Discharge Dynamics Research Articles

Compressor and Valve Control Performance Implications on Active Flow Control Aircraft

This study presents the feasibility of implementing commercial-off-the-shelf reciprocating piston compressors for a developed active flow control (AFC) actuation framework to quantify the aerospace relevant performance ramifications of control architecture and compressor operational choices. Three architectures are studied: supply valve metering, exit area metering, and a combined approach. All concepts are studied under varying compressor operation schedules. The analysis framework in this study integrates internal pneumatic actuation and discharge dynamics, an experimentally calibrated compressor pressure and thermal dynamics model, three feedback control architectures, and flight dynamics models. The framework is implemented in simulation to provide a user-friendly tool for linking AFC architecture choices to achievable flight trajectories. Actuator performance is evaluated using actuation time, output, compressor duty cycle, and specific energy consumption. Aircraft tracking performance is evaluated as usable time and slalom centerline deviation. The analysis indicates that a supply-volume-based metering approach is comparatively inefficient concerning an exit-area-based metering, resulting in high flight tracking error. Exit area metering provides the best efficiency and run time with some structural drawbacks, while the combined approach provides the best flight tracking performance at the expense of additional complexity. These results inform the choice of onboard AFC hardware choices.

Cross-machine comparison of runaway electron generation during tokamak start-up for extrapolation to ITER

A cross-machine comparison of global parameters that determine the runaway electron (RE) generation and loss process during tokamak start-up was carried out with the aim to extrapolate these to ITER. The study found that all considered discharges, also those that do not show signs of RE, are non-thermal at the start, i.e. have a streaming parameter larger than 0.1. During the current ramp-up the electric field, E, remains above the critical value, E c, that allows RE in the plasma. The distinction to be made is not if RE can form but, if sufficient RE can form fast enough such that they are detected or start to dominate the dynamics of the tokamak discharge. The dynamics of the value of E, density and temperature during tokamak are key to the formation of RE. It was found that larger devices operate with E closer to E c, due to their higher temperatures, hence the RE generation is relatively slower. The slower time scales for the formation of RE, estimated to be of the order of 100s of ms in ITER simplifies the development of avoidance schemes. The RE confinement time is also an important determinant of the entire process and is found to increase with the device size. The study also revealed that drift orbit losses, a mechanism often attributed as the main RE loss mechanism during the early tokamak discharge, are actually more difficult to achieve. RE losses might be more likely attributed to RE diffusion due to magnetic turbulence.

Effect of Interplay between Parallel and Perpendicular Magnetic and Electric Fields on Partial Discharges

This paper reports on the influence of a magnetic field on the dynamics of partial discharges (PDs) in two distinct configurations with respect to the mutual orientation of electric fields. The broad application areas include electrical insulation systems of both high-voltage grids and industrial network devices as well as emerging segments such as electric vehicles or more electric aircraft. Traditionally, PD measurements are only carried out in an electric field. In all current-carrying power equipment, magnetic fields are also superimposed onto electric ones, thus influencing partial discharge behavior. It has been observed that the interplay between electric and magnetic fields influences the dynamics of PDs; parallel and perpendicular mutual orientations were specifically investigated. The measurement technique allowed us to quantitively detect the effect of magnetic fields on PDs in a corona point–plane arrangement. The novel element presented in this article is a detection of PD intensity modulated by a magnetic field, with both perpendicular and parallel orientations with respect to electric one, and a quantitative visualization in the form of the time-sequence diagrams. The simulation of electron trajectories in the presence of electric and magnetic fields revealed the elongation of the pathways and differentiation of the charged particle propagation times. The perpendicularly oriented magnetic field led to a twisting effect, whereas the parallel alignment reflected the propagation along a helical trajectory. A slightly stronger PD intensity amplification effect was observed in the case of a parallel alignment of electric versus magnetic fields as compared with the perpendicular orientation. The presented results may contribute to PD measurement methodology in both electric and magnetic fields as well as a better understanding of the underlying physical mechanisms. The observed effect of the modulation of the magnetically based PD dynamics may be relevant for the insulation systems of power equipment.

