Single Discharge Research Articles

Hydrogen Peroxide Production of Individual Nanosecond Pulsed Discharges Submerged in Water of Elevated Conductivity.

The production of hydrogen peroxide (H2 O2 ) is a key parameter for the performance of pulsed discharges submerged in water utilized as advanced oxidation process. So far, any related assessment of the underlying mechanism was conducted for the application of several hundred discharges, which did not allow for a correlation with physical processes. Moreover, the production was rarely investigated depending on water conductivity as one of the most important parameters for the development of submerged discharges. Accordingly, hydrogen peroxide generation was investigated here for individual single discharge events instigated with 100 ns high-voltage pulses in water with three different conductivities and was associated with the discharge development, i. e. spatial expansion and dissipated electrical energy. The approach necessitated the improvement of an electrochemical flow injection analysis based on the reaction of Prussian blue with H2 O2 . Hydrogen peroxide concentrations were quadratically increasing with propagation time and stable for different water conductivities. H2 O2 production per unit volume of a discharge was constant over time with an estimated rate constant of 3.2 mol ⋅ m-1 s-1 , averaged over the crosssectional area of all discharge filaments. However, the individually dissipated energy increased with conductivity, hence, the production efficiency decreased from 6.1 g ⋅ kWh-1 to 1.4 g ⋅ kWh-1 , which was explained by increased resistive losses within the bulk liquid.

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.

A Fast Activation Energy Derivation (FAED) approach for Lumped Single Particle model in lithium-ion battery module-level heat generation prediction

The performance of electric vehicles (EVs) heavily relies on the durability and longevity of lithium-ion cells, which are strongly affected by operating temperatures. Various electrochemical models have been developed to investigate the impact of operating temperature on the dynamic heat generation at cell level. Among these, the Lumped Single Particle (LSP) model stands out due to its lower computational cost and higher accuracy under >1C-rates. However, key electrochemical parameters (i.e. the ohmic overpotential, exchange current, and diffusion time constant) in the LSP model are temperature-sensitive, requiring Arrhenius dependencies. Conventional activation energy measuring approaches, relying on testing under discrete fixed temperatures to obtain activation energies, are time-consuming. To address this, this paper proposes a FAED approach that fits the temperature-sensitive parameters and corresponding activation energies to experimental data with a single discharge process, reducing the testing time to a minimum of one hour. This approach was experimentally validated on a Tesla battery module (74P6S), demonstrating a good agreement between simulation and experimental results up to 1.5 C-rates, ranging from 16 ℃ to 46 ℃. Furthermore, this approach is suitable for cells with different lithium chemistries, formats, and properties, making it an effective method for thermal analysis of EV packs.

A comparative study on the different energy supply modes for a micro-cathodic arc thruster

The energy supply mode of a micro-cathodic arc thruster (μ-CAT) was adjusted based on the charge and discharge characteristics of the energy storage element, and the cathode discharge characteristics of μ-CAT were studied under different energy supply modes. We applied an electrical method to measure the discharge characteristics of μ-CAT, with an enhanced intensified charge coupled device spectrum detector to measure the plasma parameters of μ-CAT, allowing analysis of the internal logic among thruster plasma parameters, arc discharge characteristics, and thruster energy supply mode. The mechanisms of μ-CAT were analyzed and characteristics of accumulated discharge, energy distribution, and ion velocity distribution of thruster were compared under different energy supply modes to obtain the effect of the energy supply mode on the discharge characteristics of the interelectrode of μ-CAT. The results show that the energy supply mode of μ-CAT affected the ionization characteristics and ionization stability of the micro-cathodic arc thruster, causing a multistage ionization difference in the cathode metal target. This would not only affect the propulsion performance of the thruster, but also affect the change of the number of particles in the cathode region in a single discharge cycle.

