The paper focuses on the numerical treatment of transient acoustic problems using finite element (FE) and boundary element (BE) methods. The FE method relies on a pressure formulation and the use of an implicit integration schemes for solving the related second-order differential system. The procedure is shown on cavity (interior) problems but can be extended to exterior problems using the DtN ...

We consider the scattering of acoustic perturbations in a presence of a flow. We suppose that the space can be split into a zone where the flow is uniform and a zone where the flow is potential. In the first zone, we apply a Prandtl–Glauert transformation to recover the Helmholtz equation. The well-known setting of boundary element method for the Helmholtz equation is available. In the second z...

An adaptive nite element–boundary element algorithm is proposed to compute an approximate solution of a given boundary value problem. The convergence in H ( ) is controlled by a boundary element based a-posteriori error estimator from which an adaptive re nement strategy is derived. Corresponding error estimates are given based on appropriate boundary element error estimates in negative Sobolev...

This document defines the forwarding element (FE) model used in the Forwarding and Control Element Separation (ForCES) protocol. The model represents the capabilities, state, and configuration of forwarding elements within the context of the ForCES protocol, so that control elements (CEs) can control the FEs accordingly. More specifically, the model describes the logical functions that are pres...

Boundary elements are thought to define the peripheries of chromatin domains and to restrict enhancerpromoter interactions to their target genes within their domains. We previously characterized a cDNA encoding the BEAF-32A protein (32A), which binds with high affinity to the scs* boundary element from the Drosophila melanogaster 87A7 hsp70 locus. Here, we report a second protein, BEAF-32B, tha...

While most ceramics are composed of ubiquitous elements (the ten most abundant elements within the Earth's crust), many advanced materials are based on rare elements. A 'rare-element crisis' is approaching owing to the imbalance between the limited supply of rare elements and the increasing demand. Therefore, we propose a 'ubiquitous element strategy' for materials research, which aims to apply...

We study the solution of large-scale nonlinear optimization problems by methods which aim to exploit their inherent structure. In particular, we consider the property of partial separability, first studied by Griewank and Toint [Nonlinear Optimization, 1981, pp. 301–312]. A typical minimization method for nonlinear optimization problems approximately solves a sequence of simplified linearized s...

We describe a hybrid method which combines the boundary element method (BEM) and the finite element method (FEM) to compute circuit models for layout dependent capacitances. The method can handle irregularities in the stratification of the layout of the integrated circuits (IC’s). New in the method are the models for the interface between the regions where the BEM and the FEM are applied. We sh...

This paper presents an element of a 2×2-element array antenna for Inmarsat BGAN/GPS applications. The element is an axial mode printed quadrifilar helical antenna that has been integrated with a compact feed network to provide sequential phase rotation for circular polarization (CP) radiation. The novel integrated lumped-element feed network is designed to provide a balanced RF power to the fou...