Numerical validation of compressive strength prediction for hollow concrete blocks

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

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.São 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

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 $T$-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 $T$-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 $^{40}$K-$^6$Li 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

Reforço à flexão de vigas de concreto armado com Tecido de Polímero Reforçado com Fibras de Carbono (PRFC) aderido a substrato de transição constituído por compósito cimentício de alto desempenho

Resistance to corrosion, high tensile strength, low weight, easiness and rapidity of application, are characteristics that have contributed to the spread of the strengthening technique characterized by bonding of carbon fibers reinforced polymer (CFRP). This research aimed to develop an innovate strengthening method for RC beams, based on a high performance cement-based composite of steel fibers (macro + microfibers) to be applied as a transition layer. The purpose of this transition layer is better control the cracking of concrete and detain or even avoid premature debonding of strengthening. A preliminary study in short beams molded with steel fibers and strengthened with CFRP sheet, was carried out where was verified that the conception of the transition layer is valid. Tests were developed to get a cement-based composite with adequate characteristics to constitute the layer transition. Results showed the possibility to develop a high performance material with a pseudo strain-hardening behavior, high strength and fracture toughness. The application of the strengthening on the transition layer surface had significantly to improve the performance levels of the strengthened beam. It summary, it was proven the efficiency of the new strengthening technique, and much information can be used as criteria of projects for repaired and strengthened structures

Mapeamento de QTL associados à mancha angular e ao oídio em feijão com base em um mapa de ligação enriquecido com marcadores RGA.

Este trabalho teve como objetivos a construção de um mapa genético enriquecido com marcadores RGA (Resistance Gene Analogs) em feijão (2n = 22) e o seu uso no mapeamento de QTL de resistência ao oídio (Erysiphe polygoni) e à mancha angular (Phaeoisariopsis griseola)

Crystal structures of the GH18 domain of the bifunctional peroxiredoxin-chitinase CotE from Clostridium difficile

CotE is a coat protein that is present in the spores of Clostridium difficile, an obligate anaerobic bacterium and a pathogen that is a leading cause of antibiotic-associated diarrhoea in hospital patients. Spores serve as the agents of disease transmission, and CotE has been implicated in their attachment to the gut epithelium and subsequent colonization of the host. CotE consists of an N-terminal peroxiredoxin domain and a C-terminal chitinase domain. Here, a C-terminal fragment of CotE comprising residues 349-712 has been crystallized and its structure has been determined to reveal a core eight-stranded β-barrel fold with a neighbouring subdomain containing a five-stranded β-sheet. A prominent groove running across the top of the barrel is lined by residues that are conserved in family 18 glycosyl hydrolases and which participate in catalysis. Electron density identified in the groove defines the pentapeptide Gly-Pro-Ala-Met-Lys derived from the N-terminus of the protein following proteolytic cleavage to remove an affinity-purification tag. These observations suggest the possibility of designing peptidomimetics to block C. difficile transmission

Assessment of genetic stability among in vitro plants of Arachis retusa using RAPD and AFLP markers for germplasm preservation.

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

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

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

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

Development and validation of a low dose simulator for computed tomography

To develop and validate software for facilitating observer studies on the effect of radiation exposure on the diagnostic value of computed tomography (CT). A low dose simulator was developed which adds noise to the raw CT data. For validation two phantoms were used: a cylindrical test object and an anthropomorphic phantom. Images of both were acquired at different dose levels by changing the tube current of the acquisition (500 mA to 20 mA in five steps). Additionally, low dose simulations were performed from 500 mA downwards to 20 mA in the same steps. Noise was measured within the cylindrical test object and in the anthropomorphic phantom. Finally, noise power spectra (NPS) were measured in water. The low dose simulator yielded similar image quality compared with actual low dose acquisitions. Mean difference in noise over all comparisons between actual and simulated images was 5.7 +/- 4.6% for the cylindrical test object and 3.3 +/- 2.6% for the anthropomorphic phantom. NPS measurements showed that the general shape and intensity are similar. The developed low dose simulator creates images that accurately represent the image quality of acquisitions at lower dose levels and is suitable for application in clinical studies.Radiolog