Search results for " electronic engineering"
showing 10 items of 8284 documents
Influence of temperature on the synthesis of thiol-stabilized CdTe nanoparticles in aqueous solutions
2010
We have investigated the evolution of thiol-capped cadmium telluride nanocrystals prepared in aqueous solutions at low and room temperature followed by heating at 50–100 °C. The UV–visible absorption spectra, as well as transmission electron microscopy, atomic force microscopy, and dynamic light scattering observations made it possible to reveal differences in size and structure originating from different heating temperatures. It was shown that minimization of the nucleation process temperature provided formation of larger nanoparticles than at higher temperatures.
ZnO nanorod arrays fabrication via chemical bath deposition: Ligand concentration effect study
2010
A new ligand, N, N, N', N'-tetramethylethylenediamine, has been used to grow ZnO nanorods on silicon substrates via a two steps approach. A preliminary seeding on silicon substrates has been combined with chemical bath deposition using a Zinc acetate - N, N, N', N'-tetramethylethylenediamine aqueous solution. The used diamino ligand has been selected as Zn(2+) complexing agent and the related hydrolysis generates the reacting ions (Zn(2-) and OH(-)) responsible for the ZnO growth. The seed layer has been annealed at low temperature (<200 degrees C) and the ZnO nanorods have been grown on this ZnO amorphous layer. There is experimental evidence that the ligand concentration (ranging from 5 t…
Crystallization of the CaCO3 mineral in the presence of the protein ovalbumin
2004
Abstract The kinetics of CaCO3 mineralization was studied by SANS in a 0.1 M aqueous CaCl2 solution in the presence of the protein ovalbumin found in chicken eggs. As the scattering from the protein and the mineral was observed within different Q regimes the evolution of the protein and mineral could be followed independently. It is observed that ovalbumin denaturates during the first 3 h and leads to a strong enhancement of mineralization.
A calcined clay fixed bed adsorption studies for the removal of heavy metals from aqueous solutions
2021
Abstract A natural clay material from southern Tunisia was used as a low cost sorbent in a column-wise removal of metal pollutants. This is fundamentally important for a sustainable wastewater treatment strategy. This work has been performed within the framework of a project aiming to the valorization of natural geomaterials, from Tunisia, in several environmental applications. Column adsorption experiments were carried out for a better production of cleaner effluents and further understanding of the main mechanisms involved in the removal process, through a dynamic methodology, that would allow an industrial scale treatment. A calcined clay sample was used as an adsorbent for the removal o…
Influence of chloride anions on the electrodeposition and electroactivity of the polymer matrix in polypyrrole, poly( N -methylpyrrole) and polypyrro…
2004
We report electrochemical studies on the influence of a small concentration of chloride ions on the electroactivity of the polymer matrix of polypyrrole (PPy), poly(N-methylpyrrole) [p(N-MePy)] and a poly(titanocene-propyl-pyrrole) derivative, p(Tc3Py) [Tc(CH2)3NC4H4; Tc=CpCp′TiCl2; Cp=C5H5; Cp′=C5H4] in acetonitrile (AN), tetrahydrofuran (THF) and N,N-dimethylformamide (DMF). The polymer films were obtained on Pt disc electrodes from AN solutions of the monomers containing 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF6) as the supporting electrolyte and then transferred to the corresponding monomer-free solution. Studies in Cl−-containing solutions have shown that the p(Tc3Py) matrix…
Pricing of electricity futures based on locational price differences : The case of Finland
2018
We find that the pricing of Finnish electricity market futures has been inefficient during the latest 10 years, when the trading volumes of Electricity Price Area Differentials (EPADs) have more than doubled. Even though the calculated futures premium on EPADs is related to some risk measures and the variables capturing the demand and supply conditions in the spot electricity markets, there has been a significant positive excess futures premium in the Finnish market, and financial market participants should have been able to utilize this also in economic terms. This finding is new and relevant for the participants of the Nordic electricity markets also in the future, because both the specul…
EUA and sCER Phase II Price Drivers: Unveiling the reasons for the existence of the EUA-sCER spread
2011
International audience; This article studies the price relationships between EU emissions allowances (EUAs) - valid under the EU Emissions Trading Scheme (EU ETS) - and secondary Certified Emissions Reductions (sCERs)--established from primary CERs generated through the Kyoto Protocol's Clean Development Mechanism (CDM). Given the price differences between EUAs and sCERs, financial and industrial operators may benefit from arbitrage strategies by buying sCERs and selling EUAs (i.e. selling the EUA-sCER spread) to cover their compliance position as industrial operators are allowed to use sCERs towards compliance with their emissions cap within the European system up to 13.4%. Our central res…
Towards the Preservation and Dissemination of Historical Silk Weaving Techniques in the Digital Era
2019
Historical weaving techniques have evolved in time and space giving as result more or less fabrics with different aesthetical characteristics. These techniques were transferred along the main silk production centers, thanks to the European Silk Road and creating a common European Frame on themes and techniques. These had made it complicated to determine whether a fabric corresponds to one century or another. Moreover, in order to understand their creation, it is necessary to determine the number of weaves and interlacements that each textile has, therefore, mathematical models can be extracted from these layers. In this sense, three dimensional (3D) virtual representations of the internal s…
Statistical analysis of engraving traces on a 3D digital model of prehistoric stone stelae
2016
International audience; Studying cultural heritage artefacts, using 3D digital models, is gaining interest. It not only allows applications in documentation and visualisation, but also permits further contact-less examination. In this paper, we are presenting a statistical analysis of stone engravings based on features that were semi-automatically extracted from 3D acquisition data. Our objects of study are two Neolithic stone stelae and a faithful replica that was created in the course of an archaeological study. We use common statistical methods and investigate the populations of depth and diameter of the engraving traces, as well as their correlation. We observe that the erosion of the t…
Deep learning to detect built cultural heritage from satellite imagery. - Spatial distribution and size of vernacular houses in Sumba, Indonesia -
2021
Abstract In Sumba Island – Indonesia, the implantation of vernacular houses, inside and outside traditional villages, is considered to be an efficient proxy for the on-going complex cultural transformations resulting from globalization. This study presents an easily reproducible workflow allowing buildings to be automatically detected from satellite imagery, demonstrating how modern computer vision methods based on deep learning can help in this task, which would be far too time-consuming when undertaken by hand. Eight deep learning architectures based on convolutional neural networks were compared in terms of ability to identify and locate precisely traditional houses from satellite images…