Repetitive Discharges Research Articles

Association of Complex Repetitive Discharges With Chronicity and Clinical Symptoms in Radiculopathies.

Complex repetitive discharges (CRDs) are incompletely understood needle electromyography (EMG) waveforms seen in both myopathic and neurogenic disorders including radiculopathies. This study aimed to clarify the significance of CRDs in patients with radiculopathies. This case-control study randomly identified 100 patients with needle EMG evidence of radiculopathy demonstrating at least one CRD in the electrodiagnostically involved myotome between January 2017 and January 2022. These patients were compared with 100 randomly selected patients with EMG evidence of radiculopathy without CRDs controlled for sex, age at EMG testing, and affected nerve root segment. Patient clinical symptoms, neurologic examination, EMG features, and imaging were analyzed. A paired sample t-test for categorial data and χ2 test for nonparametric data were used for statistical analysis with significance defined as P < 0.05. Patients with radiculopathies with CRDs had longer disease duration averaging 59 months (range 1-480) compared with patients with radiculopathies without CRDs averaging 26 months (range 1-192, P < 0.01). Clinical symptoms of paresthesias and weakness were both significantly more common in patients with radiculopathies with CRDs than those without CRDs (P < 0.01 and 0.01, respectively). Needle EMG demonstrated a greater average number of muscles with neurogenic motor unit potentials per radiculopathy in patients with radiculopathies with CRDs compared with those without CRDs. Imaging studies of patients with radiculopathies with CRDs were more likely to reveal evidence of nerve root compression (P < 0.01). The presence of CRDs in patients with radiculopathies is consistent with clinically more symptomatic radiculopathies and a longer duration of nerve root compromise.

Polymer Protective Layer Releasing Additives to Electrolyte of Lithium Metal Anode

As the need of batteries with high energy density raises, lithium metal anode has attracted considerable attention due to its high theoretical specific capacity and low reduction potential. However, there are several technical issues in practical use of lithium metal anode due to the growth of lithium dendrite and chemical instability with liquid electrolyte. It is essential to form the stable solid electrolyte interphase (SEI) layer on lithium metal anode to prevent lithium dendrite growth and minimize side reaction of liquid electrolyte. Designing the SEI with high Li+ ion conductivity and mechanical strength is imperative to stabilize lithium metal anode. Recently, various additives have been investigated to form a stable SEI layer on Li metal. However, during repetitive charge and discharge process, the additives in the electrolyte can be depleted by continuously forming SEI, which results in capacity fading of batteries. In this work, we developed the polymer protection layer containing excessive amount of additives that form the stable SEI layer. The additives can be stored in the polymeric layer, continuously released to the electrolyte during the repeated cycling. Electrochemical analyses such as linear sweep voltammetry and cyclic voltammetry were investigated, and the Li/Li symmetric cells showed the regulation of lithium deposition with small overpotential. The cycling performance of lithium metal batteries with protection layer was evaluated with high nickel NCM cathode.

Internal Magnetic Fields for Improved Cyclability in Aqueous Zn-Br2 Static Batteries

Owing to their high safety and low-cost, aqueous zince-bromine batteries (AZBBs) are envisioned as being highly applicable in both portable and stationary energy storage. The highly reversible Zn/Zn2+ (-0.76 V vs. RHE) and Br-/Br2 (1.08 V vs. RHE) redox couples have been employed in Zn-Br2 flow batteries (1.84 V vs. RHE), although widespread implementation has not been realized. This is largely because parasitic losses in overall battery performance rapidly occur due to i) dendritic growth of Zn deposits during the repetitive discharge process, leading to internal short circuits and ii) the cross-diffusion of highly soluble Br- (Br3 -) ions causing severe self-discharge and reduced cycle life. Common approaches to mitigate these problems include electrode engineering and incorporating additives and ion-selective membranes into the system for improving cycle life and coulombic efficiency. This talk will highlight the benefits of fabricating an aqueous Zn-Br2 static battery with internally contained magnetic fields, (~ 30, 40, 50 and 60 mT) at the anode and cathode by incorporating 1 mm thick Nd permanent magnets. Here we show that moderate internal magnetic fields are capable of simultaneously mitigating dendrite growth while drastically reducing cross-diffusion, leading to enhanced cycle life and improved energy and voltage efficiency. Operando UV-Vis spectroscopy, scanning electro microscopy (SEM), and electrochemical methods (electrochemical impedance spectroscopy and cyclic voltammetry) were used to to rationalize the effect of magnetic fields on the performance and cyclability of AZBBs.

