101 research outputs found

    Experimental Evaluation of the Mechanical Properties of Steel Reinforcement at Elevated Temperature

    Get PDF
    This paper describes an experimental investigation into the influence of elevated temperatures on the mechanical properties of steel reinforcement. The study includes tests carried out at ambient temperature as well as under steady-state and transient elevated temperature conditions. A complementary test series, in which the residual post-cooling properties of reinforcing bars were examined, is also described. The experimental study focussed on assessing the performance of reinforcement of 6 and 8 mm diameter, although 10 mm bars were also considered in some cases. The specimens included both plain and deformed bars. After providing an outline of the experimental set-up and loading procedures, a detailed account of the test results is presented and discussed. Apart from the evaluation of stress–strain response and degradation of stiffness and strength properties, particular emphasis is given to assessing the influence of temperature on enhancing the ductility of reinforcement. The findings of this study have direct implications on procedures used for predicting the ultimate behaviour of structural floor elements and assemblages during, and following, exposure to elevated temperatures

    Towards an Architecture Proposal for Federation of Distributed DES Simulators

    Get PDF
    The simulation of large and complex Discrete Event Systems (DESs) increasingly imposes more demanding and urgent requirements on two aspects accepted as critical: (1) Intensive use of models of the simulated system that can be exploited in all phases of its life cycle where simulation can be used, and methodologies for these purposes; (2) Adaptation of simulation techniques to HPC infrastructures, as a method to improve simulation efficiency and to have scalable simulation environments. This paper proposes a Model Driven Engineering approach (MDE) based on Petri Nets (PNs) as formal model. This approach proposes a domain specific language based on modular PNs from which efficient distributed simulation code is generated in an automatic way. The distributed simulator is constructed over generic simulation engines of PNs, each one containing a data structure representing a piece of net and its simulation state. The simulation engine is called simbot and versions of it are available for different platforms. The proposed architecture allows, in an efficient way, a dynamic load balancing of the simulation work because the moving of PN pieces can be realized by moving a small number of integers representing the subnet and its state

    What Is the Important Point Related to Follow-Up Sonographic Evaluation for the Developmental Dysplasia of the Hip?

    Get PDF
    Developmental dysplasia of the hip (DDH) is an important cause of childhood disability. Subluxation or dislocation can be diagnosed through pediatric physical examination; nevertheless, the ultrasonographic examination is necessary in diagnosing certain borderline cases. It has been evaluated routine sonographic examination of 2,444 hips of 1,222 babies to determine differences in both, developmental dysplasia and types of hips, and evaluated their development on the 3-month follow-up. Evaluating the pathologic alpha angles under 59, there was no statistically significant differences between girls and boys in both right (55.57 +/- 3.73) (56.20 +/- 4.01), (p = 0.480), and left (55.79 +/- 3.96) (57.00 +/- 3.84), (p = 0.160) hips on the 45th day of life. Routine sonographic examinations on the 45th day of life revealed that 51 of (66.2%) 77 type 2a right hips were girls and 26 (33.8%) were boys. The number of the right hips that develop into type 1 was 38 (74.5%) for girls and 26 (100%) for boys on the 90th day of life (p = 0.005). A total of 87 type 2a left hips included 64 girls (73.6%) and 23 boys (26.4%). In the 90th day control, 49 right hip of girls (76.6%) and 21 right hip of boys (91.3%) developed into type 1 (p = 0.126). In the assessment of both left and right hips, girls showed a significantly higher frequency in latency and boys showed significantly higher development in the control sonography. A total of 31 girls (2.5%) and 11 boys (0.9%) accounted for a total of 42 (3.4%) cases who showed bilateral type 2a hips in 1,222 infants. On the 90th day control, 26 girls (83.9%) and all 11 boys (100%) developed into type 1 (p = 0.156). The study emphasizes the importance of the sonographic examination on the 90th day of life. Results of the investigation include the data of sonographic screening of DDH on the 45th day, and also stress the importance of the 90th-day control sonography after a close follow-up with physical examination between 45th and 90th days of life

    Masonry compressive strength prediction using artificial neural networks

    Get PDF
    The masonry is not only included among the oldest building materials, but it is also the most widely used material due to its simple construction and low cost compared to the other modern building materials. Nevertheless, there is not yet a robust quantitative method, available in the literature, which can reliably predict its strength, based on the geometrical and mechanical characteristics of its components. This limitation is due to the highly nonlinear relation between the compressive strength of masonry and the geometrical and mechanical properties of the components of the masonry. In this paper, the application of artificial neural networks for predicting the compressive strength of masonry has been investigated. Specifically, back-propagation neural network models have been used for predicting the compressive strength of masonry prism based on experimental data available in the literature. The comparison of the derived results with the experimental findings demonstrates the ability of artificial neural networks to approximate the compressive strength of masonry walls in a reliable and robust manner.- (undefined

