Search results for "working"
showing 10 items of 2747 documents
Thermolytic reverse electrodialysis heat engine: model development, integration and performance analysis
2019
Abstract Salinity gradient heat engines represent an innovative and promising way to convert low-grade heat into electricity by employing salinity gradient technology in a closed-loop configuration. Among the aqueous solutions which can be used as working fluid, ammonium bicarbonate-water solutions appear very promising due to their capability to decompose at low temperature. In this work, an experimentally validated model for a reverse electrodialysis heat engine fed with ammonium bicarbonate-water solutions was developed. The model consists of two validated sub-models purposely integrated, one for the reverse electrodialysis unit and the other for the stripping/absorption regeneration uni…
Outlining the Limits of Friction Stir Consolidation as Used as an Aluminum Alloys Recycling Approach
2021
Friction stir consolidation (FSC) is a solid-state process that recycles metal scraps economically and eco-friendly compared to the conventional melting method. The process parameters especially processing time and rotational speed, have a crucial role in achieving a sound disc during FSC. The current study answers the research question of how far these process parameters can be effective when the mass of chips to be recycled increases. In specific, an experimental setup was analyzed that was previously identified as challenging for recycling 20 g chips of aluminum alloy AA 2024-O. Rotational speed was set doubled, and processing time was increased up to 1.5 times of their initial values. T…
Safety in Hazelnut Mechanical Harvesting
2022
Hazelnut cultivation occupies an area of about 13,000 ha in Sicily, 10,000 of which are concentrated in the province of Messina, specifically in the pedo-mountain municipalities of the Nebrodi. These are heterogeneous plants by cultivar and planting time. To date, the hazelnut represents a scarcely mechanized marginal crop, with a characteristic training system as the multi stemmed bush. The harvest takes place as soon as the hazelnuts reach maturity and detach from the herbaceous dome that surrounds them falling to the ground. Before harvesting, swathing is carried out by hand using rakes, or facilitated by backpack blowers, or mechanically by means of a swather or with a tractor-mounted b…
Disasters in the Society of Fear
2019
From immemorial times, Aborigines and ancient cultures were frightened of disasters because these events were seen as divine reprisals or punishment for their sins (as the Noah’s Ark myth shows). Although modern science introduced instrumental thinking to understand disasters, improving the quality of life, it is equally true that capitalism obscured the diagnosis of scientists to protect the system. Blind to see the real problems of earth, today, capitalism offers distorted answers to the problem of climate change, migration and refugee crises, and even to the economic downturn. Based on the tactics of blaming Others, the elite allude to poverty as the precondition toward humanitarian disa…
Effect of the surrounding aeration on microcapillary electrochemical cell experiments
2008
In the microelectrochemical capillary cell technique a silicone rubber gasket is used to avoid any electrolyte leakage between the pulled glass capillary and the working electrode (the metallic tested material). In this study, it is demonstrated that the oxygen reduction reaction (ORR) is strongly affected by the use of the silicone rubber. Experiments under a surrounding argon gas shielding of the pulled capillary in contact with the metallic surface have been performed showing a large effect on the ORR. Considering the high permeation rate of oxygen through silicone, the decrease of the reaction rate observed experimentally was validated by FEM modelling assuming that the air/silicone/wat…
Graphical analysis of electrochemical impedance spectroscopy of two consecutive irreversible electron transfers. 2. Zinc anodic dissolution in acid m…
2006
The graphical analysis of the impedance plots is used in the study of the electrodic systems that take place through two consecutive single electron transfers. The zinc anodic dissolution is studied by using this procedure. The characteristic points easily allow us to explain and to simulate the impedance behavior of this electrodic system according to the steady-state potential and the roughness of the working electrode. The direct procedure for parametrical identification from the graphical analysis allows us to reduce the time needed for an impedance experiment. This graphical analysis is suggested for studying thin coated galvanized steels.
Layer-by-layer identification of copper alteration products in metallic works of art using the voltammetry of microparticles.
2010
An in situ technique for layer-by-layer electrochemical analysis of solid surfaces using the voltammetry of microparticles is presented. The method is based on the determination of several shape-dependent parameters for voltammetric curves recorded at a graphite pencil working electrode in contact with the sample, all immersed into aqueous electrolytes. Repetitive square wave voltammetry and sequential application of constant potential reductive steps and voltammetric scans yield discernible responses for the corrosion products distributed in stratified layers on metal-based surfaces. This methodology is applied to identify alteration products of copper and copper alloys distributed in diff…
Direct Writing on Copper Ion Doped Silica Films by Electrogeneration of Metallic Microstructures
2017
International audience; A facile and rapid localized electrochemical reduction of colloid copper particles is proposed using the scanning electrochemical,microscope (SECM), technique. In this purpose, thin films of composite silica :glass containing copper salts were prepared by the sol-gel method via the dip coating technique. Acid-catalyzed tetraethylorthosilane (TEOS) solutions charged with copper nitrate were used as precursors. This one-pot experiment can be performed in mild conditions. The localized generation of copper metallic nanostructures on silica film has been performed by electroreduction of methyl viologen on an ultramicroelectrode (UME). The UME generates reducing species, …
Correlationship between microscopic observations and electrochemical behaviour of different kind of galvanized steel.
2005
Zinc anodic dissolution has been studied according to the steel galvanized method by means of the electrochemical impedance spectroscopy (EIS) and microscopic observations. Relevant information on the galvanized method is provided by the analysis of experimental data. The galvanized method has no influence on the kinetics parameters of the zinc anodic dissolution process. The galvanized method only changes the surface texture of the working electrode. Thus, the EIS fitting allows to calculate the fractal dimension of the surface of the working electrode.
Correlation between the fractal dimension of the electrode surface and the EIS of the zinc anodic dissolution for different kinds of galvanized steel
2004
The roughness of the working electrode is one of the factors that affects the electrochemical impedance spectroscopy (EIS) data of the zinc anodic dissolution process. The fractal dimension of digital images of shooping plate, hot dip galvanized steel, continuous hot-dipped galvanized steel and electro-galvanized steel are related with their respective EIS data. Keywords: EIS, Fractal dimension, Roughness, Galvanized steel, Corrosion