Influence of frequency on the partial discharge characteristics of biaxially oriented polypropylene film under nanosecond pulse voltage

Partial discharge (PD) is one of the key factors leading to premature insulation failure of film capacitors used in pulse power devices. To study the effect of frequency on the PD characteristics of biaxially oriented polypropylene (BOPP) film, a sphere-plate electrode was used to simulate defects of the air gap between the film layers. PD experiments of the BOPP film were carried out under 1, 10, 100, 500 Hz, and 1 kHz with a rising edge of 65 ns and a pulse width of 300 ns. The results show that the repetitive partial discharge inception voltage (RPDIV), the number of discharges, the rising stage discharge (RSD) amplitude, and the falling stage discharge (FSD) time-lag, all show an increase and then decrease with increasing pulse frequencies and reach a maximum value at a pulse frequency of 100 Hz. Moreover, the FSD discharge amplitude and the RSD discharge time-lag increase with an increasing pulse frequency. From the perspective of initial electron generation, the quantitative mathematical relationship between PD characteristics (RPDIV, PD amplitude, PD number, and PD time-lag) and frequency was established based on the Fowler–Nordheim field emission effect for the first time, which can reflect the influence of frequency on the memory effect and the development process of PD. The results can provide an experimental basis and a mechanistic explanation for the evaluation of PD characteristics for film capacitors under nanosecond pulse voltage.

Formation mechanism of Fe-based amorphous powders produced by spark erosion

Spark erosion is a convenient, flexible, and low-cost method to quickly produce fine powders of metals, alloys, and semiconductors in size ranging from nearly a hundred micrometers to submicrometer by repetitive spark discharges. Due to the complexity of the powder-forming journey, normally accompanied by high temperature, high pressure, decomposition, diffusion and rapid quenching caused by discharge plasma, the mechanisms of powder formation and possible contaminant infiltration are still controversial, posing a significant challenge to control particle size and chemical composition of the powder produced by this method. In this study, Fe-based amorphous powders in different particle-size distributions with high sphericity were fabricated by spark erosion under different discharge-energy conditions. The maximum particle size of the resultant powders can be correlated with discharge parameters, crater depth, and crater radius, respectively. A multi-ring-breakup model is proposed to reveal the particle-size distribution of the powder formed from the electrode melt under a single-pulse discharge. Furthermore, a dielectric-element infiltration model is provided to quantitatively evaluate the infiltration mass ratio of the contaminant elements, stemming from the decomposed products of dielectric liquid, in the resultant powder with different particle sizes. The models verified through the experimental data are significant for the development of high-performance fine Fe-based amorphous powder with controlled particle size and chemical composition.

Potential Benefit of Channel Activators in Loss-of-Function Primary Potassium Channelopathies Causing Heredoataxia.