    Data from an International Multi-Centre Study of Statistics and Mathematics Anxieties and Related Variables in University Students (the SMARVUS Dataset)

    Get PDF
    This large, international dataset contains survey responses from N = 12,570 students from 100 universities in 35 countries, collected in 21 languages. We measured anxieties (statistics, mathematics, test, trait, social interaction, performance, creativity, intolerance of uncertainty, and fear of negative evaluation), self-efficacy, persistence, and the cognitive reflection test, and collected demographics, previous mathematics grades, self-reported and official statistics grades, and statistics module details. Data reuse potential is broad, including testing links between anxieties and statistics/mathematics education factors, and examining instruments’ psychometric properties across different languages and contexts. Data and metadata are stored on the Open Science Framework website [https://osf.io/mhg94/]

    Estimates of Particulate Organic Carbon Flowing from the Pelagic Environment to the Benthos through Sponge Assemblages

    Get PDF
    Despite the importance of trophic interactions between organisms, and the relationship between primary production and benthic diversity, there have been few studies that have quantified the carbon flow from pelagic to benthic environments as a result of the assemblage level activity of suspension-feeding organisms. In this study, we examine the feeding activity of seven common sponge species from the Taputeranga marine reserve on the south coast of Wellington in New Zealand. We analysed the diet composition, feeding efficiency, pumping rates, and the number of food particles (specifically picoplanktonic prokaryotic cells) retained by sponges. We used this information, combined with abundance estimates of the sponges and estimations of the total amount of food available to sponges in a known volume of water (89,821 m3), to estimate: (1) particulate organic carbon (POC) fluxes through sponges as a result of their suspension-feeding activities on picoplankton; and (2) the proportion of the available POC from picoplankton that sponges consume. The most POC acquired by the sponges was from non-photosynthetic bacterial cells (ranging from 0.09 to 4.69 g C d−1 with varying sponge percentage cover from 0.5 to 5%), followed by Prochlorococcus (0.07 to 3.47 g C d−1) and then Synechococcus (0.05 to 2.34 g C d−1) cells. Depending on sponge abundance, the amount of POC that sponges consumed as a proportion of the total POC available was 0.2–12.1% for Bac, 0.4–21.3% for Prochlo, and 0.3–15.8% for Synecho. The flux of POC for the whole sponge assemblage, based on the consumption of prokaryotic picoplankton, ranged from 0.07–3.50 g C m2 d−1. This study is the first to estimate the contribution of a sponge assemblage (rather than focusing on individual sponge species) to POC flow from three groups of picoplankton in a temperate rocky reef through the feeding activity of sponges and demonstrates the importance of sponges to energy flow in rocky reef environments

    European Red List of Habitats Part 1. Marine habitats

    Get PDF
    The European Red List of Habitats provides an overview of the risk of collapse (degree of endangerment) of marine, terrestrial and freshwater habitats in the European Union (EU28) and adjacent regions (EU28+), based on a consistent set of categories and criteria, and detailed data and expert knowledge from involved countries1. A total of 257 benthic marine habitat types were assessed. In total, 19% (EU28) and 18% (EU28+) of the evaluated habitats were assessed as threatened in categories Critically Endangered, Endangered and Vulnerable. An additional 12% were Near Threatened in the EU28 and 11% in the EU28+. These figures are approximately doubled if Data Deficient habitats are excluded. The percentage of threatened habitat types differs across the regional seas. The highest proportion of threatened habitats in the EU28 was found in the Mediterranean Sea (32%), followed by the North-East Atlantic (23%), the Black Sea (13%) and then the Baltic Sea (8%). There was a similar pattern in the EU28+. The most frequently cited pressures and threats were similar across the four regional seas: pollution (eutrophication), biological resource use other than agriculture or forestry (mainly fishing but also aquaculture), natural system modifications (e.g. dredging and sea defence works), urbanisation and climate change. Even for habitats where the assessment outcome was Data Deficient, the Red List assessment process has resulted in the compilation of a substantial body of useful information to support the conservation of marine habitats
    • 

    corecore