Electrostatic Discharge Research Articles

Improving contact efficiency by novel powder forming film for high output DC-triboelectric nanogenerator

Charge generation and collection are key points for energy harvesting efficiency of direct current triboelectric nanogenerator (DC-TENG) based on the triboelectrification and electrostatic discharge. Herein, we propose a superior contact DC-TENG using polytetrafluoroethylene (PTFE) powder forming film and polyurethane (PU) foam as tribo-materials and multi-channel charge collection design. Different from traditional PTFE/PU TENG, the highly efficient contact of PTFE powder with PU foam increases electron transition in the triboelectrification process. The charge output of PTFE powder forming film TENG (PPF-TENG) increases by 40 % and 159 % than traditional PTFE film TENG with thickness of 30 µm and 140 µm, respectively. Three pairs of channels designed on slider with total area 21.6 cm2 realize the charge complete collection. The output current of PPF-TENG reaches its saturation in one period, 300 times faster than the traditional PTFE film TENG. The average power density of PPF-TENG up to 8.32 W m–2 is the highest record of sliding dual dielectric DC-TENGs. The PPF-TENG enables direct operation of 30 hydro-thermometers and 2880 green LEDs by hand motion, even under 85 % relative humidity conditions. This work provides a simple and efficient method to improve the output performance of TENG and gives the deep understanding of contact efficiency of tribo-layers.

Strategies to mitigate electrostatic charging during coffee grinding

Coffee grinding generates electrostatically charged particles, causing clumping, spark discharge, and beyond. When brewing, the particle aggregates affect liquid-solid surface accessibility, leading to variable extraction quality. Here, we study four charge mitigation strategies. De-electrification is readily achieved by adding small amounts of water to whole beans or by bombarding the grounds with ions produced from a high-voltage ionizer. While these techniques helped reduce visible mess, only water inclusion was found to impact coffee extracts prepared as espresso. Wetting whole beans with less than 0.05mL/g resulted in a marked shift in particle size distribution, by preventing clump formation and preventing fine particles from sticking to the grinder. This particle size shift results in at least a 15% higher coffee concentration for espresso extracts prepared from darker roasts. These findings encourage the widespread implementation of water use to de-electrify coffee during grinding with the benefit of increased coffee extraction efficiency.

Прогнозирование помех электростатического разряда в электронном устройстве с использованием искусственной нейронной сети

Electrostatic discharge is a dangerous source of natural electromagnetic interference to the operation of modern electronic devices. Although measures have been taken to reduce and remove electrostatic discharge from the operating area of electronic devices, the absence of such discharge cannot be guaranteed. Therefore, when designing modern electronic devices, it is necessary to take into account the possibility of such electrostatic discharges in advance and take protective measures. The article proposes a method for predicting the amplitude of interference in the communication line of an electronic device when exposed to an electrostatic discharge on its metal case. The technique is based on the use of an artificial neural network. The technique includes the analysis of significant input parameters that affect the amount of interference in an electronic device; development of an experimental stand for measuring interference; choosing the structure and parameters of a neural network for predicting interference; choosing a training method for an artificial neural network; choosing a metric for assessing the quality of training; normalization of training data; training an artificial neural network using experimental noise data; predicting the amplitude of interference in the communication line of an electronic device when exposed to an electrostatic discharge on its body; where necessary, selecting and implementing electrostatic discharge protection measures. Examples of training an artificial neural network based on experimental data are given. The training was carried out for 572 epochs. For the training and testing sets, the discrepancy between the predicted data and the average measured noise values was 3.61% and 3.95%, respectively. Examples are given of predicting the amplitude of interference when exposed to electrostatic discharge. The results obtained indicate the possibility of practical use of an artificial neural network to solve problems of electromagnetic interference analysis.

Ectonic Model and Erosion Mechanisms in a Pulsed Vacuum Arc Initiated by a Spark Discharge along the Dielectric Surface

Ectonic Model and Erosion Mechanisms in a Pulsed Vacuum Arc Initiated by a Spark Discharge along the Dielectric Surface

A gas spark switch electrode impact pressure test platform.