Potassium channels (KCN) are transmembrane complexes that regulate the resting membrane potential and the duration of action potentials in cells. The opening of KCN brings about an efflux of K+ ions that induces cell repolarization after depolarization, returns the transmembrane potential to its resting state, and enables for continuous spiking ability. The aim of this work was to assess the role of KCN dysfunction in the pathogenesis of hereditary ataxias and the mechanisms of action of KCN opening agents (KCO). In consequence, a review of the ad hoc medical literature was performed. Among hereditary KCN diseases causing ataxia, mutated Kv3.3, Kv4.3, and Kv1.1 channels provoke spinocerebellar ataxia (SCA) type 13, SCA19/22, and episodic ataxia type 1 (EA1), respectively. The K+ efflux was found to be reduced in experimental models of these diseases, resulting in abnormally prolonged depolarization and incomplete repolarization, thereby interfering with repetitive discharges in the cells. Hence, substances able to promote normal spiking activity in the cerebellum could provide symptomatic benefit. Although drugs used in clinical practice do not activate Kv3.3 or Kv4.3 directly, available KCO probably could ameliorate ataxic symptoms in SCA13 and SCA19/22, as verified with acetazolamide in EA1, and retigabine in a mouse model of hypokalemic periodic paralysis. To summarize, ataxia could possibly be improved by non-specific KCO in SCA13 and SCA19/22. The identification of new specific KCO agents will undoubtedly constitute a promising therapeutic strategy for these diseases.

Associated factors with stimulation induced seizures and the relevance with surgical outcomes

ObjectiveTo analyze the associated factors with stimulation-induced seizures (SIS) and the relevant factors in predicting surgical outcomes. MethodsWe analyzed 80 consecutive epilepsy patients explored by stereo-electroencephalography with routine electrical stimulation mapping (ESM). If seizures induced by ESM, patients were classified as SIS-positive (SIS-P); otherwise, SIS-negative (SIS-N). Patients received radical surgery were further classified as favorable (Engel I) and unfavorable (Engel II–IV) groups. ResultsOf the 80 patients included, we identified 44 (55.0%) and 36(45.0%) patients in the SIS-P and SIS-N groups, respectively. Multivariate analysis revealed that the seizure onset pattern (SOP) of preceding repetitive epileptiform discharges following LVFA (PRED→LVFA) (OR 3.319, 95% CI 1.200–9.183, P = 0.021) and pathology of focal cortical dysplasia (FCD) type II (OR 3.943, 95% CI 1.093–14.226, P = 0.036) were independent factors influencing whether the electrical stimulation can induce a seizure. Among the patients received radical surgery, there were 55 and 15 patients in the favorable and unfavorable groups separately. Multivariate analysis revealed that the SOP of PRED→LVFA induced seizures by stimulation (OR 11.409, 95% CI 1.182–110.161, P = 0.035) and bilateral implantation (OR 0.048, 95% CI 0.005–0.497, P = 0.011) were independent factors affecting surgical outcomes. The previous epilepsy surgery had a trend to be a negative factor with SIS (OR 0.156, 95% CI 0.028–0.880, P = 0.035) and surgical outcomes (OR 0.253, 95% CI 0.053–1.219, P = 0.087). ConclusionESM is a highly valuable method for localizing the seizure onset zone. The SOP of PRED→LVFA and FCD type II were associated with elicitation of SIS by ESM, whereas a previous epilepsy surgery showed a negative association. Furthermore, the SOP of PRED→LVFA together with SIS in the same patient predicted favorable surgical outcomes, whereas bilateral electrode implantation predicted unfavorable outcomes.

D-type K+ current rules the function of electrically coupled neurons in a species-specific fashion.

Electrical synapses supported by gap junctions are known to form networks of electrically coupled neurons in many regions of the mammalian brain, where they play relevant functional roles. Yet, how electrical coupling supports sophisticated network operations and the contribution of the intrinsic electrophysiological properties of neurons to these operations remain incompletely understood. Here, a comparative analysis of electrically coupled mesencephalic trigeminal (MesV) neurons uncovered remarkable difference in the operation of these networks in highly related species. While spiking of MesV neurons might support the recruitment of coupled cells in rats, this rarely occurs in mice. Using whole-cell recordings, we determined that the higher efficacy in postsynaptic recruitment in rat's MesV neurons does not result from coupling strength of larger magnitude, but instead from the higher excitability of coupled neurons. Consistently, MesV neurons from rats present a lower rheobase, more hyperpolarized threshold, as well as a higher ability to generate repetitive discharges, in comparison to their counterparts from mice. This difference in neuronal excitability results from a significantly higher magnitude of the D-type K+ current (ID) in MesV neurons from mice, indicating that the magnitude of this current gates the recruitment of postsynaptic-coupled neurons. Since MesV neurons are primary afferents critically involved in the organization of orofacial behaviors, activation of a coupled partner could support lateral excitation, which by amplifying sensory inputs may significantly contribute to information processing and the organization of motor outputs.

