Elastic behaviour and phase stability of pyrophyllite and talc at high pressure and temperature     

G. Diego Gatta  Paolo Lotti  Marco Merlini  Hanns-Peter Liermann  Andrea Lausi  Giovanni Valdrè  Alessandro Pavese 《Physics and Chemistry of Minerals》2015,42(4):309-318

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Reliability of digit length impression as a character of tetrapod ichnotaxobase: considerations from the Carboniferous–Permian ichnogenus Ichniotherium     

Marco Romano  Paolo Citton 《Geological Journal》2015,50(6):827-838

Although the relative length of digit impressions is often adopted as a binding character in ichnotaxa discrimination and trackmaker identification, it cannot be considered unequivocally operative. The reliability of this character has been evaluated by means of principal component analysis on several well‐preserved footprints (both manus and pes) referred to as Ichniotherium sphaerodactylum from the Early Permian Tambach Formation (Thuringia, Germany). The analysis reveals a substantial variability of digit impression length (especially in the manus), relativizing the validity of digit IV length as a diagnostic character as practised in different ichnological studies. Regarding the use of such a character, results clearly suggest the need to preliminarily conduct explorative analysis on the whole available ichnological material in order to detect which digit is the most consistent from an ichnotaxonomical standpoint, thus avoiding an arbitrary selection. Such a preliminary analysis should provide a better control on ichnotaxonomical splitting/lumping, particularly in the case of allied footprints, and can also be considered a valuable tool, if associated to functionality analysis, in improving and refining trackmaker identification. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

On the misinterpretation of the North Atlantic Oscillation in CMIP5 models     

Paolo Davini  Chiara Cagnazzo 《Climate Dynamics》2014,43(5-6):1497-1511

The representation of the wintertime North Atlantic Oscillation (NAO) and its relationship with atmospheric blocking and the Atlantic jet stream is investigated in a set of CMIP5 models. It is shown that some state-of-the-art climate models are unable to correctly simulate the physical processes connected to the NAO. This is especially true for models with a strongly underestimated frequency of high-latitude blocking over Greenland. In these models the first empirical orthogonal function (EOF1) of the Euro-Atlantic sector can represent at least three different categories of dominant modes of variability associated with different prevalent regions of blocking occurrence and jet stream displacements. It is therefore possible to show that such “biased NAOs” are connected with different dynamical processes with respect to the canonical NAO seen in observations. Since the NAO is a widely used concept in scientific community, the consequent “dynamical misinterpretation” of the NAO that can result when climate models are analyzed may have important implications for the NAO-related studies. This may be especially relevant for the ones involving climate scenarios, since these modeled NAOs may react differently to greenhouse gas forcing.  相似文献   

Local Circulation Diurnal Patterns and Their Relationship with Large-Scale Flows in a Coastal Area of the Tyrrhenian Sea   总被引：1，自引：0，他引：1  

Igor Petenko  Giangiuseppe Mastrantonio  Angelo Viola  Stefania Argentini  Lucia Coniglio  Paolo Monti  Giovanni Leuzzi 《Boundary-Layer Meteorology》2011,139(2):353-366

In order to characterise the local low-level circulation in the Tyrrhenian Sea coastal area near Rome, the wind field observed by conventional anemometers, Doppler sodar, and rawinsonde has been analysed. The prevailing diurnal behaviour of wind speed and direction as a function of season was highlighted, and the existence of two different patterns of the local circulation, mainly due to land and sea breezes and to the drainage flow from the mouth of the Tiber valley, revealed. The comparison between the low-level circulation and synoptic flow allowed us to determine the influence of the large-scale flow on nocturnal currents that are observed at the Pratica di Mare site and the way that wind direction evolves during the day. Numerical simulations are consistent with experimental data and depict the main features of the low-level wind field in the area.  相似文献   

Vulnerability study on a large industrial area using satellite remotely sensed images     

Barbara Borzi  Fabio Dell��Acqua  Marta Faravelli  Paolo Gamba  Gianni Lisini  Mauro Onida  Diego Polli 《Bulletin of Earthquake Engineering》2011,9(2):675-690

