982 research outputs found
Heat and helium production during exothermic reactions between gases through palladium geometrical elements loaded with hydrogen
In this research, thexffect of the shape of hydrogenloaded
palladium elements on exothennic reactions between
gases is shown. It was found that an element with
parts of its sulface next to each other spontaneously triggers
reactions, whereas an element whose su$aces are
not next to each other needs outside triggering. The heat
developed makes the temperature of the elements rise even
by a few hundredths of a degree centigrade.
Through photographic techniques, it was shown that
the elements, when releasing heat, emit radiation connected
to nuclearfusion reactions. These reactions, confirmed
also by the analysis of the used hydrogen, showed
helium formation. All these tests have confirmed the reproducibility
of the phenomenon
VARIAZIONI NEL FLUSSO DI CO2 OSSERVATE NEL MARZO-APRILE 2009 IN ITALIA CENTRALE
In tutto il mondo nelle aree di collisione tettonica è stata osservata la presenza di sorgenti di
acque calde o di gas di origine endogena (Italiano et al., 2001 e riferimenti citati). Il gas emesso piĂš
importante sotto il profilo quantitativo è lâanidride carbonica il cui ruolo è stato spesso sottolineato
per giustificare la generazione di anomalĂŹe di carattere geochimico osservate nelle acque sotterranee
o nelle emissioni gassose. NellâItalia centro-meridionale esistono numerose emissioni spontanee
di anidride carbonica note come mofete o mefite. Nel corso della sequenza sismica del 1997
verificatasi in Umbria-Marche sono state monitorate le caratteristiche fisiche e composizionali di
alcune emissioni di CO2 presenti nel territorio interessato dai principali eventi di carattere tettonico
(Martinelli e Albarello, 1997). In particolare nel corso del 1997 sono state osservate variazioni di
flusso di gas totale nelle emissioni di Monte Castello di Vibio, Umbertide e Massa Martana. Nelle
stesse aree sono state osservate variazioni significative di carattere composizionale in grado di confermare
la non stazionarietĂ dellâorigine dei gas emessi (Italiano et al., 2004; Italiano et al., 2009 e
bibliografia citata). Nel Comune di Massa Martana è localizzata lâemissione spontanea di anidride
carbonica di San Faustino. Lâemissione principale è captata da una opera di presa composta da una
stanza sotterranea e da un insieme di tubi che convogliano il gas verso lâesterno. Alla fine del percorso
di tubi è stata installata una strumentazione in grado di misurare la portata del gas. Il sensore
è del tipo a âfilo caldoâ. Altri parametri di carattere ambientale sono monitorati nel sito e nella zona.
Nel periodo 2005-2008 sono state osservate variazioni nei valori di portata del gas emesso in parte
probabilmente ascrivibili alla attivitĂ tettonica della zona. Nel corso del 2009 sono stati affrontati e
risolti problemi tecnici di alimentazione elettrica, ripristinata nel corso del mese di marzo. Alla fine
del mese di Marzo 2009 e nel mese di aprile 2009 i valori di portata registrati sono stati pari a circa
il doppio della normalitĂ . I valori di portata sono poi ridiscesi entro la normalitĂ entro un mese
dalla data dellâevento principale della sequenza sismica del 2009 che ha interessato vaste aree dellâAbruzzo.