Avoidance behaviour of aquatic macroinvertebrates for real-time detection of micropollutant surge in wastewater effluents

Micropollutants are regularly detected at the outlets of wastewater treatment plants (WWTPs). Across urban and industrial WWTPs, monitoring directives only require assessment for a handful of chemicals via sampling methods that fail to capture the temporal variability in micropollutant discharge. In this study, we develop a biotest for real-time on-line monitoring of micropollutant discharge dynamics in WWTPs effluents. The selected biomonitoring device ToxMate uses videotracking of invertebrate movement, which was used to deduce avoidance behaviour of the amphipod Gammarus fossarum. Organism conditioning was set up to induce a state of minimal locomotor activity in basal conditions to maximise avoidance signal sensitivity to micropollutant spikes. We showed that with a standardised protocol, it was possible to minimise both overall movement and sensitivity to physio-chemical variations typical to WWTP effluents, as well as capture the spikes of two micropollutants upon exposure (copper and methomyl). Spikes in avoidance behaviour were consistently seen for the two chemicals, as well as a strong correlation between avoidance intensity and spiked concentration. A two-year effluent monitoring case study also illustrates how this biomonitoring method is suitable for real-time on-site monitoring, and shows a promising non-targeted approach for characterising complex micropollutant discharge variability at WWTP effluents, which today remains poorly understood.

Dynamics of a 2D silo discharge: A competition between structural domains before clogging

Dynamics of a 2D silo discharge: A competition between structural domains before clogging

Analysis of the Dynamics of Water Flow and Suspension Flow Discharge in Volcano Watershed with Settlement Land Use

Suspension flow into the upstream of volcano watershed is sensitive to land use. In Indonesia, a settlement is a form of land use in several volcanic landscapes. There is currently no detailed study on the suspension flow sediment from the settlement land use. The purpose of this study is to investigate the characteristics of the relationship between water and suspension flow discharge. The study was conducted through the measurements at a gully outlet that produced 747 suspension load data. For each rainfall event, suspension load measurements were made in the field, followed by laboratory analysis. Additionally, field surveys were used to determine the characteristics of settlement land use and the water flow into the gully system. According to the findings, the peak flow discharge corresponds to the peak suspension discharge, the peak flow discharge comes before the peak suspension discharge, and the peak flow discharge happens after the peak suspension discharge. The average time lag between initial rainfall events and suspension flow was 10.36 minutes, and the suspension peak content varied by an average of 2.22 gl-1. The grain size was also dominated by the clay fraction, averaging 67.86% on the ascending branch and 67.82% on the descending branch.
 Keywords: Erosion; Discharge; Settlements; Suspension; Watershed
 
 Copyright (c) 2023 Geosfera Indonesia and Department of Geography Education, University of Jember
 This work is licensed under a Creative Commons Attribution-Share A like 4.0 International License

Spatial and temporal dynamics of single nanosecond discharges in air with water droplets

Discharges generated in water or water-containing media have great potential for various technological applications. However, a fundamental understanding of plasma–liquid interactions, particularly the ignition and propagation of a discharge in a gap containing liquid droplets, is lacking. This study investigates the electrical characteristics and the spatial-temporal dynamics of nanosecond discharges in air containing one or two millimetric droplets of deionized water. Analysis of the effects of voltage amplitude (V a) and pulse width on the discharge mode shows that at low V a, the discharges are run in streamer mode; however, at high V a, a streamer-to-spark transition is observed. Although the droplet size (diameter between 2 and 4 mm) does not significantly influence the discharge dynamics, its position with respect to the gap (on- or off-axis) has a strong effect. Time-resolved imaging of three droplet configurations (one on-axis droplet, one off-axis droplet, and two on-axis droplets) was used to unveil the ignition and propagation dynamics of streamers and sparks at nanosecond time scale. The findings are of interest and contribute to a better understanding of` the plasma–droplet interactions, which is crucial for the development and optimization of plasma-based applications.

