Discharge Mode Research Articles

Modelling of Capillary Discharge in Repetition Mode for Short Capillary Systems with Various Filling Methods

Modelling of Capillary Discharge in Repetition Mode for Short Capillary Systems with Various Filling Methods

An experimental and computational investigation of discharge mode transitions in a partially magnetized radio frequency capacitively coupled oxygen discharge

AbstractA magnetized capacitively coupled oxygen plasma was studied synergistically using phase resolved optical emission spectroscopy and particle‐based kinetic simulation. Discharge mode transitions from ambipolar mode into drift mode and finally into α mode induced by increasing the magnetic field were observed at different driving frequencies and different electrode gaps. The simulation results demonstrate that the discharge operating in the same mode exhibits a similar degree of electronegativity. By increasing driving frequency or electrode gap, the same discharge mode transition tends to occur at a lower magnetic field, and, meanwhile, the high electric field and electron power absorption shift from the bulk region to the sheath edge.

Novel multineedle-to-cylinder plasma coupled with bimetallic catalysts for efficient removal of sulfides and ammonia in odor gases

Dielectric barrier discharge (DBD) plasma is a promising technology for treating odor gases. This study developed an innovative multineedle-to-cylinder (MC) configuration DBD plasma reactor and investigated its synergistic effect with bimetallic catalysts. The results demonstrated that MC-DBD plasma achieved complete elimination of ammonia and organic sulfides, while the removal efficiencies of inorganic H2S and CS2 reached 44.0 % and 53.0 % respectively. Compared with conventional plasma, the specific energy input (SEI) of MC-DBD was significantly reduced to 4.44 J/L. Furthermore, with the incorporation of Mn-Ce/ZSM-5 catalyst, optimal removal efficiencies of H2S and CS2 were significantly improved to 82.6 % and 90.7 %, and the SEI was reduced by 18 %. The electrical performance revealed that the low energy consumption was mainly attributed to stable fast-pulse micro-discharge channels and significantly enhanced inhomogeneous electric fields achieved by the filament discharge mode. Catalyst characterization (X-ray photoelectron spectroscopy and O2-temperature programming desorption) confirmed that surface catalytic reaction mainly follows the Mars-van Krevelen mechanism, where increased lattice oxygen content and the electron transfer between Mn and Ce play crucial roles in enhancing malodor degradation performance. This work proposes an efficient solution for degrading mixed malodors and provides an experimental and theoretical basis for optimizing plasma structure as well as researching treatment of mixed pollutants.

Design and evaluation of a geothermal power plant integrated with Mg(OH)₂/MgO thermochemical energy storage system: A dynamic simulation for assessing flexibility in power generation, energy, and economics

This study proposes a Carnot battery system that integrates MgO/Mg(OH)2-thermochemical energy storage (TCES) in a fluidized bed reactor (FBR) with Kalina cycle of a geothermal power plant. In the charge mode, surplus electricity from variable renewable energy is converted into heat and stored through the dehydration of Mg(OH)2. In the discharge mode, the hydration of MgO occurs in the FBR, and the reaction heat is converted into electricity through the Kalina cycle. Dynamic simulations of the charge and discharge modes were conducted using a non-steady state fluidized bed model. Results show the energy storage efficiency and capital cost were 76.4% and 68 USD/MJth for the base case, respectively. Round-trip efficiency and levelized cost of storage were 8.62% and 0.291–0.769 USD/kWhe, respectively, when the charging electricity cost was 0–0.042 USD/kWhe. A cost-competitive Carnot battery system using MgO/Mg(OH)2-TCES with high energy storage density and an easy-to-operate FBR has been developed.

