Advanced real-time acquisition of the Vrancea earthquake early warning system

The Vrancea seismogenic zone in Romania represents a peculiar source of seismic hazard, which is a major concern in Europe, especially to neighboring regions of Bulgaria, Serbia and Republic of Moldavia. Earthquakes in the Carpathian–Pannonian region are confined to the crust, except the Vrancea zone, where earthquakes with focal depth down to 200 km occur. One of the cities most affected by earthquakes in Europe is Bucharest. Situated at 140–170 km distance from Vrancea epicenter zone, Bucharest encountered many damages due to high energy Vrancea intermediate-depth earthquakes; the March 4, 1977 event (M_w=7.2) produced the collapse of 36 buildings with 8–12 levels, while more than 150 old buildings were seriously damaged. A dedicated set of applications and a method to rapidly estimate magnitude in 4–5 s from detection of P wave in the epicenter were developed. They were tested on all recorded data. The magnitude error for 77.9% of total considered events is in the interval [−0.3, +0.3] magnitude units. This is acceptable taking into account that the magnitude is computed from only 3 stations in a 5 s time interval (1 s delay is caused by data packing). The ability to rapidly estimate the earthquake magnitude combined with powerful real-time software, as parts of an early warning system, allows us to send earthquake warning to Bucharest in real time, in about 5 s after detection in the epicenter. This allows 20–27 s warning time to automatically issue preventive actions at the warned facility.     

Mathematical models of climate evolution in Dobrudja

The understanding of processes that occur in climate change evolution and their spatial and temporal variations are of major importance in environmental sciences. Modeling these processes is the first step in the prediction of weather change. In this context, this paper presents the results of statistical investigations of monthly and annual meteorological data collected between 1961 and 2007 in Dobrudja (a region situated in the South–East of Romania between the Black Sea and the lower Danube River) and the models obtained using time series analysis and gene expression programming. Using two fundamentally different approaches, we provide a comprehensive analysis of temperature variability in Dobrudja, which may be significant in understanding the processes that govern climate changes in the region.     

Magnetic Bianchi type II string cosmological model in loop quantum cosmology

The loop quantum cosmology of the Bianchi type II string cosmological model in the presence of a homogeneous magnetic field is studied. We present the effective equations which provide modifications to the classical equations of motion due to quantum effects. The numerical simulations confirm that the big bang singularity is resolved by quantum gravity effects.     

Reconstructing the spatial distribution of large vegetation formations during the mid-Holocene in Romania: a predictive modeling approach

The present study tests the usefulness of SoLIM software and GIS techniques for the reconstruction of large vegetation formations from the mid-Holocene period in Romania. We used current reference climate data (temperature, precipitation) and the current extent of ecological regions in Romania to derive climate optimality functions for each vegetation formation. The optimality functions were used to simulate current and past distributions of vegetation. The results showed that the current and mid-Holocene simulated spatial distributions of vegetation are quite similar. Changes were found for about 14% of the Romanian territory (33 946 km²), the most important being the retreat of coniferous forests in favor of mixed forests and of mixed forests in favor of forest steppe. The former is validated by previous pollen-based studies showing the transition from coniferous forests to mixed forests that occurred in several areas of the country after the mid-Holocene. The study demonstrates the potential of this methodological approach to reconstruct past vegetation formations, and at the same time that it is a straightforward and expert knowledge-based method. Although our application uses only climate factors, the results can be further refined by incorporating additional drivers (soil and landform information, site-specific pollen and fossil data, wildfire data) for a more accurate inference of paleovegetation.     

Identification of hydrodynamic coefficients for manoeuvring simulation model of a fishing vessel

The results of numerical and experimental investigations on the manoeuvring performance of a fishing vessel, typical for Mediterranean Sea, are here presented. PMM experiments were used for evaluating hydrodynamic derivatives and implementing the theoretical model. The simulation model was validated, both with zig-zag and spiral experimental model tests results in still water and compared with Tribon Initial Design module results.     

La séparation des signaux utiles gravimétriques du fond des perturbations

Summary The paper is dealing with the separation problem of weak intensity anomalies from the perturbation background. By means of the Shannon's form and based on the values estabilished for a measured gravitational field, g, the mean quantity of information sent forth at the source — perturbating body — is calculated in order to intercept the g set. This quantity takes a maximum value above the perturbating body, while for the remainder a deadening of the perturbations is obtained.     

Separation of small nonferrous particles using a two successive steps eddy-current separator with permanent magnets

The paper presents a method for separating the small metallic nonferrous particles from two component metallic nonferrous mixtures using a new type of dynamic eddy-current separator with permanent magnets. The so-called two successive steps eddy-current separator (TSECS) consists of a horizontal rotary drum covered with permanent magnets, alternately N–S and S–N oriented. The separation process takes place in two stages, first the strongly conducting particles are separated on the upper part of the drum, and then the remaining undecided and poorly conducting particles are separated at the lower part of the magnetic drum. The experimental results and comments regarding the values obtained for separation efficiency, grade and recovery for wastes consisting in Cu–Pb and Cu–Al mixtures are given. The obtained results are in good agreement with the theoretical analysis.