Search results for "electric [mass]"
showing 10 items of 1101 documents
Microstructure and electric properties of low-pressure plasma sprayed β-FeSi 2 based coatings
2017
Abstract Thermoelectric material β-FeSi 2 based coating was fabricated by the technique low-pressure plasma spray (LPPS) on the Al 2 O 3 substrate from different alloy powders. During the process LPPS, the phase transformation had occurred through the peritectoid, eutectoid reaction and their inverse reaction. The grain size of the as-sprayed β-FeSi 2 doped Co coatings was reduced comparing with the original feedstock powders, which implied the thermal conductivity could effectively decreased by the LPPS process. The room temperature electrical conductivity showed metal and semiconductor properties on the as-sprayed and annealed coatings. This method and the results could solve the problems…
Half-Heusler compounds: novel materials for energy and spintronic applications
2012
Half-Heusler compounds are an impressive class of materials with a huge potential for different applications such as future energy applications and for spintronics. The semiconducting Heusler compounds can be identified by the number of valence electrons. The band gap can be tuned between 0 and 4 eV by the electronegativity difference of the constituents. Magnetism can be introduced in these compounds by using rare-earth elements, manganese or ‘electron’ doping. Thus, there is a great interest in the fields of thermoelectrics, solar cells and diluted magnetic semiconductors. The combination of different properties such as superconductivity and topological edge states leads to new multifunct…
Measuring rain energy with the employment of “Arduino”
2016
This paper presents the performances of rainfall energy harvesting through the use of a piezoelectric transducer and an Arduino-based measuring system. Diverse studies agree on the possibility of generating electricity from rainfall, but to date, a study that can measure the quantity of energy produced during rainfall is still missing. The present study begins with results obtained from laboratory researchers using piezoelectric transducers and oscilloscopes — to measure the energy produced from a single raindrop — and concludes with an ad hoc Arduino-based measuring system, aimed at measuring the actual amount of electrical energy produced by a piezoelectric transducer that is exposed to r…
Dielectric behaviour of BaTi1-xZrxO3ceramics obtained by means of a solid state and mechanochemical synthesis
2016
ABSTRACTIn this study the comparison of dielectric behaviour of BaTi1-xZrxO3 (BTZx) ceramic samples prepared by means of a solid state and mechanochemical synthesis was presented. A single phase of perovskite structure was identified in the samples at room temperature. No significant impurities were detected in an EDS spectrum and the samples had a good stoichiometric ratio. The morphology of the investigated samples was characterized by a scanning electron microscopy (SEM). The investigation of dielectric properties of the BTZx samples within the temperature range from 140 K to 600 K was performed by means of a dielectric spectroscopy method at the frequency ranging from 0.1 Hz to 10 MHz. …
A Planar Generator for a Wave Energy Converter
2019
This article presents a permanent magnet planar translational generator which is able to exploit multiple modes of sea wave energy extraction. Linear electrical generators have recently been studied for the exploitation of sea wave energy, but, to the best of our knowledge, no synchronous planar translational generator has been proposed. In this article, to maximize the energy extraction, we have considered all the potential modes of motion due to wave excitation and included them within the mathematical model of the proposed system. The principle of operation of the generator can be summarized as follows: the moving part (translator) of the generator is driven from the sea waves and induce…
The Role of Right Interpretation of Space Charge Distribution for Optimized Design of HVDC Cables
2019
In the field of high-voltage transmission systems, different degradation phenomena affect the reliability of the employed components. In particular, under dc stress, the space charge accumulation phenomenon is believed to be the most responsible of the dielectrics lifetime reduction. To measure the accumulated space charges in flat specimens, the pulsed electro-acoustic (PEA) method is one of the most used techniques. The working principle of the PEA cell is based on the acoustic waves propagation and detection. As is well known, the acoustic waves propagating in different means are partially transmitted and partially reflected. Therefore, the piezoelectric sensor of the PEA cell is subject…
Radiofrequency and 2.45 GHz electron cyclotron resonance H−volume production ion sources
2016
The volume production of negative hydrogen ions () in plasma ion sources is based on dissociative electron attachment (DEA) to rovibrationally excited hydrogen molecules (H2), which is a two-step process requiring both, hot electrons for ionization, and vibrational excitation of the H2 and cold electrons for the formation through DEA. Traditionally ion sources relying on the volume production have been tandem-type arc discharge sources equipped with biased filament cathodes sustaining the plasma by thermionic electron emission and with a magnetic filter separating the main discharge from the formation volume. The main motivation to develop ion sources based on radiofrequency (RF) or electro…
Acoustic Wave Behavior in a Specimen Containing an Air Void Defect
2019
The PEA method is the most used technique for the space charge measurements. As is well known, this method uses pressure waves to detect the charges accumulated in solid dielectrics. Based on its working principle, the generated acoustic waves travel within PEA cell and the specimen under test in order to be finally detected by the piezoelectric sensor. For a multilayer specimen and, in particular, in case of different materials that make up the specimen, the acoustic wave reflection is inevitable. Considering that, in several cases, the reflected waves could be detected by the piezoelectric sensor before than the main signals, the PEA cell output profile could results distorted. Based on t…
An Experimental Study of Waveguide Coupled Microwave Heating with Conventional Multicusp Negative Ion Source
2015
Negative ion production with conventional multicusp plasma chambers utilizing 2.45 GHz microwave heating is demonstrated. The experimental results were obtained with the multicusp plasma chambers and extraction systems of the RFdriven RADIS ion source and the filament driven arc discharge ion source LIISA. A waveguide microwave coupling system, which is almost similar to the one used with the SILHI ion source, was used. The results demonstrate that at least one third of negative ion beam obtained with inductive RF-coupling (RADIS) or arc discharge (LIISA) can be achieved with 1 kW of 2.45 GHz microwave power in CW mode without any modification of the plasma chamber. The co-extracted electro…
High sensitivity characterization of the nonlinear electric susceptibility of a glass ceramic in the microwave range
2019
The nonlinear electric susceptibility of a glass ceramic is characterized in the microwave range by measuring intermodulation of two high-power signals. To achieve the necessary sensitivity for dielectric nonlinearities, the setup ensures that the measured intermodulation can be ascribed to the material under test while all other intermodulation sources are suppressed. This is achieved by coupling three dielectric resonators in a cut-off waveguide. The third order nonlinearity of the glass ceramic is found to be χ3/er = (1.6 ± 0.8) × 10−15 m2/V2 at 950 MHz. The magnitude is comparable to the previously measured high-end sintered ceramics. The power of the intermodulation signal as a functio…