3,606 research outputs found
A component-level methodology to evaluate the seismic repair costs of infills and services for Italian RC buildings
The reliable estimation of seismic losses due to damage to buildings is paramount for the post-emergency management and the planning of recovery activities. For residential reinforced concrete (RC) infilled buildings, a significant role in the computation of seismic loss is played by non-structural components, above all infills, partitions and services, as shown in past earthquakes. In this work, a component-based methodology is proposed to assess seismic losses for residential RC buildings in Mediterranean region. The attention is focused on the repairing activities for masonry infills (typical enclosure or partitions elements in Italian and Mediterranean RC buildings), and for services (plumbing systems, electric equipment, floor/wall tilesâŠ), commonly enclosed within the infill panels for the considered building typology. The described methodology can be used starting from the expected damage level to infills and partitions. It adopts given repair unit costs at different damage states of infills. The loss estimation methodology has been, first, validated by comparing predicted and actual repair costs for specific case-study buildings damaged by LâAquila (Italy) 2009 earthquake. Then, the methodology has been applied to a wide dataset of RC buildings (about 2500 residential buildings) damaged by LâAquila earthquake available from the literature, to show its possible application at a large-scale level. A good agreement between observed and predicted costs is obtained both for specific case-study buildings and for the wider building stock, especially when damage to structural components is very limited
Seismic Loss Estimation in Pre-1970 Residential RC Buildings: The Role of Infills and Services in LowâMid-Rise Case Studies
The lessons learned after recent earthquakes have highlighted the key role played by infills and services in damage and loss of Reinforced Concrete (RC) buildings. Their influence in seismic performance and loss estimation of selected RC building case studies is thoroughly analyzed here. The case study selection aims to be representative of existing buildings built in Italy before 1970, and covers a different number of stories and design typologies. The seismic responses of the case-study buildings are numerically analyzed by means of non-linear static pushover analysis (PO) considering a lumped plasticity approach with a quadri-linear flexural response for beam/column elements (properly calibrated for RC elements reinforced with plain bars) and a tri-linear compressive-only axial response with diagonal concentric struts for infill panels (empirically derived from experimental data on hollow clay masonry walls). Economic loss estimation is carried out via a component-based methodology that relies on the main repairing activities and resultant costs required for the refurbishment of infills and services for different damage levels. Accordingly, a damage analysis is performed herein, given the intensity measure, based on a comparison between Interstory drift demand from PO analysis and drift-based fragility functions specific for masonry infills. Loss curves, relating the total building repair cost to peak ground acceleration (PGA), are presented and compared for the analyzed case study buildings to show their trends and quantify the incidence of infills and services with respect to the reconstruction cost. A comparison between these outcomes and those recently found in the literature emphasizes the robustness of the considered approach and the reliability of the hypotheses about damage and loss assessment
Frictional melting of peridotite and seismic slip
The evolution of the frictional strength along a fault at seismic slip rates (about 1 m/s) is
a key factor controlling earthquake mechanics. At mantle depths, friction-induced melting
and melt lubrication may influence earthquake slip and seismological data. We report on
laboratory experiments designed to investigate dynamic fault strength and frictional melting
processes in mantle rocks. We performed 20 experiments with Balmuccia peridotite in a
high-velocity rotary shear apparatus and cylindrical samples (21.8 mm in diameter) over a
wide range of normal stresses (5.4â16.1 MPa), slip rates (0.23â1.14 m/s), and displacements
(1.5â71 m). During the experiments, shear stress evolved with cumulative displacement in
five main stages (stages 1â5). In stage 1 (first strengthening), the coefficient of friction m
increased up to 0.4â0.7 (first peak in friction). In stage 2 (abrupt firstweakening), m decreased
to about 0.25â0.40. In stage 3 (gradual second strengthening), shear stress increased toward
a second peak in friction (m = 0.30â0.40). In stage 4 (gradual second weakening), the
shear stress decreased toward a steady state value (stage 5) with m = 0.15. Stages 1 and 2 are
of too short duration to be investigated in detail with the current experimental configuration.
