On the behaviour of structural steel beams under natural compartment fire

Fire is an extreme action, to which a steel structure may be submitted, and therefore, must be designed to resist. Traditionally, the fire resistance of structural steel beams has been determined in standard fire tests, with the temperature-time curveISO834representing more severe heating conditions compared to that which occurs in many typical natural fire compartments.Thereforeto design a steelstructure safely and economically, it is necessary to calculate temperature distribution in steel beamsunder natural fire. In this paper, the temperature profiles in a steel beams under natural fire arestudied first, using spread-sheets written by authorsand compared to standard fire. Secondly, twoCardington compartment corner office tests are highlighted,and analysis of primary and secondary steel beamsis presented.Simple theoretical natural fire models based on Eurocode EN 1991-1-2 parametric compartment fire are used and a comparison is made using the experimental results from tests conducted at Cardington research centre, UK. Compartment temperatures and cross-section temperature distribution respectively demonstrates that analytical fire models and experimental results are in good agreement in the case of timber cribs fire load

Finite element investigation on the behaviour of structural steel beams subjected to standard & parametric fire

This paper intends to present an investigation of the behaviour of steel beams under high temperatures rise due to fire using finite elements simulations with ANSYS software. Cases of study for solid as well as open web beams are considered and take into account uniform and transient temperature rise, material and geometric non-linear behaviour. Input fire scenarios are standard temperature-time curve ISO834 and parametric compartment fire model based upon Eurocode EN 1991-1-2. For the latter a comparison is made using the experimental results from BRE-Cardington tests data. Thermal and mechanical analysis is done using the effect of temperature dependent material properties and the Eurocode recommendations in estimating reduction mechanical steel properties. Three types of cellular beams are studied and the number of cells is shown to be critical for their behaviour under fire conditions. Results are related to temperature profiles in steel beam cross-sections, variation of displacements with respect to temperature change and critical temperatures.info:eu-repo/semantics/publishedVersio

Simulation numerique du comportement non-lineaire des portiques métalliques en situation d’incendie

Pour des raisons pratiques d’exploitation et de durabilité, les bâtiments industriels, sont dans la majorité des cas conçu en charpente métallique. Cependant le matériau acier quoi que ductile, il reste vulnérable aux excès de températures. Les récents événements d’incendies concernant les structures et bâtiments industriels de Sonatrach, à Alger dans une zone urbaine ou à Skikda dans une zone industrielle, nous rappellent le danger réel et le risque potentiel des incendies. Les nouvelles normes Européennes définissent des exigences actives et passives concernant le comportement au feu des bâtiments industriels. L’objectif de ce travail concerne l’étude du comportement non-linéaire des structures industrielles en acier selon plusieurs scénarios de feu. L’analyse numérique par la MEF et utilisant le logiciel ANSYS est considérée afin d’évaluer la résistance de ces structures et d’optimiser leur protection au feu. Une analyse, utilisant les non linéarités géométrique et matérielle, est conduite avec une variation progressive des températures jusqu’à la ruine. Différents taux de chargement ainsi que différents scénarios de feu seront utilisés pour évaluer la température critique ainsi que les déplacements des portiques en fonction de l’évolution de la température

Etude par simulation numérique du comportement des portiques métalliques en situation d’incendie

