843 research outputs found

    Numerical validation of compressive strength prediction for hollow concrete blocks

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    The results of a numerical modeling program to evaluate the behavior of hollow concrete blocks under uniaxial compression are addressed. It has been considered appropriate to use interface elements to represent the confinement effect at the top and bottom of blocks. The response of the numerical simulations is compared with experimental data of masonry units. Laboratory tests were carried out utilizing standard flat platens and brush platens to evaluate the confinement effect due block geometry. The elastic and inelastic parameters compressive strength, tensile strength, stress-strain relationships and fracture energy were acquired from concrete samples that constitute the blocks. The results from the theoretical analysis are discussed with respect to the ability to reproduce the experimental tests. Good agreement between experimental and numerical results was found for the peak load

    Triaxial compression tests on bedding mortar samples looking at confinement effect analysis

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    This paper presents an analysis of the mechanical behavior of bedding mortar samples under triaxial compression tests. When masonry is subjected to vertical loads, mechanical interactions between blocks and bedding mortar at the joints induce lateral tension and compression stresses. Thus, the mortar layer is submitted to a triaxial stress state that modifies its mechanical properties and behavior under confinement effects. This phenomenon may affect the failure mode of masonry and almost no information about this subject is found in literature. Here, test procedures are detailed and results are discussed. In addition to the compressive strength test results, also elastic modulus and Poisson ratio values are addressed. Significant differences were observed among triaxial and uniaxial standard test results. The obtained mortar behavior under different levels of lateral pressure is compared with test results done by other researchers in order to produce relevant conclusions for different mortar compositions.SĂŁo Paulo State Research Support Foundation (FAPESP)Brazilian Research Support Foundation (CAPES

    Superfluid phase transition and strong-coupling effects in an ultracold Fermi gas with mass imbalance

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    We investigate the superfluid phase transition and effects of mass imbalance in the BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein condensation) crossover regime of an cold Fermi gas. We point out that the Gaussian fluctuation theory developed by Nozi\`eres and Schmitt-Rink and the TT-matrix theory, that are now widely used to study strong-coupling physics of cold Fermi gases, give unphysical results in the presence of mass imbalance. To overcome this problem, we extend the TT-matrix theory to include higher-order pairing fluctuations. Using this, we examine how the mass imbalance affects the superfluid phase transition. Since the mass imbalance is an important key in various Fermi superfluids, such as 40^{40}K-6^6Li Fermi gas mixture, exciton condensate, and color superconductivity in a dense quark matter, our results would be useful for the study of these recently developing superfluid systems.Comment: 7 pages, 4 figures, Proceedings of QFS-201

    Rmi1 stimulates decatenation of double Holliday junctions during dissolution by Sgs1-Top3

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    double Holliday junction (dHJ) is a central intermediate of homologous recombination that can be processed to yield crossover or non-crossover recombination products. To preserve genomic integrity, cells possess mechanisms to avoid crossing over. We show that Saccharomyces cerevisiae Sgs1 and Top3 proteins are sufficient to migrate and disentangle a dHJ to produce exclusively non-crossover recombination products, in a reaction termed "dissolution." We show that Rmi1 stimulates dHJ dissolution at low Sgs1-Top3 protein concentrations, although it has no effect on the initial rate of Holliday junction (HJ) migration. Rmi1 serves to stimulate DNA decatenation, removing the last linkages between the repaired and template DNA molecules. Dissolution of a dHJ is a highly efficient and concerted alternative to nucleolytic resolution that prevents crossing over of chromosomes during recombinational DNA repair in mitotic cells and thereby contributes to genomic integrity

    Anthropomorphizing brands: The role of attributed brand traits in interactive CSR communication and consumer online endorsements

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    Consumers tend to relate to brands in similar ways as they relate to individuals and groups. However, relatively little is known about the attribution of human traits to brands in online contexts. The current research focused on the role of attributed brand traits in interactive corporate social responsibility (CSR) communication and positive electronic word‐of‐mouth intentions. Results of an online survey (N = 174) revealed that higher levels of perceived interactivity were associated with stronger attributions of morality, sociability, and competence traits to brands. Yet only attributed brand morality was associated with consumers' willingness to endorse the brand and its CSR message on social networking sites. These findings underline the importance of brands' openness to dialogue regarding the pr
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