By interrupting the experiments during stages 3, 4, and 5, microstructural (Field Emission
Scanning Electron Microscope) and geochemical (Electron Probe Micro-Analyzer and
Energy Dispersive X-Ray Spectroscopy) analysis of the slipping zone suggest that second
strengthening (stage 3) is associated with the production of a grain-supported melt-poor
layer, while second weakening (stage 4) and steady state (stage 5) are associated with the
formation of a continuous melt-rich layer with an estimated temperature up to 1780 C.
Microstructures formed during the experiments were very similar to those found in natural
ultramafic pseudotachylytes. By performing experiments at different normal stresses
and slip rates, (1) the ââthermalââ (as it includes the thermally activated first and second
weakening) slip distance to achieve steady state from the first peak in strength decreased
with increasing normal stress and slip rate and (2) the steady state shear stress slightly
increased with increasing normal stress and, for a given normal stress, decreased with
increasing slip rate. The ratio of shear stress versus normal stress was about 0.15, well below
the typical friction coefficient of rocks (0.6â0.8). The dependence of steady state shear stress
with normal stress was described by means of a constitutive equation for melt lubrication.
The presence of microstructures similar to those found in natural pseudotachylytes and the
determination of a constitutive equation that describes the experimental data allows
extrapolation of the experimental observations to natural conditions and to the study of
rupture dynamics in mantle rocks
E-Defense 2015 ten-story building: beamâcolumn joint assessment according to different code-based design
Recent devastating earthquakes worldwide pointed out the importance of seismic detailing and their influence on the observed damage and subsequent repairability of reinforced concrete buildings. Several studies and post-earthquake observations remarked the role of beamâcolumn joints (BCJs) on the global building response and the effectiveness of transverse reinforcement in increasing the joint shear strength and the ultimate deformation. Although number of experimental and theoretical studies focused on the seismic response of BCJs, their mechanical behaviour is still a discussed topic. This resulted in number of design approaches available in worldwide code or standards that lead to different quantity of joint stirrups. This study focuses on the response of BCJs of a 10-story prototype building designed according to Japanese standards and tested in 2015 on the E-Defense shaking table. First the damage assessment at global (building) and local (joint) level is performed at increasing intensities and considering the building in the base slip and base fixed configurations. A refined numerical model is then developed and validated against global and local experimental results. Then, the joint stirrups are re-designed according to different international standards (ACI, EC8, NZS) and different numerical models are developed. The numerical results are then compared in terms of interstorey drift demand and joint shear strain. Finally, a comparison in terms of expected damage varying the design approach of joint stirrups is proposed
Arthropods on Mars?
As presented in this report numerous fossils like forms resembling a variety of marine arthropods including crustaceans, sea spiders, scorpions, arachnids, nematodes, annelids, tube worms, sea snakes, Kimberlla, Namacalathus, Lophotrochozoa, armored trilobites and millipedes have been found in Gale Crater (on Sols 302, 553, 753, 781, 809, 869, 880, 905, 1032), and Meridiani Planum both of which have hosted rivers, lakes, and inland seas. Similar specimens are mixed within a variety of divergent fossillike forms and are also found on distant sediment and mud stone. All specimens are distinct from underlying substrate and there are no obvious patterns or repetitions typically produced by erosion or weathering. Although without extraction and direct examination it is impossible to precisely determine the identity of all these specimens, the same problems bedevil identification of Burgess Shale fossils some of which are presented in this report for comparative analysis. The discoveries presented here and in other reports supports the theory that metazoans and other marine organisms evolved in the lakes, oceans and inland seas of Mars
MULTIDISCIPLINARY STUDY OF SUBSIDENCE AND SINKHOLE OCCURRENCES IN THE ACQUE ALBULE BASIN (ROMA, ITALY)
Abstract We present the results of a combined analysis of remote sensing and geophysicalâgeotechnical data carried out in the Acque Albule Basin, a sinkhole prone area located close to the city of Roma, where a wide travertine wedge is present. We carried out geophysical measurements and borehole drillings over two test areas to image the subsoil where paroxysmal surficial dynamics occur. One site is marked by subsidence occurring at least since the early 2000s, whereas the other site hosts the "La Regina" and "Colonnelle" sinkhole lakes, which discharge sulfurâcarbonated waters. The stability of these two sites threatens highway, railway, and airport facilities, and this study helps to assess the geological hazard. For example, InSAR and LiDAR data helped define wide scale subsidence over the last 20 years and previously undetected smallâscale morphologies. Geophysical measurements of the latter revealed shallow and deep dissolution affecting the travertine and driving surficial paroxysmal events. Both study sites were found to lie inside a large depression located at the junction between Jurassic carbonate and PlioâPleistocene units in association with paleo karst morphologies in the travertine deposits and affected by the presentâpast spillage of sulfurous waters. Given these elements, multidisciplinary geophysical observations are crucial for assessing and mitigating the geological risk and guiding land use planning and management
Participation in medical decision-making across Europe: an international longitudinal multicenter study
Background: The purpose of this paper was to examine national differences in the desire to participate in decision-making of people with severe mental illness in six European countries.
