Single Corona Research Articles

An experimental study on heat transfer using electrohydrodynamics (EHD) over a heated vertical plate.

The Corona effect offers significant potential for improving heat transfer efficiency in air. This study thoroughly examined how a single corona discharge affects heat transfer on a heated vertical flat plate. Key parameters tested included corona voltage, the aspect ratio of the vertical plate (y/L), and the inter-electrode discharge gap ratio (x/d). The findings revealed that increasing the corona voltage and decreasing the discharge gap enhanced heat transfer efficiency along the vertical surface. A predictive formula for the local Nusselt number was developed to characterize heat transfer on the plate. Additionally, Particle Image Velocimetry (PIV) was used to analyze the corona wind generated by the discharge. The study observed that the corona wind formed a vortex in the upstream region, which resulted in lower heat transfer rates upstream compared to the downstream region.

Reducing ion diffusion at atmospheric pressure through intermingled positive and negative ions

Increasing ion molecule reaction times for ambient ionization techniques can increase sensitivity of detection. Longer reaction times result in an increase in analyte signal relative to the reactant ion signal, however with a subsequent decrease in the total ion intensity. This loss in the total number of ions reaching the detector limits the extent to which increased reaction time can improve detection in practical applications. In this study ion loss was measured using either electric fields or gas flow to control ion transit time. Ion transit times ranged from 40 ms to 8 s, which resulted in ion densities ranging from 5 × 106 to 2 × 104 ions/cm3, respectively. These results provide insights into practical reaction time limitations or experimental boundaries when exploring sensitivity enhancements in ambient ionization. When exploring longer reaction times with an atmospheric flow tube coupled to a mass spectrometer (AFT-MS), an additional corona discharge ionization source of the same polarity was added in an attempt to increase total ion signal, but no improvement in signal was observed. This observation suggested that there was a maximum ion density being reached by the corona discharge that could not be increased by adding more of the same polarity ions. A hypothesis was that intermingling both polarities of ions would reduce ion loss and increase the measured ion signal. When two corona discharge sources—one each of positive and negative polarity—were used simultaneously in an AFT-MS, the total ion signal of either polarity measured by the MS was approximately double the current from a single corona discharge source. An increase in the negative ion signal was also observed when ∼10 parts-per-trillion vapor levels of an explosive (RDX, also known as hexogen) were introduced. In this case both the nitrate reactant ions and the RDX signal more than doubled with the addition of a corona discharge source producing positive ions. When intermingling positive and negative ions, an increase in ion current was also observed when the AFT was coupled directly to a Faraday detector or to an ion mobility spectrometer (IMS). This was the first demonstration of interfacing the AFT to an IMS. The observations and developments from this work will help in creating more portable instruments with improved sensitivity for detection of chemicals.

Transmitting, Mutational and Pandemic Nature of Corona: The Role oF Transposons, IS1::Tn::IS1 and CRISPR- CAS-9.

Corona/ Covid19/Omicron / SARS/ MARS similar viruses have no individual genetic mechanism to make them encapsulated spore forming microbes similar to bacteria, fungi, algal blooms involved spreading allergy. Transmission in all such cases need fluid dynamics of water and air. This flow does not require any support of matrix, i.e. nano particles of carbon, silicates and dust of animate inanimate molecules. They enter into lung alveoli surface epithelial cell, adhere on the surface of body saliva, originated due to cold and other infections. In support of ACE-I and II (Angiotensin Converting Enzyme I and II) [1]. So, there are two releasing mechanisms are existing in corona infection; one is the release of corona virus from the alveoli cells with matrix binds of one comorbid patients directly to other healthy recipient at the distance of 6 m in a closed environment by its self-development irritation and allergy, as received by sudden irritating smoke developed from kitchen, pollen, that grows during grass cutting, cleaning and sanitization. Transcription of m-RNA, in a matrix based single corona after entering into lung alveoli starts to transcribe and translate to many molecules of corona viruses, damages alveoli cells of lung, caused due to individual physiological conditions, old (above 70 years) and young (below 40), co-morbid(sick) and healthy people at similar age groups. IS::Tn::IS), Crispr/Cas-9 DNA transposons existing in corona m-RNA starts to act during transcription, and translation.

