679 research outputs found
First results from the VIMOS-IFU survey of gravitationally lensing clusters at z~0.2
We present the on-going observational program of a VIMOS Integral Field Unit
survey of the central regions of massive, gravitational lensing galaxy clusters
at redshift z~0.2. We have observed six clusters using the low-resolution blue
grism (R about 200), and the spectroscopic survey is complemented by a wealth
of photometric data, including Hubble Space Telescope optical data and near
infrared VLT data. The principal scientific aims of this project are: the study
of the high-z lensed galaxies, the transformation and evolution of galaxies in
cluster cores and the use of multiple images to constrain cosmography. We
briefly report here on the first results from this project on the clusters
Abell 2667 and Abell 68.Comment: 5 pages, 5 figures. To appear in "Sciences Perspectives for 3D
Spectroscopy. ESO Astrophysics Symposia". Ed by M.Kissler-Patig, M.M. Roth
and J.R. Wals
Size-effect independence of hybrid fiber-reinforced roller-compacted concrete fracture toughness
The present paper aims to prove the size-effect independence of Hybrid Fiber-Reinforced RCC (HyFR-RCC) fracture toughness determined through the Modified Two-Parameter Model (MTPM). A micromechanical numerical model is applied to simulate the fracture behavior of seven series of single edge-notched specimens, made of both plain-RCCs and FR-RCCs (single and hybrid reinforcements), subjected to three-point bending. The MTPM is applied to the numerical load vs CMOD curves to compute the fracture toughness. A comparison with experimental values, available in the literature, is performed. Therefore, RCC specimens with different sizes are numerically simulated and the fracture toughness is analytically determined through the MTPM, proving the size-effect independence
A novel methodology for fatigue assessment of Ductile Cast Iron (DCI) with solidification defects
In the present research work, the fatigue strength assessment of a DCI containing solidification defects is theoretically carried out by means of a procedure implementing: (i) a defect content analysis, (ii) the varea-parameter model, and (iii) the multiaxial critical plane-based criterion by Carpinteri at al. An experimental campaign available in the literature, performed on DCI specimens under multiaxial fatigue loading, is analysed. The comparison between the obtained results and the experimental data shows a quite satisfactory agreement, highlighting the criterion accuracy
The ATESP Radio Survey II. The Source Catalogue
This paper is part of a series reporting the results of the Australia
Telescope ESO Slice Project (ATESP) radio survey obtained at 1400 MHz with the
Australia Telescope Compact Array (ATCA) over the region covered by the ESO
Slice Project (ESP) galaxy redshift survey. The survey consists of 16 radio
mosaics with ~8"x14" resolution and uniform sensitivity (1sigma noise level ~79
microJy) over the whole area of the ESP redshift survey (~26 sq. degrees at
decl. -40 degr). Here we present the catalogue derived from the ATESP survey.
We detected 2960 distinct radio sources down to a flux density limit of ~0.5
mJy (6sigma), 1402 being sub-mJy sources. We describe in detail the procedure
followed for the source extraction and parameterization. The internal accuracy
of the source parameters was tested with Monte Carlo simulations and possible
systematic effects (e.g. bandwidth smearing) have been quantified.Comment: 14 pages, 14 Postscript figures, Accepted for publication in A&A
Suppl. Corrected typos and added Journal Referenc
Observing the high redshift universe using the VIMOS-IFU
We describe the advantages of using Integral Field Spectroscopy to observe
deep fields of galaxy. The VIMOS Integral Field Unit is particularly suitable
for this kind of studies thanks to its large field-of-view (~ 1 arcmin^2).
After a short description of the VIMOS-IFU data reduction, we detail the main
scientific issues which can be addressed using observations of the Hubble Deep
Field South with a combination of Integral Field Spectroscopy and broad band
optical and Near-Infrared imaging.Comment: 4 pages, accepted for publishing in AN (ref. proc. of Euro3D Science
workshop, IoA Cambridge, May 2003
Spectroscopic surveys:a different approach to data reduction
We present VIPGI, an automatized human supervised reduction environment,
developed within the VIRMOS project to handle VIMOS guaranteed time data. VIPGI
is now offered to the international community to be used on site in Milano and
Marseille. Born to handle the highly multiplexed MOS VIMOS data, it has been
extended to accomodate also IFU data. The widespread and extensive use of VIPGI
has suggested the idea of an integrated environment allowing users not only to
reduce, but also to organize data in logical structures, to insert results in a
database, and use any user defined plugin for data reduction, analysis and
inspection. See http://cosmos.mi.iasf.cnr.it/pandoraComment: Astronomical Data Analysis III conference proceedin
Experimental and numerical study on the fatigue behaviour of the shot-earth 772
The present research work is devoted to the mechanical, fracture and fatigue experimental characterization of the shot-earth 772, with a particular attention to its fatigue behaviour. To such an aim, an extensive experimental program has been carried out, consisting of: (i) flexural and compression tests, (ii) three-point bending fracture tests, and (iii) bending and compression cyclic tests. Moreover, a FE numerical model is employed to simulate both the above bending and compression cyclic tests, after the input data validation performed by simulating the above fracture tests. The numerical fatigue lifetimes are compared with the corresponding experimental ones for both pulsating bending and compression, highlighting the model accuracy. Finally, the contours of both the damage parameter and the reduced Young modulus are plotted showing the evolution of fatigue damage
Crack path estimation in the shot-earth 772 by a discrete element method
In the present paper, the fracture behaviour of the shot-earth 772, in terms of crack path, is numerically investigated. To such an aim, a version of the lattice discrete element method is used to numerically simulate fracture toughness testing performed, on the shot-earth 772, by employing the Modified Two-Parameter model. A comparison between the numerical crack path and the experimental ones is performed, highlighting as the lattice discrete element method is able to capture the kinked crack shape, typical of quasi-brittle material
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