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Roman mortars were collected from the Villa dei Quintili in Rome, an archaeological site consisting of numerous edifices from nine construction phases dating from the 2nd century A.D. to modern times. A multianalytical approach was used on 34 mortar samples to infer the evolution of production techniques over time and to identify the source area of calcareous raw materials used in the preparation of the lime. Optical microscopy, scanning electron microscopy coupled with an energy‐dispersive system, and laser ablation inductively coupled plasma mass spectrometry were used to study the samples. The major and trace element data were compared with the compositions of two types of limestone samples (Calcare Massiccio and Calcare Maiolica) collected from the Cornicolani Mountains. The results suggest that the technological practices and the calcareous raw materials used for lime production remained unchanged over the time period considered (2nd century A.D. to 3rd century A.D.). The compositions of lime‐related particles in the mortars match those of Calcare Maiolica, which suggests its use as raw material for lime production. On the whole, the results are in agreement with data from existing literature regarding both the use by Roman builders of specific raw materials for the mortars’ production and the relative supply area.  相似文献   
104.
In this work, fossil molluscan assemblages are analyzed in order to reconstruct the evolution of the Northern Gulf of Thailand during the Holocene. The marine sediments (Bangkok Clay Formation) of the Lower Central Plain of Bangkok and the coastal plain of Phetchaburi were sampled at 16 localities, obtaining fossil shells and mangrove peat whose 14C ages range from 9000 to 2000 CYBP. A statistical treatment of abundance data returned four major groups, namely the Dendostrea rosacea association (intertidal mud), the Corbula fortisulcataMactra luzonica association (shallow infralittoral sandy mud), the Nuculana mauritianaTimoclea scabra association (infralittoral sand spit) and the Timoclea scabraArcopagia pudica association (infralittoral mud). The data allowed both a stratigraphic correlation along two transects covering all of the Holocene basin and the creation of digitalized maps showing the presumable extension of the Thai paleogulf around the apex of Flandrian transgression event (about 5500 CYBP).  相似文献   
105.
A comparison of seismic risk maps for Italy   总被引:2,自引:3,他引:2  
National seismic risk maps are an important risk mitigation tool as they can be used for the prioritization of regions within a country where retrofitting of the building stock or other risk mitigation measures should take place. The production of a seismic risk map involves the convolution of seismic hazard data, vulnerability predictions for the building stock and exposure data. The seismic risk maps produced in Italy over the past 10 years are compared in this paper with recent proposals for seismic risk maps based on state-of-the-art seismic hazard data and mechanics-based vulnerability assessment procedures. The aim of the paper is to open the discussion for the way in which future seismic risk maps could be produced, making use of the most up-to-date information in the fields of seismic hazard evaluation and vulnerability assessment.  相似文献   
106.
In this paper we analytically estimate the magnetic field scale of planets with physical core conditions similar to that of Earth from a statistical physics point of view. We evaluate the magnetic field on the basis of the physical parameters of the center of the planet, such as density, temperature, and core size. We look at the contribution of the Seebeck effect on the magnetic field, showing that a thermally induced electrical current can exist in a rotating fluid sphere. We apply our calculations to Earth, where the currents would be driven by the temperature difference at the outer-inner core boundary, Jupiter and the Jupiter’s satellite Ganymede. In each case we show that the thermal generation of currents leads to a magnetic field scale comparable to the observed fields of the considered celestial bodies.  相似文献   
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An extensive experimental program of shaking table tests on reduced‐scale structural models was carried out within the activities of the MANSIDE project, for the development of new seismic isolation and energy dissipation devices based on shape memory alloys (SMAs). The aim of the experimental program was to compare the behaviour of structures endowed with innovative SMA‐based devices to the behaviour of conventional structures and of structures endowed with currently used passive control systems. This paper presents a comprehensive overview of the main results of the shaking table tests carried out on the models with and without special braces. Two different types of energy dissipating and re‐centring braces have been considered to enhance the seismic performances of the tested model. They are based on the hysteretic properties of steel elements and on the superelastic properties of SMAs, respectively. The addition of passive control braces in the reinforced concrete frame resulted in significant benefits on the overall seismic behaviour. The seismic intensity producing structural collapse was considerably raised, interstorey drifts and shear forces in columns were drastically reduced. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
109.
In the last few years, the scientific community has developed several hydrological models aimed at the simulation of hydrological processes acting at the basin scale. In this context, the portion of peak runoff contributing areas represents a critical variable for a correct estimate of surface runoff. Such areas are strongly influenced by the saturated portion of a river basin (influenced by antecedent conditions) but may also evolve during a specific rainfall event. In the recent years, we have developed 2 theoretically derived probability distributions that attempt to interpret these 2 processes adopting daily runoff and flood‐peak time series. The probability density functions (PDFs) obtained by these 2 schematisations were compared for humid river basins in southern Italy. Results highlighted that the PDFs of the peak runoff contributing areas can be interpreted by a gamma distribution and that the PDF of the relative saturated area provides a good interpretation of such process that can be used for flood prediction.  相似文献   
110.
The detection of detached nearshore wedges formed in response to relative sea-level drops is considered one of the hottest topics in sequence stratigraphic analysis due to their importance as reservoir analogues. In fact, they usually constitute sandy and porous bodies generally encased in impermeable clay, thus presenting a good potential as traps for fluids. This paper focuses on the sequence stratigraphic analysis of the Pliocene deposits cropping out in the central-southern sector of the Siena Basin (Tuscany, Italy), a post-collisional basin of the Northern Apennines. The exposed sedimentary succession was investigated through a detailed sedimentological and stratigraphic approach, integrated by biostratigraphic analyses, aimed at a better characterization of the infilling history of this sector of the basin. Specifically, this study revealed the occurrence of repeated facies shifts that allowed the identification of two depositional sequences. In detail, a thick sand-rich body far from the basin margins, and previously considered as a turbiditic lobe, has been reinterpreted as formed in a nearshore setting during a fall in relative sea level. This body is totally encased in offshore clay, and due to the lack of physical connection with the related HST deposits, it has to be considered as a detached forced-regressive wedge. The present work led to the recognition of some sedimentological and stratigraphic features typical of falling stage systems tract deposits (e.g. presence of intrabasinal recycled materials, sedimentological evidence of a pre-existing fluvial network subsequently eroded) that can provide useful clues for the identification of detached forced-regressive nearshore wedges in core studies and poorly exposed settings.  相似文献   
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