Discharge mode and particle transport in radio frequency capacitively coupled Ar/O2 plasma discharges

Abstract Simulations are conducted on capacitively coupled Ar/O2 mixed gas discharges employing a one-dimensional fluid coupled with an electron Monte Carlo (MC) model. The research explores the impact of different O2 ratio and pressures on the discharge characteristics of Ar/O2 plasma. At a fixed Ar/O2 gas ratio, with the increasing pressure, higher ion densities, as well as a slight increase in electron density in the bulk region can be observed. The discharge remains dominated by the drift–ambipolar (DA) mode, and the flux of O(3P) at the electrode increases with the increasing pressure due to higher background gas density, while the fluxes of O(1D) and Ar* decrease due to the pronounced loss rate. With the increasing proportion of O2, a change in the dominant discharge mode from α mode to DA mode can be detected, and the O2-associated charged particle densities are significantly increased. However, Ar+ density shows a trend of increasing and then decreasing, while for neutral fluxes at the electrode, Ar* flux decreases, and O(3P) flux increases with the reduced Ar gas proportion, while trends in O(1D) flux show slight differences. The evolution of the densities of the charged particle and the neutral fluxes under different discharge parameters are discussed in detail using the ionization characteristics as well as the transport properties. Hopefully, more comprehensive understanding of Ar/O2 discharge characteristics in this work will provide a valuable reference for the industry.

Integrating Residents – Organizational Quality Metric of reducing 30-day readmission of patients with acute decompensated heart failure (Interdisciplinary QI project)

Introduction: Hospital readmissions post-discharge for congestive heart failure (CHF) pose a significant burden on patients and healthcare systems, indicating potential gaps in care quality. The 2022 heart failure guidelines advocate for structured workflows to address this issue. Despite this, McLaren Flint Hospital witnessed a rise in 30-day readmissions for CHF exacerbation, highlighting the need for intervention. To tackle this challenge, our resident-faculty Quality Improvement (QI) team has partnered with institutional QI/Patient Safety (PS) initiatives. Our goal is to establish a coordinated approach involving various healthcare professionals to optimize the discharge process and transition of care for CHF patients at McLaren Flint Hospital. Methods and Materials: Our intervention comprises two crucial tools: a CHF workflow sheet and a CHF medication sheet. The workflow begins with patient identification through daily census reports. Upon discharge, nurses implement the CHF medication sheet, with medications prescribed by medical floor doctors. Pharmacists and dietitians review and educate patients about medications and dietary considerations, respectively. Additionally, case managers organize post-discharge phone calls and appointments with primary care physicians within 48 to 72 hours and 7 days, respectively. Weekly reports on patients requiring cardiac rehabilitation are also dispatched. Plan-Do-Study-Act (PDSA) Toolkit guides our implementation, allowing for continuous improvement and adaptation. Results: The initial implementation phase commenced on March 6th, 2024. Nursing staff are well-versed in the workflow, and CHF medication forms are readily accessible in patient charts. However, challenges in timely medication reconciliation and orders pose operational hurdles, necessitating resolution. Ongoing evaluation will provide more comprehensive results approximately two months post-completion of the first PDSA cycle. Conclusion: Our initiative aims to address areas for improvement in reducing 30-day readmission rates post-CHF exacerbation at McLaren Flint Hospital. Utilizing the PDSA cycle toolkit, we will monitor outcomes and refine our process accordingly.

Gliding arc discharge in combination with Cu/Cu2O electrocatalysis for ammonia production

Highly efficient and green ammonia production is an important demand for modern agriculture. In this study, a two-step ammonia production method is developed using a gliding arc discharge in combination with Cu/Cu2O electrocatalysis. In this method, NO x is provided by the gliding arc discharge and then electrolyzed by Cu/Cu2O after alkaline absorption. The electrical characteristics, the optical characteristics and the NO x production are investigated in discharges at different input voltage and the gas flow. The dependence of ammonia production through Cu/Cu2O electrocatalysis on pH value and reduction potential are determined by colorimetric method. In our study, two discharge modes are observed. At high input voltage and low gas flow, the discharge is operated with a stable plasma channel which is called the steady arc gliding discharge mode (A-G mode). As lowering input voltage and raising gas flow, the plasma channel is destroyed and high frequency breakdown occurs instead, which is known as the breakdown gliding discharge mode (B-G mode). The optimal NO x production of 7.34 mmol h−1 is obtained in the transition stage of the two discharge modes. The ammonia yield reaches 0.402 mmol h−1 cm−2 at pH value of 12.7 and reduction potential of −1.0 V versus reversible hydrogen electrode (RHE).

The Healthcare Improvement and Innovation in Quality (THINQ) Collaborative: A Novel Quality Improvement Training Program for Undergraduate and Postgraduate Students.

