Search results for "FLUX"

Circadian pattern of intragastric acidity in patients with non-erosive reflux disease (NERD)

2003

Summary Background : Most patients with gastro-oesophageal reflux disease have non-erosive reflux disease. Proton pump inhibitors are less effective than expected in these patients, but no previous study has measured their 24-h gastric pH values. Aims : To evaluate whether there are differences in 24-h intragastric acidity between reflux patients with and without oesophagitis and controls. The influence of Helicobacter pylori on the gastric pH of reflux patients was also assessed. Methods : Sixty-three consecutive patients with gastro-oesophageal reflux disease symptoms who agreed to undergo endoscopy and 24-h pH-metry were recruited. Twenty-five (39%) had erosive oesophagitis and 38 (61%) …

Dipole reorientation and local density of optical states influence the emission of light-emittingelectrochemical cells

2020

Herein, we analyze the temporal evolution of the electroluminescence of light-emitting electrochemicalcells (LECs), a thin-film light-emitting device, in order to maximize the luminous power radiated bythese devices. A careful analysis of the spectral and angular distribution of the emission of LECsfabricated under the same experimental conditions allows describing the dynamics of the spatial regionfrom which LECs emit,i.e.the generation zone, as bias is applied. This effect is mediated by dipolereorientation within such an emissive region and its optical environment, since its spatial drift yields adifferent interplay between the intrinsic emission of the emitters and the local density of …

VOLCANIC CO2 FLUX MEASUREMENTS BY TUNABLE DIODE LASER ABSORPTION SPECTROSCOPY

2013

Introduction In the last decades, the use of near-infrared room-temperature diode lasers for gas sensing has grown significantly. The use of these devices, for instance in combination with optical fibers, is particularly convenient for volcanic monitoring applications [1,2]. Here, we report on the first results of the application of an open-path infrared tunable laser-based at Campi Flegrei (Southern Italy). Such Diode-laser-based measurements were performed, during two field campaigns (october 2012, and january 2013), in the attempt to obtain novel information on the current degassing unrest of Solfatara and Pisciarelli fumarolic fields. Results and Discussion At each site, we used an ad-h…

CISTOSONOGRAFIA MINZIONALE (VUS) CON MDC ECOGRAFICO DI SECONDA GENERAZIONE VS CISTOURETROGRAFIA NELL'IDENTIFICAZIONE E CLASSIFICAZIONE DEL VUR: NOSTR…

2018

Perspectives for CNO neutrino detection in Borexino

2018

International audience; Borexino measured with unprecedented accuracy the fluxes of solar neutrinos emitted at all the steps of the pp fusion chain. Still missing is the measurement of the flux of neutrinos produced in the CNO cycle. A positive measurement of the CNO neutrino flux is of fundamental importance for understanding the evolution of stars and addressing the unresolved controversy on the solar abundances. The measurement of the CNO neutrino flux in Borexino is challenging because of the low intensity of this component (CNO cycle accounts for about 1% of the energy emitted by Sun), the lack of prominent spectral features and the presence of background sources. The main background c…

• Volcanic CO2 measurements via Tunable Diode Laser Spectrometer

2014

The analysis of volcanic gas datasets offer key information to build/validate geological models relevant to a variety of volcanic processes and behaviours, including eruptions. In the last decades, near-infrared room-temperature diode lasers, though in an experimental phase, are finding applications in volcanic gas studies. Here, we report on the application of the GasFinder 2.0, a commercial tunable diode infrared laser-receiver unit, operating in the 1.3-1.7 μm wavelength range, to measuring CO2 concentrations in volcanic gas emissions. At first, our field tests were conducted in three different campaigns at Campi Flegrei volcano (near Pozzuoli, Southern Italy), and, subsequently, also in…

Volcanic CO2 mapping and flux measurements at Campi Flegrei by Tunable Diode Laser absorption Spectroscopy

2014

Near-infrared room-temperature Tunable Diode Lasers (TDL) have recently found increased usage in atmospheric chemistry and air monitoring research, but applications in Volcanology are still limited to a few examples. Here, we explored the potentiality of a commercial infrared laser unit (GasFinder 2.0 from Boreal Laser Ltd) to measurement of volcanic CO2 flux emissions. Our field tests were conducted at Campi Flegrei (near Pozzuoli, Southern Italy), where the GasFinder was used (during three campaigns in October 2012, January 2013 and May 2013) to repeatedly measure the path-integrated concentrations of CO2 along cross-sections of the atmospheric plumes of the two main fumarolic fields in t…

CO2 degassing at La Solfatara volcano (Phlegrean Fields): Processes affecting d13C and d18O of soil CO2

2010

Abstract The soil CO2 degassing is a ected by processes of isotope exchange and fractionation during transport across the soil, which can deeply modify the pristine isotope composition. This has been observed in 10 the Solfatara volcano, upon a eld survey of 110 points, where the CO2 ux was measured, together with temperature, CO2 concentra- tion and oxygen and carbon isotopes within the soil. Furthermore, in some selected sites, the measurements were made at di erent depths, in order to analyze vertical gradients. Oxygen isotope composition 15 appears controlled by exchange with soil water (either meteoric or fumarolic condensate), due to the fast kinetic of the isotopic equilib- rium betw…

Total CO2 output from Vulcano island (Aeolian Islands, Italy)

2012

Total CO2 output from fumaroles, soil gas, bubbling gas discharges and water dissolved gases discharged from the island, was estimated for Vulcano island, Italy. The CO2 emission from fumaroles from the La Fossa summit crater was estimated from the SO2 crater output, while CO2 discharged through diffuse soil emission was quantified on the basis of 730 measurements of CO2 fluxes from the soil of the island, performed by using the accumulation chamber method. The results indicate an overall output of ≅500 t day 1 of CO2 from the island. The main contribution to the total CO2 output comes from the summit area of the La Fossa cone (453 t day 1), with 362 t day 1 from crater fumaroles and 91 t d…

Les climats régionaux : observation et modélisation : actes du colloque

2012

6 pages; International audience; L'objectif de cette étude est de caractériser les variations spatio-temporelles des flux sédimentaires de la basse vallée du Mono-Couffo (bassin versant partagé par le Bénin et le Togo), à partir des données de matières en suspension (MES), de débits solides (TSS), de pluie, du débit et des données concernant l'occupation du sol pour mieux apprécier l'impact de la dégradation du couvert végétal sur le flux des sédiments terrigènes. Il ressort de l'analyse une diminution de plus de 60 % des formations naturelles entre les années 1956 et 2000, contribuant à une augmentation des apports spécifiques dans la basse vallée. Une charge solide considérable en matière…