Dynamic Matrix-Fracture Transfer Behaviour in Dual-Porosity Models

Imperial Users onl

Hybrid system of expert system and artificial neural networks for objective evaluation of product sensuous quality

Basic problems and the bottleneck of current approaches for objective assessment of product sensuous quality (PSQ) are discussed. As a solution, a new approach, an expert system (ES) based on artificial neural networks (ANNs) is proposed, in which the ES and ANNs co-operate in a superiority compensation way. T he knowledge base of the system can be effectively built and the evaluation of PSQ can be conducted on-line. As a case study, the new approach has been applied in leather handle test and it proves that the approach is capable of handling non-linear relationships among multiple measured PSQ parameters

Closed expression of the interaction kernel in the Bethe-Salpeter equation for quark-antiquark bound states

The interaction kernel in the Bethe-Salpeter equation for quark-antiquark bound states is derived from the Bethe-Salpeter equations satisfied by the quark-antiquark four-point Green's function. The latter equations are established based on the equations of motion obeyed by the quark and antiquark propagators, the four-point Green's function and some other kinds of Green's functions which follow directly from the QCD generating functional. The B-S kernel derived is given an exact and explicit expression which contains only a few types of Green's functions. This expression is not only convenient for perturbative calculations, but also suitable for nonperturbative investigations.Comment: 27 pages,no figure

Classification of derivation-simple color algebras related to locally finite derivations

We classify the pairs $(A,D)$ consisting of an $(\epsilon,\Gamma)$-olor-commutative associative algebra $A$ with an identity element over an algebraically closed field $F$ of characteristic zero and a finite dimensional subspace $D$ of $(\epsilon,\Gamma)$-color-commutative locally finite color-derivations of $A$ such that $A$ is $\Gamma$-graded $D$-simple and the eigenspaces for elements of $D$ are $\Gamma$-graded. Such pairs are the important ingredients in constructing some simple Lie color algebras which are in general not finitely-graded. As some applications, using such pairs, we construct new explicit simple Lie color algebras of generalized Witt type, Weyl type.Comment: 15 page

Random walks on the torus with several generators

Our paper gives bounds for the rate of convergence for a class of random walks on the d-dimensional torus generated by a set of n vectors in R^d/Z^d. We give bounds on the discrepancy distance from Haar measure; our lower bound holds for all such walks, and if the generators arise from the rows of a "badly approximable" matrix, then there is a corresponding upper bound. The bounds are sharp for walks on the circle.Comment: 10 pages; related work at http://www.math.hmc.edu/~su/papers.htm

Revisiting Play School: A historical case study of the BBC’s address to the pre-school audience

Although clearly recognised in broader institutional histories of British children’s television as a significant moment in the BBC’s address toward the pre-school child, Play School (BBC 1964-88) has not been the focus of sustained archival analysis. This arguably reflects the fact that a good deal of work on children’s television in Britain adopts either an institutional or an audience focus, and the study of programmes cultures is often more neglected. This article seeks to revisit Play School using available historical documentation – including memos, scripts and press cuttings - from the BBC Written Archive Centre, as well as early surviving episodes (principally from 1964). In doing so, it seeks to explore how it fitted into BBC’s historical address to the pre-school child, how it intersected with discourses on pre-school education, and the range of institutional and social contexts surrounding its emergence. Key Words: Play School * Pre-school television * BBC * Child audienc

Thurston's metric on Teichm\"uller space and the translation lengths of mapping classes

We show that the Teichm\"uller space of a surface without boundary and with punctures, equipped with Thurston's metric is the limit (in an appropriate sense) of Teichm\"uller spaces of surfaces with boundary, equipped with their arc metrics, when the boundary lengths tend to zero. We use this to obtain a result on the translation distances for mapping classes for their actions on Teichm\"uller spaces equipped with their arc metrics

Natural evidence for garnet-spinel transition (GST) in the Earth's mantle

This study based on compiled world-wide garnet peridotite data confirms the GST in high P and T conditions, which was obtained from Al-free experimental system (MgO-Cr~2~O~3~-SiO~2~) by Klemme (2004). A new spinel-phase peridotite zone, garnet peridotite discontinuous zone, is defined, and another GST, although no experimental data, is principally and presumably proposed to exist. The garnet inclusion-bearing spinel harzburgite from Lashaine (Tanzania) provides the first evidence for the existence of ultra-high spinel zone and is explained as recrystallized minerals hosting the interacted residue of ancient oceanic lithosphere subducted into the great depth of more than 220km. These previously unexpected findings are generating great challenges to phase transition in extreme conditions and to our understanding of layered-structure of the Earth. In addition, coexistent five-phase peridotite is suggested to be naturally useful tool to constrain the GST