The Hermann tortoise (Testudo hermanni boettgeri Mojsisovics, 1889) is present in Romania at its range limit. The main range is located in the Southwestern part of the country, in a sub-optimal sub-Mediterranean climate. Testudo hermanni boettgeri is also found in the Southeastern part of the country, the population there being insignificant to be included in our study. The range from Southwestern part of Romania has a surface of similar to 4420 sq km, from which only similar to 672 sq km is favorable to the tortoise. From the range extension point of view, the Hermann tortoise is a subspecies with a restrictive habitat, and the population is strongly declining-a tendency that most likely will continue in the future. This decline is accentuated by the habitat loss. The main threats for the Hermann tortoise are due to housing and urban area encroachment, tourism and recreation areas, annual and perennial non-timber crops, mining and quarrying, energy production and mining, recreational activities, increase in fire frequency/intensity, droughts, temperature extremes, climate change and severe weather. The threatened status established according to IUCN criteria for the regional level under uncertainty have led to framing the species in the endangered EN Blab(i,ii,iii,v) category.
The Benchmark of the Rance beams has been organised in order to evaluate the capabilities of various modelling tools, to predict the residual load carrying capacity of corroded beams. The Rance beams have been corroded in a marine environment for nearly 40 years. Different types of prestressed beams, made of different types of cement, have been subjected to four points bending monotonous and cyclic tests as well as direct traction tests. The tests have been carried on up to failure, in order to evaluate the residual carrying capacity of the beams. Different teams have participated to the blind prediction of the tests results. In this framework, the CEA/DM2S/LM2S team has performed bidimensionnal modellings which are described in details in this paper. The various constitutive elements of the beams are represented: for concrete, the isotropic Mazars' damage model is used, in a non local version, for prestressing and passive steels, an elasto-plastic strain hardening model is adopted. The corrosion effects, taken into account for the longitudinal rebars, are derived on one hand from the measurements performed on the beams after the tests, and on the other hand from the literature. They consist mainly in a reduction of the rebars cross-section, as well as in their ductility. In principle, the properties of the bond between steel and rebars are also modified by the corrosion. Here, because of the unavailability of specific data on the smooth rebars of the Rance beams, the bond has been modelled by means of specific joint finite elements. The load carrying capacity has been calculated for the monotonous as well as the cyclic tests. Moreover, a sensitivity analysis has been performed, by considering variants where either the rebars are sane, or they have only reduced sections, with their original ductility. The results are compared to the experimental database, and discussed.
We present a new nonlinear solid-state technique for temporal femtosecond pulses cleaning. The contrast reaches 10 -10 for millijoule input pulse. Efficiency is demonstrated at 800 nm and 1 μm. The method is reliable enough to solve the contrast issue for Petawatt class lasers.
Results of experimental investigation and numerical modeling of high strain rate behavior of aluminium alloys AMg-6 and D-16 are presented. Using Split Hopkinson Pressure Bar (SHPB) parameters of Johnson-Cook's model and other models from LS-DYNA library were determined in strain rate range 10(2)-10(4) s(-1). For verification of the models a comparison of the results of numerical modeling and model experiments was carried out. Modificated Taylor's test and modification of SHPB test for high-speed penetration were carried out as model experiments.
The paper presents the range and possibilities of using expert systems at diagnostic measurements of insulation systems of power appliances taken by the acoustic emission (AE) method. Multi -parametric descriptors characterizing the AE signals, which can be used in the knowledge base as criteria making the identification of basic partial discharge forms (PDs) possible, have been characterized in detail. The tables show descriptors describing the AE signals registered in time, frequency, time-frequency domains and statistical data. Moreover, computational tools that can be used in the process of conclusion drawing were suggested and the range of the research work done by the authors of the paper aiming at creating a computerized expert system was presented.
