Search results for " Ear"
showing 10 items of 9299 documents
Failure Rate Measurement on Silicon Diodes Reverse Polarized at High Temperature
2017
This paper calculates the failure rate on reversed polarized silicon diodes with the aim to justify, experimentally, the rules of the European Space Agency (ESA) which are referred to the component life’s extension, the reliability increase and the end of life performance enhancement, by using oversized devices (derating rules). In order to verify the derating rules, 80 silicon diodes are used, which are reverse polarized in a high temperature environment. The diodes are divided in 4 groups of 20 diodes, applying a different voltage to each group, in order to relate the failure rate to the applied derating rule. The experiment described in this paper is developed using a temperature acceler…
Towards automatic calibration of 2-D flood propagation models
2010
Abstract. Hydraulic models for flood propagation description are an essential tool in many fields and are used, for example, for flood hazard and risk assessments, evaluation of flood control measures, etc. Nowadays there are many models of different complexity regarding the mathematical foundation and spatial dimensions available, and most of them are comparatively easy to operate due to sophisticated tools for model setup and control. However, the calibration of these models is still underdeveloped in contrast to other models like e.g. hydrological models or models used in ecosystem analysis. This has two primary reasons: first, lack of relevant data against which the models can be calibr…
Temperature variability in the Iberian Range since 1602 inferred from tree-ring records
2017
Abstract. Tree rings are an important proxy to understand the natural drivers of climate variability in the Mediterranean Basin and hence to improve future climate scenarios in a vulnerable region. Here, we compile 316 tree-ring width series from 11 conifer sites in the western Iberian Range. We apply a new standardization method based on the trunk basal area instead of the tree cambial age to develop a regional chronology which preserves high- to low-frequency variability. A new reconstruction for the 1602–2012 period correlates at −0.78 with observational September temperatures with a cumulative mean of the 21 previous months over the 1945–2012 calibration period. The new IR2Tmax reconstr…
Ground instability in the old town of Agrigento (Italy) depicted by on-site investigations and Persistent Scatterers data
2012
We combine on-site investigations with the interpretation of satellite Persistent Scatterers (PS) to analyse ground instability in the historic town of Agrigento, Italy. Geological and geomorphologic surveys, together with geostructural and kinematic analyses, depict the deformational patterns of the northwestern sector of the town, previously documented by extensive literature available for the neighbouring Valley of the Temples. The geological and geomorphologic maps are reconstructed by combining bibliographic studies, field surveys and aerial stereo-interpretation. ERS-1/2 PS data reveal deformation velocities up to 18–20 mm yr<sup>−1</sup> in 1992–2000 over the Addolorata l…
Human activity and damaging landslides and floods on Madeira Island
2011
Abstract. Over the last few decades, the island of Madeira has become an important offshore tourism and business center, with rapid economic and demographic development that has caused changes to the landscape due to human activity. In Madeira's recent history, there has been an increase over time in the frequency of occurrence of damaging landslide and flood events. As a result, the costs of restoration work due to damage caused by landslide and flood events have become a larger and larger component of Madeira's annual budget. Landslides and floods in Madeira deserve particular attention because they represent the most serious hazard to human life, to property, and to the natural environme…
Use of metallurgical dust for removal chromium ions from aqueous solutions
2018
The aim of the study was to determine the potential for the application of dust from steel plant as an effective sorbent for removing Cr(III) and Cr(VI) in the form of simple and complex ions – Acid Blue 193 dye from aqueous solutions. Three isotherms models were used to interpret the experimental results namely: Langmuir, Freundlich, and Dubinin–Radushkevich. Estimated equations parameters allowed to determine the binding mechanism. Based on laboratory studies it was found that the dust was characterized by high sorption capacities for Cr ions and dye from the aqueous solution. The sorption capacity of the dust for Cr(III) and Cr(VI) ions depended on the degree of oxidation, pH of solution…
Sensitivity of a mesoscale model to different convective parameterization schemes in a heavy rain event
2011
Abstract. The Valencia region, on the Mediterranean coast of the Iberian Peninsula, is propitious to heavy precipitation, especially the area encompassing the South of Valencia province and the North of the Alicante province. In October 2007 a torrential rain affected the aforementioned area, producing accumulated rainfall values greater than 400 mm in less than 24 h and flash-floods that caused extensive economic losses and human casualties. This rain event has been studied in numerical experiments using the Regional Atmospheric Modeling System. The present paper deals with the effect of using the different convective parameterizations (CP) currently implemented in the Regional Atmospheric…
Numerical study of the October 2007 flash flood in the Valencia region (Eastern Spain): the role of orography
2010
Abstract. A torrential rain event took place in the Valencia region in October 2007, mainly affecting coastal areas and nearby mountains in the center-south of the region, in northern Alicante province. More than 400 mm in 24 h were recorded at some stations in these areas, with lower accumulations in the rest of the region where rainfall was less intense. In the first part of this work a description of the meteorological situation is given. The synoptic frame of the event is characterised by an advection of easterly maritime winds across the Western Mediterranean, lasting for at least 48 h, driving moist air towards the Iberian Peninsula eastern coast and the presence of an upper level iso…
Predicting storm-triggered debris flow events: application to the 2009 Ionian Peloritan disaster (Sicily, Italy)
2015
Abstract. The main assumption on which landslide susceptibility assessment by means of stochastic modelling lies is that the past is the key to the future. As a consequence, a stochastic model able to classify past known landslide events should be able to predict a future unknown scenario as well. However, storm-triggered multiple debris flow events in the Mediterranean region could pose some limits on the operative validity of such an expectation, as they are typically resultant of a randomness in time recurrence and magnitude and a great spatial variability, even at the scale of small catchments. This is the case for the 2007 and 2009 storm events, which recently hit north-eastern Sicily …
Hot water injection in relation to 1982-84 microseismic events at Campi Flegrei Caldera by thermo-hydro-mechanical simulation
2020
The repeated deformations and seismic unrests at Campi Flegrei caldera (southern Italy) have been identified due to a fluid injection source in volcano active area. We investigated the role of hot water injection in the seismic unrests of 1982-1984 with a view to gaining insights into the caldera’s dynamics, by applying coupled TOUGHREACT-FLAC3D simulator to our computational domain of 10 × 1 × 3 km with a single-phase steam isothermal (HM) and non-isothermal (THM) simulations comparison. The results indicated that the overlying caprock blocks the uprising hot water injection, leading to the building up of pore pressure and shear stress underneath over time. This process substantially modif…