185,750 research outputs found
Decisiones R.P.D. Marcelli Crescentij Rotae auditoris postea S.R.E. cardinalis super causis per RR. DD. auditores in eodem sacro palatio relatis ex communibus & concordibus eorundem votis & suffragijs : sub titulis secundùm ordinem Decretalium redactae epithomatibus, summarijs & indice locupletatae. Quibus accessit Tractatus de tribunalibus Vrbis & eorum praeuentionibus
No full textO impresor consta en 1º colofón (r. de EE\b6\s)Outro colofón ó final da segunda obra (v. de L\b3\s) onde consta: "apud Iacobum Ruffinellum"Marca de Marcantonio Moretti en ports.e ó finSign.: [cruz latina]4, 2[cruz latina]2, A-Z4, AA-DD4, EE6; A-L4Texto a dúas col.A segunda obra con port., pax e sign. propia
Uncovering quasi-degenerate Kaluza-Klein Electro-Weak gauge bosons with top asymmetries at the LHC
No full textBy exploiting the correlation between charge and spin polarisation asymmetries in t-tbar, we show that combining the two observables could identify the presence of quasi-degenerate states in a resonant signal at the LHC. As an example, we investigate experimental signatures emerging in top-antitop final states in the context of a model where the Standard Model Electro-Weak sector is allowed to propagate in large extra--dimensions of TeV-1 size while the colour sector is localised. Assuming current experimental constraints from the 7 and 8 TeV runs and taking into account the estimated top (anti-top) reconstruction efficiencies, we find that the 14 TeV upgraded LHC with the planned integrated luminosity L=100 fb-1 could access these quasi-degenerate multiple resonances and explore for the first time the rich phenomenology in the asymmetry observables. The main outcome would be having measurable quantities, complementary to the usual total and differential cross sections, capable of distinguishing a quasi-degenerate multiply resonant spectrum from a 'standard' single resonance that could present a similar signal in a bump hunt analysis
SULFUR SOLUBILITY IN SILICATE MELTS: A THERMOCHEMICAL MODEL
No full textA termochemical model for calculating sulfur solubility of simple and complex
silicate melts has been developed in the framework of the Toop-Samis polymeric
approach combined with a Flood - Grjotheim theoretical treatment of silicate slags
[1,2]. The model allows one to compute sulfide and sulfate content of silicate melts
whenever fugacity of gaseous sulphur is provided.
"Electrically equivalent ion fractions" are needed to weigh the contribution of the
various disproportion reactions of the type:
MOmelt + 1/2S2,gas ,MSmelt + 1/2O2,gas (1)
MOmelt + 1/2S2,gas + 3/2O2,gas ,MSO4,melt (2)
Eqs. 1 and 2 account for the oxide-sulfide and the oxide-sulfate disproportionation
in silicate melt.
Electrically equivalent ion fractions are computed, in a fused salt Temkin notation,
over the appropriate matrixes (anionic and cationic). The extension of such matrixes
is calculated in the framework of a polymeric model previously developed [1,2,3]
and based on a parameterization of acid-base properties of melts. No adjustable
parameters are used and model activities follow the raoultian behavior implicit in the
ion matrix solution of the Temkin notation. The model is based on a huge amount of
data available in literature and displays a high heuristic capability with virtually no
compositional limits, as long as the structural role assigned to each oxide holds.
REFERENCES:
[1] Ottonello G., Moretti R., Marini L. and Vetuschi Zuccolini M. (2001), Chem.
Geol., 174, 157-179.
[2] Moretti R. (2002) PhD Thesis, University of Pisa.
[3] Ottonello G. (2001) J. Non-Cryst. Solids, 282, 72-85.
Contesti territoriali e reti tra organizzazioni museali: cooperazione e processi di valorizzazione
No full text
Terremoto in Emilia Romagna (2012): le attività del Centro Operativo Emergenza Sismica
No full textCome definito negli accordi riportati nell’ambito della Convenzione1 esistente tra l’Istituto Nazionale di Geofisica e Vulcanologia (INGV) e il Dipartimento di Protezione Civile (DPC), a poche ore dal forte terremoto che nella notte del 20 maggio 2012 ha colpito una vasta area dell’Emilia [Moretti et al., 2012; 2013a], è stato attivato il Pronto Intervento Sismico dell’INGV [Govoni et al., 2008; Moretti e Govoni, 2011; Moretti et al., 2010c]. Durante la prima settimana dell’emergenza l’obiettivo principale della struttura emergenziale INGV ha riguardato il miglioramento del monitoraggio sismico; sono state quindi attivate le reti sismiche mobili [maggiori dettagli in Moretti et al., 2012; 2013a] con il fine di integrare le stazioni permanenti della Rete Sismica Nazionale [RSN, Amato e Mele, 2008; Delladio et al., 2011].
Solo in una secondo momento, dopo circa 10 giorni dall’inizio della sequenza sismica è stato ufficialmente attivato il Centro Operativo Emergenza Sismica [COES, Moretti et al., 2010a], a seguito del decreto del Capo del DPC, con il quale è stata costituita la Direzione di Comando e Controllo (Di.Coma.C.2) presso l’Agenzia della Protezione Civile Regionale dell’Emilia Romagna (AgDPC) in Bologna. L’allestimento e il coordinamento del COES sono stati realizzati grazie alla collaborazione tra il Centro Nazionale Terremoti (CNT), a cui afferisce la struttura, e la Sezione INGV di Bologna, sita nel capoluogo della regione colpita dall’emergenza.
