Characterization and evolution of matrix and interface related damage in [0/90]S laminates under tension. Part I: Numerical predictions

This paper considers damage development mechanisms in cross-ply laminates using an accurate numerical method that assumes a Generalized Plane Strain (GPS) state. A 2D Boundary Element Method (BEM) model is generated to investigate the two types of damage progression in a [0/90]_S laminate: transverse cracks in the 90° lamina and delamination between both laminae. The model permits the contact between the surfaces of the cracks. The study is carried out in terms of the dependence of the Energy Release Rates (ERR) of the two types of crack on their respective lengths. A special emphasis is put on the mechanisms of the joining of the two aforementioned types of crack, including the study of the distribution of the stresses along the interface between the two plies when the transverse crack is approaching this interface.     

Early age deformations of concrete with high content of mineral additions

Under the project “EcoBéton” (Green concrete) funded by the French National Agency (ANR), concrete mixtures with a high quantity of mineral additions, such as blast-furnace slag and fly ash were studied. A first approach to quantify their cracking risk was to measure their plastic shrinkage evolution. In parallel, the evolution of other parameters such as setting, capillary depression and porosity were also monitored to relate this deformation to the evolution of the microstructure of the studied mixtures. Setting monitoring by means of ultrasonic measurements allows obtaining significant macroscopic information such as hardening process and rigidity evolution. The correlation between these different parameters shows that the plastic shrinkage evolution can be divided into three phases driven by different mechanisms. Moreover, it appears that the use of mineral additions has an effect on the plastic shrinkage behaviour, but this impact is not proportional to the percentage of additions. It depends on the hydration process and the microstructure of the cementitious materials. So, it seems that an optimum content of cement replacement by mineral additions must be sought to limit the development of plastic shrinkage of concretes with mineral additions at early age. However, a high rate of substitution of cement may affect the early age compressive strength of the concrete. So these mixtures were also optimised to obtain a significant compressive strength at an early age, but this optimisation leads to a higher risk of cracking for some of them.     

Physicochemical properties of ready‐to‐eat extruded nixtamalized maize‐based snacks enriched with grasshopper

The aim of this research was to prepare an extruded snack based on nixtamalized maize flour (Zea mays L.) (NMF) enriched with grasshopper meal (Sphenarium purpurascens Ch.) (GM) using a single screw extruder with a compression screw ratio of 3:1. A central experimental design comprising three independent variables, namely, extrusion temperature (T = 120–180 °C), feed moisture content (FMC = 18–22 g/100 g) and the grasshopper meal proportion (GMP = 0–40 g/100 g), was used. Increasing T decreased (P < 0.05) the expansion index (EI), bulk density (BD) and hardness (H). Increasing the FMC increased (P < 0.05) the EI. Increasing the GMP decreased (P < 0.05) the EI, H and water absorption index (WAI) and increased (P < 0.05) the BD and total colour difference (ΔE). The treatments that resulted in better general acceptability were those that contained a lower GMP. An extruded snack acceptable to the consumer can be obtained from a blend of NMF and GM, and up to 8.11 g/100 g of GM can be incorporated without affecting the physicochemical properties and acceptance of the snack.     

Fully automated runtime enforcement of component-based systems with formal and sound recovery

International Journal on Software Tools for Technology Transfer - We introduce runtime enforcement of specifications on component-based systems (CBS) modeled in the behavior, interaction and...     

Electrically conductor black zirconia ceramic by SPS using graphene oxide

The use of graphene as a component for developing electroconductive ceramic composites is being profusely studied. It is a very promising additive as it has excellent mechanical properties, high electrical and thermal conductivities, it is lightweight and its aspect ratio allows reaching percolation with low contents.In the particular case of zirconia, preparation of black coloured materials remains a challenge while many high added value applications are waiting for a solution. Graphene appears as a candidate for fulfilling all these requirements. In this work, 3Y–TZP/rGO composites were prepared by Spark Plasma Sintering Zirconia-rGO mixtures. Simultaneous sintering and in-situ reduction of graphene oxide opens a very interesting technological route for preparing this type of materials. The influence of graphene content on the electrical, mechanical and optical properties was studied. An rGO content as low as 0,29 vol% allows nanostructured black zirconia to be obtained but it has to be increased up to 1 vol% in order to reach electrical resistivity values <100Ωcm, required for electrodischarge machining.     

Free-scaling your data center

The increasing popularity of both small and large private clouds and expanding public clouds poses new requirements to data center (DC) architectures. First, DC architectures should be incrementally scalable allowing the creation of DCs of arbitrary size with consistent performance characteristics. Second, initial DC deployments should be incrementally expandable supporting small-scale upgrades without decreasing operation efficiency. A DC architecture possessing both properties satisfies the requirement of free-scaling.Recent work in DC design focuses on traditional performance and scalability characteristics, therefore resulting in symmetric topologies whose upgradability is coarse-grained at best. In our earlier work we proposed Scafida, an asymmetric, scale-free network inspired DC topology which scales incrementally and has favorable structural characteristics. In this paper, we build on Scafida and propose a full-fledged DC architecture achieving free-scaling called FScafida. Our main contribution is threefold. First, we propose an organic expansion algorithm for FScafida; this combined with Scafida’s flexible original design results in a freely scalable architecture. Second, we introduce the Effective Source Routing mechanism that provides near-shortest paths, multi-path and multicast capability, and low signaling overhead by exploiting the benefits of the FScafida topology. Third, we show based on extensive simulations and a prototype implementation that FScafida is capable of handling the traffic patterns characteristic of both enterprise and cloud data centers, tolerates network equipment failures to a high degree, and allows for high bisection bandwidth.     

Competition,virulence, host body mass and the diversification of macro-parasites

Adaptive speciation has been much debated in recent years, with a strong emphasis on how competition can lead to the diversification of ecological and sexual traits. Surprisingly, little attention has been paid to this evolutionary process to explain intrahost diversification of parasites. We expanded the theory of competitive speciation to look at the effect of key features of the parasite lifestyle, namely fragmentation, aggregation and virulence, on the conditions and rate of sympatric speciation under the standard ‘pleiotropic scenario’. The conditions for competitive speciation were found similar to those for non-parasite species, but not the rate of diversification. Adaptive evolution proceeds faster in highly fragmented parasite populations and for weakly aggregated and virulent parasites. Combining these theoretical results with standard empirical allometric relationships, we showed that parasite diversification can be faster in host species of intermediate body mass. The increase in parasite load with body mass, indeed, fuels evolution by increasing mutants production, but because of the deleterious effect of virulence, it simultaneously weakens selection for resource specialization. Those two antagonistic effects lead to optimal parasite burden and host body mass for diversification. Data on the diversity of fishes'' gills parasites were found consistent with the existence of such optimum.     

A theoretical model for the automatic generation of tag clouds

This paper presents a new approach to information retrieval from non-structured attributes in databases, which involves the processing of text attributes. To make retrieval more effective, frequent text sequences are extracted and mathematically represented as intermediate forms which permit a clearer and more precise definition of operations on texts. These intermediate forms appear to users in the form of tag clouds to facilitate content identification, exploration, and querying. In this sense, tag cloud visualization is a simple, user-friendly visual interface to data. This paper proposes a theoretical model for the representation of frequent text sequences and their operations as well as a general procedure for generating tag clouds from text attributes in databases. The tag clouds thus obtained were compared with conventional tag clouds composed of single terms. Our study showed that automatically generated multi-term tag clouds provide better results than mono-term tag clouds.