High Voltage Electric Research Articles

BEHAVIOR OF THE SQUARE WAVE IN BIOLOGICAL STRUCTURES

This study is to experimentally investigate the behavior of quadratic waves in biological structures. Transcutaneous frequency stimulation was regulated so that the system provided high frequency and low electrical voltage to observe possible changes in deeper layers of the anatomical structure analyzed. Electrodes were positioned from the dermis and probing electrodes were positioned at the subdermal, intradermal, skeletal muscle, periosteum, endosteum, and medulla levels. A function generator connected to a digital oscilloscope produced a square wave of 33 kHz at 10µs pulse speed and voltage of 16 volts DC. A voltage decay was observed as the signal reached deeper layers of different tissues. However, the frequency of 33 kHz remained uniform even at the bone marrow level. This observation opens the way for the application of the square electronic frequency as a stimulus for drug activation.

Risk Assessment and Treatment Measures of Electrical High Voltage Test

Risk Assessment and Treatment Measures of Electrical High Voltage Test

Experimental Characterization and Dynamic Modelling of Electrical Cables

<div class="section abstract"><div class="htmlview paragraph">Electric high voltage (HV) cables are commonly used in electrified vehicles. These cables are well known for being potential flanking transmission paths for structure-borne sound in a broad frequency range and must therefore be included in the NVH design process. Although many different layouts exist automotive HV cables fundamentally exhibit a layered structure consisting of a conductive core covered by, in sequence, an isolating sheath, a wire mesh shield to minimize electromagnetic interference and an outer jacket. The conductive core consists of hundreds of thin copper or aluminum wires organized in strands which are wound in a helical pattern. An extensive measurement campaign was carried out to dynamically characterize different cable specimen in terms of multi-degree of freedom transfer impedances. It was shown that although the cable exhibits a direction-dependent Young’s modulus and loss factor suitable results could be obtained by modelling the conductive core using an isotropic multi-layer continuum model. The model was experimentally validated for a test case featuring strong dynamic coupling and showed encouraging results until 2 kHz.</div></div>

Thermodynamically metastable α-, ε- (or κ-), and γ-Ga2O3: From material growth to device applications

Gallium oxide (Ga2O3) has attracted tremendous attention in power electronics and ultraviolet photodetectors because of the large bandgap of 4.9–5.3 eV available to all polymorphs, as well as its high electric breakdown voltage. Recently, there has been increasing research interest in thermodynamically metastable phases such as α-, ε- (or κ-), and γ-Ga2O3, because they are predicted to exhibit superior properties compared with β-Ga2O3, the most stable phase of Ga2O3. For example, α-Ga2O3 (bandgap, Eg = 5.3 eV; expected breakdown field, Ec = ∼10 MV/cm) is expected to be a better potential candidate in power electronics than β-Ga2O3 (Eg = 4.5–4.8 eV; Ec = 8 MV/cm) because of its larger bandgap and higher breakdown field. Because these thermodynamically metastable phases cannot be grown using melt-growth techniques, they are grown heteroepitaxially on foreign substrates. We extensively illustrate the growth of these metastable phases and their alloys by employing various growth techniques and then discuss their doping and electronic properties. Finally, we emphasize their applications in devices, including power devices and solar-blind ultraviolet photodetectors.

Static High Voltage Actuation of Piezoelectric AlN and AlScN Based Scanning Micromirrors

Piezoelectric micromirrors with aluminum nitride (AlN) and aluminum scandium nitride (Al0.68Sc0.32N) are presented and compared regarding their static deflection. Two chip designs with 2 × 3 mm2 (Design 1) and 4 × 6 mm2 (Design 2) footprint with 600 nm AlN or 2000 nm Al0.68Sc0.32N as piezoelectric transducer material are investigated. The chip with Design 1 and Al0.68Sc0.32N has a resonance frequency of 1.8 kHz and a static scan angle of 38.4° at 400 V DC was measured. Design 2 has its resonance at 2.1 kHz. The maximum static scan angle is 55.6° at 220 V DC, which is the maximum deflection measurable with the experimental setup. The static deflection per electric field is increased by a factor of 10, due to the optimization of the design and the research and development of high-performance piezoelectric transducer materials with large piezoelectric coefficient and high electrical breakthrough voltage.

