliable grain refining technology may need to take a different approach. The second factor applies to all alloys and is related to the role of constitutional supercooling which, on the one hand, promotes grain nucleation and, on the other hand, forms a nucleation-free zone preventing further nucleation within this zone, consequently limiting the grain refinement achievable, particularly in low solute-containing alloys. Strategies to reduce the negative impact of these two factors are discussed. Further, the Interdependence model has been shown to apply to a broad range of casting methods from slow cooling gravity die casting to fast cooling high pressure die casting and dynamic methods such as ultrasonic treatment

IMG 305 - PEMBUNGKUSAN MAKANAN NOV.05.

We discuss the use of Agent-based Modelling for the development and testing of theories about emergent social phenomena in marketing and the social sciences in general. We address both theoretical aspects about the types of phenomena that are suitably addressed with this approach and practical guidelines to help plan and structure the development of a theory about the causes of such a phenomenon in conjunction with a matching ABM. We argue that research about complex social phenomena is still largely fundamental research and therefore an iterative and cyclical development process of both theory and model is to be expected. To better anticipate and manage this process, we provide theoretical and practical guidelines. These may help to identify and structure the domain of candidate explanations for a social phenomenon, and furthermore assist the process of model implementation and subsequent development. The main goal of this paper was to make research on complex social systems more accessible and help anticipate and structure the research process

The numerical modelling of steep waves interacting with structures

The interaction of steep waves with structures is a complex problem which is still not fully understood, and is of great importance for the design of offshore structures. A particular problem of interest is the phenomenon of ringing which is highly nonlinear. In this thesis a number of inviscid free surface flow problems are simulated using a finite element model. The free surface boundary condition is fully nonlinear, meaning nonlinear effects up to very high order can be simulated, depending on mesh resolution. The model uses a fully automatic unstructured mesh generator; this allows the mesh to change its shape and structure as the free surface deforms. Two unstructured mesh generators have been developed, one based on the advancing front method, the other on the Voronoi technique. Variations of each method are examined. Both methods give good quality meshes. The advancing front technique is found to be faster, but the Voronoi method is more robust and reliable. In addition to the standard finite element method, a sigma transformed version of the finite element formulation has been developed as an alternative. Both techniques have been used for the numerical simulations. The sigma transformation involves stretching of the mesh between the bed and free surface, and so has the advantage that remeshing is avoided. The standard finite element method is straightforward to apply to problems involving submerged arbitrary shaped bodies. Simulations have been performed of a number of test cases, such as a standing wave of large amplitude, a base excited tank and steep travelling waves. Convergence tests were carried out and results found to be in close agreement with analytical and alternative numerical solutions of Wu and Eatock Taylor (1994), Wu et al. (1998) and Chern et al. (1999). The force on a submerged horizontal cylinder due a travelling wave has been calculated. First and second order components have been obtained by Fourier analysis. The results have been compared with the theoretical predictions of Ogilvie (1963), Vada (1987) and Wu and Eatock Taylor (1990) and the experimental results of Chaplin (1984).</p