This study sought to apply nanotechnology to develop the electrical characteristics of palm oil. Experiments were conducted using three types of nanoparticles: zinc oxide (ZnO), titanium dioxide ...(TiO2), and barium titanate (BaTiO3). The nanofluid samples were prepared by mixing the nanoparticles with palm oil using various processes. In the first scenario, a combination of palm oil with nanoparticles at 0.01 vol% was created, while the next sample had 0.03 vol% of nanoparticles. The samples were then fully dispersed using a magnetic stirrer, followed by ultrasonic dispersal in order to ensure homogeneity of the nanofluid. The electrodes were set 2.5 mm apart and the test was performed six times on each test sample in compliance with the IEC 60156 standard. The voltage breakdown characteristics were recorded for each of the liquids at temperatures varying from 35 °C to 90 °C. The results showed that for the palm oil samples containing nanoparticles, the voltage breakdown was greater than for the samples containing unmodified palm oil.
Cu/SiO2 diffusion at hybrid bonding interface without diffusion barrier was investigated in order to validate the electrical insulation of interconnects. The Cu thermal diffusion was studied by ...ToF-SIMS analysis of the dielectrics stack facing bonding pads after a bonding annealing (400 °C, 2 h) and a diffusion annealing (400 °C, 14 h). No trace of copper was found above the limit of detection 1017 at·cm−3. Cu ions drift was followed by I-V measurements on specially designed comb-serpentine that maximize the electrical field at bonding interface. Their efficiency was confirmed since physical failure analysis located the dielectric breakdown damage between bonding pads. Breakdown voltages coupled to wafer-to-wafer misalignments enabled the extraction of the SiO2 breakdown strength: 3.4 MV·cm−1. This study proves that at room temperature, hybrid bonding interconnects remain electrically insulated despite thermal budgets involved by the bonding process.
•Evaluation of Cu diffusion through SiO2 at hybrid bonding interface under stresses•No Cu trace above 1017 at·cm−3 detected after a 400 °C-16 h thermal budget•I-V measurements evidenced that the voltage breakdown is misalignment dependent.
Pseudospark (PS) sourced electron beam with high energy can be produced by a multigap PS discharge-based plasma cathode electron (PD-PCE) source under high-voltage operations. The process of ...successive high-voltage breakdown and plasma formation inside hollow cathode (HC) and in the gaps play significant role for electron beam generation. An investigation has been carried out for the analysis of discharge processes in different multigap PS structures using the 2-D kinetic plasma simulation code. It has been observed that the distribution of equipotential contour lines in the HC cavity as well as gaps is important to investigate the occurrence of the breakdown and plasma generation in the PD-PCE source. The higher equipotential lines start penetrating through the electrode apertures only when the plasma is formed in the adjacent previous gap. The potential lines help the electrons to run out through the electrode apertures and have collision process for the ionization in the next gaps. The radial expansion of the electrons and ions has also been analyzed which depends on the profile of equipotential contour lines. The expansion of ions is relatively more compared to electrons at the time of breakdown and plasma formation in the gaps. The expansions of electrons and ions are less in the first and last gap compared to the intermediate gaps. The equipotential contour lines determine the successive breakdown and discharge processes in the multigap PD-PCE source, which are required for the generation of efficient plasma, and energetic and high-density PS discharge-based electron beams.
Polymer film insulation degradation is a major problem for electric machines which leads to short circuits, overheating, and eventually the occurrence of catastrophic failure. Electrical insulation ...materials provide the vital function of turn-to-turn, phase-to-phase, and phase-to-ground electrical isolation for the electromagnetic coils and windings. This article investigates the characterization of early-onset degradation of thin-film magnet wire insulation at elevated temperatures from 200 to 275 <inline-formula><tex-math notation="LaTeX">^{\circ }</tex-math></inline-formula>C. Sample specimens were analyzed after ageing for 100 h in terms of their physical properties (surface roughness, mass), chemical properties Fourier transform infrared (FTIR) spectroscopy, dielectric properties (capacitance and dissipation factor), and electrical properties (voltage breakdown strength and resistance). The results show that the specimen roughness and mass increase and decrease uniformly, respectively, with increased ageing temperature. Similar degradation results trends with respect to ageing temperature for the dielectric properties and electrical insulation strength is documented. The article also reports an extended ageing study which investigates early breakdown voltage on sample specimens over a much longer time duration, that of up to 1600 h.
In this paper, we report the design and characteristics of a field-ionization gas sensor based on freestanding silicon nano structures. Silicon nanostructures fabricated using a three-step ...chemical/electrochemical technique on silicon wafer were placed between two parallel plates separated by a small gap. The sensor works based on the field ionization tunneling effect. For the first time, it is shown that silicon nanostructures can be used for the purpose. The device was tested for Ar, N 2 , O 2 , and He gases in a pressure range of 0.01 <; P <; 10 torr. The device demonstrated a distinctive I - V curve and the ionization voltages for the considered gases. Detected breakdown voltages were much lower than those reported in the literature for gas ionization sensors based on metallic nanowires.