Electron dynamics in planar radio frequency magnetron plasmas: III. Comparison of experimental investigations of power absorption dynamics to simulation results

In magnetized capacitively coupled radio-frequency (RF) discharges operated at low pressure the influence of the magnetic flux density on discharge properties has been studied recently both by experimental investigations and in simulations. It was found that the magnetic asymmetry effect allows for a control of the DC self-bias and the ion energy distribution by tuning the magnetic field strength. In this study, we focus on experimental investigations of the electron power absorption dynamics in the presence of a magnetron-like magnetic field configuration in a low pressure capacitive RF discharge operated in argon. Phase resolved optical emission spectroscopy measurements provide insights into the electron dynamics on a nanosecond-timescale. The magnetic flux density and the neutral gas pressure are found to strongly alter these dynamics. For specific conditions energetic electrons are efficiently trapped by the magnetic field in a region close to the powered electrode, serving as the target surface. Depending on the magnetic field strength an electric field reversal is observed that leads to a further acceleration of electrons during the sheath collapse. These findings are supported by two-dimensional particle in cell simulations that yield deeper insights into the discharge dynamics.

Development and characteristics study of compact Penning ion source

A compact-size Penning ion source with a small discharge volume (1.24 cm3) is developed. It consists of two concentric cylinders of different heights that act as cathodes and one hollow cylindrical anode. A homogeneous magnetic field is achieved within the discharge volume with geometrical optimization of the ion source. As a result, dense plasma is generated at low discharge power. The dynamics of the pulse mode discharge at low pulse width and frequency of anode voltage are studied. A high discharge (hundreds of amperes) current pulse with low delay time and fast rise time is recorded. The ion source is equally efficient to operate in continuous as well as pulse modes of ionization for various gases. It is operated in a wide range of low pressure at low anode voltage. An extraction system is designed to extract ions efficiently in the axial direction at a variable extraction voltage. The beam current of 200 µA in continuous mode and 6 A fast pulse in the pulsed mode of discharge have been measured. Variable beam current can be extracted with variable extraction voltage for any potential application.

Extreme flooding controlled by stream network organization and flow regime

River floods are among the most common natural disasters worldwide, with substantial economic and humanitarian costs. Despite enormous efforts, gauging the risk of extreme floods with unprecedented magnitude is an outstanding challenge. Limited observational data from very high-magnitude flood events hinders prediction efforts and the identification of discharge thresholds marking the rise of progressively larger floods, termed flood divides. Combining long hydroclimatic records and a process-based model for flood hazard assessment, here we demonstrate that the spatial organization of stream networks and the river flow regime control the appearance of flood divides and extreme floods. In contrast with their ubiquitous attribution to extreme rainfall and anomalous antecedent conditions, we show that the propensity to generate extreme floods is well predicted by intrinsic properties of river basins. Most importantly, it can be assessed prior to the occurrence of catastrophes through measurable metrics of these properties derived from commonly available discharge data, namely the hydrograph recession exponent and the coefficient of variation of daily flows. These results highlight the propensity of certain rivers for generating extreme floods and demonstrate the importance of using hazard mapping tools that, rather than solely relying on past flood records, identify regions susceptible to the occurrence of extreme floods from ordinary discharge dynamics.

How do storm characteristics influence concentration-discharge hysteresis in a high-elevation tropical ecosystem?