Impact of jet velocity profile on the propulsive performance and vortex ring formation of pulsed jet propulsion

A squid-inspired jet propulsion system that indudes a deformable body and a nozzle exit attached to it is numerically studied. By prescribing the body deformation during a single discharge, we examine the impact of jet speed profiles on the vortex ring formation and propulsion performance of the system. Our results show that a secondary vortex ring following the leading vortex ring can be produced by the reverse cosine jet speed pattern at a given maximum stroke ratio, and for the other profiles (i.e., constant, cosine, reverse cosine, half cosine and rever half cosine styles) only distributed vortices are seen behind the leading vortex ring. The constant jet speed produces the largest time-averaged thrust due to jet momentum flux related thrust associated with its large jet speed. Except for the constant speed style, the largest mean thrust production and propulsion factor are obtained by the reverse cosine profile among the other four styles attributed to the formation of the secondary vortex ring. Nevertheless, this secondary vortex ring would not be produced at a small maximum stroke ratio for the reverse cosine speed fashion. We also find that the mean thrust production can reach a maximum under a specific maximum stroke ratio (Γm = 7.60) when two vortex rings are produced. This work may provide insight into the mechanical and control design of jet-based biomimetic propellers and robots.

Study on the electric discharge behaviour of a single contact in EV motor bearings

Electric current discharge in motor bearings is becoming more of a concern with the move toward electric vehicles (EV), since it can damage bearing surfaces and potentially cause premature failures. Electric discharge (ED) tests were carried out utilizing a self-improved ball-on-disc instrument under elastohydrodynamic lubrication (EHL) regime to better understand the nature of electric discharge in EV motor bearings. The experiments prove that the discharge behaviour is related to the lubricant film thickness and the discharges appear at the minimum film thickness area. An electric discharge energy model was developed to describe the relationship between working conditions and the energy of a single discharge. The model was qualitatively verified by comparing the predicted ED damages with the ball-on-disc test results.

Photo-Electro-Thermal Model and Fuzzy Adaptive PID Control for UV LEDs in Charge Management

Inertial sensors can serve as inertial references for space missions and require charge management systems to maintain their on-orbit performance. To achieve non-contact charge management through UV discharge, effective control strategies are necessary to improve the optical power output performances of UV light sources while accurately modeling their operating characteristics. This paper proposes a low-power photo-electro-thermal model for widely used AlGaN-based UV LEDs, which comprehensively considers the interaction of optical, electrical, and thermal characteristics of UV LEDs during low-power operations. Based on this model, an optical power control system utilizing a fuzzy adaptive PID controller is constructed, in which a switch is introduced to coordinate the working state of the controller. Thus, the steady-state performance is effectively improved while ensuring dynamic performance. The results show that the proposed model has an average prediction error of 5.8 nW during steady-state operations, and the fuzzy adaptive PID controller with a switch can reduce the fluctuation of light output to 0.67 nW during a single discharge task, meeting the charge management requirements of high-precision inertial sensors.

Behavioral State-Dependent Modulation of Prefrontal Cortex Activity by Respiration.

Respiration-rhythmic oscillations in the local field potential emerge in the mPFC, a cortical region with a key role in the regulation of cognitive and emotional behavior. Respiration-driven rhythms coordinate local activity by entraining fast γ oscillations as well as single-unit discharges. To what extent respiration entrainment differently engages the mPFC network in a behavioral state-dependent manner, however, is not known. Here, we compared the respiration entrainment of mouse PFC local field potential and spiking activity (23 male and 2 female mice) across distinct behavioral states: during awake immobility in the home cage (HC), during passive coping in response to inescapable stress under tail suspension (TS), and during reward consumption (Rew). Respiration-driven rhythms emerged during all three states. However, prefrontal γ oscillations were more strongly entrained by respiration during HC than TS or Rew. Moreover, neuronal spikes of putative pyramidal cells and putative interneurons showed significant respiration phase-coupling throughout behaviors with characteristic phase preferences depending on the behavioral state. Finally, while phase-coupling dominated in deep layers in HC and Rew conditions, TS resulted in the recruitment of superficial layer neurons to respiration. These results jointly suggest that respiration dynamically entrains prefrontal neuronal activity depending on the behavioral state.SIGNIFICANCE STATEMENT The mPFC, through its extensive connections (e.g., to the amygdala, the striatum, serotoninergic and dopaminergic nuclei), flexibly regulates cognitive behaviors. Impairment of prefrontal functions can lead to disease states, such as depression, addiction, or anxiety disorders. Deciphering the complex regulation of PFC activity during defined behavioral states is thus an essential challenge. Here, we investigated the role of a prefrontal slow oscillation that has recently attracted rising interest, the respiration rhythm, in modulating prefrontal neurons during distinct behavioral states. We show that prefrontal neuronal activity is differently entrained by the respiration rhythm in a cell type- and behavior-dependent manner. These results provide first insight into the complex modulation of prefrontal activity patterns by rhythmic breathing.

