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Variables affecting strain sensing function in cementitious composites with carbon fibers

  • Baeza, F.J.;Zornoza, E.;Andion, L.G.;Ivorra, S.;Garces, P.
    • Computers and Concrete
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    • v.8 no.2
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    • pp.229-241
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    • 2011
  • In this work, cement paste samples with 1% (by cement mass) of a conductive carbon fiber admixture have been studied under uniaxial compression. Three different arrangements were used to measure the resistivity of the samples. According to the results obtained, the resistance should be measured using the four wire method in order to obtain good sensitivity and repeatability. The effect of the load value and the load rate on the fractional change of the volume resistivity has been determined. It has been observed that the gage factor (fractional change in resistance respect to strain) increases when the maximum load is increased, and the loading rate does not affect significantly this parameter. The effect of the sample ambient humidity on the material piezoresistivity has also been studied, showing that the response of the composite is highly affected by this parameter.

LA SIGNIFICATION DE LA CULTURE DU LIVER IMP RIME AU DEBUT DE LA DYNASTIE DE CHOSON (조선건국초 인서문화의 의의)

  • LEE HEE-JAE
    • Journal of the Korean Society for Library and Information Science
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    • v.13
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    • pp.121-142
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    • 1986
  • Au debut de la dynastie de Choson, qui represente une periode de la regne des rois T'aejo et T'aejong, il fallait etablir et codifier la .nouvelle politique nationale, et c'est dans ce contexte que les caracteres kyemi, qui ont joue Ie role tres important dans l'histoire de la typographie mondiale, furent crees. Le sujet de ce memoire n'est qu'une enumeration des faits historiques de l'edition ou de l'imprimerie dans cet epoque, mais une recherche sur la vraie signification de la culture du livre imprime. Done, on peut etudier ici; d'abord, less activites de l'imprimerie a l'epoque du roi T'aejo et du roi T'aejong, et enfin, la signification et le bilan synthetique de ces activites, surtout des caracteres kyemi sur le point de l'histoire de la civilisation mondiale.

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Synthesis and Cations Binding Properties of a New C,N-bipyrazolic Ligand

  • Attayibat, Ahmed;Radi, Smaail;Ramdani, Abdelkrim;Lekchiri, Yahya;Hacht, Brahim;Bacquet, Maryse;Willai, Stephanie;Morcellet, Michel
    • Bulletin of the Korean Chemical Society
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    • v.27 no.10
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    • pp.1648-1650
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    • 2006
  • The synthesis of a new C,N-bipyrazolic ligand with a functionalized donor-group is reported. The binding properties of the ligand and two other ligand of similar structures towards heavy metal ions ($Hg^{2+}$, $Cd^{2+}$, $Pb^{2+}$, $Zn^{2+}$, $Cu^{2+}$) and alkaline metal ions ($K^+$, $Na^{+}$, $Li^+$) were studied by a liquid-liquid extraction process and the extracted cation percentage was determined by atomic absorption measurements. The selectivity of the ligand to Hg(II) has been mentioned in the abstract.

ER-mediated stress induces mitochondrial-dependent caspases activation in NT2 neuron-like cells

  • Arduino, Daniela M.;Esteves, A. Raquel;Domingues, A. Filipa;Pereira, Claudia M.F.;Cardoso, Sandra M.;Oliveira, Catarina R.
    • BMB Reports
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    • v.42 no.11
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    • pp.719-724
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    • 2009
  • Recent studies have revealed that endoplasmic reticulum (ER) disturbance is involved in the pathophysiology of neurodegenerative disorders, contributing to the activation of the ER stress-mediated apoptotic pathway. Therefore, we investigated here the molecular mechanisms underlying the ER-mitochondria axis, focusing on calcium as a potential mediator of cell death signals. Using NT2 cells treated with brefeldin A or tunicamycin, we observed that ER stress induces changes in the mitochondrial function, impairing mitochondrial membrane potential and distressing mitochondrial respiratory chain complex Moreover, stress stimuli at ER level evoked calcium fluxes between ER and mitochondria. Under these conditions, ER stress activated the unfolded protein response by an overexpression of GRP78, and also caspase-4 and-2, both involved upstream of caspase-9. Our findings show that ER and mitochondria interconnection plays a prominent role in the induction of neuronal cell death under particular stress circumstances.

First Evaluation of an Outbreak of Bovine Babesiosis and Anaplasmosis in Southern Brazil Using Multiplex PCR

  • Canever, Mariana Feltrin;Vieira, Luisa Lemos;Reck, Carolina;Richter, Luisa;Miletti, Luiz Claudio
    • Parasites, Hosts and Diseases
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    • v.52 no.5
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    • pp.507-511
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    • 2014
  • Outbreaks of tick-borne disease cases in Santa Catarina, Brazil are known, but the presence of the pathogen DNA has never been determined. In this study, the first survey of Anaplasma marginale, Babesia bigemina, and Babesia bovis DNA on blood samples of 33 cattle from an outbreak in Ponte Alta Municipality, Santa Catarina, Brazil, has been carried out. A multiplex PCR detected 54.5% of animals were co-infected with 2 or 3 parasites, while 24.2% were infected with only 1 species. The most prevalent agent was B. bigemina (63.6%) followed by A. marginale (60.6%). This is the first report of tick-borne disease pathogens obtained by DNA analysis in Southern Brazil.

