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81.
Fabrizio Rama Konrad Miotlinski Davide Franco Henry X. Corseuil 《Hydrogeology Journal》2018,26(6):1887-1902
A time-series approach to the estimation of recharge rate in unconfined aquifers of highly variable water level is proposed. The approach, which is based on the water-table fluctuation method (WTF), utilizes discrete water-level measurements. Other similar techniques require continuous measurements, which makes them impossible to apply in cases where no data from automatic loggers are available. The procedure is deployed at the Ressacada Farm site, southern Brazil, on a coastal shallow aquifer located in a humid subtropical climate where diurnal water-level variations of up to 1 m can follow a precipitation event. The effect of tidal fluctuations on the groundwater levels is analyzed using a harmonic component builder, while a time-variable drainage term is evaluated through an independent analysis and included in the assessment. The estimated recharge values are compared with those obtained from the continuous measurements showing a good agreement with the approaches for discrete dataset intervals of up to 15 days. Subsequently, the estimated recharge rates are incorporated into a transient groundwater-flow model and the water levels are compared showing a good match. Henceforth, the approach extends the applicability of WTF to noncontinuous water-level datasets in groundwater recharge studies. 相似文献
82.
G. Lecca C. Lai F. Murgia R. Biddau L. Fanfani P. Maggi 《Earth Science Informatics》2009,2(1-2):83-95
AQUAGRID is the subsurface hydrology computational service of the Sardinian GRIDA3 infrastructure, designed to deliver complex environmental applications via a user-friendly Web portal. The service aims to provide to water professionals integrated modeling tools to solve water resources management problems and aid decision making for contaminated soil and groundwater. In this paper, the AQUAGRID application concept and enabling technologies are illustrated. At the heart of the service are the computational models to simulate complex and large groundwater flow and contaminant transport problems and geochemical speciation. AQUAGRID is built on top of compute-Grid technologies by means of the EnginFrame Grid framework. Distributed data management is provided by the Storage Resource Broker data-Grid middleware. The resulting environment allows end-users to perform groundwater simulations and to visualize and interact with their results, using graphs, 3D images and annotated maps. The problem solving capability of the platform is demonstrated using the results of two case studies deployed. 相似文献
83.
Frederick?S.?ScharfEmail author John?P.?Manderson Mary?C.?Fabrizio Jeffrey?P.?Pessutti John?E.?Rosendale Robert?J.?Chant Allen?J.?Bejda 《Estuaries and Coasts》2004,27(3):426-436
Seasonal and interannual patterns in the spatial distribution of bluefish (Pomatomus saltatrix) within a Middle Atlantic Bight estuary were examined using multipanel gillnets fished biweekly at 14 fixeds stations in
the Sandy Hook Bay-N avesink River estuary during May–November of 1998 and 1999. To characterize habitats along the estuarine
gradient, we measured several abiotic and biotic variables concurrently with gillnet sampling. Juvenile (age-0 and age-1+)
bluefish were captured regularly during both years along with large numbers of Atlantic menhaden (Brevoortia tyrannus), which were confirmed by diet analyses to be bluefish’s primary forage species. The date of initial appearance of age-0
bluefish and menhaden in the estuary varied between years and may have been related to interannual differences in seawater
temperatures on the continental shelf during spring. Delayed estuarine arrival of prey fishes may have contributed to variability
in bluefish diets between years. Within the estuary, bluefish spatial distribution were consistent across seasons and years:
bluefish were most common in areas associated with high concentrations of suspended materials and the presence of menhaden.
Community analyses also indicated habitat overlap between bluefish and menhaden. Spatial distribution patterns revealed the
consistent occurrence of piscivorous bluefish in shallow estuarine habitats that retained suspended materials and aggregated
prey fishes. Foraging success of bluefish and other estuarine piscivores may be closely linked with the availability of these
productive habitat, highlighting the need for future study of biological interactions and the governing physical processes. 相似文献
84.
85.
Fabrizio Nestola Tiziana Boffa Ballaran Mario Tribaudino Haruo Ohashi 《Physics and Chemistry of Minerals》2005,32(3):222-227
A single-crystal of composition CaNiSi2O6 (space group C2/c) was investigated at high pressure up to about 7.8 GPa by X-ray diffraction. The unit-cell parameters were measured at 18 different pressures. The P-V data were fitted by a third-order Birch-Murnaghan equation of state V0=435.21(1) Å3, K 0=117.6(3) GPa and K=6.4(1). The linear axial compressibilities a, b, c and a sin are 2.14(1), 3.00(1), 2.43(1) and 1.63(1) × 10–3 GPa–1. Comparing the compressibility data with other CaM1Si2O6 pyroxenes we suggest that the empirical K × V = constant relationships are followed in C2/c pyroxenes only if the same valence electron character is shared. 相似文献
86.