La distanza tra il sito di osservazione e lâarea epicentrale dellâevento principale della sequenza simica dellâaprile 2009 è di circa 80 km. Nella letteratura scientifica sono state riportateanomalĂŹe di carattere geofisico e geochimico rilevate a distanze paragonabili a quelle descritte in
concomitanza con eventi simici significativi. Fenomeni di possibile degassamento terrestre sono
stati rilevati in quasi contemporaneitĂ da altre unitĂ di ricerca in grado di monitorare fenomenologie
di area vasta con lâausilio di tecniche satellitari (Aliano et al., 2009; Tramutoli et al., 2009). Il
fenomeno osservato è iniziato alcuni giorni prima dellâevento sismico (Mw=6.3) del 6 aprile 2009
e può essere, in principio, interpretato come esito di processi di deformazione crostale osservati da
altre unitĂ di ricerca (e.g. Caporali, 2009). La composizione chimica di gas campionati nellâarea epicentrale
indica lâesistenza di fenomeni di fratturazione profonda e di liberazione di anidride carbonica
di origine non superficiale (Bonfanti et al., 2009 e bibliografia citata, Italiano et al., 2009). La
generazione e liberazione di gas di origine profonda è, in principio, in grado di confermare lâesistenza
di possibili ulteriori anomalĂŹe osservate nei fluidi della zona (e.g. Plastino et al., 2009). Il
fenomeno osservato potrebbe essere interpretato come un fenomeno precursore dellâevento principale
registrato e analizzato a posteriori. La possibile applicabilitĂ del fenomeno osservato come
strumento utile per migliorare le valutazioni di hazard è discussa e commentata
Dominating sets and connected dominating sets in dynamic graphs
In this paper we study the dynamic versions of two basic graph problems: Minimum Dominating Set and its variant Minimum Connected Dominating Set. For those two problems, we present algorithms that maintain a solution under edge insertions and edge deletions in time O( 06\ub7polylog n) per update, where 06 is the maximum vertex degree in the graph. In both cases, we achieve an approximation ratio of O(log n), which is optimal up to a constant factor (under the assumption that P 6= NP). Although those two problems have been widely studied in the static and in the distributed settings, to the best of our knowledge we are the first to present efficient algorithms in the dynamic setting. As a further application of our approach, we also present an algorithm that maintains a Minimal Dominating Set in O(min( 06, m)) per update
Insights into mantle-type volatiles contribution from dissolved gases in artesian waters of the Great Artesian Basin, Australia
The geochemical features of the volatiles dissolved in artesian thermal waters discharged over three basins (Millungera, Galilee and Cooper basin) of the Australian Great Artesian Basin (GAB) consistently indicate the presence of fluids from multiple gas sources located in the crust (e.g. sediments, oil reservoirs, granites) as well as minor but detectable contributions of mantle/magma-derived fluids. The gases extracted from 19 water samples and analyzed for their chemical and isotopic composition exhibit amounts of CO up to about 340mlSTP/L marked by a δC (Total Dissolved Carbon) ranging from -16.9 to +0.18â° vs PDB, while CH concentrations vary from 4.4Ă10 to 4.9mlSTP/L. Helium contents were between 9 and >2800 times higher than equilibrium with Air Saturated Water (ASW), with a maximum value of 0.12mlSTP/L. Helium isotopic composition was in the 0.02-0.21 Ra range (Ra = air-normalized He/He ratio). The three investigated basins differ from each other in terms of both chemical composition and isotopic signatures of the dissolved gases whose origin is attributed to both mantle and crustal volatiles. Mantle He is present in the west-central and hottest part of the GAB despite no evidence of recent volcanism. We found that the partial pressure of helium, significantly higher in crustal fluids than in mantle-type volatiles, enhances the crustal He signature in the dissolved gases, thus masking the original mantle contribution. Neotectonic activity involving deep lithospheric structures and magma intrusions, highlighted by recent geophysical investigations, is considered to be the drivers of mantle/magmatic volatiles towards the surface. The results, although pertaining to artesian waters from a vast area of >542,000km, provide new constraints on volatile injection, and show that fluids' geochemistry can provide additional and independent information on the geo-tectonic settings of the Great Artesian Basin and its geothermal potential
Anomalous fluid emission of a deep borehole in a seismically active area of Northern Apennines (Italy)
The Miano borehole, 1047 m deep, is located close to the river Parma in the Northern Apennines, Italy. A
measuring station has been installed to observe the discharge of fluids continuously since November
2004. The upwelling fluid of this artesian well is a mixture of thermal water and CH4 as main components.
In non-seismogenic areas, a relatively constant fluid emission would be expected, perhaps overlaid
with long term variations from that kind of deep reservoir over time. However, the continuous record of
the fluid emission, in particular the water discharge, the gas flow rate and the water temperature, show
periods of stable values interrupted by anomalous periods of fluctuations in the recorded parameters. The
anomalous variations of these parameters are of low amplitude in comparison to the total values but significant
in their long-term trend. Meteorological effects due to rain and barometric pressure were not
detected in recorded data probably due to reservoir depth and relatively high reservoir overpressure.
