Search results for "NOBLE GASES"

Noble Gases Investigation on Etnean Volcanic Gases and on the Erupted Products During the 2001-2006 Period

2008

Data acquired during the last 20 years of geochemical monitoring of volcanic gases lead us to better understand how volcanoes work. According to theoretical and experimental investigations, both the chemical and isotopic changes in sampled volcanic gases have been interpreted in terms of magma ascent using the models proposed by Nuccio & Paonita, (2001) and Caracausi et al. (2003). On the basis of numerical simulations of volatile degassing, we have been able to recognize episodes of magma migration from deeper reservoirs of Mount Etna to the shallower storage volume, until magma is erupted. The 3He/4He isotope ratios of gas emitted at the periphery of Mount Etna volcanic edifice exhibit sy…

MRI using hyperpolarized noble gases.

1998

The aim of this study was to review the physical basis of MRI using hyperpolarized noble gases as well as the present status of preclinical and clinical applications. Non-radioactive noble gases with a nuclear spin 1/2 (He-3, Xe-129) can be hyperpolarized by optical pumping. Polarization is transferred from circularly polarized laser light to the noble-gas atoms via alkali-metal vapors (spin exchange) or metastable atoms (metastability exchange). Hyperpolarization results in a non-equilibrium polarization five orders of magnitude higher than the Boltzmann equilibrium compensating for the several 1000 times lower density of noble gases as compared with liquid state hydrogen concentrations in…

Functional magnetic resonance imaging of the lung

2003

Volatile contents of mafic-to-intermediate magmas at San Cristóbal volcano in Nicaragua

2017

San Cristóbal volcano in northwest Nicaragua is one of the most active basaltic–andesitic stratovolcanoes of the Central American Volcanic Arc (CAVA). Here we provide novel constraints on the volcano's magmatic plumbing system, by presenting the first direct measurements of major volatile contents in mafic-to-intermediate glass inclusions from Holocene and historic-present volcanic activity. Olivine-hosted (forsterite [Fo] < 80; Fo< 80) glass inclusions from Holocene tephra layers contain moderate amounts of H2O (0.1–3.3 wt%) and S and Cl up to 2500 μg/g, and define the mafic (basaltic) endmember component. Historic-present scoriae and tephra layers exhibit more-evolved olivines (Fo69…

EVIDENCES OF ENRICHED MANTLE (EM-2) SOURCE CONTRIBUTION TO ETNEAN MAGMAS: A COMPREHENSIVE STUDY ON FLUID AND MELT INCLUSIONS OF 2001-2006 ERUPTIONS

2009

A TWO-COMPONENT MANTLE EXTENDING FROM MT ETNA TO HYBLEAN PLATEAU (EASTERN SICILY) AS INFERRED BY AN INTEGRATED APPROACH WITH NOBLE GASES, TRACE ELEME…

2012

Noble gases investigation in fluid inclusions of olivines and pyroxenes from Etnean products erupted in the 2001-2004 period.

2008

Elemental and isotope covariation of noble gases in olivines and pyroxenes from Etnean volcanics erupted during 2001-2005, and genetic relation with …

2009

Mixture and dissolution of laser polarized noble gases: Spectroscopic and imaging applications

2012

High gas pressure: An innovative method for the inactivation of dried bacterial spores

2012

In this article, an original non-thermal process to inactivate dehydrated bacterial spores is described. The use of gases such as nitrogen or argon as transmission media under high isostatic pressure led to an inactivation of over 2 logs CFU/g of Bacillus subtilis spores at 430 MPa, room temperature, for a 1 min treatment. A major requirement for the effectiveness of the process resided in the highly dehydrated state of the spores. Only a water activity below 0.3 led to substantial inactivation. The solubility of the gas in the lipid components of the spore and its diffusion properties was essential to inactivation. The main phenomenon involved seems to be the sorption of the gas under pres…