Transmitting, mutational and pandemic nature of corona: the role of transposons, is1: tn:is1 and crispr- cas-9

Corona/ Covid19/Omicron / SARS/ MARS similar viruses have no individual genetic mechanism to make them encapsulated spore forming microbes similar to bacteria, fungi, algal blooms involved spreading allergy. Transmission in all such cases need fluid dynamics of water and air. This flow does not require any support of matrix, i.e., nano particles of carbon, silicates and dust of animate inanimate molecules. They enter into lung alveoli surface epithelial cell, adhere on the surface of body saliva, originated due to cold and other infections. In support of ACE-I and II (Angiotensin Converting Enzyme I and II). So, there are two releasing mechanisms are existing in corona infection; one is the release of corona virus from the alveoli cells with matrix binds of one co-morbid patients directly to other healthy recipient at the distance of 6 m in a closed environment by its self-development irritation and allergy, as received by sudden irritating smoke developed from kitchen, pollen, that grows during grass cutting, cleaning and sanitization. Transcription of m-RNA, in a matrix based single corona after entering into lung alveoli starts to transcribe and translate to many molecules of corona viruses, damages alveoli cells of lung, caused due to individual physiological conditions, old (above 70 years) and young (below 40), co-morbid(sick) and healthy people at similar age groups. IS: Tn:IS), Crispr/Cas-9 DNA transposons existing in corona m-RNA starts to act during transcription, and translation

Covid-19 Analysis and Detection Using Chest X-Ray Images

Abstract: COVID-19 is the most lethal and life-threatening sickness induced by a single corona virus. In December 2019, the Corona virus, which seems originated in Wuhan, China and has been accountable for a significant quantity of fatalities, soon distributed around the world. A correct diagnostic can enable the rapid identification of COVID-19, even if there are no evident manifestations, and this can help people live longer. The most common clinical procedures Diagnostic tests and chest X-rays can both diagnose this illness. This study found that COVID-19 may be spotted using an object recognition method of chest X-ray images and Tomography. Such pictures give vital info on the COVID-19 virus, thus according to ongoing study based on radiology imaging methods... This suggested method, utilizing state-of-the-machine learning capabilities, which has been determined to be profitable in recognizing COVID-19 and when combined with chest radiography, can assist in the correct identification of the condition. The suggested approach for binary classification is designed to offer reliable diagnosis for patients with and without COVID. The results show that VGG-19 is the optimal configuration cantered on the picture, with 98.87% in connection comparisons and 95.91 percentage efficacies in insurance status identification. Each layer has its own filtering, hence convolutional layers were utilized. As a result, the VGG-19 classification system was competent in categorizing COVID-19 instances. . This approach, on the other hand, might be considerably enhanced by changing it or adding a convolution operation on front of it. Our system can help radiology validate their initial screenings and can also be used to quickly test affected role over the web

A theoretical study of the time lags due to Comptonization and the constraints on the X-ray corona in AGNs

ABSTRACT We study the Fourier time lags due to the Comptonization of disc-emitted photons in a spherical, uniform, and stationary X-ray corona, which located on the rotational axis of the black hole. We use monk, a general relativistic Monte Carlo radiative transfer code, to calculate Compton scattering of photons emitted by a thin disc with a Novikov–Thorne temperature profile. We find that the model time lags due to Comptonization remain constant up to a characteristic frequency and then rapidly decrease to zero at higher frequencies. We provide equations that can be used to determine the time lags and cross-spectra for a wide range of values for the corona radius, temperature, optical depth, height, and for various accretion rates and black hole masses. We also provide an equation for the X-ray luminosity of a single corona, as a function of its characteristics and location above the disc. Remarkably, the observed X-ray time lags of nearby, bright active galaxies can be successfully reproduced by inverse Comptonization process of multiple dynamic coronae.

