OPTIMUM RELIABILITY OF A STEEL TAPERED PORTAL FRAME STRUCTURE EXPOSED TO FIRE

In this study, the optimum reliability of a tapered steel portal frame structure is presented for several cases. The aim of the research is to define target reliability indices for fire design situation since some research works (Balogh and Vigh, 2015a; 2015b) pointed that the achievable reliability (with using the prescriptive rules of Eurocode standards) is lower in extreme and seismic design situations than the suggested target value in (EN0, 2002). It seems that the target reliability indices of (JCSS, 2000) are preferable in these cases. In this paper, the optimum reliability is investigated as described in (Holickỳ, 2011), but total cost function is formulated with two decisive variables with respect to the amount of active and passive safety measures. The structural reliability is obtained with the help of a complex FORM (First Order Reliability Method) algorithm. The results of this investigation can help also to answer the question, whether active or passive safety measures are more effective tools to achieve optimal solutions in case of fire design of steel portal frames

A függetlenség az Európai Központi Bank esetében. Elméleti megközelítés, koncepcióalkotás és gyakorlat

Az európai monetáris hatóság úgy került kialakításra, hogy abban meghatározóak legyenek a tagállamok nemzeti bankjainak vezető tisztségviselői. A legfőbb döntések meghozatalára a Kormányzótanács került felhatalmazásra, melynek tagjai az eredeti EMU koncepció létrehozásakor a tagállamok egyenlőségét jelképezve és hangsúlyozva kerültek kijelölésre. A Gazdasági és Monetáris Unió 2007-es bővítése után azonban már olyan nagy többségbe kerülnének a kisebb méretű államok az EMU-ban, hogy saját nemzetinek elvárásaikat képviselve a náluknál sokkal jelentősebb szerepű tagok érdekeivel ellentétes (vagy legalábbis, azokkal nem teljesen egyező) célokat valósíthatnának meg. Éppen ezért ennek a legfőbb döntéseket alkotó testületnek a belső szerkezetét úgy változtatták meg résztvevő államok, hogy a jövőben mindig a nagyobb gazdasági hátteret képviselő államok érdekei kerüljenek előtérbe

A sportolói értékek vizsgálata a sporttípus és a befektetett munka viszonylatában

Jelen kutatás azt elemzi, hogy a nemzetközi felmérésekhez hasonlóan alakul-e a magyar sportolók pszichológiai hozzáállása a sportban nyújtott teljesítmény elérése és az ezáltal nyerhető öröm összefüggésében. Ezen felül megvizsgálja azt, hogy a csapatjátékokat űző sportolók jelentősebbnek érzik-e a társakkal való közös munka értékét, vagy nincs különbség az egyéni sportolók vélekedéséhez képest. Az elemzés kérdőíves megkérdezés során nyert adatok statisztikai elemzésével bizonyítja, illetve cáfolja a feltevéseket

Reliability Assessment Methodology of Blast Protective Steel Moment Resisting Frame Using NiTi SMA-based Connection

This paper proposes a methodology framework for the reliability assessment of smart steel Moment Resisting Frame structures (MRFs) equipped with Nickle Titanium Shape Memory Alloy (NiTi SMA) connections subjected to blast loading. The reliability assessment framework is formulated based on a two-step approach algorithm. In the 1st Step, the Monte Carlo Latin Hypercube Sampling Strategy simulation (MC-LHS) is adapted to generate the uncertain parameters sample points. Considering the numerical simulations, the 2nd Step employs simplified performance functions and the generated random outcomes from the 1st Step. The proposed reliability approach is verified against direct Monte Carlo Simulation (MCS) and First-Order Reliability Method (FORM). The performance functions are columns’ axial force and bending moments, rotation capacity at the connections, and Inter-Story Drift Ratio (ISDR). Throughout the development of the reliability assessment, the probabilistic models are parametrized on geometrical properties, material properties, vertical loads, model errors, and charge weights. The developed reliability framework is applied to a prototype 4-story smart MRF. The structural safety level is obtained in terms of the Reliability Index (β). The results show that the reliability framework provides an accurate and efficient structural collapse prediction of the MRFs equipped with NiTi SMA-based connections. Finally, sensitivity analysis is performed to indicate the sensitivity of building collapse to blast wave characteristics, material strength, vertical gravity loads, and column profile dimensions. The sensitivity analysis results also confirm the efficiency of the proposed reliability framework in observing the highly sensitive parameters, which is explosive charge weight

Selective modification of cytoplasmic membrane fluidity by catalytic hydrogenation provides evidence on its primary role in chilling susceptibility of the blue-green alga, Anacystis nidulans

AbstractCytoplasmic and thylakoid membranes were isolated at different stages of catalytic hydrogenation of fatty acyl double bonds in living cells of Anacystis nidulans. The reaction was limited to the lipids of cell-surface membranes during the initial period of hydrogenation, thus, we were able to produce alga cells, modified exclusively in the cytoplasmic membrane. In these unique cells, neither compositional nor physical changes were detected in the lipid phase of thylakoids. Due to the rigidification of the alkyl chains of its lipids, however, the cytoplasmic membrane became leaky and phase separated at considerably higher chilling temperatures.Since an irreversible inactivation of photosynthetic electron transport was found simultaneously, it provided direct evidence for the hypothesis that the thermotropic properties of the lipids within cytoplasmic membranes, and not those of the thylakoids, control chilling susceptibility of the blue-green alga, A.nidulans

A methodology for the development of historical building archetypes for seismic performance assessment

The probabilistic estimation of the magnitude of historical earthquakes requires the analysis of actual building structures affected by those earthquakes. The analysis complicates because most of these buildings no longer exist or were greatly modified, present a great variety of features and the number of analysis for probabilistic assessment is high. As it is not practical to analyze all structures, an alternative is to use structural archetypes representing the affected buildings. This paper presents an approach to develop a quantitative framework for the generation of historical archetypes. The method is illustrated via the definition of a specific archetype for the study and assessment of the effects of the 1763 Komárom earthquake. The historical survey of Tata, Hungary, is assumed as representative of the region and one historical building is utilized to illustrate the archetypes evaluation process