Hydrometeorological characteristics can influence stream chemistry variability and the identification of their dominant drivers provides much needed insight into catchment functioning in the tropics. Particularly, the rainfall-runoff processes that determine catchment capacity to retain and deliver solutes. In this context, concentration-discharge (C-Q) relationships allow assessing solute delivery mechanisms to streams. Here, we used a high-frequency 5-minute multi-solute data set (Al, Cu, DOC, TNb, Ba, Ca, Mg, Na, Sr, K, Si, Rb) to derive hysteresis indicators (direction, magnitude and area) in relation to hydrometeorological variables for a high-elevation tropical experimental catchment. We found geogenic solutes (Na, Sr, K, Si, and Rb) were mostly defined by clockwise hysteresis loops and dilution patterns. Conversely, biogenic solutes influenced by soil processes (Al, Cu, DOC and TNb) resulted in anti-clockwise hysteresis behaviors and mobilization with streamflow. The hysteresis indicators were most strongly influenced by discharge magnitude and the solute concentration itself. As the discharge and the concentration increases (>90th of the flow duration curve) the loop area and the hysteresis index turned to cero showing a direct linear response of the solute to discharge dynamics. Additionally, increasing discharge drives greater dilution or mobilization patterns for the geogenic and biogenic solutes. Higher discharge increases water volume to dilute geogenic solutes and is related to more water passing through shallow soils leaching biogenic solutes. This study contributes to our understanding of how Páramo catchments store and release solutes for a more adequate water resource management.

Discharge in air in contact with water: influence of electrical conductivity on the characteristics and the propagation dynamics of the discharge

Due to the high reactivity and the non-thermal properties of streamer discharges, they are applied in various fields, such as water treatment and medicine. Streamer discharges are usually produced in the gas phase before interacting with a liquid or solid surface. Although the dynamics of a streamer discharge in gases is well described, its propagation at liquid surfaces remains poorly understood. In this study, we investigate the influence of water electrical conductivity (σ), between 2 and 1000 µS cm−1, on the characteristics and propagation dynamics of pulsed positive DC nanosecond discharges with the solution serving as a cathode. σ strongly influences τ r (the dielectric relaxation time), and two discharge modes may be obtained, depending on whether τ r is shorter or longer than the delay to achieve breakdown (τ pulse). This latter can be indirectly modified by adjusting the voltage amplitude (V a). In the case of V a = 14 kV, the breakdown voltage (V bd) at low σ is lower than that measured at high σ, probably because τ pulse < τ r and > τ r, respectively. In the case of V a = 20 kV, V bd decreases slightly with σ, probably because of the decrease of the resistivity of the global electrical circuit as τ pulse ∼ τ r for high σ. In addition to the electrical characterization, the dynamics of the discharge at the solution’s surface is investigated using 1 ns-time-resolved imaging. Its morphology was found to evolve from a disc to a ring before it splits into highly organized plasma dots (streamers’ head). The number (N dots) and propagation velocity of plasma dots are determined as a function of σ. At V a = 14 kV, N dots does not vary significantly with σ despite the increase of V bd; this latter likely compensates the neutralization of charge accumulated at the surface by ions in solution. In the case of V a = 20 kV, N dots decreases with σ, and it can be related to a decrease of accumulated charge at the water surface. Finally, based on the electrical measurements, we found that the charge per plasma dot (Q dot) increases with σ, which does not correlate with the imaging results that show a short length of propagation at high σ. Then, considering the plasma dot mobility at low σ and the instantaneous propagation velocities at high σ, a more realistic Q dot is measured.

Coupling of SWAT and DSAS Models for Assessment of Retrospective and Prospective Transformations of River Deltaic Estuaries

River deltaic estuaries are dynamic ecosystems characterised by linkages between tidal currents, river water discharge, and sediment from the basin. The present study is based on the application of remote data: multispectral satellite images, DEM, LULC (Land use and land cover), lithology, and hydroclimatic factors. The standardised methodology was based on the adoption of a coupled modelling approach for this work, involving the semi-distributed catchment scale hydrological Soil and Water Assessment Tool (SWAT) model and the statistical Digital Shoreline Analysis System (DSAS) for (1) identifying environmental drivers of sediment transport changes of the estuarine reach; (2) analysis of retrospective changes in shoreline configuration; (3) assessing discharge and sediment dynamics of the estuarine section, and (4) generating future projection scenarios for the estuary’s state to take action for its long-term ecological stability. Our study employs a coupled modelling framework to fill the research gap for Subarnarekha deltaic estuary. Integrating outputs derived from DSAS and SWAT, a comprehensive understanding of the changes in watershed hydrology, water diversions, and damming of rivers have altered the magnitude and temporal patterns of freshwater flow and sediment, which potentially contributed to the receding of the Digha Coast shoreline.