High-efficiency EDM based on a composite pulse current

EDM technology is still facing a big bottleneck problem unsolved: low molten material removal rate, resulting in low machining speed and poor surface quality. To improve the material removal amount in each discharge process of EDM, the composite pulse current waveforms were proposed. The single pulse discharge experiments demonstrate that under the same discharge energy, the material removal volume in the discharge with the end composite pulse could be twice as high as that with the square pulse. Furthermore, due to high molten material removal rate of the end composite pulse, the thickness of the recast layer generated in the discharge with the end composite pulse was much thinner than that with the square pulse under the same discharge energy. The MD simulation results also revealed that in the discharge with the end composite pulse, the basic current mainly melted the material to form a larger molten pool, then, the inrush current, which had higher energy density and higher material removal motivity, could remove the molten pool material largely. Thus, the end composite pulse can improve the molten material removal rate and decrease the recast layer. Finally, EDM milling experiments show that higher average material removal volume in each discharge process of EDM milling with the end composite pulse was the main reason for higher material removal rate (MRR) in EDM milling with the end composite pulse. In addition, the relative tool wear ratio (RTWR) in EDM milling with the end composite pulse can be approximately equal to or slightly lower than that with the square pulse at a high material removal rate in EDM milling, which shows a great application potential of the end composite pulse in EDM.

P40 LIGHTS AND SHADOWS OF THE MICROCOAXIAL PUMP DEVICE IN A UNIQUE SETTING: CARDIOGENIC SHOCK DUE TO ACUTE MYOCARDIAL INFARCTION IN PATIENT WITH UNKNOWN HYPERTROPHIC CARDIOMYOPATHY

Abstract Cardiogenic shock remains the leading cause of death in patients with acute myocardial infarction (AMICS). The IntraAortic Balloon Pump (IABP) has been the device of first choice for these patients for years, but it has not shown a mortality benefit over optimal medical therapy. The Impella (AbioMed, Danvers, Massachusetts) is an alternative circulatory support system that produces cardiac output appropriate for the needs of the patient. A 59–year–old mailman suddenly lost consciousness during his work. Basic life support was administered, and ROSC was achieved after a single effective defibrillator discharge. When the ambulance arrived, the patient presented conscious but complained of oppressive chest pain, with soreness in his left arm and head. EKG showed an ST elevation in aVR and aVL and a right bandle branch block (Fig 1). Aspirin, Heparin, and opioids were administered. During the transport, hemodynamic parameters appeared to deteriorate towards cardiogenic shock. Coronary angiography showed a total occlusion of the left main. Cangrelor was started promptly. Hemodynamic conditions dictated the application of a mechanical circulatory support device (MCSD), so IABP was applied. Primary angioplasty was performed with restoration of TIMI 3 flow. A 3.50 x 23 mm everolimus–eluting stent was implanted with a good result. Norepinephrine was ineffective in achieving satisfactory hemodynamic status with systemic arterial pressure below 50 mmHg. After volemic restoration, neither IABP nor the vasopressor could interrupt the spiral of cardiogenic shock. A coaxial pump, i.e. the Impella CP, was applied via left arterial femoral access. Despite the precise placement of this device, the parameters suggested a poor suction capacity from the pump–inlet into the left ventricle (LV) to systemic circulation in aorta. Meanwhile, echocardiogram revealed an unknown and severe hypertrophic cardiomyopathy that did not allow a proper functioning of the Impella CP device (Fig. 2). When a temporary pacemaker was applied due to reperfusion bradycardia, there were a better LV diastolic filling and Impella functioning due to right pacing. The patient was transferred to the intensive care unit, Impella was removed after 3 days, he was extubated within two weeks, no brain damage was reported but he is still hospitalised after a concomitant urinary infection, with predictable low ejection fraction (around 30%). We‘ll see: luckily, slow improvement, it is still an improvement!