The aim of this paper is to disseminate knowledge in the seismic science community about a possible tool which is not largely popular, despite its potential usefulness. In this paper it will be shown how satellite remotely sensed images may represent a powerful source of information where traditional sources of information are unable to deliver it, or at least to do so timely. Even when traditional information flow can ensure delivery, an advantage may still be found in terms of sooner availability and smaller amount of labour required. In the case shown here a vulnerability study was made on a vast industrial area in the gulf of Siracusa, Sicily, Italy. A series of concurrent factors made it particularly troublesome to obtain information on the structures found in the site (tanks, pipes, chimneys, roads, ...), required to suitably carry out the study. Satellite images were then acquired to obtain the information needed. Processing of the images was carried out relying on in-house software formerly developed for similar information extraction issues, and integrated with new, specifically developed elements, some pieces of information were obtained useful for seismic risk evaluation. In particular, location, footprint, elevation of significant structures (e.g. tanks, chimneys) could be evaluated, obtaining results in a format compatible with the most widespread GIS (Geographic Information System) standards. Such compatibility allowed a considerable savings on labour time required to lay a GIS of the area, which is a fundamental tool for risk and vulnerability analyses.  相似文献   

A Review of Higher Order Ionospheric Refraction Effects on Dual Frequency GPS   总被引：1，自引：0，他引：1  

Elizabeth?J.?PetrieEmail author  Manuel?Hernández-Pajares  Paolo?Spalla  Philip?Moore  Matt?A.?King 《Surveys in Geophysics》2011,32(3):197-253

Higher order ionospheric effects are increasingly relevant as precision requirements on GPS data and products increase. The refractive index of the ionosphere is affected by its electron content and the magnetic field of the Earth, so the carrier phase of the GPS L1 and L2 signals is advanced and the modulated code delayed. Due to system design the polarisation is unaffected. Most of the effect is removed by expanding the refractive index as a series and eliminating the first term with a linear combination of the two signals. However, the higher order terms remain. Furthermore, transiting gradients in refractive index at a non-perpendicular angle causes signal bending. In addition to the initial geometric bending term, another term allows for the difference that the curvature makes in electron content along each signal. Varying approximations have been made for practical implementation, mainly to avoid the need for a vertical profile of electron density. The magnetic field may be modelled as a tilted co-centric dipole, or using more realistic models such as the International Geomagnetic Reference Field. The largest effect is from the second term in the expansion of the refractive index. Up to several cm on L2, it particularly affects z-translation, and satellite orbits and clocks in a global network of GPS stations. The third term is at the level of the errors in modelling the second order term, while the bending terms appear to be absorbed by tropospheric parameters. Modelling improvements are possible, and three frequency transmissions will allow new possibilities.  相似文献   

Laboratory parallel-beam transmission X-ray powder diffraction investigation of the thermal behavior of nitratine NaNO<Subscript>3</Subscript>: spontaneous strain and structure evolution     

Paolo Ballirano 《Physics and Chemistry of Minerals》2011,38(7):531-541

Present work provides in-situ structural data at a fine temperature scale from RT to the melting point of nitratine, NaNO₃. From the analysis of log e ₃₃ versus log t plots, it is possible to prove that an univocal indication on the R \( \overline{3} \) c (low temperature, LT) → R \( \overline{3} \) m (high temperature, HT) transition mechanism cannot be obtained because of the relevant role played by the arbitrary assumptions required for defining the c ₀ dependence from temperature of the HT phase. This is due to the occurrence of excess thermal expansion for the HT phase. A significantly better fit for an Ising-spin structural model over a non-Ising rigid-body one has been obtained for the LT phase. Moreover, the Ising model led to a smooth variation of the oxygen site x fractional coordinate throughout the transition. The structure of the HT polymorph has been successfully refined considering an oxygen site at x, 0, ½, with 50% occupancy. Such model was the only acceptable one from the crystal chemical point of view as the alternative model (oxygen site at x, y, z with 25% occupancy) led to unrealistically aplanar \( {\text{NO}}_{3}^{ - } \) groups.  相似文献   

Displacement patterns of a landslide affected by human activities: insights from ground-based InSAR monitoring   总被引：2，自引：0，他引：2  

Francesca Bozzano  Ivan Cipriani  Paolo Mazzanti  Alberto Prestininzi 《Natural Hazards》2011,59(3):1377-1396