Enhancement of palm oil extraction yield by applying underwater shock wave pre-treatment at different voltage

The present work aimed to investigate the effect of underwater shock wave (USW) on palm oil yield. Palm fruits were prepared and treated by applying USW before oil extraction. Strong USWs were generated by discharging high electric voltage into water, and varying the supplied voltage in the range of 2 - 10 kV. Following USW treatment, two methods of palm oil extraction namely screw-press and solvent extraction were used to determine the oil yield. Oil yield extraction and microstructure morphology of palm mesocarp were also investigated. It was found that at 10 kV of the USW treatment, the highest yield of palm oil extraction through screw-press method was 66.35%, while the solvent extraction method yielded 70.38%, which were 3.1 and 6.3% improvement, respectively, as compared to the untreated extraction. Microstructure analysis by scanning electron microscope (SEM) of palm mesocarp showed that the oil cells had significant cracks on the surface following treatment with USW. This confirmed that the application of USW was effective in increasing palm oil yield extraction. With a reliable strength and repetition of the treatment, USW treatment is promising for practical application in the palm oil industry and also other plant oil extraction.

The Changes in GABA, GAD and DAO Activities, and Microbial Safety of Soaking- and High Voltage Electric Field-Treated Adzuki Bean Sprouts

The level of γ-aminobutyric acid (GABA) in nongerminated adzuki bean seeds is low, but it increases substantially during germination and sprouting. In this study, three seed treatments, including soaking (S), high voltage electric field (HVEF), and soaking plus HVEF (SHVEF), were used to examine their effects on sprout growth, sprout GABA content, sprout glutamate decarboxylase (GAD), and diamine oxidase (DAO) activities and microbial loads on 6-day-old adzuki bean sprouts. All the treatments enhanced sprout growth, increased sprout’s GABA, and increased sprouts’ GAD and DAO activities. The examined seed treatments also significantly reduced the microbial loads of the produced 6-day-old adzuki bean sprouts. The most effective treatment that improved the morphological and biochemical traits and reduced microbial loads on produced sprouts was the SHVEF treatment. SHVEF treatment also achieved a 5-log reduction in the microbial loads of total aerobic bacterial counts, total coliform counts, and total mold counts on the produced adzuki bean sprouts. Therefore, SHVEF is effective for increasing adzuki bean sprout production. It can also be used to improve nutritional quality and provide an intervention technique against microbial contamination on produced sprouts.

Enhanced Electromechanical Response in PVDF-BNBT Composite Nanofibers for Flexible Sensor Applications.

Wearable energy harvesters and sensors have recently attracted significant attention with the rapid development of artificial intelligence and the Internet of Things (IoT). Compared to high-output bulk materials, these wearable devices are mainly fabricated by thin-film-based materials that limit their application. Therefore, the enhancement of output voltage and power for these devices has recently become an urgent topic. In this paper, the lead-free bismuth titanate-barium titanate (0.93(Na0.5Bi0.5)TiO3-0.07BaTiO3(BNBT)) nanoparticles and nanofibers were embedded into the PVDF nanofibers. They produced high inorganic electrical voltage coefficients, high electromechanical coupling coefficients, and environmentally friendly properties that enhance the electromechanical performance of pure PVDF nanofibers, and they are all the critical requirements for modern flexible pressure sensors. In detail, PVDF and PVDF-based composites nanofibers were prepared by electrospinning, and different flexible sandwich composite devices were fabricated by the PDMS encapsulation method. As a result, the six-time enhancement maximum output voltage was obtained in a PVDF-BNBT (fiber)-based composite sensor compared to the pure PVDF one. Our results indicate that the output voltage of the pressure sensors has been significantly enhanced, and the development gate is enabled by analyzing the related physical process and influence mechanism.

Three-Level Reduced Switch AC/DC/AC Power Conversion System for High Voltage Electric Vehicles

Two of the main challenges of recent electric vehicles (EVs) are the charging time and high initial cost. To solve the problem associated with long charging time, the car manufacturers are moving from 400 V battery EV (BEV) to 800 V BEV, which enables the utilization of multi-level converters in EV applications. This paper presents a power conversion system consisting of a Vienna rectifier and a two/three level hybrid inverter as a machine-side inverter to drive a permanent-magnet synchronous motor (PMSM). The Vienna rectifier improves the quality of the grid-side current and provides a regulated DC-link voltage. The proposed inverter, known as a 10-switch inverter, offers high output current quality with a lower number of active switches, making it compact and cost-effective. The field-oriented control (FOC), along with the SPWM modulation, is implemented to control the system. A reliable and cost-effective PMSM drive system demands sensorless control; therefore, a sliding mode observer (SMO) is used to estimate the rotor position and velocity. The accuracy of the proposed system was proved through the simulation results from MATLAB/Simulink.

