Deep Supported Excavation in Difficult Ground Conditions in the City of Patras, Greece — Measured vs. Predicted Behavior

The technical characteristics of a deep supported excavation project using anchored diaphragm walls and the measured (by inclinometers) behavior of the soil retaining system are presented. The measured behavior is then compared with the predicted behavior using a finite element model of the excavation. The comparison shows a good agreement in a location where the soil profile is well defined. However, differences in the magnitude of the displacements were observed when the information on the soil profile was incomplete due to the variability of the deposits on site

Site Dependent Ground Response for the City of Patras, Greece

Results of a preliminary study of seismic ground response at different sites of the coastal city of Patras, in Southern Greece, are presented. At each site equivalent linear 1-D response analyses were conducted by using the finite element program LUSH 2. Values of dynamic properties of soils were obtained from either cross-hole tests or empirical correlations. The \u27rigid base\u27 excitation was selected as to best simulate the expected bedrock motions in Patras from local and distant earthquakes. The results of the analyses indicate a strong differentiation of seismic site response when moving from the coastal region of the city to the inland area. Peak surface accelerations were found to vary from 0.10 g in the coastal region to 0.50 g in the inland area, whereas the corresponding values of spectral acceleration ranged from 0.30 g to 2.0 g. Strong motion records obtained in the city during the July 14, 1993 MS = 5.4 Patras earthquake are in agreement with the results of this study. It is concluded that a systematic microzonation study of Patras would contribute to the seismic protection of the city

Creep Effects on Low-Amplitude Modulus of Clays

The investigation considered effects of on-going or previous drained creep on the low amplitude dynamic shear modulus of normally consolidated artificial and natural clay soils. Resonant column tests using the Hardin and Hall devices determined the low-amplitude shear modulus. Results indicated that the strain-rate of on-going creep determined the kind of effect on shear modulus. High strain-rates produced reduced values whereas low strain-rates slightly increased values of modulus, compared to the no-creep values. Previous creep produced higher values of modulus, when the clay was tested under after-creep isotropic confinement. The rate of secondary increase of shear modulus was not affected by the drained creep action. The behaviors of the remolded kaolinite clay and the undisturbed natural clay were remarkably similar

Topography Effects in the Athens 1999 Earthquake: The Case of Hotel Dekelia

The effects of surface topography on the seismic ground response of the site of Hotel DEKELIA, which partially collapsed in the Athens 1999 earthquake, is studied by the finite element method. The hotel site is located at the crest of a 40m high bank of a stream crossing the area. 2-D and I-D analyses of seismic ground response were conducted using five accelerograms recorded in past earthquakes (including the Athens 1999 earthquake) as input motion. Geotechnical data for the site were obtained from the results of a geotechnical investigation conducted at the hotel site whereas a VSO vs. depth profile was estimated by using the SASW method. The ground response analyses were conducted by assuming both equivalent-linear and truly non-linear soil behavior. The results indicate that surface topography has the potential of amplifying the peak horizontal accelerations and the maximum spectral accelerations (for period values ranging from 0.35sec to 0.50 sec) at the hotel site by up to 35% and loo%, respectively. It was also found that the local soil conditions at the site may have amplified significantly the input motion. It is concluded that the combined effects of surface topography and local soil conditions may have contributed to the partial collapse of the hotel

Two languages, two minds: flexible cognitive processing driven by language of operation.

People make sense of objects and events around them by classifying them into identifiable categories. The extent to which language affects this process has been the focus of a long-standing debate: Do different languages cause their speakers to behave differently? Here, we show that fluent German-English bilinguals categorize motion events according to the grammatical constraints of the language in which they operate. First, as predicted from cross-linguistic differences in motion encoding, bilingual participants functioning in a German testing context prefer to match events on the basis of motion completion to a greater extent than do bilingual participants in an English context. Second, when bilingual participants experience verbal interference in English, their categorization behavior is congruent with that predicted for German; when bilingual participants experience verbal interference in German, their categorization becomes congruent with that predicted for English. These findings show that language effects on cognition are context-bound and transient, revealing unprecedented levels of malleability in human cognition

CoBiToM Project -- II: Evolution of contact binary systems close to the orbital period cut-off

Ultra-short orbital period contact binaries (Porb < 0.26 d) host some of the smallest and least massive stars. These systems are faint and rare, and it is believed that they have reached a contact configuration after several Gyrs of evolution via angular momentum loss, mass transfer and mass loss through stellar wind processes. This study is conducted in the frame of Contact Binaries Towards Merging (CoBiToM) Project and presents the results from light curve and orbital analysis of 30 ultra-short orbital period contact binaries, with the aim to investigate the possibility of them being red nova progenitors, eventually producing merger events. Approximately half of the systems exhibit orbital period modulations, as a result of mass transfer or mass loss processes. Although they are in contact, their fill-out factor is low (less than 30 per cent), while their mass ratio is larger than the one in longer period contact binaries. The present study investigates the orbital stability of these systems and examines their physical and orbital parameters in comparison to those of the entire sample of known and well-studied contact binaries, based on combined spectroscopic and photometric analysis. It is found that ultra-short orbital period contact binaries have very stable orbits, while very often additional components are gravitationally bound in wide orbits around the central binary system. We confirmed that the evolution of such systems is very slow, which explains why the components of ultra-short orbital period systems are still Main Sequence stars after several Gyrs of evolution

A flexible format for exchanging pulsar data

We describe a data format currently in use amongst European institutions for exchanging and archiving pulsar data. The format is designed to be as flexible as possible with regard to present and future compatibility with different operating systems. One application of the common format is simultaneous multi-frequency observations of single pulses. A data archive containing over 2500 pulse profiles stored in this format is now available via the Internet (see http://www.mpifr-bonn.mpg.de/pulsar/data), together with a small suite of computer programs that can read, write and display the data

New Supernova Constraints on Sterile Neutrino Production

We consider the possibility that a light sterile-neutrino species $\nu_S$ can be produced by $\nu_e$ scattering during the cooling of a proto-neutron star. If we parameterize the sterile neutrino production cross-section by a parameter $A$ as $\sigma (\nu_e X\rightarrow \nu_S X) = A \sigma(\nu_e X\rightarrow \nu_e X)$, where $X$ is an electron, neutron or proton, we show that $A$ is constrained by limits to the conversion of $\nu_e$ to $\nu_S$ in the region between the sterile-neutrino trapping region and the electron-neutrino trapping region. This consideration excludes values of $A$ in the range between 10^{-4} \la A \la 10^{-1}.Comment: 12 pages; Late

On the asymptotic behaviour of solutions to the fractional porous medium equation with variable density

We are concerned with the long time behaviour of solutions to the fractional porous medium equation with a variable spatial density. We prove that if the density decays slowly at infinity, then the solution approaches the Barenblatt-type solution of a proper singular fractional problem. If, on the contrary, the density decays rapidly at infinity, we show that the minimal solution multiplied by a suitable power of the time variable converges to the minimal solution of a certain fractional sublinear elliptic equation.Comment: To appear in DCDS-