118,200 research outputs found
SIMPLE LATERAL MECHANISM ANALYSIS (SLaMA) FOR THE SEISMIC ASSESSMENT OF UNREINFORCED MASONRY STRUCTURES
No full textOf the broad range of displacement-based assessment methods available to structural engineers, one that has seen recent uptake on a design code level is the Simple Lateral Mechanism Analysis (SLaMA). In particular, the 2017 New Zealand Technical Guidelines for (seismic) Engineering Assessments and the Dutch practice note NPR9998:2018 both enable the use of SLaMA for the seismic assessment of unreinforced masonry structures. This paper investigates the merits and drawbacks of SLaMA as a seismic assessment method for unreinforced masonry structures based on practical experience in New Zealand and the Netherlands.
In general, the SLaMA method focuses on calculating the force and displacement capacities of individual structural elements and then identifying a global failure mechanism. The global displacement capacity of the structural system is then evaluated against the displacement demand on an equivalent single-degree-of-freedom system. This approach can easily be facilitated by hand or spreadsheet-based calculation and alleviates the need to develop a numerical model, which can often be complex for masonry structures. Consequently, SLaMA is generally found to be a cost-effective assessment methodology. This is well suited to masonry structures, which, due to their typically historic nature and limitations of the construction material, are often low-rise structures with relatively lower asset values.
Following an overview of the SLaMA methodology, its specific application to masonry structures is discussed and a number of key considerations identified. It is then shown that there are a number of merits and drawbacks in utilizing SLaMA for the assessment of masonry structures. The paper also provides an example application of SLaMA to a typical Dutch unreinforced masonry terraced house. This example helps to elucidate the peculiarities of masonry structures and some of the technical challenges the engineer might face. Furthermore, the example demonstrates that SLaMA is very efficient when applied to relatively simple masonry buildings and when a reasonable set of starting assumptions are used
Optimizing irrigation and determining the most sensitive development stage to drought in barley (Hordeum vulgare L.) in a semi-arid environment
No full textRising temperatures and increasing water scarcity, which are already important issues, are expected to intensify in the near future due to global warming. Optimizing irrigation in agriculture is a challenge. Understanding the response of crop development stages to water deficit stress provides an opportunity for optimizing irrigation. Here we studied the response of two barley varieties (Rihane, Martin), to water deficit stress at three development stages (tillering, stem elongation, and heading) by measuring water status and grain yield components in a field experiment in Tunisia. The three stages were selected due to their importance in crop growth and grain development. Water deficit stress was initiated by withholding water for 21 days at the three stages with subsequent re-watering. Water deficit led to a progressive decrease in leaf water potential. In both varieties, heading was the stage most sensitive to water deficit. Leaf water potential measurements indicated that water deficit stress was more severe during heading, which to some extent may have influenced the comparison between growth stages. During heading, the number of ears per plant and weight of a thousand grains were reduced by more than 70% and 50%, respectively compared with stress at tillering. Comparison of yield components showed differences between the two barley varieties only when the water deficit was produced during the tillering stage
[Entretien] Une remise en cause de l’Etat de droit désormais assumée
No full textInternational audience’Etat de droit est aujourd’hui remis en question, aussi bien en discours qu’en actes :dans le monde mais aussi en Europe, en France. C’est le constat inquiétantque dresse Serge Slama, professeur de droit public (université Grenoble-Alpes,Centre de recherches juridiques-CRJ), dans cette interview accordée à D&L
Exciton properties and optical spectra of light harvesting complex II from a fully atomistic description
No full textWe present a fully atomistic simulation of linear optical spectra (absorption, fluorescence and circular dichroism) of the Light Harvesting Complex II (LHCII) trimer using a hybrid approach, which couples a quantum chemical description of the chlorophylls with a classical model for the protein and the external environment (membrane and water). The classical model uses a polarizable Molecular Mechanics force field, thus allowing mutual polarization effects in the calculations of the excitonic properties. The investigation is performed both on the crystal structure and on structures generated by a μs long classical molecular dynamics simulation of the complex within a solvated membrane. The results show that this integrated approach not only provides a good description of the excitonic properties and optical spectra without the need for additional refinements of the excitonic parameters, but it also allows an atomistic investigation of the relative importance of electronic, structural and environment effects in determining the optical spectra
A Framework and Tool for Knowledge-Based Seismic Risk Assessment of School Buildings: SLaMA-School
No full textWhen dealing with seismic risk assessment at a large scale, the collection of relevant building data is still deemed a challenging task, often leading to limited building knowledge and, consequently, high uncertainties. Therefore, innovative yet standardized frameworks and adaptive tools are needed to support the seismic risk assessment of buildings. Towards this goal, this paper proposes a simplified multi-knowledge seismic assessment methodology involving the analytical-mechanical SLaMA (Simple Lateral Mechanism Analysis) method. An ad-hoc data collection form is first developed to identify the building vulnerabilities by merging and building on existing institutional forms at the international level and integrating new input data. The data are then used to implement the SLaMA-based methodology, at different building knowledge levels, to assess the seismic safety and the economic losses of buildings. The proposed data structure and approach is planned to be included in the “Seismic-Response” module for PELL (Public Energy Living Lab)-School platform, aiming to become a standardized and interoperable database for relevant data of Italian schools and a dashboard for allowing stakeholders to continuously monitor their energetic and static/seismic conditions. The paper discusses the potential and effectiveness of the proposed procedure for large-scale applications and its integration into platforms assessing the energy efficiency of buildings
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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