985 research outputs found
Which Is the Correct Form of the Popular Name for Our Galaxy: Kumova Slama or Kumovska Slama?
No full textThe paper discusses the formational suffix in the generally accepted Croatian name for our galaxy, the Milky Way. Since there are two forms that occur in normative handbooks: Kumova Slama and Kumovska Slama, the woman author comments the use and the meaning
of the suffixes -ov and -ski for the formation of adjective
A comparison between the SLaMA method and NLFEA for 2D and 3D analyses of masonry structure
No full textEach year, the province of Groningen experiences many induced earthquakes due gas extraction, which has been ongoing since 1963. The earthquakes cause damage to the buildings situated in the Groningen area, and they constitute a potential danger for the safety of the residents. These buildings are typically unreinforced masonry structures which are designed without knowledge of the presence of seismic activity in this area. It is therefore essential develop and use assessment methods that are on one end reliable and accurate, but on the other hand allow to perform a large number of assessments of the vulnerability of the buildings in a short time. In other words, the assessment of all the buildings requires a quick and reliable assessment method. Such an assessment method should offer a strong understanding of the occurring failure mechanism during an earthquake, an acceptable prediction of the ground acceleration at which the collapse of the building may occur (maximum base shear force) and the displacement capacity of unreinforced masonry (URM) building. The NPR9998 recommends four seismic assessment approaches, which differ in complexity and assessment time needed to be performed. The most comprehensive and time-consuming assessment method is the NLTHA (nonlinear time history analysis), which includes both the dynamic and nonlinear effects. In practice, this method is used only in special cases, such as in the case of monumental buildings. A simpler approach is the NLPO (nonlinear pushover) analysis, which is static and considers the nonlinear properties of the structure. An NLPO is less time consuming than an NLTHA, even when the finite element method (FEM) is considered. A more simplified approach is the Simple Lateral Mechanism Analysis (SLaMA). This method is a simplified mechanism-based analytical approach. If the SLaMA method predicts realistically conservative global capacities, it could serve as an effective alternative assessment method for URM buildings, and especially to the NLPO FEM analysis. This study focusses on the comparison between the SLaMA method and the NLPO FEM analysis. Therefore, this study aims to answer the following research question: Could the SLaMA method be a realistically conservative and effective alternative to the NLPO FEM analysis in making a seismic assessment for two-storey unreinforced masonry buildings? In conclusion, the SLaMA method could be a realistically conservative and effective alternative to the NLPO FEM analysis in predicting the maximum base shear force. The displacement capacity predicted using the SLaMA method is validated only for buildings with RC floors. This predicted SLaMA method was realistically conservative compared with the ultimate displacement achieved using the NLPO FEM analysis. The SLaMA method is overall suitable for obtaining a quick understanding of the behaviour of an URM building. However, it requires a proper evaluation of the analyses to identify properly the type and the location of the failure mechanisms. For this reason, this method could be valuable to be applied before using a more complex assessment method.<br/
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
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.Structural Design & Mechanic
The atomistic modeling of light-harvesting complexes from the physical models to the computational protocol
No full textThe function of light-harvesting complexes is determined by a complex network of dynamic interactions among all the different components: the aggregate of pigments, the protein, and the surrounding environment. Complete and reliable predictions on these types of composite systems can be only achieved with an atomistic description. In the last few decades, there have been important advances in the atomistic modeling of light-harvesting complexes. These advances have involved both the completeness of the physical models and the accuracy and effectiveness of the computational protocols. In this Perspective, we present an overview of the main theoretical and computational breakthroughs attained so far in the field, with particular focus on the important role played by the protein and its dynamics. We then discuss the open problems in their accurate modeling that still need to be addressed. To illustrate an effective computational workflow for the modeling of light harvesting complexes, we take as an example the plant antenna complex CP29 and its H111N mutant. (c) 2022 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).2022 Author(s)
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