The Healthcare Improvement and Innovation in Quality (THINQ) Collaborative is a uniquely designed program that engages undergraduate and postgraduate students to participate in improving health care and addressing important clinical problems. In 9 years, over 120 THINQ Fellows have been trained in quality improvement (QI) frameworks and methodologies focusing on research skills, social justice, leadership development, and problem-solving. Program evaluation has included surveying current and former THINQ Fellows about their experiences with the program and its subsequent impact on their careers. THINQ's research and outreach initiatives have contributed to improvements in workflows and clinical care on topics such as interdisciplinary team communication, discharge and care transition, sepsis management, and physician burnout. The THINQ Program has equipped future health care leaders to engage with and address QI issues in clinical practice. The structures, processes, and outcomes discussed here can guide other institutions in creating similar QI programs.

Research on topology technology of integrated battery energy storage system with reconfigurable battery and converter

In traditional battery energy storage systems (BESS), batteries are usually connected in a simple series or parallel form, and separate converters and balancing modules are typically used for energy exchange between the battery and external sources, as well as for balancing energy between batteries. This paper proposes an integrated battery energy storage system (IBESS) with reconfigurable batteries and DC/DC converters, resulting in a more compact structure. The IBESS can reconfigure the connection of energy storage batteries based on the battery's status and external demand. The DC/DC converters can operate in different modes such as boost, buck, or buck-boost converters. The IBESS has five working modes: discharging mode, balancing mode, battery discharging and balancing mode, constant current and constant voltage (CCCV) charging mode and backup mode. To verify the feasibility of the proposed energy storage system, a model with four battery modules was built using MATLAB/SIMULINK, and the operation of all working modes was demonstrated. The simulation results verified the system's performance and reliability, demonstrating its flexibility and efficiency in different operating modes.

Characterization of heated volume generation by nanosecond pulsed plasma actuator with various pressure environments

Nanosecond dielectric barrier discharge (NS-DBD) has emerged as a promising technique for controlling high-speed flows, generating a heated volume that generates strong density and viscosity gradients, thereby perturbing flow dynamics. Since its potential application in low-pressure, high-speed flows, understanding how the size and growth of the heated volume correlate with surrounding pressure is crucial. In this study, we employed typical schlieren and background-oriented schlieren (BOS) techniques to investigate the heated volume’s sensitivity to surrounding pressure in quiescent air. The observed heated volume’s size variations with surrounding pressure likely stemmed from the increase in thermal diffusivity at lower pressures. BOS findings unveiled a nearly linear decrease in heated volume’s core density with energy input. Meanwhile, the heated volume’s size augmented with energy input but exhibited gradual saturation, attributable possibly to shear stresses impeding volume expansion as temperature and viscosity rose, or to consumption of energy in vibration excitation and other reactions. In the cases of 100 and 50 kPa, the sensitivity of the heated volume’s size to the reduced electric field appeared to be similar. However, at 10 kPa, where the reduced electric field is higher compared to that of the 100 and 50 kPa cases due to the lower air density, the size sensitivity drastically decreased. This suggested a transition in discharge mode from filamentary to diffusive behavior at lower pressures.

Enhanced surface performance of insulating ceramic by plasma polymerization with nanosecond-pulse dielectric barrier discharge: Insight into the effect of the repetition frequency

Insulating ceramics are widely used in power systems, but their high polarity makes them prone to wet and pollution flashover. In this paper, an Ar/polydimethylsiloxane dielectric barrier discharge excited by a parametric nanosecond-pulse power source is utilized for plasma polymerization to enhance ceramic surface insulating performance. Diagnosis of the discharge characteristics and surface physiochemical properties is conducted at different repetition frequencies to investigate the mechanism associated with the relationship between repetition frequency and the plasma polymerization process. The results indicate that a superhydrophobic surface can be achieved at repetition frequencies above 2 kHz. This transformation brings about multiple effects, including a decrease in surface polarity, an increase in charge dissipation, and an improvement in surface dry and wet flashover voltages. It is discovered that the discharge mode shifts from homogeneous to filamentary due to the memory effect of high repetition frequencies. Additionally, several filaments are generated simultaneously during a single pulse, facilitating the polymerization reactions. For high repetition frequencies, a low-polarity silicon-containing film with micro-nanometer structures is deposited on the ceramic surface, while scattered polymer fragments are generated on the surface without a cross-linked film for repetition frequencies below 2 kHz, despite longer treatment durations.