Discharge dynamics from an x-ray generating tribosource

When an adhesive tape is peeled in vacuum, x rays are generated in burst of short duration (order nanosecond) whose origin is not yet fully understood. In this work, we analyze the electrical discharge dynamics occurring when a pressure-sensitive adhesive tape is peeled from its own backing in x-ray emitting conditions. We characterize these dynamics with the time between consecutive discharges and study its statistical properties as a function of both peeling speed and surrounding air pressure. We find that processes whose dynamics are characterized by shorter timescales generate the high energy portion of the x-ray spectrum. Furthermore, the air pressure affects the emission intensity but not the maximum single photon energy attainable. Our results indicate that there exist more complex physical mechanisms at play than previously thought in this system. Understanding the physical processes behind these dynamics may help improve the yield from devices that use this technology for x-ray production.

Impact of surface charges on energy deposition in surface dielectric barrier discharge: a modeling investigation

Surface charges have significant impact on the evolution of surface dielectric barrier discharge (SDBD). In this work, the role of residual surface charges on repetitively nanosecond pulsed SDBD in atmospheric air is investigated using a two-dimensional fluid model, based on the assumption of preserving the distribution of surface charges at the end of the previous high voltage (HV) pulse. In the bipolar mode when the polarity of residual surface charges is opposite to that of the current HV pulse, a lower breakdown voltage and more deposited energy can be observed, showing an obvious enhancement of SDBD. In the unipolar mode, residual surface charges suppress the development of discharges and energy deposition. It is found that more residual surface charges are accumulated during the negative pulsed discharge, which have a more pronounced effect on the subsequent positive pulsed one. This is explained by the fact that the negative surface streamers directly contact the dielectric and charge it, while the positive surface streamers float above the dielectric, forming a ion-rich region near the surface. The results in this work demonstrate the mechanism of how residual surface charges affect discharge dynamics, which can be utilized to regulate energy deposition in SDBDs.

Analysis of ozone generation in a planar atmospheric pressure air dielectric barrier discharge reactor

This work investigates O3 production in a planar atmospheric pressure air dielectric barrier discharge reactor numerically and experimentally. The surface temperature of the reactor is measured by an infrared (IR) thermal imager, and the O3 densities of cases in the reactive zone are measured by ultraviolet absorption spectroscopy. The 1.5D plasma fluid model (PFM) with transverse convection is employed to capture the average properties of a single microdischarge (MD) generated in the reactor. The concept of equivalent reaction is proposed to calculate spatial-cyclic average species sources obtained by the 1.5D PFM and provided to the chemical model of a 3D gas flow model (GFM) for obtaining density distributions of reactive species generated by MDs in the reactive zone. The simulated temperature distribution of the reactor surface is validated by that measured with the IR thermal imager since the gas temperature was reported as a critical discharge parameter for O3 generation. The simulated O3 densities show the same trend as the flow rate changes, which demonstrates the proposed model captures the average discharge dynamics in different operating conditions. In the 1.5D PFM, the simulated results show that the O3 molecules produced in the case of 4 SLM are much more than those produced in the case of 1 SLM though the O atoms produced in the case of 1 SLM are around 20% more than those produced in the case of 4 SLM. In the case of 1 SLM, more than 48% of O3 molecular generated are destructed, while only around 14% of O3 molecules are destructed in the case of 4 SLM. The analysis shows that around 73% of O atoms generated in the 1.5D PFM are consumed in the formation of O3 molecules in the case of 4 SLM, while only 18% of O atoms generated in the case of 1 SLM are consumed in the formation of O3 molecules. In the 3D GFM, the O3 destructed is around 24% of that destructed in the 1.5D PFM in the case of 4 SLM due to the oxidation reaction of NO, while only 11% of O3 molecules destructed as that destructed in the 1.5D PFM in the case of 1 SLM. The amounts of O3 molecules generated in the 3D GFM are minor if they are compared with those generated in the 1.5D PFM in all cases. The overall O3 yield efficiency reaches 97 g kWh−1 with the O3 concentration increasing up to 2700 ppm in the case of 4 SLM, while the O3 yield efficiency decreases to 10 g kWh−1 and O3 concentration drops to 1400 ppm in the case of 1 SLM.

