External Discharge Research Articles

Dielectric Barrier Corona Activation of Electrical Discharge in a Cavitating Liquid.

Water treatment methods based on cold plasma discharge in cavitating liquid have been actively developing in recent years. However, some conditions, such as the conductivity of the medium, can limit the possibility of plasma ignition. The authors proposed a new method for activating an electric discharge in a cavitating liquid environment based on the use of an external corona discharge electrode in the plasma reactor. It has been experimentally shown that, in such a configuration, the breakdown voltage is significantly reduced. A theoretical analysis of the process was carried out, and a modified Paschen's curve was constructed on the basis of experimental data. The following graph shows the basic diagram of the setup and plasma reactor: 1, input water tank; 2, pump; 3, reactor; 4, generator; and 5, output tank. "Gap 0" expresses the gap between the two ring electrodes, and "gap" expresses the gap between the corona electrode and the lower ring electrode.

Study on the Oil-Water Separation Performance of Axial-Flow Hydrocyclone Enhanced by Condensate Bubbles

Abstract Produced water is the main by-product of the oilfield extraction process. Due to its high emulsification degree and density close to water, micron oil droplets are inefficiently separated by ordinary cyclone, and it is difficult to meet the standards of external discharge and reinjection after treatment. In this study, micron bubbles were prepared by mixing hydrocarbon components as gas and passed into the cyclone separator to enhance the oil-water separation effect. After the bubbles entered the cyclone, due to the pressure environment inside, the heavier components in the bubbles were found to condense and precipitate from the bubble surface, while the lighter components did not undergo phase change. The heavy hydrocarbons condense and spread out in the bubble and form a condensate film, because the condensate and oil droplets belong to the hydrocarbon homologue is easier to capture the oil droplets. This technology realizes the modification of lipophilic and hydrophobic surface of the bubbles. After the oil removal experiments found that the traditional axial cyclone separator separation of 65%, through the ordinary bubble assisted separation efficiency of 74%, and through the preparation of condensate bubbles to enhance flotation can be raised to 89% of the oil removal efficiency. Therefore, the condensate bubble-enhanced cyclone separator oil-water separation has a good application prospect.

An example of a wastewater treatment project for high concentrations of benzene, xylene, acetophenone, and DOPO generated in the production of phosphorus flame retardant

ABSTRACT Wastewater generated in the production of phosphorus flame retardants contains benzene, xylene, acetophenone, and 9, 10-dihydro-9-oxa-10-phosphoxanthine-10-oxide (DOPO) with larger benzene rings, which are more difficult to biodegrade directly. In this study, the wastewater generated in the production of phosphorus flame retardants applied for high-temperature nylon and reactive phosphorus flame retardant was first treated by the combined process of lime emulsion–flocculation reaction and precipitation–ozone oxidation reaction for degradation of benzene, xylene, acetophenone, and DOPO, and then processed by the secondary combined process of upflow anaerobic sludge bed anaerobic digestion–air flotation–membrane bioreactor bio-contact oxidation; thus, the final concentration of pollutants in the wastewater can reach the relevant limit either for external discharge or as the supplemental water for other production devices. In addition, the detailed chemical degradation mechanisms and removal effects of benzene, xylene, acetophenone, and DOPO in an ozone reactor were explored. After the project had been normally operated for half a year, the test results of the effluent were as follows: chemical oxygen demand, 50 mg/L; BOD5, 20 mg/L; NH3-N, 5.0 mg/L; total phosphorus, 0.5 mg/L; benzene ≤ 0.1 mg/L; xylene ≤ 0.4 mg/L; acetophenone ≤ 0.4 mg/L; and DOPO ≤ 0.02 mg/L. Ultimately, the cost was 2.1 $/m3. It provides a useful process for wastewater treatment related to phosphorus flame retardants.