Topological optimization procedure considering nonlinear material behavior for reinforced concrete designs

  • Franca, Marcela Bruna Braga;Greco, Marcelo;Lanes, Ricardo Morais;Almeida, Valerio Silva
    • Computers and Concrete
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    • v.17 no.1
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    • pp.141-156
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    • 2016
  • The search for new structural systems capable of associating performance and safety requires deeper knowledge regarding the mechanical behavior of structures subject to different loading conditions. The Strut-and-Tie Model is commonly used to structurally designing some reinforced concrete elements and for the regions where geometrical modifications and stress concentrations are observed, called "regions D". This method allows a better structural behavior representation for strength mechanisms in the concrete structures. Nonetheless, the topological model choice depends on the designer's experience regarding compatibility between internal flux of loads, geometry and boundary/initial conditions. Thus, there is some difficulty in its applications, once the model conception presents some uncertainty. In this context, the present work aims to apply the Strut-and-Tie Model to nonlinear structural elements together with a topological optimization method. The topological optimization method adopted considers the progressive stiffness reduction of finite elements with low stress values. The analyses performed could help the structural designer to better understand structural conceptions, guaranteeing the safety and the reliability in the solution of complex problems involving structural concrete.

Dynamic analysis of nanoscale beams including surface stress effects

  • Youcef, Djamel Ould;Kaci, Abdelhakim;Benzair, Abdelnour;Bousahla, Abdelmoumen Anis;Tounsi, Abdelouahed
    • Smart Structures and Systems
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    • v.21 no.1
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    • pp.65-74
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    • 2018
  • In this article, an analytic non-classical model for the free vibrations of nanobeams accounting for surface stress effects is developed. The classical continuum mechanics fails to capture the surface energy effects and hence is not directly applicable at nanoscale. A general beam model based on Gurtin-Murdoch continuum surface elasticity theory is developed for the analysis of thin and thick beams. Thus, surface energy has a significant effect on the response of nanoscale structures, and is associated with their size-dependent behavior. To check the validity of the present analytic solution, the numerical results are compared with those obtained in the scientific literature. The influences of beam thickness, surface density, surface residual stress and surface elastic constants on the natural frequencies of nanobeams are also investigated. It is indicated that the effect of surface stress on the vibrational response of a nanobeam is dependent on its aspect ratio and thickness.

Le bilan synthetique de la typagraphie careenne pendant la dynastie de Chason (조선조 활자주조 및 문헌간행의 종합적 평가)

  • Lee Hee-Jae
    • Journal of the Korean Society for Library and Information Science
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    • v.9
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    • pp.53-74
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    • 1982
  • On admet Jusqu'ici que le XVe siecle est une $\acute{e}poque$ phare de l'histoire de l'imprimerie avec l'apparition de la typographie en Orient et en Occident, $c'est-\acute{a}-dire$ en $Cor\acute{e}e$ sur le Rhim. Cependant, $l'\acute{e}poque$ de l'invention typographique en $Cor\acute{e}e$ doit $\hat{e}tre$ $devanc\acute{e}e$ encore d'un ou deux siecle. Outre cette question, il est $\acute{a}$ noter ici que les caracteres mobiles $m\acute{e}talliques$ Kyemi, fondus en 1403, ont $jou\acute{e}$ un $r\hat{o}le$ $tr\acute{e}s$ important dans l'histoire de la typographie mondiale et que les $caract\acute{e}res$ kabin qui leur $succ\acute{e}derent$ en 1434 menerent la typographie $cor\acute{e}enne$ a son $apog\acute{e}e$. Or, les recherches $cor\acute{e}ennes$ se satifait de la primaute de l'invention en Coree des caracteres mobiles metalliques, mais n'adoptent pas une attitude suffisament critique. Aussi, l'auteur a-toil voulu s'interroger sur la veritable valeur de la typographie de la dynastie de Choson tant au point de vue de l'histoire de l'imprimerie mondiale. En premier lieu, on etudie, comme une chronique, les caracteres mobiles metalliques importants tout au long de la dynastie de Choson sans donner une interpretation nouvelle. C'est dans deux derniers, qu'on essaie de developper ses idees sur la typographie en Coree notamment la question technologique qui devrait etre le fond des recherches. Aussi, on y etudie, la technique de la typographie ancienne en Coree interpretee selon une methode scientifique et moderne et, enfin, le bilan synthetique en cherchant les raisons qui freinerent son developpement en Coree malgre la performance de ses debuts. A l'issue de ces recherches, on ne peut s'empecher d'eprouver une certaine insatisfaction a cause de l'ambiguite des explications que l'on trouve dans des documents fondamentaux. Avec ce difficulte on a voulu, au moins, exposer des points discutatables qui devraient etre les recherches a futur.

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