Methods: The data was taken from a European longitudinal observational study (CEDAR; ISRCTN75841675). A sample of 514 patients with severe mental illness from the study centers in Ulm, Germany, London, England, Naples, Italy, Debrecen, Hungary, Aalborg, Denmark and Zurich, Switzerland were assessed as to desire to participate in medical decision-making. Associations between desire for participation in decision-making and center location were analyzed with generalized estimating equations.
Results: We found large cross-national differences in patientsâ desire to participate in decision-making, with the center explaining 40% of total variance in the desire for participation (p<0.001). Averaged over time and independent of patient characteristics, London (mean=2.27), Ulm (mean=2.13) and Zurich (mean=2.14) showed significantly higher scores in desire for participation, followed by Aalborg (mean=1.97), where scores were in turn significantly higher than in Debrecen (mean=1.56). The lowest scores were reported in Naples (mean=1.14). Over time, desire for participation in decision-making increased significantly in Zurich (b=0.23) and decreased in Naples (b=-0.14). In all other centers, values remained stable.
Conclusions: This study demonstrates that patientsâ desire for participation in decisionmaking varies by location. We suggest that more research attention be focused on identifying specific cultural and social factors in each country to further explain observed differences across Europe
Evidence of Genetic Instability in Tumors and Normal Nearby Tissues
We have analyzed the sequence heterogeneity of the transcripts of the human HPRT and G6PD single copy genes that are not considered tumor markers. Analyses have been performed on different colon cancers and on the nearby histologically normal tissues of two male patients. Several copies of each cDNA, which were produced by cloning the RT-PCR-amplified fragments of the specific mRNA, have been sequenced. Similar analyses have been performed on blood samples of two ostensibly healthy males as reference controls. The sequence heterogeneity of the HPRT and G6PD genes was also determined on DNA from tumor tissues. The employed analytical approach revealed the presence of low-frequency mutations not detectable by other procedures. The results show that genetic heterogeneity is detectable in HPRT and G6PD transcripts in both tumors and nearby healthy tissues of the two studied colon tumors. Similar frequencies of mutations are observed in patient genomic DNA, indicating that mutations have a somatic origin. HPRT transcripts show genetic heterogeneity also in healthy individuals, in agreement with previous results on human T-cells, while G6PD transcript heterogeneity is a characteristic of the patient tissues. Interestingly, data on TP53 show little, if any, heterogeneity in the same tissues. CONCLUSIONS/SIGNIFICANCE: These findings show that genetic heterogeneity is a peculiarity not only of cancer cells but also of the normal tissue where a tumor arises
âI luoghi di Mercalliâ: a travelling exhibition as a tool for scientists to dialogue with the public on volcanoes and earthquakes
On March 19, 1914 Giuseppe Mercalli, a seismologist and volcanologist, well-known around the world for the
Intensity scale of earthquakes bearing his name, died tragically. A hundred years after, the Istituto Nazionale di
Geofisica e Vulcanologia (INGV) has promoted a variety of activities and cultural events that will take place under the
Patronage of the President of the Italian Republic within a year, the so called âAnno Mercallianoâ (the Year of
Mercalli).
The opening ceremony took place in Naples, Italy, on March 19, 2014, in the Convitto Nazionale Vittorio Emanuele
II. A scientific conference was held with the participation of experts from INGV and the university of Milano â
Bicocca, and presentations of students. On that day the exhibition entitled âI luoghi di Mercalliâ (Mercalli's places) was
also inaugurated, at the presence of local authorities.