Effect of Cell-to-Cell Internal Resistance Variations on the Thermal Performance of Lithium-Ion Batteries for Urban Air Mobility

This study examines the thermal behavior of lithium-ion battery modules intended for Urban Air Mobility (UAM), a forthcoming urban transport system designed to facilitate efficient and secure passenger and cargo transport within city centers. UAM applications necessitate batteries with high energy densities capable of sustaining elevated discharge rates during critical phases such as takeoff and landing. The battery module evaluated in this study comprises four cells arranged in series and configured as a submodule for UAM applications. A three-dimensional thermal model was utilized to analyze the impact of external temperature fluctuations and high discharge rates on the performance of the battery module. The numerical findings indicated considerable variations in temperature and internal resistance among the cells, especially under high discharge rates at low temperatures, with a maximum temperature deviation of 32.952 °C observed at an 8 C discharge rate. These thermal non-uniformities were attributed to variations in cell capacity and internal resistance, which were amplified by manufacturing inconsistencies and operational conditions. The study underscores the necessity of robust thermal management strategies to mitigate the risk of thermal runaway and ensure the operational safety and reliability of UAM systems. The results emphasize the critical role of advanced Battery Management Systems (BMS) in monitoring and controlling cell voltage and temperature to achieve consistent performance across the battery module. This research contributes valuable insights into the design of more efficient and reliable battery modules for UAM, highlighting the importance of addressing cell-to-cell performance discrepancies to enhance overall module efficacy and durability.

Clinical outcome of cats with suppurative otitis media and intact tympanum submitted to myringotomy: retrospective findings from 26 cases.

The efficacy of medical treatment associated with single myringotomy in cats with suppurative otitis media (OM) and intact tympanum was retrospectively evaluated. Patients' records were retrieved from cats with suppurative OM. Cats were included in this retrospective study based on fluid content within the tympanic cavity on imaging, intact tympanum on otoendoscopic examination and neutrophils on ear bulla exudate cytological examination. A total of 26 cats with middle ear suppurative otitis were included. Just over half of the cats (54%) presented bilateral involvement. Clinical signs included head tilt (13/26), otalgia (9/26), Horner's syndrome (7/26), external ear discharge (5/26), and nystagmus and facial paralysis (1/26). Cocci were identified on cytological examination in 18/40 samples and rods in 2/40. Bacterial culture results were positive in 15/40 samples, with Pseudomonas species (4/15), Pasteurella multocida (3/15), Staphylococcus felis (3/15), Staphylococcus schleiferi (2/15), Staphylococcus canis (2/15), Escherichia coli (2/15), Staphylococcus pseudintermedius (1/15) and Serratia marcesens (1/15) isolation. After myringotomy and gentle flushing of middle ear bullae (0.5-2 ml saline per ear), all cats were treated with oral corticosteroids and a 1-month course of systemic antibiotics according to sensitivity testing. In total, 19 (73%) cats were clinically healed 60-240 days after treatment. One cat was euthanased because of failure to eradicate a Pseudomonas species infection. Another cat died a few hours after the procedure. The five remaining cats were cured after ventral bulla osteotomy. OM without an aural polyp is a frequent diagnosis in cats, but data on medical treatment are scarce. This simple therapeutic technique, single myringotomy procedure and mild ear flushing, offers a practical, safe and efficient first-line treatment of suppurative OM with an intact tympanum in cats with or without neurological signs.

Tribocharged solids in protoplanetary discs: internal and external discharge time-scales

ABSTRACT Particles regularly tribocharge in collisions. Here, we study how long charges can persist on such particles in the environment of a protoplanetary disc. We set up three complementary experiments to quantify discharge time-scales. We first directly measure the time dependency of charge on triboelectrically charged objects. For this aspect, we performed two long-time experiments under different environmental conditions. We find that the charge persists on the tribocharged bodies on time-scales between minutes and years. Discharge might be mediated by external ions or internally, by conduction. To constrain the latter, we also determined the specific electric resistance of dust samples as simulants for dust aggregates in protoplanetary discs. In this third experiment, we see an increase in resistivity at decreasing ambient pressure up to the limit of the instrument. These findings are consistent with the assumption that water on all relevant surfaces including dust grains within the pore space of aggregates is the main driver of discharge. Under disc conditions, the charge might persist for weeks to years. This leaves net-charged isolated grains in dense parts of the mid-plane of protoplanetary discs charged in between collisions.