Dielectric Properties of Electrical Insulating Liquids for High Voltage Electric Devices in a Time-Varying Electric Field

The motivation to improve components in electric power equipment brings new proposals from world-renowned scientists to strengthen them in operation. An essential part of every electric power equipment is its insulation system, which must have the best possible parameters. The current problem with mineral oil replacement is investigating and testing other alternative electrical insulating liquids. In this paper, we present a comparison of mineral and hydrocarbon oil (liquefied gas) in terms of conductivity and relaxation mechanisms in the complex plane of the Cole-Cole diagram and dielectric losses. We perform the comparison using the method of dielectric relaxation spectroscopy in the frequency domain at different intensities of the time-varying electric field 0.5 kV/m, 5 kV/m, and 50 kV/m. With the increasing intensity of the time-varying electric field, there is a better approximation of the Debye behavior in all captured polarization processes of the investigated oils. By comparing the distribution of relaxation times, mineral oil shows closer characteristics to Debye relaxation. From the point of view of dielectric losses at the main frequency, hydrocarbon oil achieves better dielectric properties at all applied intensities of the time-varying electric field, which is very important for practical use.

Heat transfer enhancement on saturated porous samples using electrostatic precipitator process in k-ε turbulent model

An influence of the electrostatic precipitator process was numerically investigated for heat transfer enhancement on saturated porous samples in a k-ε turbulent model. The condition of the water entering a test section was the inlet temperature was 30 oC (303 K), and inlet velocity was tested in the range of 1 – 2.5 m/s. The electrical voltage and time varied between 0 – 30 kV and 0 – 1 s, respectively. The initial temperature of saturated porous samples was 10 oC (283 K), and both first and second samples were set in semicircle shapes. The numerical results within the water channel showed that the electric field and electric potential zone appeared and were concentrated when using the electrostatic precipitator process. The high electric voltage could increase disturbance and turbulence within the water channel. The maximum flow field zone appeared above the saturated porous sample area, and the maximum velocity field increased with the inlet velocity and electrical voltage. The maximum pressure was increased to the high voltages, but the pressure was marginally increased with high inlet velocity. The vorticity contour for an electrostatic precipitator process was more concentrated than without the electrostatic precipitator process. Therefore, the temperature contour line in case of high inlet velocity, electrical voltage, and time can be more disturbing than the other cases. In addition, heat from the water was transferred within the sample, so the temperature within the porous sample gradually increased. The fluid velocity within the front porous sample was more within the saturated porous samples than within the porous back sample. Therefore, the flow could move through and within the samples and induce temperature within both saturated porous samples. Finally, the heat transfer within samples was enhanced by fluid flow in the water channel, so the local heat transfer coefficient within samples was induced by the fluid velocity in the water channel.

Review of High Power and High Voltage Electric Motors for Single-Aisle Regional Aircraft

This paper presents a review of the state of the art in electric propulsion for regional aircraft in the MW range. The implications surrounding the implementation of this technology, such as the need of high-power density or the use of high-voltage at high-altitude, are presented. Along with the challenges, the available technologies to face them are reviewed. Those are, as follows, the emerging new motor topologies for this purpose, the winding technologies, the materials employed for electric motors for aircraft propulsion and the ground-breaking use of high-temperature superconductors (HTS) as a high-power density enabler. Finally, a conclusion is presented gathering the main ideas of the paper.

Hydrophobic Poplar Prepared via High Voltage Electric Field (HVEF) with Copper as Electrode Plate

In order to improve hydrophobic characteristics which will affect the service performance of fast-growing poplar due to growing bacteria in the humid environment. In this study, a simple method was proposed to treat poplar via the high voltage electric field (HVEF) with copper as the electrode plate. Scanning electron microscope (SEM), Fourier transforms infrared spectroscopy (FTIR), X-ray diffraction (XRD) and contact angle tester were adopted to evaluate the surface morphology, surface group of poplar, crystallinity and wettability under HVEF. It was found by SEM that a large number of copper particles were uniformly attached to the surface of poplar. In all three sections, the weight percentage of the Cu element was accounting for more than half. The diffraction peaks of copper-containing compounds appeared in the (XRD). FTIR analysis confirmed that the reaction between copper and poplar took place. The surface contact angle of three sections of poplar increased in the following order: cross section < radial section < tangential section (increased by 34°, 45° and 53°, respectively). An environmentfriendly and efficient method of HVEF treating fast-growing wood with copper as the electrode plate can promote its outdoor application.