Influences due to the ambient temperature after the discharge were evaluated by statistical analysis.
Our results suggest that recorded changes in fluid emission parameters can be interpreted as a mixing
process of different fluid components at depth by variations in pore pressure as a result of seismogenic
stress variation. Local seismicity was analyzed in comparison to the fluid physico-chemical data. The
analysis supports the idea that an influence on fluid transport conditions due to geodynamic processes
exists. Water temperature data show frequent anomalies probably connected with possible precursory
phenomena of local seismic events
Long-term geochemical monitoring and extensive/compressive phenomena: case study of the Umbria Region (Central Apennines, Italy)
Long-term geochemical monitoring performed in the seismic area of the Umbria-Marche region of Italy (i.e. Central
Apennines) has allowed us to create a model of the circulation of fluids and interpret the temporal chemical
and isotopic variations of both the thermal springs as well as the gas vents. Coincident with the last seismic crisis,
which struck the region in 1997-1998, an enhanced CO2 degassing on a regional scale caused a pH-drop in
all the thermal waters as a consequence of CO2 dissolution. Furthermore, much higher 3He/4He isotope ratios
pointed to a slight mantle-derived contribution. Radon activity increased to well above the Âą2 sinterval of the earlier
seismic period, after which it abruptly decreased to very low levels a few days before the occurrence of the
single deep-located shock (March 26, 1998, 51 km deep). The anomalous CO2 discharge was closely related to
the extensional movement of the normal faults responsible for the Mw 5.7, 6.0 and 5.6 main shocks that characterized
the earlier seismic phase. In contrast, a clear compressive sign is recognizable in the transient disappearance
of the deep-originating components related to the Mw 5.3, 51 km-deep event that occurred on March 26,
1998. Anomalies were detected concomitantly with the seismicity, although they also occurred after the seismic
crisis had terminated. We argue that the observed geochemical anomalies were driven by rock permeability
changes induced by crustal deformations, and we describe how, in the absence of any release of elastic energy, the
detection of anomalies reveals that a seismogenic process is developing. Indeed, comprehensive, long-term geochemical
monitoring can provide new tools allowing us to better understand the development of seismogenesis
Mud volcanoes and methane seeps in Romania: main features and gas flux
Romania is one of the European countries with the most vigorous natural seepage of methane, uprising from
pressurised natural gas and petroleum reservoirs through deep faults. The largest seepage zone is represented by
large mud volcanoes, with CH4 >80% v/v, occurring on the Berca-Arbanasi hydrocarbon-bearing faulted anticline,
in the Carpathian Foredeep. Smaller mud volcanoes have been identified in other areas of the Carpathian
Foredeep, in the Transylvanian Depression and on the Moldavian Platform. New surveys carried out in Transylvania
allowed us to discover the richest N2 mud volcano zone in the world (N2>90% v/v), with a remarkably
high He content and a helium isotopic signature which highlights a contribution of mantle-derived source. The
large mud volcanoes are generally quiescent, with rare explosive episodes and provide a methane flux in the order
of 102-103 t kmâ2 yâ1. Independently from mud volcanism, a remarkable dry macroseepage, however, has been
found, with a degassing rate up to three orders of magnitude higher than that of mud volcanoes (i.e. 103-105 t
kmâ2 yâ1). The total gas flux from all investigated macroseepage zones in Romania is estimated in the range of
1500-2500 t yâ1. The emission from microseepage, pervasively occurring throughout the hydrocarbon-prone
basins, has yet to be assessed and added to the total gas output to the atmosphere
Long-term geochemical monitoring and extensive/compressive phenomena: case study of the Umbria Region (Central Apennines, Italy)
Long-term geochemical monitoring performed in the seismic area of the Umbria-Marche region of Italy (i.e. Central
Apennines) has allowed us to create a model of the circulation of fluids and interpret the temporal chemical
and isotopic variations of both the thermal springs as well as the gas vents. Coincident with the last seismic crisis,
which struck the region in 1997-1998, an enhanced CO2 degassing on a regional scale caused a pH-drop in
all the thermal waters as a consequence of CO2 dissolution. Furthermore, much higher 3He/4He isotope ratios
pointed to a slight mantle-derived contribution. Radon activity increased to well above the Âą2 sinterval of the earlier