Time Domain Measurement System for Electric Field of Radio Interference Generated by Corona Discharge

When corona discharge occurs around the wire, it will be accompanied by the movement of space charge, and then generate corona discharge effects such as radio interference and audible noise. In order to reveal time domain characteristics of the electric field of radio interference generated by corona discharge, a set of time domain measurement systems for radio interference, including oscillator antenna, sampling resistance, and data acquisition system, is developed. Based on the characteristics of corona-generated radio interference and antenna theory, the size of the antenna, the equivalent circuit model, and the selection of sampling resistance are discussed carefully to satisfy the requirements for the measurement of corona-generated radio interference. To verify the effectiveness of the measurement system, an experimental platform with a single corona source is built, and the time domain waveforms of corona current and radio interference are simultaneously measured. Besides, the attenuation law of radio interference is obtained by using a time domain measurement system. The results show that the amplitude of the measured voltage of radio interference decreases exponentially with distance. The time domain measurement system presented in this paper can lay a solid foundation for the time-domain evaluation of the radio interference level generated by corona discharge.

Correlating Corona Composition and Cell Uptake to Identify Proteins Affecting Nanoparticle Entry into Endothelial Cells.

The formation of the biomolecule corona on the surface of nanoparticles upon exposure to biological fluids critically influences nanocarrier performance in drug delivery. It has been shown that in some cases corona proteins can mediate specific nanoparticle interactions with cell receptors. Within this context, in order to identify corona proteins affecting nanoparticle uptake, in this work, correlation analysis is performed between the corona composition of a panel of silica nanoparticles of different sizes and surface functionalities and their uptake in four endothelial cell types derived from different organs. In this way, proteins that correlate with increased or decreased uptake were identified, and their effects were validated by studying the uptake of nanoparticles coated with a single protein corona and competition studies in brain and liver endothelium. The results showed that precoating nanoparticles with histidine-rich glycoprotein (HRG) alone strongly decreased uptake in both liver and brain endothelium. Furthermore, our results suggested the involvement of the transferrin receptor in nanoparticle uptake in liver endothelium and redirection of the nanoparticles to other receptors with higher uptake efficiency when the transferrin receptor was blocked by free transferrin. These data suggested that changes in the cell microenvironment can also affect nanoparticle uptake and may lead to a different interaction site with nanoparticles, affecting their uptake efficiency. Overall, correlating the composition of the protein corona and nanoparticle uptake by cells allows for the identification of corona molecules that can be used to increase as well as to reduce nanoparticle uptake by cells.

A Psychosocial Impact of Covid-19 Pandemic on Frontline Workers and General People in Kathmandu Valley

A new variant of the corona virus family found in the Wuhan city market of the China causing serious harm to human being. After the WHO decided COVID-19 as a pandemic situation, everyone has started to measure the prevention from infectious disease according to WHO guidelines. It includes social distancing, isolation, quarantine, lockdown, sanitation and masking respectively. During the time researcher has observed the difficulties of cultivating new normal to people in Nepal. People have perceived the single corona virus differently; common populations and frontline workers have different perception towards to corona virus. Researcher started to measures the psychosocial impact of COVID-19 pandemic into frontline workers and general populations in Kathmandu valley. The total number of sample unit for this research is 82; it includes 52 general populations and 30 frontline workers.

