1,112 research outputs found
Space-time discontinuous Galerkin method for the compressible Navier-Stokes equations on deforming meshes
An overview is given of a space-time discontinuous Galerkin finite element method for the compressible Navier-Stokes equations. This method is well suited for problems with moving (free) boundaries which require the use of deforming elements. In addition, due to the local discretization, the space-time discontinuous Galerkin method is well suited for mesh adaptation and parallel computing. The algorithm is demonstrated with computations of the unsteady \ud
ow field about a delta wing and a NACA0012 airfoil in rapid pitch up motion
Load-depth sensing of isotropic, linear viscoelastic materials using rigid axisymmetric indenters
An indentation experiment involves five variables: indenter shape, material
behavior of the substrate, contact size, applied load and indentation depth.
Only three variable are known afterwards, namely, indenter shape, plus load and
depth as function of time. As the contact size is not measured and the
determination of the material properties is the very aim of the test; two
equations are needed to obtain a mathematically solvable system.
For elastic materials, the contact size can always be eliminated once and for
all in favor of the depth; a single relation between load, depth and material
properties remains with the latter variable as unknown.
For viscoelastic materials where hereditary integrals model the constitutive
behavior, the relation between depth and contact size usually depends also on
the (time-dependent) properties of the material. Solving the inverse problem,
i.e., determining the material properties from the experimental data, therefore
needs both equations. Extending Sneddon's analysis of the indentation problem
for elastic materials to include viscoelastic materials, the two equations
mentioned above are derived. To find the time dependence of the material
properties the feasibility of Golden and Graham's method of decomposing
hereditary integrals (J.M. Golden and G.A.C. Graham. Boundary value problems in
linear viscoelasticity, Springer, 1988) is investigated and applied to a single
load-unload process and to sinusoidally driven stationary state indentation
processes.Comment: 116 pages, 29 figure
Modelling food storage management in ants: mechanisms and social implications.
According to the complementary learning systems (CLS) account of word learning, novel words are rapidly acquired (learning system 1), but slowly integrated into the mental lexicon (learning system 2). This two-step learning process has been shown to apply to novel word forms. In this study, we investigated whether novel word meanings are also gradually integrated after acquisition by measuring the extent to which newly learned words were able to prime semantically related words at two different time points. In addition, we investigated whether modality at study modulates this integration process. Sixty-four adult participants studied novel words together with written or spoken definitions. These words did not prime semantically related words directly following study, but did so after a 24-hour delay. This significant increase in the magnitude of the priming effect suggests that semantic integration occurs over time. Overall, words that were studied with a written definition showed larger priming effects, suggesting greater integration for the written study modality. Although the process of integration, reflected as an increase in the priming effect over time, did not significantly differ between study modalities, words studied with a written definition showed the most prominent positive effect after a 24-hour delay. Our data suggest that semantic integration requires time, and that studying in written format benefits semantic integration more than studying in spoken format. These findings are discussed in light of the CLS theory of word learning
Tekst & Uitleg CJ 2,3,15 Impp. Valerianus et Gallienus AA. et Valerianus nobilissimus C. Pactumeio:Enige opmerkingen over het pactum successorium en de schenkingsakte van Rembrandt van Rijn
- …