Heat Metrics and Maternal-Child Health Diagnoses in Emergency Departments in the United States: A Scoping Review.

To summarize current research on associations between heat metrics and emergency department discharge diagnoses for US pregnant women and children from birth to age 18 via a scoping review. Climate change directly contributes to extreme weather conditions and environmental changes and indirectly affects health and the health care system. Pregnant women and children are believed to be more susceptible to extreme heat, but few empirical studies have been conducted evaluating effects of heat metrics on these populations. Ovid MEDLINE, CIHAHL, SCOPUS, Web of Science, JSTOR, and PsycINFO databases were searched using a combination of key words. Twelve studies were selected for this review. In pregnant women, positive associations were found between mean daily temperature and multiple subtypes of pregnancy complications, including threatened or spontaneous abortion, renal diseases, infectious diseases, diabetes, and hypertension. In children, positive associations were found with all-cause diagnoses; asthma; dehydration; electrolyte disorders; heat-related illness; infection; endocrine, nutritional, and metabolic diseases; injury; and otitis media and external emergency department discharge diagnoses and temperature or heatwave versus non-heatwave. By tracking associations between maternal-child emergency department discharge diagnoses and various heat metrics, researchers can contribute to better clinical practices that promote environmental justice and climate resilience.

Antifungal Susceptibility Pattern of Fungi Isolated from Patients with Otomycosis Attending a Tertiary Health Care Institution in Sokoto, Nigeria

Abstract Background: Antifungal therapy is an important component of patient management for acute and chronic mycoses. However, treatment choices are restricted because of the scanty number of antifungal drug classes. Medical treatment of otomycosis is further compromised by the emergence of antifungal drug resistance, and these limits available drug classes as treatment options. Once considered a rare occurrence, antifungal drug resistance is on the rise in many high-risk medical centers. Most concerning is the evolution of multidrug-resistant organisms refractory to several different classes of antifungal agents, especially among common Candida species. Aim: This study seeks to identify the fungal species implicated in otomycosis among patients attending a tertiary health-care institution in Sokoto, Nigeria and determine its susceptibility pattern using commonly used antifungal agents. Methods: A descriptive, cross-sectional, hospital-based study was conducted on 100 patients with otitis externa. The ear discharge specimens were collected and analyzed using the standard microbial techniques. The antibiotic susceptibility profiles were determined for 12 different antifungal by the standard disk diffusion method. Data were analyzed using the SPSS software version 25 and the P < 0.05 was considered as statistically significant. Results: One hundred and twenty-four external ear discharge samples were collected from either right ear, left ear, or both ears (some patients has unilateral while others have bilateral disease and those with bilateral disease, samples were taken from the two ears). Aspergillus niger 30 (40.0%) was the most commonly isolated fungi in this study, followed by Candida spp. 25 (33.3%), Aspergillus fumigatus 5 (6.7%), Mucor 5 (6.7%), Penicillum 4 (5.3%), Aspergillus flavus 3 (4.0%), and Rhizopus 3 (4.0%) %). The isolated fungi were tested for antifungal sensitivity to 6 antifungal discs. A. niger shows good susceptibility to clotrimazole (100%), nystatin (90%), and fluconazole (83.3%) but was resistant to griseofulvin, terbinafine, and ketoconazole. A. flavus and A. fumigatus also show good sensitivity to clotrimazole, nystatin, and fluconazole. Candida albicans was only susceptible to clotrimazole but resistant to other tested antifungal disc. Rhizopus and Penicillum species showed 100.0% sensitivity to clotrimazole but also resistant to other tested antifungal discs. Conclusions: This study revealed that Aspergillus and Candida species were the most common fungal pathogens causing otomycosis. A. niger is the predominant fungal isolate. Molds isolates showed good susceptibility to clotrimazole, while highest resistance was to terbinafine and ketoconazole. Yeasts isolates showed highest susceptibility to clotrimazole and highest resistance to nystatin and fluconazole.

