1,197 research outputs found
THE DESERT ROSE DOMES OF THE SOUF REGION (ALGERIA). PRELIMINARY EVALUATIONS ON THE VULNERABILITY OF A UNIQUE VERNACULAR HERITAGE
Abstract. The vernacular architecture of the Souf region in Algeria, a desert environment where wood is rare, presents multiple heritage values due to the way in which local materials (especially the desert rose stone) are exploited to build houses and erect distinctive domes. Unfortunately, extensive damage and abandonment compromise the stability of these buildings and accelerate their disappearance, which would negatively affect the urban landscape and the identity of the region. In order to safeguard this unique vernacular heritage, the study focuses on the definition of the typical typology of building, its structural and geometric characteristics, explaining the constructive technique used. Recurrent damage and pathologies that threaten this building culture are also highlighted. Then, estimation of mechanical parameters of the desert rose stone masonry is carried out defining typical characteristics according to the evaluation of the respect of "the rule of the art". Results are then used to perform numerical simulations of the structural behaviour of a typical building, through the finite element method with linear and nonlinear approaches. In particular, the structural behaviour of the dome has been investigated, being the most vulnerable element of the system
Sites for Gamma-ray Astronomy in Argentina
We have searched for possible sites in Argentina for the installation of
large air Cherenkov telescope arrays and water Cherenkov systems. At present
seven candidates are identified at altitudes from 2500 to 4500 m. The highest
sites are located at the Northwest of the country, in La Puna. Sites at 2500
and 3100 m are located in the West at El Leoncito Observatory, with excellent
infrastructure. A description of these candidate sites is presented with
emphasis on infrastructure and climatology.Comment: Submitted to Proceedings of "4th Heidelberg International Symposium
on High Energy Gamma-Ray Astronomy 2008
Insertion of the DNA for the 163-171 peptide of IL1beta enables a DNA vaccine encoding p185(neu) to inhibit mammary carcinogenesis in Her-2/neu transgenic BALB/c mice.
Insertion of the DNA for the 163–171 peptide of IL1β enables a DNA vaccine encoding p185 neu to inhibit mammary carcinogenesis in Her-2/neu transgenic BALB/c mic
Seismic Vulnerability Assessment of a 17th Century Colonial Adobe Church in the Central Valley of Chile
This paper focuses on the seismic vulnerability assessment of the San Judas Tadeo´s church in Malloa (Chile), an iconic example of Colonial Chilean architecture. This small adobe structure is a single-nave building consisting of the main nave, a bell-tower located in the façade, two external wooden galleries and additional units such as the sacristy, chapel, and two services areas.
The Church has survived several strong earthquakes larger than Mw>8. Besides, after the February 27th, 2010 Maule event it showed remarkable resilience due to the implementation of traditional timber retrofits inserted in the earthen walls. The use of traditional wooden devices such as bond beams, corner keys, and wooden gables, proved to be effective solutions against strong earthquakes.
Therefore, this church appears as a relevant case of the use of seismic resistant constructive techniques of the17th century colonial architecture and the study of its seismic behaviour holds great interest and relevance.
Aimed to assess the seismic performance of the monument, a complete preliminary study of the church was carried out using a multi-level approach comprising historical research, in situ surveys, crack pattern analysis, physical and mechanical characterization of materials, and structural analyses. In particular as part of an ongoing research, linear and incremental kinematic approaches of limit analyses have been employed with the aim of interpreting the local mechanisms activated during the 2010 Maule earthquake. In these models, the effect of friction on masonry-to-masonry and timber-to-masonry interfaces was considered with promising outcomes.
This study results prove the general validity in the field of timber seismic retrofitting of unreinforced adobe buildings
Design of a 7m Davies-Cotton Cherenkov telescope mount for the high energy section of the Cherenkov Telescope Array
The Cherenkov Telescope Array is the next generation ground-based observatory for the study of very-high-energy gamma-rays. It will provide an order of magnitude more sensitivity and greater angular resolution than present systems as well as an increased energy range (20 GeV to 300 TeV). For the high energy portion of this range, a relatively large area has to be covered by the array. For this, the construction of ~7 m diameter Cherenkov telescopes is an option under study. We have proposed an innovative design of a Davies-Cotton mount for such a telescope, within Cherenkov Telescope Array specifications, and evaluated its mechanical and optical performance. The mount is a reticulated-type structure with steel tubes and tensioned wires, designed in three main parts to be assembled on site. In this work we show the structural characteristics of the mount and the optical aberrations at the focal plane for three options of mirror facet size caused by mount deformations due to wind and gravity.Facultad de IngenierÃ
Very High Energy Gamma-Ray Emission from the Blazar Markarian 421
Very high energy gamma-ray emission from the BL Lac object Markarian 421 has
been detected over three observing seasons on 59 nights between April 1992 and
June 1994 with the Whipple 10-meter imaging Cherenkov telescope. During its
initial detection in 1992, its flux above 500 GeV was
1.610photons cm s. Observations in 1993 confirmed
this level of emission. For observations made between December 1993 and April
1994, its intensity was a factor of 2.20.5 lower. Observations on 14 and
15 May, 1994 showed an increase over this quiescent level by a factor of
10 (Kerrick et al. 1995). This strong outburst suggests that 4 episodes
of increased flux measurements on similar time scales in 1992 and 1994 may be
attributed to somewhat weaker outbursts. The variability of the TeV gamma-ray
emission from Markarian 421 stands in contrast to EGRET observations (Lin et
al. 1994) which show no evidence for variability.Comment: gzip compressed tar file including LaTeX text and 4 postscript
figures (14 pages total incl. 4 tables), accepted for publication in the
Astrophysical Journal. Contact address is [email protected]
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