Search results for "Note"
showing 10 items of 10709 documents
Applicability of Waste Engine Oil for the Direct Production of Electricity
2021
New methods for the use of waste products as input for other technologies are a constant subject of research efforts. One such product is waste engine oil. Due to the constantly increasing number of motor vehicles in the world, the recycling or application of engine oils for energy production purposes is currently of considerable importance. This paper contains research regarding the analysis of the electro-oxidation potential of waste engine oil, and thus the possibility of using such oil as a material in fuel cells. The research demonstrates the basic possibility of the electro-oxidation of this oil emulsion on a platinum electrode in an acid electrolyte (aqueous solution of H2SO4). It wa…
Metal/Semiconductor Barrier Properties of Non-Recessed Ti/Al/Ti and Ta/Al/Ta Ohmic Contacts on AlGaN/GaN Heterostructures
2019
This paper compares the metal/semiconductor barrier height properties of non-recessed Ti/Al/Ti and Ta/Al/Ta contacts on AlGaN/GaN heterostructures. Both contacts exhibited a rectifying behavior after deposition and after annealing at temperatures up to 550 °
Eulerian two-fluid model of alkaline water electrolysis for hydrogen production
2020
Hydrogen storage is a promising technology for storage of renewable energy resources. Despite its high energy density potential, the development of hydrogen storage has been impeded, mainly due to its significant cost. Although its cost is governed mainly by electrical energy expense, especially for hydrogen produced with alkaline water electrolysis, it is also driven by the value of the cell tension. The most common means of electrolyzer improvement is the use of an electrocatalyst, which reduces the energy required for electrochemical reaction to take place. Another efficient means of electrolyzer improvement is to use the Computational Fluid Dynamics (CFD)-assisted design that allows the…
Nanostructured Ni Based Anode and Cathode for Alkaline Water Electrolyzers
2019
Owing to the progressive abandoning of the fossil fuels and the increase of atmospheric CO2 concentration, the use of renewable energies is strongly encouraged. The hydrogen economy provides a very interesting scenario. In fact, hydrogen is a valuable energy carrier and can act as a storage medium as well to balance the discontinuity of the renewable sources. In order to exploit the potential of hydrogen it must be made available in adequate quantities and at an affordable price. Both goals can be potentially achieved through the electrochemical water splitting, which is an environmentally friendly process as well as the electrons and water are the only reagents. However, these devices stil…
The Membrane-Less Microbial Fuel Cell (ML-MFC) with Ni-Co and Cu-B Cathode Powered by the Process Wastewater from Yeast Production
2020
Research related to measurements of electricity production was combined with parallel wastewater parameter reduction in a membrane-less microbial fuel cell (ML-MFC) fed with industry process wastewater (from a yeast factory). Electrodes with Ni–Co and Cu–B catalysts were used as cathodes. A carbon electrode (carbon cloth) was used as a reference due to its widespread use. It was demonstrated that all analyzed electrodes could be employed as cathodes in ML-MFC fed with process wastewater from yeast production. Electricity measurements during ML-MFC operations indicated that power (6.19 mW) and current density (0.38 mA·cm−2) were the highest for Ni–Co electrodes. In addition, during the explo…
Dynamic reconfiguration systems for PV plant: Technical and economic analysis
2020
Solar plants suffer of partial shading and mismatch problems. Without considering the generation of hot spots and the resulting security issues, a monitoring system for the health of a PV plant should be useful to drive a dynamic reconfiguration system (DRS) to solve bottlenecks due to different panels’ shading. Over the years different DRS architectures have been proposed, but no suggestions about costs and benefits have been provided. Starting from technical subjects such as differences of the topologies driving the hardware complexity and number of components, this paper identifies the cost of DRS and its lifetime, and based on these issues it provides an economic analysis for a 6 kWp PV…
In-situ monitoring by Raman spectroscopy of the thermal doping of graphene and MoS2 in O-2-controlled atmosphere
2017
The effects of temperature and atmosphere (air and O2) on the doping of monolayers of graphene (Gr) on SiO2 and Si substrates, and on the doping of MoS2 multilayer flakes transferred on the same substrates have been investigated. The investigations were carried out by in situ micro-Raman spectroscopy during thermal treatments up to 430 °C, and by atomic force microscopy (AFM). The spectral positions of the G and 2D Raman bands of Gr undergo only minor changes during treatment, while their amplitude and full width at half maximum (FWHM) vary as a function of the temperature and the used atmosphere. The thermal treatments in oxygen atmosphere show, in addition to a thermal effect, an effect a…
Environment assisted photoconversion of luminescent surface defects in SiO 2 nanoparticles
2017
Abstract Time-resolved photoluminescence investigation on SiO 2 nanoparticles was carried out in controlled atmosphere, with the aim to discern the effects induced on the typical blue luminescence band by high power UV Nd:YAG laser photons (4.66 eV) and by some selected molecular species of the air (O 2 , N 2 , CO 2 , H 2 O). These factors ultimately determine both the brightness and photostability of the emitting defect, so as to limit the unique and attracting potentialities offered by this system in many applicative fields. Here it is highlighted that the effects due to photons and molecules, singularly considered, are not additive, the radiation being more dramatic in reducing the emiss…
Magnetic particle mixing with magnetic micro-convection for microfluidics
2015
International audience; In this paper we discuss the magnetic micro-convection phenomenon as a tool for mixing enhancement in microfluidics systems in cases when one of the mis-cible fluids is a magnetic particle colloid. A system of a water-based magnetic fluid and water is investigated experimentally under homogeneous magnetic field in a Hele-Shaw cell. Subsequent image analysis both qualitatively and quan-titatively reveals the high enhancement of mixing efficiency provided by this method. The mixing efficiency dependence on the magnetic field and the phys-ical limits is discussed. A suitable model for a continuous-flow microfluidics setup for mixing with magnetic micro-convection is als…
Gravity effects on mixing with magnetic micro-convection in microfluidics.
2018
Mixing remains an important problem for development of successful microfluidic and lab-on-a-chip devices, where simple and predictable systems are particularly interesting. One is magnetic micro-convection, an instability happening on the interface of miscible magnetic and non-magnetic fluids in a Hele-Shaw cell under applied field. Previous work proved that Brinkman model quantitatively explains the experiments. However, a gravity caused convective motion complicated the tests. Here we first improve the experimental system to exclude the gravitational convective motion. Afterwards, we observe and quantify how gravity and laminar flow play an important role in stabilizing the perturbations …