FEA-Based Simulation of Accelerated Ageing in a Power Cable Due to Sustained Partial Discharge Activities in a Spherical Cavity

The reliability of electrical assets is greatly influenced by the quality of their insulations. Key power installations such as power cables are manufactured with polymer-based materials as part of their insulation system. However, accelerated ageing of equipment insulations due to manifestation of defect(s), and partial discharges (PDs) can offset the operation of these systems or even lead to breakdowns. In this study, a non-deterministic model to simulate the phenomenon of repetitive discharges in a spherical air-filled cavity within a practical power cable has been investigated. In addition, the work contributes to the understanding of PD behaviour and field distribution under different ageing conditions considering changes in cavity surface conductivity. First, a section of the practical XLPE cable containing the cavity is developed in 2D using COMSOL software, and a finite element analysis (FEA) of the electric field distribution within the cable insulation is performed. The magnitude of the cavity local field, that is enough to ignite a PD, is investigated. Alongside the COMSOL model, the activity of sustained internal PD is simulated in MATLAB by introducing a random sample generating factor and adjusting the model’s parameters to obtain something close to the practical results. Furthermore, the impact of continuous PD in the power cable under different cavity dimensions and surface conductivity is likewise investigated, and a phase resolved PD (PRPD) pattern is established. The result shows that the magnitude and number of PDs per cycle increase as the cavity size and its surface conductivity increase. Finally, when the cavity surface conductivity rises, the amplitude of the electric field generated by the surface charge distribution and the number of PDs per cycle approach their maximum values.

Nanosecond plasma actuation by a bending actuator mounted on a sharp edge in quiescent air

An experimental investigation of the actuation characteristics of a repetitive nanosecond pulsed dielectric barrier discharge from bending plasma actuators mounted on a sharp edge is conducted. Four bending actuators with different bending angles are tested and compared with a planar actuator in quiescent air using schlieren imaging and electrical measurements. The results show that when fed by the same pulse, the plasma morphology, current waveform, and energy consumption of the bending and planar actuators are very similar. However, the thermal perturbations and induced flows differ significantly. In this experiment, at a low load voltage (V = 10–14 kV), when the plasma discharge is in the diffuse mode, the bending actuator can induce a stronger vortex and near-wall jet than the planar actuator, and as the bending angle decreases, the strength of the induced jet increases rapidly. At a higher load voltage (V = 18–20 kV), when the discharge is in the constricted mode, the plasma filaments produce hot plumes with both the bending and planar actuators, but the hot plumes from the bending actuator are injected into the air with a larger incidence. During the streamer-to-filament transition (V = 16 kV), induced flows from small-bending-angle (30° and 60°) actuators are characterized by a thickened near-wall jet, while those from the planar actuator are characterized by hot plumes.

ID: 214919 Rare Cause of Hyperhidrosis Associated With Lumbar Radiculopathy

Sweating is an imperative process by which our body thermoregulation itself. It is not uncommon for sweating to be associated with other conditions such as poly or mononeuropathies and myelopathies. There have been reports of cervical disc herniation leading to hyperhidrosis. Hyperhidrosis from lumbar radiculopathies, however, is very rare with only one case reported to our knowledge. Although the pathophysiology is unknown, it is thought to be related to denervation hypertrophy. Another rare phenomenon that occurs with radiculopathy in which complex repetitive discharges, that contribute to hypertrophy in type 1 muscle fibers leading to hyperhidrosis.

