Search results for " hydrothermal"

Idrothermal ageing of ionizing radiation cured epoxy matrices for carbon fibre composites

2008

Synthèses optimisées et caractérisations avancées de nanotubes de titanate et de leurs fonctionnalisations : vers l'élaboration de nanovecteurs de mo…

2017

The aim of this PhD thesis is to develop new nanohybrids based on titanate nanotubes (TiONts) in order to use them as nanocarrier of a therapeutic molecule: a stilbene phenol, 4'-hydroxy-4-(3-aminopropoxy)-trans-stilbene (HAPtS), which is a transresveratrol derivative.TiONts are synthesized by a hydrothermal treatment from a precursor of rutile titanium dioxide. Two methods of hydrothermal synthesis have been studied (the static and dynamic ones): the second approach uses an original hydrothermal device which provides a vigorous mechanical stirring during the hydrothermal process with controllable stirring time par hour. A parametric study was carried out to evaluate the effect of reaction …

Protonic ceramic fuel cell : elaboration and characterization. Investigation of the BaZr0.8Y0.2O3-d electrolyte by electrochemical impedance spectros…

2021

One of the current global challenges is to find novel, clean and efficient techniques for the energy production. The use of electrochemical cells and hydrogen is one of the solutions. These cells convert the excess energy produced by conventional systems into hydrogen by steam electrolysis. The hydrogen can be stored and transformed into electricity when needed in the fuel cell mode. Among the different electrochemical cells, protonic ceramic electrochemical cells have attracted much attention due to their high efficiency at intermediate temperature (400 – 600 °C). In addition, these systems offer the advantage of not diluting the fuel in electrolysis mode. This thesis work focuses on the e…

Estudio Hidrogeoquimico De Las Áreas Termales Del Complejo Volcánico Copahue-Caviahue

2016

Hydrogeochemical study on Thermal areas of the Copahue-Caviahue Volcanic Complex The hydrothermal system hosted in the Copahue- Caviahue Volcanic Complex consists of different geothermal areas around the Copahue volcano, whose last eruptive cycle started on December 22 of 2012. This work presents new data from the samplings of November 2012 and march 2013 in Las Maquinas, Las Maquinitas, villa de Copahue and Chancho-Có areas. These acid-sulfate and steam heated waters, presented changes in their SO4-2 concentrations, especially in Las Maquinas and Las Maquinitas areas. Meanwhile, SO4-2/Cl- ratios presented a strong decrease in the samples from November 2012, regarding the samples from 2013.…

Study of the community of Cystoseira brachycarpa J. Agardh emend. Giaccone of a shallow hydrothermal vent area of the Aeolian Islands (Tyrrhenian sea…

2011

Experimental and theoretical study to explain the morphology of CaMoO4 crystals

2018

Abstract CaMoO 4 crystals were prepared by a controlled co-precipitation method and processed in a domestic microwave-assisted hydrothermal system with two different surfactants (ethyl 4-dimethylaminobenzoate and 1,2,4,5-benzenetetracarboxylic dianhydride). The corresponding structures were characterized by X-ray diffraction and Rietveld refinement techniques, Fourier transform infrared spectroscopy, ultraviolet–visible absorption spectroscopy, and photoluminescence measurements. Field emission scanning electron microscopy was used to investigate the morphology of the as-synthesized aggregates. The structure, the surface stability of the (001), (112), (100), (110), (101), and (111) surfaces…

ELECTROSPUN NANOFIBROUS MATS IN FIBRE REINFORCED EPOXY LAMINATES

Conceptual study of the coupling of a biorefinery process for hydrothermal liquefaction of microalgae with a concentrating solar power plant

2017

A conceptual analysis of the coupling of a concentrating solar power plant with a chemical process for hydrothermal liquefaction (HTL) of microalgae to biocrude was performed. The two plants were considered coupled by molten salt recirculation that granted energetic supply to the chemical process. Preliminary estimations have been done considering a solar field constituted by 3 linear parabolic solar collectors rows, each 200 m long, using a ternary molten salts mixture as heat transfer fluid, and a chemical plant sized to process 10 kT/y of microalgae. Under adopted conditions, we have estimated a minimum selling prize of the biocrude that is similar to that achieved in non-solar HTL proce…

Diffuse soil gas emissions of gaseous elemental mercury (GEM) from hydrothermal-volcanic systems: An innovative approach by using the static closed-c…

2016

This study was aimed to test a new methodological approach to carry out measurements of gaseous elemental mercury (GEM) diffusively emitted from soils in hydrothermal-volcanic environments. This method was based on the use of a static closed-chamber (SCC) in combination with a Lumex® RA-915M analyzer that provides GEM measurements in a wide range of concentrations (from 2 to 50,000 ng m-3). Gas samples were collected at fixed time intervals from the SCC positioned on the ground (time-series samples). The Lumex® inlet port was equipped with a three-way Teflon valve allowing the free entrance of air through a carbon trap, in order to: (i) prevent disturbance to the Lumex® operative flow rate …

Catalogue of the main gas manifestations in the Hellenic territory: a first step towards the estimation of the nationwide geogenic gas output

2015

Quantification of gaseous emissions in geological systems is an important branch because it is a major source of greenhouse gas to the atmospheric budget. Of geological environments, there are two different categories: the first category includes emissions of the predominant carbon dioxide (CO2), while the second includes emissions of the predominant methane (CH4). The Hellenic territory has a very complex geodynamic setting deriving from a long and complicated geological history. It is strongly characterized by intense seismic activity and enhanced geothermal gradient. This activity, with the contribution of an active volcanic arc, favours the existence of many cold and thermal gas manifes…