Identification of Collision Simplified Model Parameters for Lithium‐Ion Batteries

The crash analysis of complete electric vehicles demands high accuracy, speed, and modeling flexibility of the crash finite element analysis of single battery and battery packs. Herein, the crash analysis process is optimized using an artificial neural network (ANN) and a genetic algorithm (GA), and according to experimental conditions, working characteristic parameters of a single 18650 lithium‐ion battery, such as state of charge value and discharge mode are examined. It is combined with the beam elements of a simplified model of a five‐layer single 18650 battery, and the mechanical characteristic parameters are identified. The process comprises two parts: prediction of the mechanical properties of the battery cell from the operating characteristics of the single 18650 battery and the rapid solution of the simplified mechanical parameters of the beam elements from the mechanical properties of the battery. The accuracy of the prediction results of the ANN model reaches over 97%, and the fit between the simulation results of the GA identification parameters and the experimental results reaches over 95%. The identification parameters can make quick responses to the experimental results under different working conditions, which ground the application of the simplified beam element model in the battery packs.

Design and Control Strategy of an Integrated Floating Photovoltaic Energy Storage System

Floating photovoltaic (FPV) power generation technology has gained widespread attention due to its advantages, which include the lack of the need to occupy land resources, low risk of power limitations, high power generation efficiency, reduced water evaporation, and the conservation of water resources. However, FPV systems also face challenges, such as a significant impact from aquatic environments on the system’s stability and safety and high operational and maintenance costs, leading to large fluctuations in the grid-connected power output. Therefore, it is necessary to integrate energy storage devices with FPV systems to form an integrated floating photovoltaic energy storage system that facilitates the secure supply of power. This study investigates the theoretical and practical issues of integrated floating photovoltaic energy storage systems. A novel integrated floating photovoltaic energy storage system was designed with a photovoltaic power generation capacity of 14 kW and an energy storage capacity of 18.8 kW/100 kWh. The control methods for photovoltaic cells and energy storage batteries were analyzed. The coordinated control of photovoltaic cells was achieved through MPPT control and improved droop control, while the coordinated control of energy storage batteries involved a droop charge–discharge mode, a constant-voltage charging mode, and a standby mode. The simulations were realized in MATLAB/Simulink and the results validated the effectiveness of the coordinated control strategy proposed in this study. The strategy achieved operational stability and efficiency of the integrated photovoltaic energy storage system.

Systematic review of contemporary interventions for improving discharge support and transitions of care from the patient experience perspective.

To synthesize the impact of improvement interventions related to care coordination, discharge support and care transitions on patient experience measures. Systematic review. Searches were completed in six scientific databases, five specialty journals, and through snowballing. Eligibility included studies published in English (2015-2023) focused on improving care coordination, discharge support, or transitional care assessed by standardized patient experience measures as a primary outcome. Two independent reviewers made eligibility decisions and performed quality appraisals. Of 1240 papers initially screened, 16 were included. Seven studies focused on care coordination activities, including three randomized controlled trials [RCTs]. These studies used enhanced supports such as improvement coaching or tailoring for vulnerable populations within Patient-Centered Medical Homes or other primary care sites. Intervention effectiveness was mixed or neutral relative to standard or models of care or simpler supports (e.g., improvement tool). Eight studies, including three RCTs, focused on enhanced discharge support, including patient education (e.g., teach back) and telephone follow-up; mixed or neutral results on the patient experience were also found and with more substantive risks of bias. One pragmatic trial on a transitional care intervention, using a navigator support, found significant changes only for the subset of uninsured patients and in one patient experience outcome, and had challenges with implementation fidelity. Enhanced supports for improving care coordination, discharge education, and post-discharge follow-up had mixed or neutral effectiveness for improving the patient experience with care, compared to standard care or simpler improvement approaches. There is a need to advance the body of evidence on how to improve the patient experience with discharge support and transitional approaches.