Electropulse stimulation provides an energy-efficient means of excavating hard rocks through repeated application of high voltage pulses to the rock surface. As such, it has the potential to confer ...significant advantages to mining and drilling operations for mineral and energy resources. Nevertheless, before these benefits can be realized, a better understanding of these processes is required to improve their deployment in the field. In this paper, we employ a recently developed model of the grain-scale processes involved in electropulse stimulation to examine excavation of hard rock under realistic operating conditions. To that end, we investigate the maximum applied voltage within ranges of 120–600 kV, to observe the onset of rock fragmentation. We further study the effect of grain size on rock breakage, by comparing fine (granodiorite) and coarse grained (granite) rocks. Lastly, the pore fluid salinity is investigated, since the electric conductivity of the pore fluid is shown to be a governing factor for the electrical conductivity of the modeled system. This study demonstrates that all investigated factors are crucial to the efficiency of rock fragmentation by electropulsing.
In the wide pressure range of the pure nitrogen and sulfur hexafluoride with small admixture of nitrogen (2,5%) the development of the breakdown during the formation of diffuse discharges initiated ...by runaway electrons and X-Ray was investigated. Nanosecond voltage pulses of both polarities with an amplitude up to ~300 kV and risetime of ~0.5 ns applied across the discharge gap did provide sharply nonuniform electric field distribution. Estimations of average propagation velocity of the ionization wave in the nitrogen and mixture sulfur hexafluoride with nitrogen were performed on the basis of data on dynamics of radiation intensity of the second positive (2 + ) nitrogen system from various regions along of the longitudinal axis of interelectrode gap. Interrelation between the glow dynamics and the local value of the electric field strength has been defined. The results showed that the breakdown is developed in the form of the ionization wave propagating from the potential electrode with the highest concentration of the electric field to the flat-grounded one. In the regions near the grounded electrode practically simultaneous increasing of radiation intensity is registered, that indicates on a possible change of the breakdown mechanism in this part of the discharge gap.
In vacuum (<inline-formula> <tex-math notation="LaTeX">p < 10^{-2} </tex-math></inline-formula> Pa) at high dc voltage (>100 kV) and with long gap (>10 −3 m), the Fowler-Nordheim (FN) emission ...current between metallic anode and cathode has superimposed random bursts which often evolve into breakdown during the voltage conditioning process. Despite the effort made to get a solid understanding of these phenomena, a satisfactory explanation has not been so far attained. A novel approach is here presented based upon the hypothesis that the electrode surface is not an ideal metal but it is instead covered by a dielectric compound layer (oxides mainly). According to the model based on this approach, the process leading to the current burst is associated with electron depletion of the cathode layer due to FN-like emission. When the electric field inside the layer exceeds its dielectric strength, a microbreakdown and a burst of current take place. The equation ruling the current emission has been solved imposing quantum indetermination relations to a solution based on classical theory. It has been found that the bursts can end up into a full breakdown, provided the voltage is high enough to start the avalanche process at the anode.
Recent circuit driven electromagnetic particle in cell simulation of the United Nations University-International Centre for Theoretical Physics plasma focus device revealed regular oscillations in ...both the voltage and current profiles. The simulated voltage waveform agreed well with the experimental profile, where similar unaccounted oscillations were also observed. In this paper, the oscillations are attributed to the plasma inductance, whose value was calculated by circuit analysis and agreed reasonably well with the computed experimental value. A circuit simulation of the prebreakdown and postbreakdown phases, with the plasma inductance incorporated, reproduced with sufficiency accuracy the electromagnetic particle in cell generated waveforms and consequently confirmed our finding.
Basic understanding of the barrier properties of biological membranes can be obtained by studying model systems, such as planar lipid bilayers. Here, we study water pores in planar lipid bilayers in ...the presence of transmembrane voltage. Planar lipid bilayers were exposed to fast and slow linearly increasing voltage and current signals. We measured the capacitance, breakdown voltage, and rupture time of planar lipid bilayers composed of 1-pamitoyl 2-oleoyl phosphatidylcholine (POPC), 1-pamitoyl 2-oleoyl phosphatidylserine (POPS), and a mixture of both lipids in a 1:1 ratio. Based on the measurements, we evaluated the change in the capacitance of the planar lipid bilayer corresponding to water pores, the radius of water pores at membrane rupture, and the fraction of the area of the planar lipid bilayer occupied by water pores.planar lipid bilayer capacitance, which corresponds to water pores, water pore radius at the membrane rupture, and a fraction of the planar lipid bilayer area occupied by water pores. The estimated pore radii determining the rupture of the planar lipid bilayer upon fast build-up of transmembrane voltage are 0.101 nm, 0.110 nm, and 0.106 nm for membranes composed of POPC, POPS, and POPC:POPS, respectively. The fraction of the surface occupied by water pores at the moment of rupture of the planar lipid bilayer The fraction of an area that is occupied by water pores at the moment of planar lipid bilayer rupture is in the range of 0.1-1.8%.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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