Search results for "Thermal gradient"

Mercury fluxes from volcanic and geothermal sources: An update

2015

OVSICORI, IAMC-CNR We review the state of knowledge on global volcanogenic Hg emissions to the atmosphere and present new data from seven active volcanoes (Poás, Rincón de la Vieja, Turrialba, Aso, Mutnovsky, Gorely and Etna) and two geothermal fields (Las Pailas and Las Hornillas). The variability of Hg contents (c. 4-125 ng m-3) measured in gaseous emissions reflects the dynamic nature of volcanic plumes, where the abundances of volatiles are determined by the physical nature of degassing and variable air dilution. Based on our dataset and previous work, we propose that an average Hg/SO2 plume mass ratio of c. 7.8 × 10-6 (± 1.5 × 10-6; 1 SE, n = 13) is best representative of open-conduit …

Methanotrophic activity and bacterial diversity in volcanic-geothermal soils at Pantelleria island (Italy)

2014

Abstract. Volcanic and geothermal systems emit endogenous gases by widespread degassing from soils, including CH4, a greenhouse gas twenty-five times as potent as CO2. Recently, it has been demonstrated that volcanic/geothermal soils are source of methane, but also sites of methanotrophic activity. Methanotrophs are able to consume 10–40 Tg of CH4 a−1 and to trap more than 50% of the methane degassing through the soils. We report on methane microbial oxidation in the geothermally most active site of Pantelleria island (Italy), Favara Grande, whose total methane emission was previously estimated in about 2.5 t a−1. Laboratory incubation experiments with three top-soil samples from Favara Gra…

A Review of “Volcano and geothermal tourism: sustainable georesources for leisure and recreation”

2013

A Sustainable Energy Mix for the Aeolian Islands

2018

The paper examines the current status of the electrical energy production in the Aeolian Islands, an Italian archipelago, composed by small island North of Sicily. Instead the availability of renewable energy sources, like wind, solar, geothermal and sea wave, these islands produce electrical energy using almost entirely fossil fuels. Starting from this initial condition, the paper proposes an energetic mix based on the available resources and focusing the attention on sea wave. An innovative device is presented in order to exploit this energy source.

Examination of coagulant additives on qualitative composition of selected thermal waters

2017

On the territory of Poland occur rich deposits of thermal waters. Although the utilisation of these waters is continuously extending, Poland is not exploiting their full geothermal potential due to high investment costs. Thermal waters industry in Poland to date indicates operations within mainly balneology as well as recreation objectives. Higher temperature values of these waters foster a washout in the surrounding rocks resulting in a high concentration of diluted substances which must be often removed. The following study investigates thermal waters from three intakes for which coagulation processes were conducted. Research clearly shows that coagulant additives not impact on the qualit…

Data from: The role of partial incubation and egg repositioning within the clutch in hatching asynchrony and subsequent effects on breeding success

2019

The main mechanism to achieve hatching asynchrony (HA) for incubating birds is to start heating the eggs before clutch completion. This might be achieved through partial incubation and/or early incubation. Even in the absence of incubation behaviour during the laying phase, clutches still experience a certain degree of asynchrony. Recent studies have shown that eggs located in the centre of the nest receive more heat than peripheral ones during incubation. Since eggs receiving more heat would develop faster, we hypothesised that HA should be shorter in nests where eggs were moved homogeneously along the centre-periphery space during incubation compared to those nests where eggs repeatedly r…

A new approach to calibrate the thermal conditions in space charge measurements on HVDC mini-cables

2019

The PEA method is currently widespread used for space charge measurements in mini-cables in order to qualify the behavior of semicon-dielectric-semicon compound under electric and thermal stress. The main goal of this research is to quantitatively evaluate the relationship between the thermal boundary conditions applied to cables or mini-cables and the maximum local electric field due to the accumulated space charge. Hitherto, several research groups have obtained thermal gradients over the dielectric's radius heating the conductor by Joule effect due to an induced current. In this paper, a numerical approach is offered to calibrate the heat exchange boundary conditions to apply to a sample…

Contour map of the top of the regional geothermal reservoir of Sicily (Italy).

2015

An integrated review of existing geological and geophysical data – partly acquired during oil and gas exploration – combined with new data provided by deep geothermal studies of selected key areas, was used for the 3D modeling and mapping of the top of the geothermal reservoir developed at a regional scale in Sicily (Central Mediterranean). The resulting 1:500,000 scale map covers the area of the whole Sicily (about 25,700 km2) and is devoted to represent the main input for both the thermal modeling and the evaluation of geothermal potential at a regional scale. As the map indicates the distribution at depth of a likely target for geothermal drilling, it can be also used as a rough indicato…