Search results for " ground"

Reliability Analysis of a Controlled Stage-Constructed and Reinforced Embankment on Soft Ground Using 2D and 3D Models

2020

Geosynthetic reinforcement has become a very practical technique to improve geotechnical structure safety. In spite of improved soil behavior, structures are affected by uncertainties related to soil and reinforcement material properties. This paper aims to present a reliability analysis in order to take statistical information (uncertainties) into account in a safety analysis of reinforced embankments. The analysis was used in a case study on a controlled stage-constructed embankment on soft ground in order to investigate its probabilistic stability. Modeling was performed by commercial geotechnical software usage (GeoStudio and RocScience packs, SIGMA/W+SLOPE/W and SLIDE³, respectively) a…

Insights into magma and fluid transfer at Mount Etna by a multiparametric approach: A model of the events leading to the 2011 eruptive cycle

2013

Carbon dioxide degassing from Tuscany and Northern Latium (Italy)

2008

Abstract The CO 2 degassing process from a large area on the Tyrrhenian side of central Italy, probably related to the input into the upper crust of mantle fluids, was investigated in detail through the geochemical study of gas emissions and groundwater. Mass-balance calculations and carbon isotopes show that over 50% of the inorganic carbon in regional groundwater is derived from a deep source highlighting gas−liquid separation processes at depth. The deep carbonate−evaporite regional aquifer acts as the main CO 2 reservoir and when total pressure of the reservoir fluid exceeds hydrostatic pressure, a free gas phase separates from the parent liquid and escapes toward the surface generating…

Global Coastal Permeability database (GCPdb)

2023

The Global Coastal Permeability Database contains both the input and output data of the Global Coastal Permeability Model developed by Tschaikowski et al. (2023) and available at DOI: 10.5281/zenodo.7845568. The model is implemented in R and calculates the coastal permeability for each shoreline segment of the global shoreline vector created by Sayre et al. (2019) with a 30-meter resolution and covering a spatial extent of 180.0°W to 180.0°E longitude and 60.8°S to 83.7°N latitude. The coastline is separated into three sections (A: coastal aquifer section, B: shoreline section, C: shallow section), and permeability values and ranges are provided for each section. Permeability values were de…

Geochemical characterization of groundwater quality in Hellenic karst systems

2019

Karst aquifers are considered to be one of the most important aquifer types, as they constitute the main drinking water resource for the majority of the global population (Ford et al., 2007). They are generated from the dissolution of carbonate rocks (e.g. limestone, dolomite, marble etc.), a phenomenon commonly known as “karstification”. This process is mainly caused by the acidity of water enriched in dissolved CO2, with the concentration of the latter being dependent on both the temperature and the CO2 partial pressure of the atmosphere in contact with the water (Bakalowicz, 2005). Carbonate rocks cover about 35% of the land surface of Greece and are mainly located in the western, centra…

Molecular hydrogen (H2) mixing ratio and stable isotopic composition (dD) at the Cabauw tall tower in the Netherlands (2008-2012)

2016

Measurements of the stable isotopic composition (dD(H2) or dD) of atmospheric molecular hydrogen (H2) are a useful addition to mixing ratio (X(H2)) measurements for understanding the atmospheric H2 cycle. dD datasets published so far consist mostly of observations at background locations. We complement these with observations from the Cabauw tall tower at the CESAR site, situated in a densely populated region of the Netherlands. Our measurements show a large anthropogenic influence on the local H2 cycle, with frequently occurring pollution events that are characterized by X(H2) values that reach up to 1 ppm and low dD values. An isotopic source signature analysis yields an apparent source s…

Mechanisms of common ground in case-based web discussions in teacher education

2002

Previous studies suggest that before participants in web-based conferencing can reach deeper level interaction and learning, they have to gain an adequate level of common ground in terms of shared mutual understanding, knowledge, beliefs, assumptions, and presuppositions (Clark & Schaefer, 1989; Dillenbourg, 1999). In this paper, the purpose is to explore how participants establish and maintain common ground in order to reach deeper level interaction in case-based web discussions. The subjects in this study consisted of 68 preservice teachers and 7 mentors from 3 universities, who participated in a web-based conferencing course for 8 weeks. The written discussion data were analyzed by means…

Highlights from the ARGO-YBJ Experiment

2012

""The ARGO-YBJ experiment at YangBaJing in Tibet (4300m a.s.l.) has been taking data with its full layout since October 2007. Here we present a few significant results obtained in gamma-ray astronomy and cosmic-ray physics. Emphasis is placed on the analysis of gamma-ray emission from point-like sources (Crab Nebula, MRK 421), on the preliminary limit on the antiproton\\\/proton flux ratio, on the large-scale cosmic-ray anisotropy and on the proton-air cross-section. The performance of the detector is also discussed, and the perspectives of the experiment are outlined.""

Application of SINTACS method to the aquifers of Piana di Palermo, Siciliy,Italy

2004

Piana di Palermo is characterized by the presence of two different aquifers: one shallow, constituted by calcarenites and the other deep in fractured carbonates. The calcarenitic aquifer presents a low potential compared to the carbonatic aquifer. The chemistry of the water in both aquifers reflects water-rock interaction, seawater intrusion, ionic exchange etc. The application of SINTACS method showed that about 80% of the study area can be classified as of high to very high vulnerability. Piana di Palermo es caracterizada por la presencia de dos acuíferos diferentes: uno somero constituido por calcarenitas y otro profundo en rocas carbonatadas fracturadas. El acuífero calcarenítico presen…

Stable isotopes of water as a tool to study groundwater–seawater interactions in coastal south-eastern Sicily

2009

Summary Stable isotopes of hydrogen (δD) and oxygen (δ 18 O) in groundwater, submarine springs and seawater collected in coastal south-eastern Sicily were investigated. While the spatial distribution of δ 18 O in groundwater showed that most of the heavy-isotope-depleted samples (from −5.7‰ to −6.9‰) were located in the higher portion of the Hyblean Mountains, more positive values (from −3.4‰ to −5.6‰) were found in the marginal areas. The isotope composition of submarine springs was characterized by significant variability (δ 18 O between −5.6‰ and +1.0‰ and δD between −30‰ and +5.0‰) reflecting seasonal variations and different seawater contributions. The isotopic and chemical composition…