Método para inspeção de sistemas de proteção de descargas atmosféricas: Plantas de armazenamento de grãos

ABSTRACT Brazil has the highest incidence of atmospheric discharges, on average of 77.8 million hitting the country yearly. Companies providing post-harvest services have a high monetary value concentrated in their predominantly metallic structures. Atmospheric discharge protection systems (ADPS) are used in this context to protect the facilities and people, composed of several elements that require visual inspection with a certain periodicity, an activity framed as working at height. This research aimed to establish a methodology for employing a Remotely Piloted Aircraft System (RPAS) in the visual analysis of the operational condition of external atmospheric discharge protection systems components located in grain storage structures to collect information during the preliminary risk analysis and planning of activities at height. A survey of the current literature related to the subject was carried out, in addition to the norms, inspection agencies, and operational prerequisites of this type of equipment in the national territory. Finally, a method was created and validated based on the inspection checklist with the main points for checking, which generates a score that represents the urgency level of intervention, applied in a unit located in western Paraná, Brazil, on 11/28/2022. This procedure eliminated the risk of workers falling during the planning and inspection stage of the structures, which helped the qualified professional to issue the technical inspection report more quickly. The disadvantage is related to the dependence on favorable weather conditions.

Bacteriology of Otitis Externa in a Tertiary Health-care Institution in Nigeria

Abstract Background: Otitis externa is the inflammation of the external auditory canal (EAC); it may be acute, subacute, or chronic in nature and the causative agents are usually bacteria, though occasionally fungi. Aim: This study aimed to determine the prevalence of bacterial acute otitis externa (AOE) and the pattern of bacterial isolates in AOE. Material and Methods: This was a cross-sectional, hospital-based study involving 100 patients with otitis externa. Patients were recruited from ear, nose, and throat (ENT) outpatient clinic using consecutive sampling technique until the required sample size was achieved. The discharge from discharging ears was taken with ear swabs and evaluated for microbial agents. Data analysis was done using SPSS-IBM version 25. Results: A total of 100 patients were recruited; the patients aged from 4 to 57 years (mean age is 18.78 ± 10.67) years, with a male-to-female ratio of 1:1.1. One hundred and twenty-four external ear discharge samples were cultured among 100 study groups, of which bacteria was isolated in 77 (62.1%) and no bacterial agent was isolated in 47 (37.1%). Pseudomonas aeruginosa 32 (41.6%) was the most common bacteria isolated, followed by Staphylococcus aureus – 13 (16.9%); others include Proteus mirabilis – 7 (9.0%), Escherichia coli – 4 (5.2%), Streptococcus pneumonia – 4 (5.2%), Klebsiella pneumoniae – 3 (3.9%), Streptococcus pyogenes – 3 (3.9%), and Enterobacter aerogenes – 2 (2.6%). Conclusion: Otitis externa affects all age groups and genders; bacteria are a more prevalent causative agent. The common predisposing factors are the use of objects in scratching or cleaning EAC, use of earpiece, and swimming. The prevalence of bacterial otitis externa was 7.1%, and Gram-negative aerobes are the most prevalent.

Characteristics of argon discharge plasma jet: comprehensive effects of discharge voltage, gas flow rate, and external magnetic field