Les structures en portiques métalliques à double versants sont largement utilisées dans les bâtiments industriels pour des raisons pratiques d’exploitation, de durabilité et de rentabilité. Cependant le matériau acier quoi que ductile, il reste vulnérable aux excès de températures. Les récents événements d’incendies concernant les structures et bâtiments industriels de Sonatrach, à Alger dans une zone urbaine ou à Skikda dans une zone industrielle, nous rappellent le danger réel et le risque potentiel des incendies. Les nouvelles normes Européennes définissent des exigences actives et passives concernant le comportement au feu des hangars industriels. L’objectif de ce travail est d’étudier, par des simulations numériques, le comportement des portiques métalliques à double versants sous différents scénarios d’incendie. L’analyse numérique par la MEF et utilisant le logiciel ANSYS est considérée afin d’évaluer la résistance de ces structures et de rationaliser leur protection au feu. Une analyse, utilisant les non linéarités géométrique et matérielle, est conduite avec une variation progressive des températures jusqu’à la ruine. Différents taux de chargement ainsi que différents scénarios de feu seront utilisés pour évaluer la température critique ainsi que les déplacements des portiques en fonction de l’évolution de la température. Les résultats du modèle numérique sont comparés à ceux calculés par les méthodes simplifiées de l’Eurocode 3info:eu-repo/semantics/publishedVersio

Preliminary Analysis for Identification of Priority Species of Small Pelagic Shared Stocks in GSA01 And GSA03 (Alborán Sea)

Small pelagic resources and particularly sardine (Sardina pilchardus) and anchovy (Engraulis encrasicholus) represent an important fishery activity for the countries bordering the Alboran Sea. This paper aims at contributing to the identification of priority species of small pelagic shared stocks in GSA01 and GSA03 (northern and southern Alboran Sea GFCM regions) for carrying out joint stock assessments and promoting new management measures that would allow the sustainability of the resources and its exploitation. The WG on small pelagic shared stocks met twice during 2011 progressing in analysing the available data on the stocks and its exploitation and building a common data base. Moreover a comparative analysis on sardine landings data from 2003-2010 in GSA01 and GSA03 was carried out explaining that the exploitation pattern in sub-areas (GSAs 01 and 03) is different but the total length-frequency distribution of sardine exploited by each country appears to be similar. A tentative in applying a LCA analysis of the Moroccan and Spanish data on sardine using different biological parameters and with the VIT software was unsuccessful but orientated for future works of the W

Multivalued SK-contractions with respect to b-generalized pseudodistances

A new class of multivalued non-self-mappings, called SK-contractions with respect to b-generalized pseudodistances, is introduced and used to investigate the existence of best proximity points by using an appropriate geometric property. Some new fixed point results in b-metric spaces are also obtained. Examples are given to support the usability of our main result

Single photon sources in 4H-SiC metal-oxide-semiconductor field-effect transistors

We present single photon sources (SPSs) embedded in 4H-SiC metal-oxide-semiconductor fieldeffect transistors (MOSFETs). They are formed in the SiC/SiO2 interface regions of wet-oxidation C-face 4H-SiC MOSFETs and were not found in other C-face and Si-face MOSFETs. Their bright room-temperature photoluminescence (PL) was observed in the range from 550 to 750 nm andrevealed variable multi-peak structures as well as variable peak shifts. We characterized a wide variety of their PL spectra as the inevitable variation of local atomic structures at the interface. Their polarization dependence indicates that they are formed at the SiC side of the interface. We also demonstrate that it is possible to switch on/off the SPSs by a bias voltage of the MOSFET

Bifunctional Avidin with Covalently Modifiable Ligand Binding Site

The extensive use of avidin and streptavidin in life sciences originates from the extraordinary tight biotin-binding affinity of these tetrameric proteins. Numerous studies have been performed to modify the biotin-binding affinity of (strept)avidin to improve the existing applications. Even so, (strept)avidin greatly favours its natural ligand, biotin. Here we engineered the biotin-binding pocket of avidin with a single point mutation S16C and thus introduced a chemically active thiol group, which could be covalently coupled with thiol-reactive molecules. This approach was applied to the previously reported bivalent dual chain avidin by modifying one binding site while preserving the other one intact. Maleimide was then coupled to the modified binding site resulting in a decrease in biotin affinity. Furthermore, we showed that this thiol could be covalently coupled to other maleimide derivatives, for instance fluorescent labels, allowing intratetrameric FRET. The bifunctional avidins described here provide improved and novel tools for applications such as the biofunctionalization of surfaces