Structural design synthesis approach to filamentary composites

Structural design methods for analysis of multilayer or laminated filamentary composite

Minimum weight design of symmetrically stiffened orthotropic cylinders under axial compression

Minimum weight design of symmetrically stiffened orthotropic cylinders under axial compressio

Stellar Populations with ELTs

The star formation, mass assembly and chemical enrichment histories of galaxies, and their present distributions of dark matter, remain encoded in their stellar populations. Distinguishing the actual distribution functions of stellar age, metallicity and kinematics at several locations in a range of galaxies, sampling across Hubble types and representative environments, is the information required for a robust description of galaxy histories. Achieving this requires large aperture, to provide the sensitivity to reach a range of environs and Hubble types beyond the Local Group, to provide high spatial resolution, since the fields are crowded, and preferably with optical performance since age-sensitivity is greatest near the main-sequence turn-off, and metallicity-sensitivity for these warm stars is greatest in the optical.Comment: IAU Symposium No. 232, eds P. Whitelock, B. Leidundgeit & M. Dennefel

The communication processor of TUMULT-64

Tumult (Twente University MULTi-processor system) is a modular extendible multi-processor system designed and implemented at the Twente University of Technology in co-operation with Oce Nederland B.V. and the Dr. Neher Laboratories (Dutch PTT). Characteristics of the hardware are: MIMD type, distributed memory, message passing, high performance, real-time and fault tolerant. A distributed real-time operating system has been realized, consisting of a multi-tasking kernel per node, inter process communication via typed messages and a distributed file system. In this paper first a brief description of the system is given, after that the architecture of the communication processor will be discussed. Reduction of the communication overhead due to message passing will be emphasized.\ud \u

Tests for the asymptotic behaviour of the gamma^* --> gamma pi^0 form factor

The gamma^* --> gamma pi^0 transition measured at different photon virtualities already provides us with a clean test for the behaviour of the pi^0 gamma^* gamma off-shell axial anomaly at large time-like squared momenta. It also allows reliable predictions for the branching ratio of heavy quarkonium decays into omega pi^0.Comment: Latex, 7 pages + 1 .ps figure, comments on the Brodsky-Lepage limit and 5 new references adde

Are stellar over-densities in dwarf galaxies the "smoking gun" of triaxial dark matter haloes?

We use N-body simulations to study the tidal evolution of globular clusters (GCs) in dwarf spheroidal (dSph) galaxies. Our models adopt a cosmologically motivated scenario in which the dSph is approximated by a static NFW halo with a triaxial shape. For a large set of orbits and projection angles we examine the spatial and velocity distribution of stellar debris deposited during the complete disruption of stellar clusters. Our simulations show that such debris appears as shells, isolated clumps and elongated over-densities at low surface brightness (>26 mag/arcsec^2), reminiscent of substructure observed in several MW dSphs. Such features arise from the triaxiality of the galaxy potential and do not dissolve in time. Stellar over-densities reported in several MW dSphs may thus be the telltale evidence of dark matter haloes being triaxial in shape. We explore a number of kinematic signatures that would help to validate (or falsify) this scenario. The mean angular momentum of the cluster debris associated with box and resonant orbits, which are absent in spherical potentials, is null. As a result, we show that the line-of-sight velocity distribution may exhibit a characteristic "double-peak" depending on the oriention of the viewing angle with respect to the progenitor's orbital plane. Kinematic surveys of dSphs may help to detect and identify substructures associated with the disruption of stellar clusters, as well as to address the shape of the dark matter haloes in which dSphs are embedded.Comment: 4 pages, 2 figures, to be published in the proceedings of "Hunting for the Dark: The Hidden Side of Galaxy Formation", Malta, 19-23 Oct. 2009, eds. V.P. Debattista & C.C. Popescu, AIP Conf. Ser., in pres

Throughput of Streaming Applications Running on a Multiprocessor Architecture

We study the timing behaviour of streaming applications running on a multiprocessor architecture. Dependencies are derived between the application throughput and the timing characteristics of the processors and communication. Four different processor organizations that strongly influenced the results are considered and compared