Inverse identification of constitutive parameters from heat source fields: A local approach applied to hyperelasticity

In this paper, a new inverse identification method of constitutive parameters is developed from full kinematic and thermal field measurements. It consists in reconstructing the heat source field from two different approaches by using the heat diffusion equation. The first one requires the temperature field measurement and the value of the thermophysical parameters. The second one is based on the kinematic field measurement and the choice of a thermo-hyperelastic model that contains the parameters to be identified. The identification is carried out at the local scale, ie, at any point of the heat source field, without using the boundary conditions. In the present work, the method is applied to the challenging case of hyperelasticity from a heterogeneous test. Due to large deformations undergone by the rubber specimen tested, a motion compensation technique is developed to plot the kinematic and the thermal fields at the same points before reconstructing the heterogeneous heat source field. In the present case, the constitutive parameter of the Neo-Hookean model has been identified, and its distribution has been characterized with respect to the strain state at the surface of a cross-shaped specimen.     

Canadian research activity in aquaculture: A bibliometric analysis

Analysis of the Canadian publications in the field of aquaculture reveals that Canada is one of the word's major contributors in this area. This confirms that Canada's expertise in science and technology often finds its stimulus in its resource-based industries. Several bibliometric indicators were used to enlighten the peculiar features of the Canadian research system. These include the channels of communication used by scientists, the authorship pattern, the level of collaboration, the identification of the institutions in which the research is performed and the uneven research effort distribution inside the country. The relevance of such quantitative measures for science policy-making is emphasized. The present study shows how bibliometric analysis, by describing the actual strengths and weaknesses of Canadian research and identifying the agents of this research activity, might foster a better understanding of the Canadian research enterprise as a whole.     

Relative involvement of protein kinase C and of the estrogen receptor in the cytotoxic action of a population of triphenylethylenes on MCF7 cells as revealed by correspondence factorial (CF) analysis

A multivariate statistical method, correspondence factorial (CF) analysis, was used to examine the correlations among the protein binding and cell proliferation effects of a series of 36 di- and triphenylethylenes (DPEs and TPEs). The analysis was applied to a study which measured their competition for estradiol binding to cytosol estrogen receptor (ER), their influence on protein kinase C (PKC) activity under different conditions of enzyme activation, their ability to promote the growth of a breast cancer cell line and to inhibit growth at high concentrations (cytotoxicity). The CF analysis revealed several levels of correlation. First, it distinguished those molecules within the population that stimulated rather than inhibited PKC activity. Second, it made apparent a strong correlation between cytotoxicity and inhibition of Ca++ and phosphatidylserine-dependent PKC activity, which was most marked when the enzyme had been activated by diacylglycerol indicating that PKC inhibition under physiological conditions might contribute to the overall cytotoxicity of these compounds. Third, a lower level of correlation was established between competition for ER binding and cytotoxicity. Taken together, the results suggest that MCF7 cells might be most sensitive to a cytotoxic effect of TPEs (via PKC and other targets) when they at the same time decrease estrogen-stimulated proliferation via an ER-mediated antiestrogenic effect.     

Object permanence and working memory in cats (Felis catus).

Cats (Felis catus) find an object when it is visibly moved behind a succession of screens. However, when the object is moved behind a container and is invisibly transferred from the container to the back of a screen, cats try to find the object at or near the container rather than at the true hiding place. Four experiments were conducted to study search behavior and working memory in visible and invisible displacement tests of object permanence. Exp 1 compared performance in single and in double visible displacement trials. Exp 2 analyzed search behavior in invisible displacement tests and in analogs using a transparent container. Exps 3 and 4 tested predictions made from Exps 1 and 2 in a new situation of object permanence. Results showed that only the position changes that cats have directly perceived are encoded and activated in working memory because they are unable to represent or infer invisible movements. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Coverage-biased random exploration of large models and application to testing

This paper presents several randomised algorithms for generating paths in large models according to a given coverage criterion. Using methods for counting combinatorial structures, these algorithms can efficiently explore very large models, based on a graphical representation by an automaton or by a product of several automata. This new approach can be applied to random exploration in order to optimise path coverage and can be generalised to take into account other coverage criteria, via the definition of a notion of randomised coverage satisfaction. Our main contributions are a method for drawing paths uniformly at random in composed models, i.e. models that are given as products of automata, first without and then with synchronisation; a new efficient approach to draw paths at random taking into account some other coverage criterion. Experimental results show promising agreement with theoretical predictions and significant improvement over previous randomised approaches. This work opens new perspectives for future studies of statistical testing and model checking, mainly to fight the combinatorial explosion problem.     