seismic period, after which it abruptly decreased to very low levels a few days before the occurrence of the
single deep-located shock (March 26, 1998, 51 km deep). The anomalous CO2 discharge was closely related to
the extensional movement of the normal faults responsible for the Mw 5.7, 6.0 and 5.6 main shocks that characterized
the earlier seismic phase. In contrast, a clear compressive sign is recognizable in the transient disappearance
of the deep-originating components related to the Mw 5.3, 51 km-deep event that occurred on March 26,
1998. Anomalies were detected concomitantly with the seismicity, although they also occurred after the seismic
crisis had terminated. We argue that the observed geochemical anomalies were driven by rock permeability
changes induced by crustal deformations, and we describe how, in the absence of any release of elastic energy, the
detection of anomalies reveals that a seismogenic process is developing. Indeed, comprehensive, long-term geochemical
monitoring can provide new tools allowing us to better understand the development of seismogenesis
Anomalous fluid emission of a deep borehole in a seismically active area of Northern Apennines (Italy)
The Miano borehole of 1047 m depth is located close to the river Parma in the Northern Apennines, Italy. A measuring station is installed to observe the discharge of fluids continuously since November 2004. The upwelling fluid of this artesian well is a mixture of thermal water and methane as main components. In non-seismogenic areas, we would expect a relative constant fluid emission perhaps overlaid with long term variations from that kind of deep reservoirs during the time. However, the continuously record of the fluid emission, in particular the water discharge, the gas flow rate and the water temperature, show periods of stable values interrupted by anomalous periods of fluctuations in the recorded parameters. The anomalous variations of these parameters are of low amplitude in comparison to the total values but significant in their long-term trend. Meteorological influences of rain and barometric pressure were not detected in recorded data probably due to reservoir depth and relatively high reservoir overpressure. Influences due to the ambient temperature after the discharge were evaluated by statistical analysis. We consider that recorded changes in fluid emission parameters can be interpreted as a mixing process of different fluid components in depth by variations in pore pressure as result of seismogenic stress variation. Local seismicity was analyzed in comparison to fluidâs physico-chemical data. The analysis supports the idea of an influence to fluid transport conditions due to geodynamic processes exist. Water temperature data show frequent anomalies probably connected with possible precursory phenomena of local seismic events
Effect of COVID-19 isolation measures on physical activity of children and their parents, and role of the family environment: a cross-sectional study
Background. The rigorous isolation measures due to the COVID-19 pandemic seriously impacted childrenâs lifestyles. A descriptive cross-sectional study was carried out to collect and analyze information about physical activity habits of children and their parents during the social distancing period resulting from the COVID-19 pandemic.
Methods. An online questionnaire was administered to 363 families (507 children aged 5-13) recruited by convenience sampling, asking for physical activity type and frequency before, during, and after the lockdown period (9th March - May 3rd 2020), education, outdoor spaces, and childrenâs weight gain perception.
Results. Results show a remarkable decrease in childrenâs physical activity during lockdown (88.9 vs
39.8% active children) associated with older age and low availability of outdoor spaces (p<0.001). Parentsâ physical activity was related to educational level, and a slight but significant correlation between parentsâ education and childrenâs physical activity was found, especially with fatherâs university degree (p<0.05).
Active mothers significantly influenced childrenâs physical activity during the lockdown, especially if not
engaged in smart working. The return to an active lifestyle by children did not reach previous levels (75.9% active children) and was directly related to parentâs physical activity. Finally, the risk of weight gain was lower in active children during the lockdown (OR = 0.46; p<0.001).
Conclusions. This work highlights the importance of physical activity during a pandemic event to prevent the risk of gaining weight, and underlines the relevance of the entire family system as a source of promotion of healthy behaviors in children
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