Investigation on Energy Characteristics of Shock Wave in Rock-Breaking Tests of High Voltage Electric Pulse Based on Hilbert-Huang Transform

Investigation on Energy Characteristics of Shock Wave in Rock-Breaking Tests of High Voltage Electric Pulse Based on Hilbert-Huang Transform

Electric Potential Value of Microbial Fuel Cell Technology from Chinese Food Restaurant Waste Using Variation of Electrode Pairs

Indonesia's rapid population growth means that power demand will continue to rise year after year. Indonesia's growing population has resulted in an increase in restaurants, including Chinese food restaurants. As the number of restaurants grows, so does the amount of waste produced. Microbial Fuel Cells (MFC) that create electrical energy are one solution to this challenge. The study aimed to explore the utilization of MFC systems for power generation. It measured the performance of MFC in liquid waste in generating electrical value by utilizing a series of electrode types, particularly Aluminum (Al), Copper (Cu), Zinc (Zn), and Lead (Pb), and a blend of the four types of electrodes. The measured electrical value indicated that MFC can produced the high electrical voltage value was the pair of zinc (anode) and copper (cathode) of (0.863 V) and then the highest electric current value is 0.14 mA with electrode Cu and Zn. The maximum power density is 0.00464 W/m2 using a combination of Zn/Cu electrodes and then electrical energy with highest value is 0.75168 J with Zn/Cu.

Study on Common Abnormal Analysis and Treatment Measures in High Voltage Electric Test of Power Plant

Study on Common Abnormal Analysis and Treatment Measures in High Voltage Electric Test of Power Plant

Analysis of Some Problems Easily Neglected in High Voltage Electric Test of Power Plant

Analysis of Some Problems Easily Neglected in High Voltage Electric Test of Power Plant

Ultralight NiCo@rGO aerogel microspheres with magnetic response for oil/water separation

Improving the adsorption capacity of the adsorbent and realizing rapid separation are quite important for water treatment. Herein, one kind of novel Ni/Co-contained reduced graphene oxide aerogel microspheres (rGOAMs-M) with high surface area and magnetic response are synthesized by a novel process comprised of electrospraying, droplets spherification, crosslinking immobilizing of metal, lyophilization and thermal reduction. The aqueous dispersion mixture of graphene oxide and sodium alginate is electrosprayed under high electric voltages to produce droplets, which are collected in a nickel/cobalt acetate tetrahydrate solution and then crosslinked between alginate and metal ions. The obtained rGOAMs-M have the cabbage-like inner structures, and possess the organic solvent/oil adsorption capacities of 107–270 g.g−1 and also extraordinary oil/water emulsion separation ability. The rGOAMs-M also can be rapidly assembled and separated from the medium under a magnetic field.

3D printed bidirectional rotatory hybrid nanogenerator for mechanical energy harvesting

In the world of automotive technologies, a tremendous amount of small-scale rotational energy is wasted and not being converted into a usable energy form. A rotatory triboelectric nanogenerator can be a fortune technology to harvest such waste mechanical energy and convert it into electricity. In this regard, we developed a fully three-dimensional (3D) printed bidirectional rotatory hybrid nanogenerator (BR-HNG) to convert waste rotational energy into electricity, via a contact and separation mode mechanism. Initially, a single HNG was fabricated with porous sodium niobate and polydimethylsiloxane polymer (i.e., NaNbO3/PDMS) composite film, which was operated vertically against the aluminum to optimize a high and stable electrical output. After the robust and stability test of the single HNG, multiple HNGs were integrated into a 3D printed bidirectional rotatory frame to harvest the rotational energy. It was observed that the BR-HNG had a stable and high electrical direct current voltage of 37.5 V. Furthermore, the BR-HNG was attached to a bicycle to harvest the rotational energy while bicycling in everyday human life and power up various portable electronics.

Increased density of high electric voltage lines causing hazardous effect on plants

Environmental effect of power distribution lines includes loss of vegetation, loss of agricultural lands and altered human and animal activity. However, the hazardous effect of power lines on the individual growth, metabolism, yield and reproduction of plants has not been studied in detail. Current understanding confirms that the vicinity of power lines can alter plant life because of static electric field. These effects include altered growth, burning of plant parts, altered biochemical parameters such as (i) Mechanical damage (ii) Altered growth (iii) Reduced seed germination (iv) Altered respiration parameters (v) Altered biochemical parameters such as changes in elemental concentration, enzymatic activity, chlorophyll content and phenol content (vi) Altered membrane functions and (vii) Altered cell cycle. However, the effect of proximity of power lines on the most significant molecular parameters such as DNA replication, transcription and translation and DNA repair activity has not been studied.