Sociodemographic Characteristics and Clinical Profile of Inpatients in the Psychiatry Unit of a Tertiary Care Hospital in Assam: A Retrospective Study

Objectives Recent years have seen a significant evolution in the understanding pertaining to mental health issues. The analysis of the intricate interplay between an individual’s sociodemographic factors, genetic makeup, the environment, and clinical profile (diagnosis and treatment) of patients will help us understand the prevalence and types of mental health disorders prevalent in Assam, which is a culturally, ethnically and socially diverse state. The pattern of utilization of electroconvulsive therapy has also been analyzed. The aims and objectives of the study is to analyze the sociodemographic characteristics and clinical profile of patients admitted in Psychiatry ward, Assam Medical College and Hospital. Material and Methods An analysis on the case records of all individuals admitted to the hospital’s Psychiatry ward between August 1, 2022 and July 31, 2023 was done. Data on socio-demographic details such as age, gender, domicile and clinical profile (diagnosis, mode of discharge, duration of stay and treatment) was compiled using semi-structured format designed by authors. Information regarding patients undergoing electroconvulsive therapy was also gathered from the records. Statistical analysis: The data were subjected to analysis utilizing the Statistical Package for Social Sciences (IBM SPSS Statistics for Windows, version 25.0). Results A total of 680 patients got admitted of which higher proportion constituted of male (77.58%) and majority individuals were aged between 30 and 39 years (29.65%). The predominant diagnosis among the inpatients was substance use disorders (39.09%). Out of all the psychotropic drugs, olanzapine (17.94%) was mostly prescribed on discharged followed by risperidone (10.15%). Escitalopram (3.97%) was the mostly prescribed antidepressant on discharge. Patients diagnosed as substance use disorders were mostly discharged on lorazepam (5%), baclofen (14.26%) and received an average number of 1.8 sessions of Motivational Enhancement Therapy (MET). Whereas, schizophrenia and related disorders was the most common diagnosis among inpatients receiving ECT (51.52%). Conclusion Our study helped to understand the socio-demographic attributes and clinical profile of the inpatients to foster better management approaches.

Modern engineering solutions for an original domestic nitric oxide generator (“Tianox”)

Nitric oxide (NO) is a biologically active molecule approved for the treatment of persistent pulmonary hypertension in newborns in the USA, Japan, and most European countries in 1999 – 2008. Inhaled NO is currently used to treat a spectrum of cardiopulmonary disorders, including pulmonary hypertension in children and adults. A commercially available NO delivery system uses pressurized cylinders as a source of NO. Current cylinder-based delivery systems are widely used around the world, but they are bulky, expensive and dependent on a reliable supply chain. The aim of the work was to present an original domestic generator for NO inhalation therapy. Over the past few years, to overcome the limitations of the balloon technology, specialists from the Federal State Unitary Enterprise “Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics” have developed a plasma-chemical NO generator that produces NO from ambient air using a nonequilibrium spark discharge plasma. In this case, a diffuse discharge mode is implemented, which ensures the most efficient synthesis of NO with the participation of excited nitrogen molecules (N2+) according to a chain mechanism similar to the Zeldovich – Semenov chain reaction. The result is a high-quality NO-containing gas mixture that does not contain toxic by-products (electrode material, ozone, etc.) usually formed in the known systems of this type. Conclusion. Based on the developed generator, the Federal State Unitary Enterprise “Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics” designed and created the world’s first commercially available device for inhalation therapy, “Tianox”. The device was approved for circulation on the territory of the Russian Federation by order of the Federal Service for Surveillance in Healthcare (2020) based on the results of technical and clinical tests. Serial production of “Tianox” meets the requirements of ISO 13485-2016 and GOST ISO 13485-2017.