Large-scale ion generation for precipitation of atmospheric aerosols

Abstract. Artificial rain is explored as a remedy for climate change caused farmland drought and bushfires. Increasing the ion density in the open air is an efficient way to generate charged nuclei from atmospheric aerosols and induce precipitation or eliminate fog. Here we report on the development of a large commercial-installation-scale atmospheric ion generator based on corona plasma discharges, experimental monitoring, and numerical modeling of the parameters and range of the atmospheric ions, as well as the application of the generated ions to produce charged aerosols and induce precipitation at the scale of a large cloud chamber. The coverage area of the ions generated by the large corona discharge installation with the 7.2 km long wire electrode and applied voltage of −90 kV is studied under prevailing weather conditions including wind direction and speed. By synergizing over 300 000 localized corona discharge points, we demonstrate a substantial decrease in the decay of ions compared to a single corona discharge point in the open air, leading to large-scale (30 m ×23 m ×90 m) ion coverage. Once aerosols combine with the generated ions, charged nuclei are produced. Higher wind speed has led to larger areas covered by the plasma-generated ions. The cloud chamber experiments (relative humidity 130±10 %) suggest that charged aerosols generated by ions with a density of ∼104 cm−3 can accelerate the settlement of moisture by 38 %. These results are promising for the development of large-scale installations for the effective localized control of atmospheric phenomena.

Dual Corona Vesicles with Intrinsic Antibacterial and Enhanced Antibiotic Delivery Capabilities for Effective Treatment of Biofilm-Induced Periodontitis.

Periodontitis is a common disease caused by plaque biofilms, which are important pathogenic factors of many diseases and may be eradicated by antibiotic therapy. However, low-dose antibiotic therapy is a complicated challenge for eradicating biofilms as hundreds (even thousands) of times higher concentrations of antibiotics are needed than killing planktonic bacteria. Polymer vesicles may solve these problems via effective antibiotic delivery into biofilms, but traditional single corona vesicles lack the multifunctionalities essential for biofilm eradication. In this paper, we aim to effectively treat biofilm-induced periodontitis using much lower concentrations of antibiotics than traditional antibiotic therapy by designing a multifunctional dual corona vesicle with intrinsic antibacterial and enhanced antibiotic delivery capabilities. This vesicle is co-assembled from two block copolymers, poly(ε-caprolactone)-block-poly(lysine-stat-phenylalanine) [PCL-b-P(Lys-stat-Phe)] and poly(ethylene oxide)-block-poly(ε-caprolactone) [PEO-b-PCL]. Both PEO and P(Lys-stat-Phe) coronas have their specific functions: PEO endows vesicles with protein repelling ability to penetrate extracellular polymeric substances in biofilms ("stealthy" coronas), whereas P(Lys-stat-Phe) provides vesicles with positive charges and broad spectrum intrinsic antibacterial activity. As a result, the dosage of antibiotics can be reduced by 50% when encapsulated in the dual corona vesicles to eradicate Escherichia coli or Staphylococcus aureus biofilms. Furthermore, effective in vivo treatment has been achieved from a rat periodontitis model, as confirmed by significantly reduced dental plaque, and alleviated inflammation. Overall, this "stealthy" and antibacterial dual corona vesicle demonstrates a fresh insight for improving the antibiofilm efficiency of antibiotics and combating the serious threat of biofilm-associated diseases.

Modeling of a Dielectric-Barrier Discharge-Based Cold Plasma Combustion Ignition System

We present a computational modeling study of plasma phenomena in a dielectric-barrier discharge (DBD) for automotive combustion ignition applications. The study was performed using a self-consistent, two-temperature plasma model with finite-rate plasma chemical kinetics for methane-air combustion mixture. The structure of a DBD discharge and the yield of active combustion enhancing radicals from the discharge is quantified for positive and negative pulsing, and a comparison is made with a single electrode corona discharge. The DBD plasma develops as a streamer discharge with individual streamers preferentially emerging from sharp features on the bare electrode of DBD which quickly propagates to the opposite dielectric surface where it is quenched. The dielectric barrier therefore self-limits the discharge resulting in a total radical yield that saturates in time. The corona on the other hand provides a radical yield that can continuously increase in time. The negative polarity pulsing of the DBD results in a more intense plasma with a higher radical yield compared to a positive polarity pulse. Simulations are also performed for a long 1-μs duration afterglow period once the active pulse is terminated. The active combustion enhancing radicals are found to remain relatively stable in density over this duration, indicating that ~100-kHz pulse repetition rates can sustain or even gradually increase the radical densities over long durations of transient time.