Confined sulfur electrode to achieve quasi-solid state sulfur conversion reaction in Li[sbnd]S battery

An ordered mesoporous carbon (OMC) inlaid with micropores was derived via a hard template method. OMC micropores loaded with sulfur (S-OMC) were used as a cathode for the LiS battery. A comparison of UV–Visible analysis of S, S-OMC and S-loaded carbon nanotube (S-CNT) indicated lower solubility of S into the electrolyte from S-OMC. Controlling the solubility of S into the electrolyte is important to reduce the polysulfide concentration in the electrolyte. Cyclic voltammetry and galvanostatic charge-discharge measurements of S-OMC indicated the merging of solid-S → polysulfide and liquid-polysulfide → lower-order lithium sulfide transitions. Instead of the two-plateau discharge curve normally observed in S‑carbon composite electrodes, a single sloppy discharge curve was observed with S-OMC. Which possibly due to lower S concentration in the electrolyte, which results in reduced polysulfide concentration and lowers dynamic viscosity of the electrolyte. At 0.2C, nearly 1254 mAh g−1 of capacity was realized with capacity loss <5 mAh g−1 even after 50 cycles in lean electrolyte condition (3 μL/mgS). Distributed relaxation time analysis performed using a series of Nyquist plots recorded at various stages of charging and discharging indicate sudden decrease in the solution+contact resistance as a result of improved electrolyte access into the pores due to sudden volume contraction associated with Li2S → S at potentials >2.2 V in the confined zone. Due to the confinement effect, the growth of Li2S occurs slowly both at the anode and cathode, thereby enabling high voltage and capacity discharge with S-OMC compared to the S-CNT.

Investigation of Partial Discharges within Power Oil Transformers by Acoustic Emission

This paper presents the authors’ multi-channel measurement systems designed and built to conduct research on partial discharge phenomena using the acoustic emission method. The systems provide real-time monitoring, recording of signals and analysis of recorded signals. The analysis is carried out in time, frequency, time-frequency and discrimination threshold domains. In particular, a descriptor with the ADC acronym is defined, which ranks the signals according to the so-called degree of advancement. Studies have been carried out, showing that for a single partial discharge source, when tested in parallel, using the electrical and acoustic emission methods, the ranking of the signals using this descriptor is identical to the ranking according to the value of the apparent charge introduced by sources. This paper presents the authors’ patented method of partial discharge location and identification in power oil transformers. The results of tests of power oil transformer at the test station, conducted in parallel with the electric method and the authors’ method, and the results of tests in three selected transformers carried out during ongoing in-situ operation using the authors’ method are presented. Based on these results, the authors make diagnoses of the condition of the insulation systems in the tested transformers. The inspections of these transformers confirm the diagnoses.

