C1− Continuous crack propagation for mixed-mode fracture problems

In this work a C1− continuous crack propagation algorithm is proposed to improve the numerical simulation of localized deformation patterns, using higher order elements. The algorithm is applied for a standard smeared crack model and is validated by a mixed-mode fracture problem. From the results a reduction of mesh-induced directional bias is observed

Literatuurscan oorzaken geweld tegen kinderen en jongeren in afhankelijkheidsrelaties

Naar aanleiding van het rapport van de Commissie Seksueel misbruik van minderjarigen in de Rooms-Katholieke Kerk (Commissie Deetman), heeft de Minster van Veiligheid en Justitie, mede namens de Staatssecretaris van VWS, een onderzoek naar dieperliggende oorzaken van seksueel geweld en andere vormen van geweld in afhankelijkheidsrelaties toegezegd aan de Tweede Kamer. Dit onderzoek heeft betrekking op de eerste fase van het onderzoek. Het betreft een literatuurscan die de stand van de wetenschappelijke kennis op hoofdlijnen in kaart moet brengen met betrekking tot de etiologie van seksueel geweld en fysiek geweld tegen kinderen en jongeren, binnen afhankelijkheidsrelaties. De volgende deelvragen staan daarbij centraal: - Wat is de stand van de kennis over de etiologie van fysieke kindermishandeling en seksueel misbruik? - Waar liggen grofweg de mogelijkheden om te interveniëren? - Op welke thema's zou nader, al dan niet empirisch, onderzoek in Nederland wenselijk zijn en hoe zou dat er idealiter uitzien

Projected free energies for polydisperse phase equilibria

A `polydisperse' system has an infinite number of conserved densities. We give a rational procedure for projecting its infinite-dimensional free energy surface onto a subspace comprising a finite number of linear combinations of densities (`moments'), in which the phase behavior is then found as usual. If the excess free energy of the system depends only on the moments used, exact cloud, shadow and spinodal curves result; two- and multi-phase regions are approximate, but refinable indefinitely by adding extra moments. The approach is computationally robust and gives new geometrical insights into the thermodynamics of polydispersity.Comment: 4 pages, REVTeX, uses multicol.sty and epsf.sty, 1 postscript figure include

Children's Pronoun Interpretation Problems Are Related to Theory of Mind and Inhibition, But Not Working Memory

In several languages, including English and Dutch, children’s acquisition of the interpretation of object pronouns (e.g., him) is delayed compared to that of reflexives (e.g., himself). Various syntactic and pragmatic explanations have been proposed to account for this delay in children’s acquisition of pronoun interpretation. This study aims to provide more insight into this delay by investigating potential cognitive mechanisms underlying this delay. Dutch-speaking children between 6 and 12 years old with autism spectrum disorder (ASD; n = 47), attention-deficit/hyperactivity disorder (ADHD; n = 36) or typical development (TD; n = 38) were tested on their interpretation and production of object pronouns and reflexives and on theory of mind, working memory, and response inhibition. It was found that all three groups of children had difficulty with pronoun interpretation and that their performance on pronoun interpretation was associated with theory of mind and inhibition. These findings support an explanation of object pronoun interpretation in terms of perspective taking, according to which listeners need to consider the speaker’s perspective in order to block coreference between the object pronoun and the subject of the same sentence. Unlike what is predicted by alternative theoretical accounts, performance on pronoun interpretation was not associated with working memory, and the children made virtually no errors in their production of object pronouns. As the difficulties with pronoun interpretation were similar for children with ASD, children with ADHD and typically developing children, this suggests that certain types of perspective taking are unaffected in children with ASD and ADHD

Numerical investigation of the impact behaviour of bioinspired nacre-like aluminium composite plates

Inspired by the hierarchical structure of nacre, an aluminium alloy (AA) 7075 based composite featuring layer waviness and cohesive interface is studied as a low weight impact resistant material. To investigate the mechanical response and the ballistic performance of this laminated structure, a numerical study of the proposed nacre-like composite plates made of 1.1-mm thick AA 7075 tablets bonded with toughened epoxy resin was performed using Abaqus/Explicit. Target thicknesses of 5.4-mm, 7.5-mm and 9.6-mm impacted by a rigid hemi-spherical projectile were simulated. The epoxy material was modelled using a user-defined interface cohesive element with compressive strength enhancement. A significant performance improvement was recorded for the 5.4-mm nacre-like plate (compared to the same thickness bulk plate), which was explained by the hierarchical structure facilitating both localised energy absorption (by deformation of the tablet) and more globalized energy absorption (by inter-layered delamination and friction). For a given projectile, however, the performance improvement of using the proposed composite decreased with increasing laminate thickness, which was attributed to the increased likelihood of ductile failure occurring prior to perforation in thicker bulk plates. For 5.4-mm thick plates impacted at high velocity, the nacre-like plate had a better ballistic performance than that of the plates made of continuous (flat and wavy) layers, which was attributed to the larger area of plastic deformation (observed in the nacre-like plate after impact) due to the tablets arrangement.The Australian Research Council Centre of Excellence for Design in Light Metals (CE0561574); National Natural Science Foundation of China (No. 11232003); The Australian Research Council via project DP1093485

Permeability characteristics of human endothelial monolayers seeded on different extracellular matrix proteins.

OBJECTIVE: To investigate whether endothelial monolayer permeability changes induced by inflammatory mediators are affected by the extracellular matrix protein used for cell seeding. METHODS: Human umbilical venular endothelial cells (HUVEC) were grown to confluent monolayers on membranes coated with either collagen, fibronectin or gelatin. The permeability to albumin and dextran was then assessed, both under normal conditions and after treatment with tumor necrosis factor-alpha (TNF-alpha) and bacterial lipopolysaccharide (LPS). RESULTS: With any of the three protein coatings, tight junctions were formed all over the monolayers. The permeability of the coated membranes to albumin and dextran was reduced strongly by confluent monolayers; the relative reduction was similar for the three matrix proteins used. Pre-incubation of the monolayers with either TNF-alpha or LPS increased permeability dose dependently. However, the relative increase due to either treatment was independent of the protein used for membrane coating. CONCLUSION: The extracellular matrix protein used for initial seeding of endothelial cultures plays a minor role in determining the permeability changes induced in HUVEC monolayers by inflammatory mediators