87.
Geoffrey D. Bromiley Fabrizio Nestola Ming Zhang 《Geochimica et cosmochimica acta》2010,74(2):705-445
The solubility and incorporation mechanisms of water in synthetic and natural MgAl2O4 spinel have been investigated in a series of high-pressure/temperature annealing experiments. In contrast to most other nominally anhydrous minerals, natural spinel appears to be completely anhydrous. On the other hand, non-stoichiometric Al-rich synthetic (defect) spinel can accommodate several hundred ppm water in the form of structurally-incorporated hydrogen. Infrared (IR) spectra of hydrated defect spinel contain one main O-H stretching band at 3343-3352 cm−1 and a doublet consisting of two distinct O-H bands at 3505-3517 cm−1 and 3557-3566 cm−1. IR spectra and structural refinements based on single-crystal X-ray data are consistent with hydrogen incorporation in defect spinel onto both octahedral and tetrahedral O-O edges. Fine structure of O-H bands in IR spectra can be explained by partial coupling of interstitial hydrogen with cation vacancies, or by the effects of Mg-Al disorder on the tetrahedral site. The concentration of cation vacancies in defect spinel is a major control on hydrogen affinity. The commercial availability of large single crystals of defect spinel coupled with high water solubility and similarities in water incorporation mechanisms between hydrous defect spinel and hydrous ringwoodite (Mg2SiO4) suggests that synthetic defect spinel may be a useful low-pressure analogue material for investigating the causes and consequences of water incorporation in the lower part of Earth’s mantle transition zone. 相似文献
88.
<正>Global climate change is a common challenge facing mankind, which has evolved from a scientific issue into a global economic and political issue of universal concern to the international community(IPCC, 2007). Global surface temperature was 1.1°C higher in 2011–2020 than that in 1850–1900, and has increased faster since 1970 than in any other 50-year period over at least the last 2000 years(IPCC, 2023). 相似文献
89.
Gaetano Zonno Roberto Basili Fabrizio Meroni Gemma Musacchio P. Martin Mai Gianluca Valensise 《Bulletin of Earthquake Engineering》2012,10(4):1075-1107
We present a strategy for obtaining fault-based maximum observable shaking (MOS) maps, which represent an innovative concept for assessing deterministic seismic ground motion at a regional scale. Our approach uses the fault sources supplied for Italy by the Database of Individual Seismogenic Sources, and particularly by its composite seismogenic sources (CSS), a spatially continuous simplified 3-D representation of a fault system. For each CSS, we consider the associated Typical Fault, i.e., the portion of the corresponding CSS that can generate the maximum credible earthquake. We then compute the high-frequency (1–50?Hz) ground shaking for a rupture model derived from its associated maximum credible earthquake. As the Typical Fault floats within its CSS to occupy all possible positions of the rupture, the high-frequency shaking is updated in the area surrounding the fault, and the maximum from that scenario is extracted and displayed on a map. The final high-frequency MOS map of Italy is then obtained by merging 8,859 individual scenario-simulations, from which the ground shaking parameters have been extracted. To explore the internal consistency of our calculations and validate the results of the procedure we compare our results (1) with predictions based on the Next Generation Attenuation ground-motion equations for an earthquake of Mw 7.1, (2) with the predictions of the official Italian seismic hazard map, and (3) with macroseismic intensities included in the DBMI04 Italian database. We then examine the uncertainties and analyse the variability of ground motion for different fault geometries and slip distributions. 相似文献
90.
Framed structures are usually infilled with masonry walls. They may cause a significant increase in both stiffness and strength, reducing the deformation demand and increasing the energy dissipation capacity of the system. On the other hand, irregular arrangements of the masonry panels may lead to the concentration of damage in some regions, with negative effects; for example soft story mechanisms and shear failures in short columns. Therefore, the presence of infill walls should not be neglected, especially in regions of moderate and high seismicity. To this aim, simple models are available for solid infills walls, such as the diagonal no-tension strut model, while infilled frames with openings have not been adequately investigated. In this study, the effect of openings on the strength and stiffness of infilled frames is investigated by means of about 150 experimental and numerical tests. The main parameters involved are identified and a simple model to take into account the openings in the infills is developed and compared with other models proposed by different researchers. The model, which is based on the use of strength and stiffness reduction factors, takes into account the opening dimensions and presence of reinforcing elements around the opening. An example of an application of the proposed reduction factors is also presented. 相似文献