Statistical analysis of audible noise generated by AC corona discharge from single corona sources

Time-domain waveforms of sound pressure pulses generated by alternate current (AC) corona discharge from single corona sources are measured. The pulse amplitude and time interval of sound pressure pulses in positive and negative half cycles are analysed separately due to large differences of the sound pressure pulses in positive and negative half cycles. The influences of instantaneous voltages on the pulse amplitude and time interval are obtained, and statistical distributions of pulse amplitude and time interval are also obtained. Besides, empirical formulas of the pulse amplitude and time interval are derived by numerical fitting method. Based on the statistical results, stochastic simulation of the sound pressure pulses is conducted, and the validity of the simulated results is given by comparing the frequency-domain results and A-weighted sound pressure level (SPL) with the measured ones. Finally, the stochastic simulation method is used to discuss modulating influence of AC voltage on the tones emission from AC corona discharge. Besides, the influence of the measurement time on the resultant SPL is also discussed on the basis of the stochastic model. In order to insure the SPL independent of the measurement time, the measurement time should be larger than 0.2 s.

Measurement and analysis of time-domain characteristics of corona-generated radio interference from a single positive corona source

The corona-generated electromagnetic interference commonly known as radio interference (RI) has become a limiting factor for the design of high voltage direct current transmission lines. In this paper, a time-domain measurement system is developed to measure the time-domain characteristics of corona-generated RI from a single corona source under a positive corona source. In the experiments, the corona current pulses are synchronously measured through coupling capacitors. The one-to-one relationship between the corona current pulse and measured RI voltage pulse is observed. The statistical characteristics of pulse parameters are analyzed, and the correlations between the corona current pulse and RI voltage pulse in the time-domain and frequency-domain are analyzed. Depending on the measured corona current pulses, the time-domain waveform of corona-generated RI is calculated on the basis of the propagation model of corona current on the conductor, the dipolar model for electric field calculation, and the antenna model for inducing voltage calculation. The well matched results between measured and simulated waveforms of RI voltage can show the validity of the measurement and calculation method presented in this paper, which also further show the close correlation between corona current and corona-generated RI.

A numerical model of acoustic wave caused by a single positive corona source

Audible noise accompanies corona discharge, which is one of the most important electromagnetic environment issues of high voltage transmission lines. Most of the studies on the audible noise generated by corona discharge focused on statistical analysis of the experimental results and a series of empirical formulas were derived to predict the audible noise. However, few of them interpreted the generating mechanism of the audible noise. Sound wave in the air is actually the fluctuation of the air, which lead to the hypothesis that the sound wave is generated by the interaction of the charged particles and the air molecules in the discharge progress. To validate this hypothesis, experiments were carried out in this paper to study the relationship between the audible noise and the corona current, including the correlation both in time domain and in frequency domain. Based on the experimental results, the fluid equations of the particles in the air were introduced to study the interactions among the electrons, ions, and neutral molecules in the discharge, and a numerical model for the amplitude of corona acoustic emission was developed and validated.

Propagation characteristics of audible noise generated by single corona source under positive DC voltage

The directivity and lateral profile of corona-generated audible noise (AN) from a single corona source are measured through experiments carried out in the semi-anechoic laboratory. The experimental results show that the waveform of corona-generated AN consists of a series of random sound pressure pulses whose pulse amplitudes decrease with the increase of measurement distance. A single corona source can be regarded as a non-directional AN source, and the A-weighted SPL (sound pressure level) decreases 6 dB(A) as doubling the measurement distance. Then, qualitative explanations for the rationality of treating the single corona source as a point source are given on the basis of the Ingard’s theory for sound generation in corona discharge. Furthermore, we take into consideration of the ground reflection and the air attenuation to reconstruct the propagation features of AN from the single corona source. The calculated results agree with the measurement well, which validates the propagation model. Finally, the influence of the ground reflection on the SPL is presented in the paper.