Landslides interacting with large infrastructures represent a major problem for the economy, society as a whole, and the safety of workers. Continuous monitoring for 23 months using an integrated platform with a ground-based SAR interferometer (GB-InSAR), a weather station, and an automatic camera gave us the opportunity to analyze the response of an unstable slope to the different phases of work. The deformational behavior of both the natural slope and the man-made structures was recorded and interpreted in relation to the working stages and the rainfall conditions during the whole monitoring period. A typical pattern of displacement was identified for shallow landslides, debris produced by the excavation and gabions, metallic walls, and anchored bulkheads. Furthermore, insights into the dynamics and behavior of the slope and the man-made structures that interact with the landslide were obtained. Extreme rainfall is the main trigger of shallow landslides and gabion deformations, while anchored bulkheads are less influenced by rainfalls. Movement of debris that is produced by excavations and temporary metallic barrier deformation are closely related to each other. The herein proposed monitoring platform is very efficient in monitoring unstable slopes that are affected by human activities. Moreover, the recorded patterns of displacement in the slope and the man-made structures can be used as reference data for similar studies and engineering designs.  相似文献   

The Second World Landslide Forum, Rome, 3�C9 October 2011: state of art at May 2011     

Claudio Margottini  Paolo Canuti  Kyoji Sassa 《Landslides》2011,8(2):261-267

The World Landslide Forum (WLF) is a triennial mainstream conference aimed at gathering scientists, stakeholders, policy makers and industry members dealing with the management of landslide risk. The First World Landslide Forum, organised by the International Consortium of Landslides, UNESCO, WMO, Food and Agriculture Organization, UNISDR, UNU, UNEP, IBRD, UNDP, ICSU, WFEO, KU and the Japan Landslide Society, was held in 2008 at the United Nations University, Tokyo. The 1st WLF adopted the 2008 Tokyo Declaration “Strengthening the International Programme on Landslides with UNISDR”. The Second World Landslide Forum has the objective to further develop the outcomes of the First Forum in Tokyo 2008 by providing a global cross-cutting information and cooperation platform for all types of organisations representing academia, United Nations organisations, governments, private enterprises and individuals that contribute to landslide research, practice, education and decision making and are willing to strengthen landslide and other related Earth system risk reduction strategies. The emphasis of this forum will be “Putting Science into Practice” with special attention given to actual implementation of technology and research in everyday applications and procedures with the direct involvement of researchers, engineers, private enterprises, stakeholders as well as policy and decision makers. The abstract submission and pre-registration of participants was quite successful with 649 received abstracts and more than 800 participants at May 2011. The full organisation of the event is now in progress taking into consideration the new figure and interest in scientific community and stakeholders.  相似文献   

Application of the Swiss Federal Guidelines on rock fall hazard: a case study in the Cilento region (Southern Italy)     

Paolo Budetta 《Landslides》2011,8(3):381-389

On December 15, 2008, a rock slide of approximately 4,000 m³ occurred near San Severino di Centola (Cilento, Province of Salerno). The landslide occurred along very steep bedding planes intersected by tectonic joints affecting a rocky cliff. The landslide debris, formed by several boulders, came to a halt along the gentler slope below. Many blocks reached the slope base including the national road n° 562 and injuring a motorist on the road. Furthermore, the road suffered heavy damages causing a halt in traffic for many weeks. Several signs of the impacts were detected along the slope and on the road; also, the volumes of some boulders were measured. The area affected by block trajectories stretch down slope about 4,900 m². By means of 2D and 3D trajectory codes using the “lumped-mass” method, it was possible to estimate more suitable impact energy restitution and rolling friction coefficients, to reconstruct rock fall trajectories, and to calculate total kinetic energies. Extending to the surrounding slope (surface about 2 ha) these data, a hazard scenario was carried out, displaying the pattern of iso-energy distribution curves calculated along 11 critical profiles, and zones exposed to 70% and 30% of frequencies of block transits and endpoints. Successively, with reference to the Swiss Federal Guidelines, another scenario was prepared on the basis of rock fall intensity values and the return period of the 2008 landslide event. In this way, it was possible to define areas of high, moderate and low hazard. The degrees of hazard are assigned according to their consequences for construction activity and outline zones where additional protection is required. The construction of a retaining embankment was believed suitable for local risk mitigation.  相似文献