Calculation of Effective Coulomb Interaction for Pr3+Pr^{3+}, U4+U^{4+}, and UPt3UPt_3

In this paper, the Slater integrals for a screened Coulomb interaction of the the Yukawa form are calculated and by fitting the Thomas-Fermi wavevector, good agreement is obtained with experiment for the multiplet spectra of $Pr^{3+}$ and $U^{4+}$ ions. Moreover, a predicted multiplet spectrum for the heavy fermion superconductor $UPt_3$ is shown with a calculated Coulomb U of 1.6 eV. These effective Coulomb interactions, which are quite simple to calculate, should be useful inputs to further many-body calculations in correlated electron metals.Comment: 8 pages, revtex, 3 uuencoded postscript figure

Perturbation-based stochastic multi-scale computational homogenization method for woven textile composites

In this paper, a stochastic homogenization method that couples the state-of-the-art computational multi-scale homogenization method with the stochastic finite element method, is proposed to predict the statistics of the effective elastic properties of textile composite materials. Uncertainties associated with the elastic properties of the constituents are considered. Accurately modeling the fabric reinforcement plays an important role in the prediction of the effective elastic properties of textile composites due to their complex structure. The p-version finite element method is adopted to refine the analysis. Performance of the proposed method is assessed by comparing the mean values and coefficients of variation for components of the effective elastic tensor obtained from the present method against corresponding results calculated by using Monte Carlo simulation method for a plain-weave textile composite. Results show that the proposed method has sufficient accuracy to capture the variability in effective elastic properties of the composite induced by the variation of the material properties of the constituents

Strategic directions in constraint programming

An abstract is not available

Euclid, Tarski, and Engler encompassed

The research presented in this paper is situated in the framework of constraint databases that was introduced by Kanellakis, Kuper, and Revesz in their seminal paper of 1990. In this area, databases and query languages are defined using read polynomial constraints. As a consequence of a classical result by Tarski, first-order queries in the constraint database model are effectively computable, and their result is within the constraint model. In practical applications, for reasons of efficiency, this model is implemented with only linear polynomial constraints. Here, we also have a closure property: linear queries evaluated on linear databases yield linear databases. The limitation to linear polynomial constraints has severe implications on the expressive power of the query language, however. Indeed, the constraint database model has its most important applications in the field of spatial databases and, with only linear polynomials, the data modeling capabilities are limited and queries important for spatial applications that involve Euclidean distance are no longer expressible. The aim of this paper is to identify a class of two-dimensional constraint databases and a query language within the constraint model that go beyond the linear model. Furthermore, this language should allow the expression of queries concerning distance. Hereto, we seek inspiration in the Euclidean constructions, i.e., constructions by ruler and compass. In the course of reaching our goal, we have studied three languages for ruler-and-compass constructions. Firstly, we present a programming language. We show that this programming language captures exactly the ruler and compass constructions that are also expressible in the first-order constraint language with arbitrary polynomial constraints. If our programming language is extended with a while operator, we obtain a language that is complete for all ruler-and-compass constructions in the plane, using techniques of Engeler

DYNAMIC PROPERTIES OF HIGH DAMPING METALS

No abstract availabl

On the Orthographic Dimension of Constraint Databases

. One of the most important advantages of constraint databases is their ability to represent and to manipulate data in arbitrary dimension within a uniform framework. Although the complexity of querying such databases by standard means such as first-order queries has been shown to be tractable for reasonable constraints (e.g. polynomial), it depends badly (roughly speaking exponentially) upon the dimension of the data. A precise analysis of the trade-off between the dimension of the input data and the complexity of the queries reveals that the complexity strongly depends upon the use the input makes of its dimensions. We introduce the concept of orthographic dimension, which, for a convex object O, corresponds to the dimension of the (component) objects O1 ; :::; On , such that O = O1 \Theta \Delta \Delta \Delta \Theta On . We study properties of databases with bounded orthographic dimension in a general setting of o-minimal structures, and provide a syntactic characterization of firs..