Design and test of a compact capacitor-based energy storage pulsed power module with high repetitive discharge frequency

Advance in electromagnetic launch have put forward higher requirements for the pulsed power supply(PPS). A capacitive PPS for electromagnetic launcher has been constructed in NJUST recently with a basic cell of 220kJ energy storage, which has a good scalability. Design of integrated 220kJ pulsed power unit (PFU) was demonstrated in the paper. To meet the requirement of compact structure of PPS, the device design and system layout are considered and combined with simulation to optimize the magnetic field distribution in the constrained space. In order to achieve the function of continuous discharge, the reliability of thermal management system, control system and safety protection system are focused on. System description was presented in the paper. A series of experiments were conducted to verify the performance of the module. The results show that the PFU shows good reliability in 10 consecutive burst-shot tests. Due to the modular setup of this pulse formation network, it can be extended to a larger-scale pulse forming network. Flexible current pulse shapes can be formed by controlling the charging voltage and the trigger time of the PFU.

Relationship between serum neuron-specific enolase and EEG after cardiac arrest: A reappraisal

ObjectiveElectroencephalogram (EEG) and serum neuron specific enolase (NSE) are frequently used prognosticators after cardiac arrest (CA). This study explored the association between NSE and EEG, considering the role of EEG timing, its background continuity, reactivity, occurrence of epileptiform discharges, and pre-defined malignancy degree. MethodsRetrospective analysis including 445 consecutive adults from a prospective registry, surviving the first 24 hours after CA and undergoing multimodal evaluation. EEG were interpreted blinded to NSE results. ResultsHigher NSE was associated with poor EEG prognosticators, such as increasing malignancy, repetitive epileptiform discharges and lack of background reactivity, independently of EEG timing (including sedation and temperature). When stratified for background continuity, NSE was higher with repetitive epileptiform discharges, except in the case of suppressed EEGs. This relationship showed some variation according to the recording time. ConclusionsNeuronal injury after CA, reflected by NSE, correlates with several EEG features: increasing EEG malignancy, lack of background reactivity, and presence of repetitive epileptiform discharges. The correlation between epileptiform discharges and NSE is influenced by underlying EEG background and timing. SignificanceThis study, describing the complex interplay between serum NSE and epileptiform features, suggests that epileptiform discharges reflect neuronal injury particularly in non-suppressed EEG.

Neurogenetics: Congenital Myotonic Dystrophy with asymptomatic mother may be missed by whole exome sequencing; Biopsy, DMPK1 gene testing and EMG may be required to resolve VUS in neonates, A Case report. (P6-8.010)

<h3>Objective:</h3> We show how biopsy, EMG, and <i>DMPK1</i> gene testing may be required for variant resolution. Whole exome sequencing revealed <i>NEB</i> (nebulin) (OMIM #161650) variants of uncertain significance inherited in <i>trans</i>. Muscle biopsy and EMG were helpful in resolving <i>NEB</i> VUS (variants of uncertain significance) and the detection of myotonia even as young as 6 days of age, with a clinically asymptomatic mother. <h3>Background:</h3> Myotonic dystrophy type 1 (myotonia dystrophia 1) is an autosomal dominant multisystem disorder caused by CTG expansion of the <i>DMPK1</i> gene (dystrophia myotonica protein kinase) (OMIM #605377) resulting in anticipation, whereby offspring have greater repeat expansion and severity. <h3>Design/Methods:</h3> <h3>Case Report:</h3> This full-term patient was born with severe hypotonia and respiratory depression. Brain MRI, EEG, Karyotype (46, XY) and FISH were normal. Whole Exome Sequencing (WES) revealed heterozygous <i>NEB</i> VUS, in <i>trans</i>, but histochemical and electron microscopic examinations of the muscle biopsy did not show nemaline rods. EMG was performed and revealed myotonic discharges. A genetic diagnosis of myotonic dystrophy type 1 was made, with over 200 CTG repeats in the <i>DMPK1</i> gene. A week after tracheostomy and g-tube placement, oxcarbazepine was trialed, after which he was able to be weaned off ventilation and discharged to home. He made substantial progress over the next year. <h3>Results:</h3> NA <h3>Conclusions:</h3> Neonatal muscle biopsies may not show nemaline rods due to being early or sampling error and thus further testing may be required. When evaluating severe congenital myopathies, testing for myotonic dystrophy should be considered. Myotonia may be found in neonates as young as 6 days old characterized as briefer duration with waning repetitive small amplitudes between 50–100uV without the classic sound on a spectrum with complex repetitive discharges. Severe congenital myotonic dystrophy patients may be born from an asymptomatic mother and the diagnosis may be missed by whole exome sequencing. <b>Disclosure:</b> Mr. Appiah has nothing to disclose. Dr. Shergelashvili has nothing to disclose. Dr. Marr has nothing to disclose. Ahmed Eldokla has nothing to disclose. Dr. LEBEL has nothing to disclose. Dr. Sakonju has nothing to disclose.

