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Evaluating inelastic displacement demand of structures exposed to seismic hazard is required for the design of new buildings as well as for seismic risk assessment of existing structures. Most of the buildings are designed to withstand strong earthquakes by responding in the nonlinear range. Having special parts of the structure designed to develop a stable hysteretic behaviour allows the structure to deform in order to accommodate the displacement demand imposed by strong ground motions. This paper is centred on finding a correspondence between the maximum elastic and inelastic displacement responses of the single degree of freedom (SDOF) systems subjected to earthquakes generated by Vrancea seismic source. Vrancea intermediate-depth earthquakes are responsible for the seismic hazard throughout Romanian territory. They have distinctive features, such as large displacement demand and large predominant periods, which makes Romania a special seismic environment. Using a database of Romanian and Japanese strong ground motions generated by intermediate-depth earthquakes and performing nonlinear dynamic analysis on the SDOF oscillators following the Takeda model, this study estimates the inelastic to elastic displacement ratio of reinforced concrete systems. Soil conditions, epicentral distance and magnitude influence on inelastic response is analysed using constant ductility response spectra. The main findings of the study are: the local increase of the inelastic to elastic displacement ratio for type C soil (Eurocode 8 classification) for large magnitude earthquakes and the significant effect of soil conditions on the inelastic response of the SDOF systems. The inelastic amplification was evaluated using a functional form depending on system ductility, soil conditions and earthquake magnitude. [ABSTRACT FROM AUTHOR]

Mid-heavy nuclei offer unique opportunities to study the collective and single-particle aspects of nuclear structure. This mass regime is a dynamic area where protons and neutrons generally occupy different orbitals, giving rise to complex structures with a wide variety of shapes, shape evolution and shape coexistence. To that end, measurements of nuclear lifetimes and electromagnetic moments (µ,Q) can be invaluable. Recent experimental activities of the NuSTRAP group in Athens have focused on γ-spectroscopy studies employing the RoSPHERE array in Magurele, Romania. In recent studies [1, 2], the neutron-rich 144-146Ba isotopes have exhibited octupole degrees of freedom. Similar questions exist for the lighter 140Ba isotope, which is located at the onset of octupole collectivity. In addition, understanding the structure of heavier, even-even hafnium isotopes requires more data regarding shape coexistence and shape evolution. Preliminary results on lifetimes in this area pave the way to understand dynamical phenomena prior to studying more exotic species in the future. [ABSTRACT FROM AUTHOR]

A recently proposed method for scaling real accelerograms to obtain sets of code-compliant records is assessed. The method, which uses combined time and amplitude scaling, corroborated with an imposed value of an instrumental, Arias-type intensity, allows the generation of sets of accelerograms for which the values of the mean response spectrum for a given period range are not less than 90% of the elastic response spectrum specified by the code. The method, which is compliant with both for the Romanian seismic code, P1 00-1/2006, and Eurocode 8, was described in previous papers. Based on dynamic analyses of single-degree-of freedom (SDOF) and of multi-degree-of-freedom (MDOF) systems, a detailed application and assessment of the method is performed, for the case of the long corner period design spectrum in Bucharest. Conclusions are drawn on the advantages of the method, as well as on its potential improvement in the future. [ABSTRACT FROM AUTHOR]

This paper studies the horizontal components of 11 significant ground motion recordings from Romania and from the world. The dimensionless indicators e (Cartwright & Longuet-Higgins) and q (Vanmarcke) are used as stochastic measures of frequency content to characterize these ground motions. For sigle degree of freedom (SDOF) systems having different natural periods and 5% damping ratio, displacement responses have been determined to the following ground motions: 1977, 1986 and 1990 - Vrancea region, 1940 - El Centro, 1978 - Tangshan, 1979 - Montenegro, 1985 - Mexico City, 1995 - Kobe, 1999 - Kocaeli, 1999 - Duzce and 2010 - Chile. Structural responses are presented in terms of mean of maximum response and maximum response with p non-exceedance probability, where p takes the values of 10%, 50% and 90%. The results are presented in tables and graphics showing the variation of the seismic response with the natural period of the SDOF system. The conclusions drawn after these earthquakes regarding the behavior of different types of structures have been once again confirmed by this study. Correlations between the frequency content of the ground motions studied and the damages observed were also made. The paper emphasizes the importance of choosing for a future building the structural type that fits best the site's soil characteristics. [ABSTRACT FROM AUTHOR]

In this article, we critically analyze some recent attempts to assess the degree of economic freedom that countries around the world enjoy. The devised indices measure the consistency of a nation's policies and institutions with economic freedom. Although there seems to be a consensus among economists that in those countries where economic freedom is maintained economic growth follows, this hypothesis has yet to be empirically proven. The problem of bureaucratic decision-making, as a mechanism that may interfere with the economic freedom is also discussed. We then study the case of two quasi-similar, neighboring countries embarked on European integration, namely Romania and Bulgaria. [ABSTRACT FROM AUTHOR]

In order to raise the hysteresis loops in stationary dynamic regimes in the case of elastomeric insulators, specialized dynamic stands are used that may obtain both the necessary harmonic excitation by force as well as the modification of the angular arrangement discreetly variable from zero to 90 degrees. In this context, for the evaluation of the elastomeric insulators, a dynamic stand with an inertial vibrator was used, the frequency of which can be changed by continuous adjustment within the range of values from 2 Hz to 60 Hz. Forces and displacements can be measured with the appropriate sensors, and based on the recording of signals, the characteristics of rigidity, damping and the raise of hysteresis loops could be determined for three significant dynamic regimes: ante-resonance and post-resonance. Research on the dynamic stand, patented in Romania, has highlighted the fact that the parametric evaluation can be performed based on the lifting of the hysteretic loops in stationary harmonic regimes. Additionally, there are two situations specifically mentioned, one in which the significant inertial effect for the F-x loops leads to their positioning in quadrants II and IV, and the case of Q-x loops, where the inertial effect does not exist, and their positioning is only in quadrants I and III. From the analysis of the two cases, the most advantageous evaluation method for the test can be chosen. This article provides the calculation relationships established for the dynamic model with linear viscoelastic behaviour. The requirements of Voight–Kelvin modeling with a single degree of freedom is fully justified and ensured by the conditions of geometric and mass symmetry in the construction of the stand. The verification of the numerical results with the experimental ones was performed with the hysteresis loops corresponding to the previously defined three significant dynamic regimes, as well as according to the three positions of the elastomeric insulators for compression, compression-shear and shear. [ABSTRACT FROM AUTHOR]