The exhibition, organized by INGV, was realized in collaboration with the high school Vittorio Emanuele II, where
Mercalli has been teaching for 19 years, and the UniversitĂ degli Studi Suor Orsola Benincasa, where he was professor
of natural sciences.
A biographical and geographical description of the places where Mercalli operated introduces the exhibition, which
is organized in sections:
- Mercalli educator (he taught at high schools in Reggio Calabria and Naples);
- Mercalli volcanologist (Mercalli studied Vesuvius volcanic activity for more than twenty years, he was a scientific
witness of the Vesuvius 1906 eruption, and of the eruptions occurred at Vulcano (1888-90) and Stromboli (1891)
islands.
- Mercalli seismologist (Mercalli Intensity scale definition, based on his experience as witness of catastrophic
earthquakes, such as Casamicciola in 1883 and Messina in 1908).
Another section deals with the Vesuvius Observatory, directed by Mercalli between 1911 and 1914, and the
description of the three active volcanoes of the Campania region (Vesuvius, Campi Flegrei and Ischia island), which
have been the subject of studies by the well-known scientist. The exhibition is enriched by documents, manuscripts,
photos and field notebooks of Mercalli.
It is not intended to be only a celebratory exhibition; rather it is designed as a tool for dissemination of scientific
culture and to raise awareness about seismic and volcanic hazards.
In the exhibition path a continuous thread between the figure of Mercalli as a researcher and the role of an Earth
Science researcher today is highlighted, pointing to the development of scientific knowledge in the past century. The
goal is to improve the capability of learning from the disasters occurred in the past to implement preventive actions to
safely deal with future events.
The exhibition is travelling and will be provided on request to institutions and schools.PublishedMilano, Italia1V. Storia e struttura dei sistemi vulcaniciope
Anaesthesiological strategies in elective craniotomy: randomized, equivalence, open trial â The NeuroMorfeo trial
<p>Abstract</p> <p>Background</p> <p>Many studies have attempted to determine the <it>"best" </it>anaesthetic technique for neurosurgical procedures in patients without intracranial hypertension. So far, no study comparing intravenous (IA) with volatile-based neuroanaesthesia (VA) has been able to demonstrate major outcome differences nor a superiority of one of the two strategies in patients undergoing elective supratentorial neurosurgery. Therefore, current practice varies and includes the use of either volatile or intravenous anaesthetics in addition to narcotics. Actually the choice of the anaestesiological strategy depends only on the anaesthetists' preferences or institutional policies.</p> <p>This trial, named NeuroMorfeo, aims to assess the equivalence between volatile and intravenous anaesthetics for neurosurgical procedures.</p> <p>Methods/Design</p> <p>NeuroMorfeo is a multicenter, randomized, open label, controlled trial, based on an equivalence design. Patients aged between 18 and 75 years, scheduled for elective craniotomy for supratentorial lesion without signs of intracranial hypertension, in good physical state (ASA I-III) and Glasgow Coma Scale (GCS) equal to 15, are randomly assigned to one of three anaesthesiological strategies (two VA arms, sevoflurane + fentanyl or sevoflurane + remifentanil, and one IA, propofol + remifentanil). The equivalence between intravenous and volatile-based neuroanaesthesia will be evaluated by comparing the intervals required to reach, after anaesthesia discontinuation, a modified Aldrete score â„ 9 (primary end-point). Two statistical comparisons have been planned:</p> <p>1) sevoflurane + fentanyl vs. propofol + remifentanil;</p> <p>2) sevoflurane + remifentanil vs. propofol + remifentanil.</p> <p>Secondary end-points include: an assessment of neurovegetative stress based on (a) measurement of urinary catecholamines and plasma and urinary cortisol and (b) estimate of sympathetic/parasympathetic balance by power spectrum analyses of electrocardiographic tracings recorded during anaesthesia; intraoperative adverse events; evaluation of surgical field; postoperative adverse events; patient's satisfaction and analysis of costs.</p> <p>411 patients will be recruited in 14 Italian centers during an 18-month period.</p> <p>Discussion</p> <p>We presented the development phase of this anaesthesiological on-going trial. The recruitment started December 4<sup>th</sup>, 2007 and up to 4<sup>th</sup>, December 2008, 314 patients have been enrolled.</p
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