Atmospheric pressure plasma jet has received widespread attention due to its enormous potential applications in various fields, and its discharge conditions play a key role in changing their physical and chemical properties and ultimately determining its application effectiveness. Factors such as discharge voltage, gas flow rate, and the introduction of an external magnetic field intricately influence the performance of plasma jet. The combined effects of any two of these factors can yield enhanced outcomes, while also bringing complexity to the discharge phenomenon. However, there is currently a lack of research on the combined effects of external magnetic field, discharge voltage, and gas flow rate on the characteristics of plasma jets, making it difficult to comprehensively evaluate the discharge characteristics of plasma jet under multiple discharge conditions. Therefore, this paper focuses on an AC excited atmospheric pressure argon plasma jet and investigates the combined effects of external magnetic field, discharge voltage, and gas flow rate on various characteristic parameters of the plasma jet, including macroscopic morphology, discharge power, gas temperature <i>T</i><sub>g</sub>, electron excitation temperature <i>T</i><sub>exc</sub>, electron density <i>n</i><sub>e</sub>, emission intensity of excited state Ar* particles, and number density of ground state ·OH particles by using methods of camera shooting, and electrical parameter measurement, spectroscopic analysis of emission and absorption spectra. The obtained results are shown below. The effect of discharge voltage on the characteristic parameters of the plasma jet is not affected by gas flow rate or the existence of an external magnetic field. The increase of discharge voltage can improve jet performance by enhancing the discharge power, extending the plasma plume length, elevating the gas temperature <i>T</i><sub>g</sub> and electron excitation temperature <i>T</i><sub>exc</sub>, increasing the electron density <i>n</i><sub>e</sub> and emission intensity of excited state Ar* particles, as well as the number density of ground state ·OH particles. The addition of an external magnetic field can improve the jet performance without significantly changing the discharge power, and the extent of this improvement is influenced by the mode of magnetic field action. Notably, the enhancement of jet performance is most significant when the magnetic field selectively targets the plasma plume, excluding direct interaction with electrode discharge region. The effect of gas flow rate on jet performance becomes intricate: it is intertwined with the effect of voltage and the effect of external magnetic field. When an external magnetic field is present, excessive voltage and gas flow rate may reduce the number density of ground state ·OH particles generated by plasma jet. This underscores the need for a detailed understanding when optimizing jet performance under various discharge conditions. Simply combining the optimal conditions for each individual factor does not guarantee the achievement of peak jet performance when all three discharge conditions work synergistically. This study presents valuable insights into the discharge characteristics of plasma jet under different discharge conditions, providing guidance for optimizing the performance of plasma jet and promoting the advancement of atmospheric pressure plasma jet technology in different application fields.

Research on key influencing factors and mechanisms of improved nitrogen fixation efficiency in magnetic-driven gliding arc

Gliding arc is considered to be an efficient method for nitrogen fixation. In this study, an improved magnetic-driven rotating gliding arc method was adopted to investigate the effects of gas flow rate, current, magnetic field, nitrogen-to-oxygen ratio in the working gas, and relative humidity on nitrogen fixation efficiency. To further understand the relationship between the discharge mechanism and nitrogen fixation efficiency, the arc length, arc diameter, arc rotation frequency, and reaction pathway were studied to find the relationship between external parameters, discharge characteristics, and nitrogen fixation efficiency. The research results indicate that the discharge current and magnetic field not only change the rotation frequency of the gliding arc, but also affect its length and diameter, and the amount of ionizing gases involved in the working gas, thus affecting nitrogen fixation efficiency. When the nitrogen volume ratio in the feed gas is 60%, the lowest energy cost can be achieved, which is 18.6% lower than that of air. The energy cost of nitrogen fixation is closely related to the humidity of the air. As the humidity increases, the energy cost also increases. At the magnetic field strength of 160 mT, gas flow rate of 10 l min−1, and current of 40 mA, the energy cost of 1.708 MJ mol−1 is realized which is the current lowest for plasma nitrogen fixation in this study.

Planning and Design Strategies for Green Stormwater Infrastructure from an Urban Design Perspective