Distinct patterns of interictal intracranial EEG in focal cortical dysplasia type I and II

ObjectiveFocal cortical dysplasia (FCD) is the most common malformation causing refractory focal epilepsy. Surgical removal of the entire dysplastic cortex is crucial for achieving a seizure-free outcome. Precise presurgical distinctions between FCD types by neuroimaging are difficult, mainly in patients with normal magnetic resonance imaging findings. However, the FCD type is important for planning the extent of surgical approach and counselling. MethodsThis study included patients with focal drug-resistant epilepsy and definite histopathological FCD type I or II diagnoses who underwent intracranial electroencephalography (iEEG). We detected interictal epileptiform discharges (IEDs) and their recruitment into repetitive discharges (RDs) to compare electrophysiological patterns characterizing FCD types. ResultsPatients with FCD type II had a significantly higher IED rate (p < 0.005), a shorter inter-discharge interval within RD episodes (p < 0.003), sleep influence on decreased RD periodicity (p < 0.036), and longer RD episode duration (p < 0.003) than patients with type I. A Bayesian classifier stratified FCD types with 82% accuracy. ConclusionTemporal characteristics of IEDs and RDs reflect the histological findings of FCD subtypes and can differentiate FCD types I and II. SignificancePresurgical prediction of FCD type can help to plan a more tailored surgical approach in patients with normal magnetic resonance findings.

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.

After-discharge activity as a basis to change intraoperative mapping protocol for functionally significant brain areas

Background. After-discharge (AD) activity is a pattern that differs from background corticography, represented by rhythmic stereotypical slow waves and/or repetitive spike discharges with ≥1 Hz frequency, recorded after cessation of electrical stimulation and lasting for more than 2 seconds. Despite the accumulated experience in the field of intraoperative neuromonitoring, there is no unified protocol for high-frequency stimulation of cortical functional areas (FAs) upon the AD event.Objective: to demonstrate a need to change the intraoperative FAs mapping protocol in patients with brain tumor on awakening in cases of AD recording.Material and methods. Two clinical cases of awake surgical functional mapping followed by resection of the brain tumor are presented. Multimodal monitoring included high-frequency stimulation according to the approved intrahospital protocol with maximum stimulation force of auditory-speech zones of 2.5 mA, electrocorticography, and subcortical dynamic mapping.Results. In the first case, AD was registered while FAs mapping in a patient with a history of one epileptic seizure, upon reaching the maximum stimulation force of 2.5 mA, that was replaced by recording focal epileptiform activity with the following evolution to ictal generalized event and development of intraoperative convulsive seizure. In the second patient with a history of recurrent epileptic seizures, AD with spatiotemporal evolution of the pattern development of clinical ictal event was registered with stimulation at 2.5 mA. In both cases, the appearance of AD required to change mapping protocol with a stepwise decrease in stimulus strength to obtain cortical FAs data.Conclusion. Registration of AD is the basis for changing the protocol of high-frequency cortical stimulation in surgical treatment of brain tumor FAs.