Corona Discharge Modes and Their Detections Under DC and AC Voltages

Corona Discharge Modes and Their Detections Under DC and AC Voltages

Covalent surface grafting of Ti3C2Tx flakes for enhancement of symmetric supercapacitor performance

In this work the covalent surface modification of MXene flakes (Ti3C2Tx) was proposed for the increasing of the performance of subsequently created symmetric supercapacitor. Covalent surface modification was performed with utilization of diazonium salts (hydrophobic or hydrophilic) and plasmon-assisted photochemistry. Applied procedure allows to block the reactive (weak and/or catalytically active) sites on flakes surface and increase the flakes interplanar spacing, both enhancing the functionality of an MXene-based supercapacitor. Especially pronounced positive effect gives the surface modification with hydrophilic chemical moieties. In particular, we observed increase of supercapacitance from 197 to 284 F g−1 in acidic and from 86 to 142 F g−1 in alkaline conditions for flakes grafted with –C6H4–COOH chemical moieties at scan rate 20 mV/s. The flakes grafted with hydrophobic chemical moieties allow to achieve almost constant value of supercapacitance for different speed of charge discharge. In addition, the surface grafting prevents the supercapacitor degradation and decelerates the spontaneous discharge in open circuit mode. These results suggest strategy for further improvement of MXene-based supercapacitors as energy storage device.

Remediation of 3,4,3′,4′-tetrachlorobiphenyl (PCB77) contaminated soil via a fluidized bed dielectric barrier discharge

In this study, 3,4,3′,4′-tetrachlorobiphenyl (PCB77) contaminated soil was remediated by a fluidization bed dielectric barrier discharge (DBD) reactor and a fixed bed DBD reactor. The fluidized bed reactor could attain superior removal efficiency of PCB77 under same experimental parameters. In-situ discharge mode was more conducive to the degradation of PCB77 than ex-situ discharge mode due to short-lived active species existing in in-situ discharge. The influence of experimental parameters in the fluidized bed DBD reactor on the degradation of PCB77 were discussed such as electric features, gas features, soil features and initial PCB77 concentration. PCB77 removal efficiency in air discharge could reach 88.5 % after 8 min under the alkaline condition. Optical emission spectroscopy (OES) and quench tests showed that reactive oxygen species (ROS) and reactive nitrogen species (RNS) were generated in the discharge system and they both played a vital role in the degradation of PCB77. Scanning electron microscopy (SEM) results demonstrated that discharge had little effect on the morphology of soil particles. Energy dispersive spectrometer (EDS), ion chromatography (IC), and total organic carbon (TOC) results showed that the DBD could effectively mineralize and dechlorinate PCB77. The possible degradation pathway of PCB77 was inferred at the end based on the degradation products determined by gas chromatography–mass spectrometry (GC–MS).

Effect of O2/n-C5H12 Ratio on Oxygenates Production from Plasma N-pentane Partial Oxidation

Objective: Non-thermal plasma is a promising method for producing clean fuels. This work provides a deeper understanding of the impact of O2/n-C5H12 ratio on the partial oxidation of n-pentane from both physical and chemical perspectives. Moreover, this work offers insight into improving fuel combustion efficiency and technical support for the preparation of clean fuels. Methods: An experimental system based on dielectric barrier discharge plasma was established. The discharge characteristics and product generation status of n-pentane partial oxidation were measured by changing the concentration of oxygen and n-pentane to evaluate different O2/n-C5H12 ratios. Results: Research on discharge characteristics showed that the O2/n-C5H12 ratio did not affect the discharge mode, and typical Lissajous shapes were present at different ratios. Changing the O2/n-C5H12 ratio affected the oxygen concentration, average electron energy or electron density, and background temperature. As the O2/n-C5H12 ratio increased, the conversion of the n-pentane partial oxidation reaction increased. However, changing the O2/n-C5H12 ratio did not affect the type of generated products. The oxygenates exhibited a volcano curve, and an O2/n-C5H12 ratio of 1.00 achieved the highest selectivity of 35.1%. As the O2/n-C5H12 ratio continued to increase, the selectivity of oxygenates decreased and the selectivity of CO2 increased. This was potentially due to a shift from partial oxidation toward complete oxidation, which led to the generation of secondary pollutants. Thus, higher O2/n-C5H12 ratios were not conducive to clean fuel production and environmental friendliness. Conclusion: In the partial oxidation of n-pentane, the highest clean fuel production rate was achieved when the O2/n-C5H12 ratio was 1.00. When this ratio exceeded 1.00, the reaction shifted toward complete oxidation, producing secondary pollutants. This study provides ideas for improving fuel combustion efficiency and technical support for the preparation of clean fuels.