The effect of Penning ionization reactions on the evolution of He with O2 admixtures plasma jets

In this study, the effect of the O2 and N2 Penning ionization reactions on the evolution a capillary helium atmospheric pressure plasma jet (APPJ) with and without the presence of oxygen admixtures is investigated numerically using a two dimensional axi-symmetric model. In order to better understand potential applications of plasma surface interaction, the He and He + O2 (1000 ppm) APPJ is launched into a dielectric target. Moreover, the numerical model is compared with experimental measurements showing that the model captures the right physics and can elucidate the discharge dynamics. The comparison is realized for axial and radial measurements in order to have a complete picture of the plasma jet evolution. In this paper, the velocity and the shape of the plasma guided streamer were chosen as indicators of plasma jet evolution. In particular, the investigation is accomplished experimentally by tracking the spatio-temporal resolved emission of 706.5 nm (3s3S → 2p3P) line and numerically by calculating the reaction rate for the same transition. The O2 and N2 Penning reactions are then independently considered in the numerical model in order to isolate their contribution to the plasma evolution. It is shown that for the pure helium plasma, the N2 Penning reactions are more important to the plasma evolution. However, when oxygen admixtures are added to the plasma gas, the O2 Penning reactions become more important than the N2 ones.

Digital Elevation Model Development Of The Volga And Don River’s Delta And Application In Hydrological Modeling

The article describes the methodology for constructing digital elevation models for the vast delta areas of the Don and Volga rivers for further use in mathematical models of flooding from surges. The initial cartographic data and features of the delta regions are described. The methods of information processing are considered in detail. An algorithm for constructing a DEM has been developed to obtain highly detailed digital elevation models. The algorithm is based on combining the DEM of individual key features - land, the depths of the hydrographic network and the bathymetry of the receiving reservoir for the river. The topographic maps, maps of the navigable route depths, hydrographic maps, and satellite images Landsat-8 and Sentinel-2 were used to create the DEM of the Don and Volga river. To build individual DEMs, a raster of the absolute depth of the channels, a hydrography DEM, a land DEM, and a shelf DEM were created using geoinformation systems. To assess the possibility of using obtained DEMs in hydrological models based on HEC-RAS, we conducted training and verification calculations of water level during wind surge phenomena in Don Delta using different surface roughness coefficients. The calculation results show good reproducibility of observed water level fluctuation in the Don Delta using obtained DEM with a roughness coefficient of 0.0125. Also, we carried out similar calculations of storm surge phenomena in the Volga Delta using obtained DEM and combinations of various riverbed and not riverbed roughness coefficients. The combination of 0.007 for riverbed and 0.02 for not riverbed surfaces reproduces the observed water level fluctuation during storm surge phenomena in Volga Delta. The constructed DEMs for the Volga and Don deltas made it possible to reproduce the observed dynamics of river discharges and water level fluctuations during surge events. Such detailed DEMs, taking into account all the complexity of the coastal and delta relief, were created for the first time for the Volga and Don.

THE EFFECTIVENESS OF PHARMACOLOGIC TREATMENT FOR REGRESSION OF CLINICAL SYMPTOMS AND INDICATIONS FOR SURGICAL TREATMENT OF CHRONIC NASOPHARYNGITIS ASSOCIATED WITH EPSTEIN-BARR VIRUS