With the rapid advancement of ecological civilization construction, prioritizing green stormwater infrastructure to address urban stormwater management issues has become an important strategy for ecological priority and green development in sustainable urban development. Green stormwater infrastructure, as a major facility in the construction of sponge cities, can reduce the generation and external discharge of runoff and play a purification role. However, there are various types of green stormwater infrastructure, each with different control effects and applicable conditions. Therefore, to facilitate the planning, design, acceptance, assessment, and monitoring evaluation of sponge city green stormwater infrastructure, this study proposes the “sponge equivalent” method. By comparing the control effects of different facilities with bioretention facilities, the method standardizes the effects, making them easier to understand and apply. Taking a typical area of Beijing and its urban roads as examples, the study analyzed and applied planning and design control strategies. The results show that for a residential area of 1 km2, to achieve the annual runoff total control rate target of 85%, the method of converting runoff volume control equivalents, using bioretention pools as a benchmark, allows for the calculation of various combinations of areas of different types of green stormwater infrastructure, such as sunken green spaces, permeable paving bricks, green roofs, and water storage tanks. This optimizes the planning index of Beijing, which mandates stormwater detention facilities for new projects with a hardened surface area of 2000 m2 or more. The sponge equivalent method can optimize the planning and design control strategy of green stormwater infrastructure, allowing for rapid assessment and application of the design scale of green stormwater infrastructure in areas during the planning and design stage, providing theoretical and technical support for ecological and green urban stormwater management. The application of this research method helps promote green development and ecological priority in urban sustainable development strategies, and the conclusions provide valuable references for decision-makers and practitioners in related fields.

A sustainable, high-quality method for machining film cooling holes: Cryogenic airflow-assisted electrochemical discharge drilling

Film cooling hole is an essential part of aero-engines, necessitating without recast layer, no stray corrosion, and high machining efficiency. Its sustainable manufacturing has been at the forefront of industrial focus. Existing machining methods have problems such as low efficiency and environmental hazards. In order to achieve the production requirements of precision, quality, and green simultaneously, an external cryogenic airflow-assisted electrochemical discharge drilling (ECDD) is proposed. Compared with the current electrochemical drilling (ECD) or electrical discharge drilling (EDD), a glycol working fluid with ultra-low conductivity neutralizing salt replaces the high conductivity of acidic solution or spark oil to realize green machining without a recast layer. Compared to existing ECDD, the introduction of cryogenic gas with glycol can significantly reduce stray corrosion and achieve exceptionally high surface quality. In the theoretical part, the influence mechanism of a low-temperature environment on the electrochemical interface was analyzed by using the electrochemical analysis technique. In addition, a multi-physical field simulation model was established, which was finally verified by experiments. Finally, the surface characteristics were analyzed by using TEM. The results demonstrate that the cryogenic environment enhances the passivation effect, as evidenced by a 35% reduction in taper at 258 K and a 28.2% decrease in stray corrosion. The hole side has nano-roughness (Ra 0.512 μm). Notably, the material removal rate does not significantly diminish at low temperatures and achieves 0.1 mm/s, superior to EDD. As there is no need for an additional machining step after drilling, this method proves its characteristic to attain sustainability, efficiency, and high quality, indicating promising application prospects.

Electrophysical Parameters and Emission Spectra of the Glow Discharge of Difluorodichloromethane

The effect of the external discharge parameters on the electrophysical parameters and emission spectra of difluorodichloromethane plasma is analyzed. Data on the reduced electric field strength and gas temperature are obtained. It is established that the reduced electric field strength in difluorodichloromethane plasma decreases markedly with increasing gas pressure (at a constant discharge current). It is shown that a linear increase in the gas temperature with increasing pressure is due to the increase in the specific power deposited in the discharge. Atomic and molecular components are found in the emission spectra of the glow discharge of difluorodichloromethane. It is established that, with increasing current, a linear increase in the radiation intensity occurs, which corresponds to the mechanism of the direct excitation of the radiating states upon electron impact and indicates the absence of secondary processes.