In questo lavoro saranno descritte le modalità, le tempistiche e l’impegno di personale che hanno permesso e garantito l'attivazione e il buon funzionamento del COES.Published1-381.1. TTC - Monitoraggio sismico del territorio nazionaleN/A or not JCRope
Halogens in Mount Etna volcanic gas plume: insights into degassing processes
No full textThe passive and eruptive plume gas emissions from Mount Etna volcano, in Southern Italy, represent a persistent source of volcanic halogenidric acids (HCl, HF, HBr and HI) to the Earth's atmosphere. Etna's halogen source strength has been repeatedly characterized over the past few years [Francis et al., 1998; Caltabiano et al., 2004; Aiuppa et al., 2005], and the pre-eruptive Cl and F contents in Etna's basalts have been well constrained by measurements on both silicate melt inclusions and matrix glasses [Metrich et al., 2004; Spilliaert et al ., 2006a]. However, the mechanisms driving halogen degassing upon magma ascent and decompression are not entirely understood, and the significance of volatile ratios SO2/HCl and SO2/HF in the volcanic gas plume still a matter of debate [Aiuppa et al., 2002, 2004; Spilliaert et al., 2006b]. Here, we review a set of halogen measurements carried out in the Mount Etna volcanic gas plume during 2003-2007, and demonstrate that a large compositional range (e.g., SO2/HCl ratios from 0.4 to 12; CO2/HCl ratios from 0.1 to 52) characterize the sustained quiescent emissions from the volcano. By contrasting the volcanic gas data against model equilibrium compositions calculated by the Moretti et al. [2003] saturation model, we also attempt at a quantitative interpretation of the degassing process at Etna. The saturation models calculates the composition of a gas phase (in the H2O-CO2- SO2-HCl-HF system) at equilibrium with Etna's magmas at given set of P-T-X conditions, and takes into account halogen saturation by making use of the most recent experimental determinations of Cl and F partitioning between coexisting fluid and basaltic melt [Alletti et al., 2006, 2007]. Based on model calculations, we propose that the observed SO2/HCl and SO2/HF plume ratios at Etna derive from low pressure (P less than 10 MPa) open-system degassing of magmas feeding the upper conduit system of the volcano
Ionization and speciation of water in silicate melts
No full textWater in silicate melts is commonly assumed to take the form of molecular water (H2Om) and hydroxyl groups (OH), the latter bounded to network formers (T) as T-OH groups. Although free hydroxyls (OH-) were only recently ascertained in depolymerized melts (Xue and Kanzaki, 2004), the amphoteric behavior of water, was already suggested long ago (Fraser, 1977) and preliminarily modelled considering redox data (Moretti, 2005). However, autoprotolysis of water has not been assessed in silicate melts hitherto, because of the rather complex nature of such a solvent. Here, a simple theoretical frame is developed based on the extended two-sublattice hypothesis of Temkin. The theory accounts for acid-base properties of the melt phase, and reconciles differing notations. An independent proof of our appraisal is given by an algorithmic approach to chemical equilibria between O and H in polymeric silicate melts. The assessment of the ionization constant of water in melts can explain the conditions at which precipitation of hydrous minerals can occur. Because of the amphoteric behavior, melt polymerization can be affected less than that normally perceived and assumed, depending on bulk composition. This has implications for the redox behavior, which is strictly connected to melt acid-base properties, hence polymerization. These connections must be accounted for when modelling magmatic equilibria.
REFERENCES:
FRASER DG (1977) In: Thermodynamics in Geology (D.G. Fraser, ed.), D. Reidel Pub. Co.
MORETTI R. (2005) Ann. Geophysics, 48, 503-608.
XUE, X. AND KANZAKI, M. (2004) Geochim. Cosmochim. Acta, 68, 5027-5057
A NEW METHOD TO COMPUTE FLUIDS SATURATION IN C-H-O-S-SILICATE MELT SYSTEMS
No full textWe developed a method to calculate equilibrium between a
C-O-H-S fluid phase and a silicate melt based on a previous
model for the saturation of H2O-CO2 fluids (Papale, 1999) and
on a thermochemical approach for calculating sulfide and
sulfate solubilities of simple and complex melts. In particular,
this second approach combines the Toop-Samis polymeric
model with the Flood - Grjotheim theoretical treatment of silicate
melts (Ottonello et al., 2001; Moretti, 2002). Moreover,
fugacities in the gaseous phase are computed through the
SUPERFLUID code (Belonoshko et al., 1992). The C-H-O-S
saturation model allows determining the partition of H2O, CO2,
and S between silicate melt and coexisting fluid, and the
composition of the fluid phase in terms of H2O, CO2, SO2, and
H2S, as a function of pressure, temperature, volatile-free liquid
composition, oxygen fugacity, and total amount of volatile
components in the system. For the sake of simplicity, we
assumed that no reduced or oxidized sulfur-saturated solid or
liquid phases nucleate or separate from the liquid-gas system.
Minima in sulfur solubility as a function of oxygen fugacity are
depicted, in good agreement with theory and experiments.
Applications are given for rhyolitic and basaltic melts with
various oxygen fugacities in the range NNO±2, and pressure
from a few hundred MPa to atmospheric. The developed model
accounts for the reciprocal effects of volatiles on their saturation
contents, and the complex relationships between the saturation
surface of a multicomponent fluid and the liquid
composition, volatile abundance, P-T conditions and oxidation
state.
Belonoshko A, Shi PF & Saxena S, Comp. Geosci, 18, 1267-
1269, (1992).
Moretti R, PhD Thesis, University of Pisa
Ottonello G, Moretti R, Marini L& Vetuschi Zuccolini M, Chem.
Geol, 174, 157-179, (2001).
Papale P, Amer. Mineral, 84, 477-492, (1999)
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