Chronic nasopharyngitis (CNP) associated with Epstein-Barr virus (EBV) is etiopathogenetically based on the virus-induced chronic inflammation of the pharyngeal tonsil. Studies using immunological methods have shown that EBV is involved in the hypertrophy of the lymphoid tissue of the pharynx in children and adolescents, since the lymphoid tissue of the pharyngeal tonsil is the site of primary infection and persistence of the virus. The surgery does not often resolve the problem in 19-26% of patients. Therefore, there are many questions regarding the choice of the adequate therapy that would show its effectiveness.&#x0D; Objective: to evaluate the effect of treatment of CNP associated with Epstein-Barr virus with the phytoneering extract BNO 1030 on the dynamics of the main clinical symptoms and associated indications for surgery.&#x0D; Material and methods. A total of 108 outpatients divided into two groups: experimental (n-54) and control (n-54). Verification of EBV was carried out according to the ELISA reaction profile: IgM-VCA/IgG-EA/IgG-EBNA. All the patients were prescribed a background treatment and the experimental group additionally received BNO 1030. The evaluation of the effectiveness of treatment was based on the analysis of the dynamics of clinical symptoms, the degree of hypertrophy of the pharyngeal tonsil, and the existence of indications for surgical treatment. Symptom assessment was performed on V1 (day 0), V2 (day 51), V3 (day 101), V4 (day 141). Indications for surgical intervention (adenotomy) were determined on V4 together with the patient's parents.&#x0D; Results. Clinical symptoms of CNP include runny or stuffy nose, postnasal drip, nasal voice, posterior cervical lymphadenopathy. Symptoms were rated, on average, from 0 to 3 points on a 4-point MSS scale that corresponds to the moderate course of CNP. At V1, both groups showed comparable symptom scores.&#x0D; The use of the phytoneering extract BNO 1030 in addition to background therapy in patients of the main group proved its clinical efficacy. At V3 and V4, in patients of the main group, there was observed a clinically significant decrease in the severity of nasal congestion, nasality, enlarged cervical lymph nodes (p&lt;0.05). There was insignificant difference between the groups in the dynamics of nasal discharge and postnasal drip symptoms at all visits (р&gt; 0,05).&#x0D; The analysis of the dynamics of indicators of pharyngeal tonsil hypertrophy in both groups of patients was carried out before the operation. There are significant differences between hypertrophy indicators between V1 and V4 (p&lt;0.05). After eliminating the operated patients, there were no differences between the groups in the degree of hypertrophy (p&gt; 0.05). The need for surgery decreased in patients of the main group. A 14.8% decrease in adenotomy rate was observed: from 53.7% in the control group to 38.9% in the main group (p&lt;0.05). Conservative treatment was prolonged in 61.1% of patients in the main group and 46.3% of patients in the control group.&#x0D; No patient developed side effects.&#x0D; Conclusions: the adequate pharmacologic treatment of CNP associated with EBV has improved clinical symptoms and reduced the indications for surgical treatment in 61.1% of patients.

Computational study on the discharge dynamics of atmospheric pressure He plasma driven by high frequency AC voltage

A two dimensional self-consistent fluid model has been established to investigate the discharge dynamics of double-ring electrode He atmospheric pressure plasma jet (APPJ) driven by high frequency AC voltage. The difference of the internal stream and external jet and the influence of the change of applied voltage polarity on plasma discharge characteristics has been discussed. It has been discovered that the capacitive breakdown characteristic of the double ring electrode significantly enhances the intensity of the APPJ. The discharge intensity of the external jet is stronger than that of the internal stream and the propagation speed of the external jet is faster than that of the internal stream due to the ionization and Penning ionization of N2 and O2. Therefore, the density of reactive species in the external jet is greater than that in the internal stream. When the negative voltage is applied to the downstream electrode, the propagation direction of the internal stream changes to the downstream electrode. The ionization of the external jet is also concentrated near the downstream electrode and in the streamer head. The radial propagation distance of the external jet on the dielectric surface continues to increase and the peak value of the radial electric field is concentrated at the streamer head. When the applied voltage changes from negative to positive, the propagation direction of the internal stream turns to the upstream electrode and the upstream jet is formed above the electrode. At the beginning of the positive cycle, the radial propagation distance of the external jet is shortened due to the effects of the electron attachment of O2 and the radial electric field. With the increase of applied voltage, the ionization in the streamer head gradually increases, which promoted the radial propagation of external jet.