Demonstrating the application of batch anaerobic digestion recirculating slurry inoculation of food waste engineering from a microbiological perspective

In this study, the food waste recycled slurry was mixed inoculated with the discharge of the biogas station, and the effect of inoculation ratio and circulating batch on the performance of the system was studied for 2 t/d food waste anaerobic digestion to demonstrate engineering applications. The results showed that a proper proportion of the digestion slurry cycle can promote dehydrogenase activity in the system, and the activity of methanogens and the content of coenzyme F420 gradually increase with the increase of the cycle batch. Under the optimal mixing ratio (50% slurry volume ratio, R50), the time for anaerobic digestion of food waste to reach 90% of the total cumulative methane output can be shortened to 13 days, and the cumulative biogas output is as high as 16.96 L. The value of the kinetic constant k increases with the number of refluxes, and finally reaches 0.114 d−1. The microbial community gradually succeeds in an appropriate direction. The VFA and alkalinity content in the system together affects the composition of Firmicutes, Bacteroides, and Chloroflexus in the system. These results will help increase the utilization rate of biogas slurry, reduce its external discharge, and improve the performance of batch anaerobic digestion engineering applications.

Application of a Rogowski Coil Sensor for Separating Internal and External Partial Discharge Pulses in Power Transformers

Partial discharge (PD) measurement is an essential tool for evaluating the health condition of a transformer insulation system. The Conventional PD measurement systems have a major drawback since they cannot discriminate the internal PD pulses and external pulse-shaped interferences, especially in online and on-site conditions. Various de-noising techniques (e.g. wavelets) have been also used in the literature, which is effective for extracting the PD signal from the noisy signals or classifying the PD types. However, the PD pulses and some of the randomly external pulse-shaped interferences have similar time-frequency characteristics, which makes them difficult to separate. In this paper, a new cost-effective and simple logic method is proposed for the separation of these interferences. This uses the polarity comparison of the output voltages of the Rogowski Coil (RC) sensor, mounted on the bushing, and measurement impedance, connected to the test tap. The same polarity represents the internal pulse, while the opposite polarity indicates the external pulses. A distribution transformer ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$20/0.4\ {\bm{kV}},\ 500\ {\bm{kVA}})$</tex-math></inline-formula> and a condenser bushing ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$72.5\ {\bm{kV}})$</tex-math></inline-formula> were considered to evaluate the performance of the proposed system. The results confirm the effectiveness of the proposed PD measurement system for separating the pulses.

Effect of radial scaling down on the performance of low-power external discharge plasma thrusters

The external discharge plasma thruster removes the annular channel of the traditional Hall thruster, allowing the ionization region to appear outside the thruster, which is expected to reduce the plasma-wall interaction and extend the thruster lifetime. Due to its simpler structure and lighter weight, the external discharge plasma thruster is expected to be scaled down to lower power levels. In this work, the effect of radial scaling down on the performance of low-power external discharge plasma thrusters was experimentally investigated by comparing the discharge characteristics, thrust performance, beam characteristics, and spectral characteristics of thrusters with two different anode diameters of 15 and 30 mm. The 30 mm thruster has thrust of 78–235 mN, specific impulse of 566–1071 s, and anode efficiency of 11.8–23.4% at 78–235 W anode power. Compared with the 30 mm thruster, the anode power and thrust of the 15 mm thruster were decreased by approximately half. Plume diagnostic results show that the 15 mm thruster had a higher current utilization, higher ion peak energy and more active ionization due to better electron confinement. However, the propellant utilization of the 15 mm thruster was lower because of the shortened ionization region length.

Research on printed circuit board external open-circuit failure gas discharge tube under short-circuit failure

Research on printed circuit board external open-circuit failure gas discharge tube under short-circuit failure

UHF-Printed Monopole Filtenna for Partial Discharge Detection with LTE Signal Suppression

External partial discharge (PD) sensors for the ultra-high frequency (UHF) method are widely used to detect the PD signals in high-voltage power equipment for ease of installation and maintenance. However, conventional external PD sensors detect not only PD signals but also LTE signals; thus, a microwave filter is usually employed. In this work, a UHF filtering antenna (filtenna) is proposed as the external PD sensor to detect PD signals and simultaneously block LTE-band signals. The proposed UHF filtenna is the printed monopole antenna with a built-in interdigital bandpass geometry, which is selected for its compact size. Measurement results show that the proposed UHF-printed monopole filtenna operates adequately in the frequency range of 1 GHz to 1.6 GHz and simultaneously blocks LTE signals significantly.