Process Development and Analysis of Electromagnetic Multi-Spot Joining of AA5052 Sheets

In this study, two sheets of AA5052 are joined with the high-strain-rate multi-spot joining process using an electromagnetic system. While producing a single spot joint by electromagnetic joining (EMJ) is common, the distribution and application of the pressure can be modified by the design of the coil and spacers to make multiple joints at once. When a preformed dimple is used to provide the standoff distance, it can eliminate the need for spacers and provide good aesthetics for the final product. In the current study, a joint design is developed to provide three spot joints coincidentally by a single discharge of a capacitor bank. For the experiment, four distinctive discharge energies were used for joining: 7, 8, 9, and 10 kJ. The most successful joint sample was made by 8 kJ and was tested for mechanical properties. The cross-section was observed in order for us to understand the joint quality produced by the process. It was found that the ”I”-shaped rectangular coil produces a variable magnetic flux, leading to different flyer deformation variations in the joint geometry. At the centre of the ”I” coil, the minimum flux was predicted, leading to lesser sheet forming, hence a weaker centre-spot joint strength. Further, a numerical study is performed to find the Von Mises stresses, equivalent plastic strain, impact velocity, and impact pressure on the sheets. This manuscript provides new information regarding coil designing and the changes that could be further made to improve the electromagnetic sheet multi-spot joining process.

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.

Effects of pulse rise time on electron dynamics properties in nitrogen–oxygen mixture under repetitive nanosecond pulses

The effects of pulse rise time on the temporal evolution of electron energy and density under repetitive nanosecond pulses in atmospheric nitrogen with 100 ppm oxygen impurities are investigated in this paper by a two-dimensional particle-in-cell/Monte Carlo collision model. It is found that the peak value of mean electron energy increases with decreasing pulse rise time in the single pulsed discharge. However, in the repetitive pulsed discharge approximated by pre-ionization, the peak value of mean electron energy no longer varies with the pulse rise time, showing a saturation trend with decreasing pulse rise time. Whether or not pre-ionization is present, the time required for the mean electron energy to reach its peak is approximately equal to the pulse rise time. It is worth noting that the presence of pre-ionization enhances the tracking ability of the mean electron energy to the pulse waveform during the pulse rise edge. Although after the peak of the pulse, the mean electron energy terminates the tracking process to pulse waveform due to the formation of high-density avalanches and even streamers, its energy decay rate gradually decreases with the increase in the pre-ionization density. Therefore, when the pulse repetitive frequency is greatly increased or the pre-ionization density is increased by other means, it is possible to achieve the complete control of the mean electron energy by pulse waveform modulation.

Co-variations of cerebral blood volume and single neurons discharge during resting state and visual cognitive tasks in non-human primates

To better understand how the brain allows primates to perform various sets of tasks, the ability to simultaneously record neural activity at multiple spatiotemporal scales is challenging but necessary. However, the contribution of single-unit activities (SUAs) to neurovascular activity remains to be fully understood. Here, we combine functional ultrasound imaging of cerebral blood volume (CBV) and SUA recordings in visual and fronto-medial cortices of behaving macaques. We show that SUA provides a significant estimate of the neurovascular response below the typical fMRI spatial resolution of 2mm3. Furthermore, our results also show that SUAs and CBV activities are statistically uncorrelated during the resting state but correlate during tasks. These results have important implications for interpreting functional imaging findings while one constructs inferences of SUA during resting state or tasks.

Switched Discharge Device for Enhanced Energy Extraction from Li-Ion 18650

All autonomous electrically powered devices require a continuous power supply from batteries. Increasing the discharge performance is the top priority in the Lithium-Ion (Li-Ion) battery field and pulsed discharge is proving numerous advantages. In this paper, the maximum efficiency of pulsed discharge method on a constant load while the cells are alternately switched with dead-time is thoroughly studied. Therefore, a novel Li-Ion charge/discharge and measurement device (SWD) using fast switching MOSFET was designed and fabricated. The device can alternately switch up to 8.3 kHz two Li-Ion 18650 batteries, generating continuous power to the programmable load and monitor the parameters that impact the capacity of the battery. An EIS (Electrochemical Impedance Spectroscopy) analysis is employed to evaluate the impedance and the behavior of the cells at frequencies up to 10 kHz. Experimental results reveal that a maximum discharge time is determined when two cells are switched at a frequency of 5.8 kHz. As a consequence, the total capacity of two switched batteries in a single discharge cycle is increased by 16.6%. Pulsed discharge efficiency is visible starting from 70% State of Charge (SOC) and is correlated with the rest time, reduced heat loss and inductance, respectively.