The effect of the configuration of a single electrode corona discharge on its acoustic characteristics

A new sparker system based on pulsed spark discharge with a single electrode has already been utilized for oceanic seismic exploration. However, the electro-acoustic energy efficiency of this system is lower than that of arc discharge based systems. A simple electrode structure was investigated in order to improve the electro-acoustic energy efficiency of the spark discharge. Experiments were carried out on an experimental setup with discharge in water driven by a pulsed power source. The voltage–current waveform, acoustic signal and bubble oscillation were recorded when the relative position of the electrode varied. The electro-acoustic energy efficiency was also calculated. The load voltage had a saltation for the invaginated electrode tip, namely an obvious voltage remnant. The more the electrode tip was invaginated, the larger the pressure peaks and first period became. The results show that electrode recessing into the insulating layer is a simple and effective way to improve the electro-acoustic energy efficiency from 2% to about 4%.

Optimal design of corona ring on HV composite insulator using PSO approach with dynamic population size

This paper deals with the use of corona ring at the HV end fitting for improving the electric field and potential distributions and then for minimizing the corona discharges on 230 kV AC transmission line composite insulator. A single corona ring is installed at the energized end side. Three-dimensional finite element method (FEM) software is employed to compute the electric field. As the performance of high voltage insulator strings closely depends on designs and locations of corona ring, the effects of the corona ring radius, the ring tube radius and the ring vertical position are examined. The minimization of the electric field necessitates the optimization of corona ring. For this purpose, new nonlinear mathematical objective function linking the electric field strength to the corona ring structure parameters is established. The optimization problem is achieved by minimizing the objective function using a modified particles swarm optimization (PSO) algorithm with a dynamic population size. The algorithm adjusts the size of population for each iteration. Based on the average value and the best solution of the objective function, we propose a new mathematical model to update the population size. This algorithm enables the population size reduction leading to computing time decrease. According to the results, FEM-PSO hybridization technique could be very helpful in optimization of corona ring design.

Statistical characteristics and stochastic model of DC corona-generated sound pressure pulses from single corona source

The sound pressure level (SPL) has been generally accepted in the measurement and evaluation of degree of nuisance to the corona-generated audible noise from transmission lines. Quite many scholars have studied the spectrum and statistical characteristics of the SPL from transmission lines through the long-term frequency measurement. In fact, the corona sources on the transmission lines usually act as sound sources emitting sound pressure pulses with random amplitudes and random time intervals, yet the statistical characteristics of the random sound pressure pulses and their correlation to the SPL have barely been investigated. In this paper, a series of experiments with single positive corona source in a coaxial cylindrical structure were carried out to investigate the statistical characteristics of the pulse amplitudes and time intervals of sound pressure pulses. In the experiment, time-domain measurement for the audible noise was employed. Based on the statistical results, a stochastic model was developed to simulate the sound pressure pulses. The validity of the stochastic model was testified by comparing the simulated and measured A-weighted sound pressure levels. On the basis of the stochastic model, the influence of random pulse amplitudes and time intervals of the sound pressure pulses on the resultant SPL was demonstrated.

Comparison between the audible noises generated from single corona source under DC and AC corona discharge

The corona-generated audible noise (AN) factor is an important consideration in the design and operation of ultrahigh voltage direct current (DC) and alternate current (AC) transmission lines. Due to the differences in discharge process and corona-generated space charges between the DC and AC corona discharge, the audible noise from DC and AC corona has different characteristics. This paper conducts a series of experiments by measuring the time-domain waveforms of the audible noise from a single corona source under DC and AC voltage. Sound pressure pulses are extracted from a correlation analysis, and then a detailed comparison of the basic characteristics of DC and AC corona-generated AN in time-domain and frequency spectrum is given. Results from this paper stand to contribute to an explanation of existing results in AN measurement and analysis from DC and AC transmission lines.