Simplified Electrochemical Approaches for Quality Determination of the Wetting Process in Lithium‐Ion Cell Production

Electrolyte filling and wetting are safety‐relevant and time‐ and cost‐intensive processes in lithium‐ion cell production, and are hence critical process steps. Currently, only limited measurement technologies are available that would be suitable for inline monitoring and quality assurance of these process sequences. Herein, two promising electrochemical approaches for monitoring electrolyte wetting are presented, which can be utilized in low‐cost measurement devices. Starting from the introduction of a simplified impedance approach with a straightforward data evaluation, a direct current‐based method is introduced that does not require impedance equipment, and can thus be performed with standard battery cyclers. First, the extended applicability of the simplified impedance measurement is demonstrated by examining the dependence of experimental impedance results on varying electrolyte volumes, also including insufficient amounts. Subsequently, the impedance approach is transferred into the direct current method. The latter mimics impedance signals by utilizing repetitive direct current charge and discharge pulses, which are used to determine the batteries’ internal resistance during the electrolyte wetting. Both introduced approaches yield comparable results and allow the inline monitoring of the electrolyte wetting with basic equipment and with no need for demanding data evaluation.

Repetitive pulsed gas-liquid discharge in different atmospheres: from discharge characteristics to plasma-liquid interactions.

Gas-liquid discharges enable efficient plasma-liquid interactions and thus have promising applications, but many concerns remain unanswered regarding working gas, an important influencing factor. Investigations of a pulsed needle-to-water gas-liquid discharge in Ar, He, and N2 are carried out in this study. Voltage-current waveforms and intensified charge-coupled device (ICCD) images were combined to explore discharge modes and evolution processes. Experimental results demonstrate that the Ar tip spark discharge develops all the way to liquid compared with the He and N2 discharges concentrated in the tube, considerably increasing the plasma-liquid interaction efficiency. According to the optical emission spectra (OES), plasma properties are found to be strongly influenced by interactions between gas particles and interfering particles (H2O, etc.). For instance, excess water vapor causes quenching of excited species, resulting in OH (A-X) in Ar and NO (A-X) in N2 concentrated in the middle region with weak discharge. By adding dimethyl sulfoxide, it is demonstrated that OH dominates H2O2 production in Ar and contributes to both NO2- and NO3- generation in Ar and He, whereas in N2 it only affects NO3- generation. This study advances the "bridge building" between practical application and gas-liquid discharge employing different working gases.

Characterization of PDIV, PDEV, and RPDIV in Insulated Wires Under Unipolar Repetitive Square Wave Excitations for Inverter-Fed Motors

The behaviour of partial discharge inception voltage (PDIV), partial discharge extinction voltage (PDEV) and repetitive partial discharge inception voltage (RPDIV) as a function of exposure/poling time under unipolar repetitive square wave excitations at atmospheric pressure (1013 mbar) is experimentally measured and investigated. The partial discharge (PD) tests are performed on two commercially available insulated wires: Glass fibre as Type II and Polyether Ether Ketone (PEEK) as Type I insulated wires used in inverter-fed motors. The impact of excitation polarity, pulse repetition frequency and rise time on the PD quantities (i.e., PDIV, PDEV and RPDIV) is studied as a function of stressing duration. In addition, the trend of RPDIV and PDIV dispersion levels are compared as a function of poling time under positive and negative unipolar excitations with two rise times (i.e., 80 and 800 ns) and two pulse repetition frequencies (i.e., 50 Hz and 2.5 kHz), relying on the shape/slope parameter of the Weibull distribution. The collected data shows that the electric field induced by the interface charge deposited by PD occurring during consecutive pulses and the space charge accumulation in the insulation bulk plays a decisive role in PD quantities’ variations under unipolar repetitive square wave excitations.