Array Point Discharge as Enhanced Tandem Excitation Source for Miniaturized Optical Emission Spectrometer.

A new compact tandem excitation source was designed and constructed by using an array point discharge (ArrPD) microplasma for a miniaturized optical emission spectrometer through coupling a hydride generation (HG) unit as a sample introduction device. Three pairs of point discharges were arranged in sequence in a narrow discharge chamber to construct the ArrPD microplasma, for improved excitation capability owing to the serial excitation. Besides, the discharge plasma region was greatly enlarged, therefore, more gaseous analytes could be intercepted to enter into the microplasma for sufficient excitation, for improved excitation efficiency and OES signal. To better understand the effectiveness of the proposed ArrPD source, a new instrument for simultaneous detection of atomic emission and absorption spectral responses was also proposed, designed, and constructed to reveal the excitation and enhancement process in the discharge chamber. Under the optimized conditions, the limits of detection (LODs) of As, Ge, Hg, Pb, Sb, Se, and Sn were 0.7, 0.4, 0.05, 0.7, 0.3, 2, and 0.08 μg L-1, respectively, and the relative standard deviations (RSDs) were all less than 4%. Compared with a commonly used single point discharge microplasma source, the analytical sensitivities of these seven elements were improved by 3-6-fold. Certified Reference Materials (CRMs) were successfully analyzed with this miniaturized spectrometer, which features low power, compactness, portability, and high detectability, and is thereby a great prospect in the field of elemental analytical chemistry.

Experimental research on the mechanism of the delamination extension of the carbon strip with heavy electrical current at the speed of 360 km/h

Delamination wear leads to a surge in the wear loss of the carbon strip. It also has a significant influence on the physicochemical properties of the contact pairs in the pantograph-catenary system (over 250 km/h). In this paper, the pure carbon/copper-alloy friction pair was chosen as the research object to study the wear evolution mechanisms and the law of delamination wear extension of the carbon strip, using a ring-on -block wear tester with a design speed of 400 km/h. And the arc discharge energy was calculated to investigate the quantitative relationship between the delamination wear and the arc discharge in the process of the test. The experimental results show that the frictional coefficient increases gradually with the experiment. The frictional coefficient with electric current is much bigger than that without electric current under the same test conditions. Under the intense arcing (when the average single arc discharge energy e > 76J), the delamination wear initially appears on one edge of the strip and gradually extends to the middle of the strip when sliding time t exceeds a certain value, which results in the increase of the wear of the strip and the further enhancement of the arc discharge. The result also indicates that delamination wear and its extension are occurred by the cumulative effect of the heat caused by the long-time strong arc discharge.

0D Modeling of Dry-Electrical Discharge Machining Plasma Discharge

Abstract There is a growing interest in developing the dry electrical discharge machining (EDM) process as a sustainable alternative to the conventional liquid dielectric-based EDM process. It is shown that the dry EDM process possesses advantages over the conventional process in terms of thermal damage, recast layer, and tool wear. However, there is a need to increase the productivity of the dry EDM process for its successful adaptation in the industry. This paper presents a dry EDM plasma discharge model with air as the dielectric medium. The model uses global modeling (0D) approach in which equations of mass balance, energy balance, and plasma expansion are solved simultaneously to obtain a time-dependent description of the plasma in terms of its composition, temperature, diameter, and heat flux to electrodes. The model includes reaction kinetics involving 622 reactions and 55 species to determine the air plasma composition. A single discharge dry EDM operation is successfully simulated using the model, and the effects of the interelectrode gap and discharge current on the plasma are studied. An increase in the interelectrode gap decreases the average electron density, plasma temperature, and heat flux. On the other hand, an increase in the discharge current increases the electron density, temperature, and diameter of the plasma linearly, while heat flux to the workpiece increases exponentially. Overall, the model provides an essential tool to study the dry EDM process mechanisms at a fundamental level and devise methods for process improvements.