2,252 research outputs found

    Histo-anatomy and in vitro morphogenesis in Hyssopus officinalis L. (Lamiaceae)

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    The sequence of histogenesis and organogenesis in the calus of Hyssopus officinalis nodal explants was studied during treatment with growth regulators. This process represents an important indicator of the accommodation capacity of regenerated plantlets to the ex vitro conditions. The cell multiplication rate was stimulated in Murashige and Skoog medium supplemented with indole-3-butyric acid (1 mg L–1). The study was carried out from the start of the culture until the development of shoots. Leaf and stem anatomy was influenced by growth regulators. Combinations between auxine and citokinine have induced callus development at the basis of the regenerated shoots, revealing different degrees of vitrification in stems and leaves

    The SEALS Yardsticks for Ontology Management

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    This paper describes the rst SEALS evaluation campaign over ontology engineering tools (i.e., the SEALS Yardsticks for Ontology Management). It presents the dierent evaluation scenarios dened to evaluate the conformance, interoperability and scalability of these tools, and the test data used in these scenarios

    Numerical modelling of passively loaded pile groups

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    Piled foundations could be affected negatively as a result of passive loadings caused by nearby soil movement-induced activities, and failure of piles could happen in some sever cases. This paper deals with the numerical analysis of passively loaded pile groups and piled raft in sand. The complexity involved in such problems due to pile–soil, pile–pile, pile–cap, soil–cap, and moving soil-stable soil interaction needs a powerful tool to make three dimensional analysis possible. In the current study, PLAXIS 3D software was used to back analyse laboratory tests carried out by the authors. “Embedded pile” feature in which the pile is represented by beam elements, while soil-pile interaction along the pile shaft and at the pile tip is described by special interface elements was employed. The Mohr–Coulomb elastic–plastic constitutive model was used to describe the sand behaviour. Although an overestimation of the predicted deflection was obtained, the general trend of bending moment profiles of piles was in a reasonable agreement with those obtained experimentally. A number of limitations were identified as possible reasons behind the overestimation of the predicted deflections. Furthermore, parametric studies are adopted to consider the effects of pile diameter, pile–soil stiffness and pile group configuration on the response of passively loaded pile groups

    Model tests on piled raft subjected to lateral soil movement

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    Passive loadings due to lateral soil movement-induced activities are highly influencing the serviceability and safety of constructions. This research aims to investigate the influence of axial loads, sand density and the depth of moving soil on the lateral behaviour of piled raft under progressively moving sand. In order to achieve this goal taking into account the complex interaction effects of piles, cap and subsoil, a laboratory apparatus and small scale models have been designed and fabricated carefully to ensure a reasonable simulation of this geotechnical problem. It is found that the above parameters play an important role in the response of piled foundations. The value of soil displacement at which the measured moment reaches its ultimate value decreases as axial loads increase. Peak displacement of the raft has been found to be a function of soil density

    Effects of axial loads and soil density on pile group subjected to triangular soil movement

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    Laboratory tests have been carried out to investigate the response of 2x2 pile group subjected to triangular soil movement. The pile group was instrumented with displacement and tilting devices at the pile cap and strain gauges on two piles of the group. In this paper, results from four model tests were presented to study the effects of axial loads and soil density on the lateral behavior of piles. The responses in terms of bending moment, shear force, soil pressure, deflection, and rotation of piles were compared. Test results indicate that increasing the soil strength could increase the measured moment, shear, soil pressure, and pile deformations. Most importantly, adding loads to the pile cap induces additional moment to the head of frontpile row unlike the back-pile row which was influenced insignificantly

    Peace and Security Funding Index: An Analysis of Global Foundation Grantmaking - 2018 Edition

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    This research centers around a framework of three overarching categories that support activities to prevent future conflict, resolve existing conflict, and support stability and resiliency. The three categories are further broken down into 24 issue areas that more precisely describe funding for peace and security

    Researches on corrosion cracking phenomenon that occurs on welded of agricultural equipment

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    Welded construction equipments for agriculture are strongly stressed in terms of mechanics, but also in terms of environmental action and thus in many cases appears their wear by corrosion cracking phenomenon. After research it was noted that after a certain period of use of equipment, metallographic structure of welded steel structures has changed substantially and at the same time a change in the chemical composition of steel was also observed. In terms of chemical composition a reduction in carbon content was mainly observed, and an increase in sulfur content,determined mainly by the presence of large quantities of sulfur in the atmosphere. This sulfur in the atmosphere at the same time determines the acid action on metallic materials, by forming with water from precipitation of H2S. Key words
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