Multivariate analysis of the correlation between noctuidae subfamilies and the chemical structure of their sex pheromones or male attractants

Female-emitted pheromones and sex attractants of Noctuidae were investigated using a specific computer procedure to analyze data collected from the literature. Correspondence analysis was used to survey the structure-activity relationships of sex pheromones in seven subfamilies. Structural, stereochemical, and functional features of active molecules were related to taxonomy. This multidimensional analysis revealed that the prevalent chemical frame of noctuid moth pheromones was a monounsaturated acetate withZ stereochemistry and a double bond on the fifth carbon closest to the nonfunctional branch of the molecule. Possible phylogenetic relationships within Noctuidae and between Noctuidae and other families are discussed in light of the sex pheromone biochemistry. Female sex pheromones appeared to be an additional character to be considered in the classification of noctuid moths.     

Comparison of a contactor catalytic membrane reactor with a conventional reactor: example of wet air oxidation

A wet air oxidation reaction was carried out in a gas/liquid catalytic membrane reactor of the contactor type. The oxidation of formic acid was used as a model reaction. The mesoporous top-layer of a ceramic tubular membrane was used as catalyst (Pt) support, and was placed at the interface of the gas (air) and liquid (HCOOH solution) phases.

A similar reaction was carried out in a conventional batch reactor, using a steering rate high enough to avoid gas-diffusion limitations, and exactly identical conditions than for the CMR (amount of catalyst, pressure, etc.). At room temperature, the CMR showed an initial activity three to six times higher than the conventional reactor. This activity increase was attributed to an easier oxygen access to the catalytic sites. Nevertheless, the catalytic membrane gradually deactivated after a few hours of operation. Different deactivation mechanisms are presented.     

Effects of the sintering atmosphere on Nb-based dielectrics

The effects of a forming atmosphere on the stability, the sintering and the dielectric properties of Ba₅Nb₄O₁₅, BaNb₂O₆, ZnNb₂O₆ and Zn₃Nb₂O₈ ceramics were investigated, because of the primary importance of the sintering atmosphere in relation to copper sintering. These Nb-based materials were sintered in air and in Ar/H₂10%. Zn-containing samples are very sensitive to the reductive atmosphere. ZnO volatilises at 800–850 °C and the resulting compound does not exhibit the expected properties. BaNb₂O₆ and Ba₅Nb₄O₁₅ are more stable in term of relative weight loss. Nevertheless, the phase analysis reveals a modification of the BaNb₂O₆ phase, what induces the degradation of the dielectric property stability versus temperature. The properties of Ba₅Nb₄O₁₅ are not modified by a sintering in reductive atmosphere. A relative permittivity of 38.8, a permittivity temperature coefficient of −150 ppm °C⁻¹ and an insulating resistivity of 10^10.9 Ω cm were obtained for this latter.     

The Failure of the Strong Pumping Lemma for Multiple Context-Free Languages

Seki et al. (Theor. Comput. Sci. 88(2):191–229, 1991) showed that every m-multiple context-free language L is weakly 2m-iterative in the sense that either L is finite or L contains a subset of the form \(\{ u_{0} w_{1}^{i} u_{1} \cdots w_{2m}^{i} u_{2m} \mid i \in \mathbb {N}\}\) , where w ₁?w _2n ≠ε. Whether every m-multiple context-free language L is 2m-iterative, that is to say, whether all but finitely many elements z of L can be written as z=u ₀ w ₁ u ₁?w _2m u _2m with w ₁?w _2m ≠ε and \(\{ u_{0} w_{1}^{i} u_{1} \cdots w_{2m}^{i} u_{2m} \mid i \in \mathbb {N}\} \subseteq L\) , has been open. We show that there is a 3-multiple context-free language that is not k-iterative for any k.