The discharge arc of a high-current gas spark switch has a strong mechanical effect on the electrode and adjacent objects. The measurement of this mechanical effect on the electrode plays a very important role in switch design and the theoretical study of spark discharge. However, in traditional stress measurement systems, the spatial electromagnetic interference caused by the discharge and the high electrode voltage affects the measurement accuracy and can even damage the experimental instrument. In this paper, an electrode impact stress measurement system based on PVDF piezoelectric film is designed to measure the electrode stress under a strong spatial electromagnetic field and high voltage. The experimental results show that the system can measure the impact pressure of high-voltage and high-current gas spark switch electrodes. The starting time of the stress measurement waveform shows that the shock to the electrode is formed in the initial stage of current buildup. The measured results clearly show the high magnetic field force component in the electrode impact pressure waveform. The shock waveforms induced by different pulse capacitor values, breakdown voltages, and loads are examined. It is found that the shock stress waveforms applied to the electrodes are affected by the peak value of the current, dI/dt, and the discharge duration.

Spark discharge-initiated radical polymerization

A new spark discharge initiated radical polymerization (SDRP) was developed. Monomer radicals were generated by spark discharge emitted from a Tesla coil as a resonant transformer generating high frequency and high voltage, and the monomer itself acted as an initiator for propagation in polymerization at the initial stage. Poly(styrene), poly(acrylonitrile), and poly(styrene)/poly(vinyl benzoate) were successfully synthesized by the SDRP. The versatile SDRP was further developed using 2,2,6,6-tetramethylpiperidine 1-oxyl free radical (TEMPO) to create dormant species to perform nitroxide-mediated-radical-polymerization. We employed d-limonene as a solvent for the SDRP because limonene can effectively dissolve the polymers. Furthermore, solitons of polyacetylene were employed as a polymerization initiator. The solutions as a carrier in polyacetylene was generated with spark discharge. This can be referred to as "soliton-initiated polymerization".

Design of High-Reliability Low-Dropout Regulator Combined with Silicon Controlled Rectifier-Based Electrostatic Discharge Protection Circuit Using Dynamic Dual Buffer

Overshoot and undershoot caused by the current load impact the accuracy of the required output voltage and circuit performance. The transient response issue in existing low-dropout (LDO) regulators is a dynamic specification that must be addressed at the design stage. This transient response is influenced by system parameters such as stability and gain. The LDO regulator suggested in this study is designed to minimize the change in output voltage by considerably enhancing the gain using a dynamic dual buffer structure. A dynamic dual buffer is utilized to effectively control undershoot and overshoot. Under the conditions that the input voltage range is from 3.3 to 4.5 V, the maximum load current is 300 mA, the output voltage is 3 V, and the output of the proposed LDO regulator with the dynamic dual buffer structure has undershoot and overshoot voltages of 41 mV and 31 mV, respectively. That is, the output voltage of the proposed LDO regulator effectively provided and discharged an additional current suited for the undershoot/overshoot conditions to enhance the transient response characteristics. Furthermore, the electrostatic discharge (ESD) robustness characteristics of the proposed LDO regulator improved because of the silicon-controlled rectifier underlying the ESD protection device embedded in the output node and power line.

Discharge and mass transfer characteristics of atmospheric pressure gas-solid two-phase gliding arc

In this work, a gas-solid two-phase gliding arc discharge (GS-GAD) reactor was built. Gliding arc was formed in the gap between the blade electrodes, and solid powder was deposited on the sieve plate positioned beneath the blade electrodes. A range of experimental parameters, including the inter-electrode spacing, gas flow rate, applied voltage, and the type of the powder, were systematically varied to elucidate the influence of solid powder matter on the dynamics of gliding arc discharge (GAD). The discharge images were captured by ICCD and digital camera to investigate the mass transfer characteristics of GS-GAD, and the electrical parameters, such as the effective values of voltage, current, and discharge power were record to reveal the discharge characteristics of GS-GAD. The results demonstrate that powder undergoes spontaneous movement towards the upper region of the gliding arc due to the influence of electric field force. Increasing the discharge voltage, decreasing relative dielectric constant of the powder and reducing the electrode-to-sieve-plate distance all contribute to a greater involvement of powder in the GAD process, subsequently resulting in an enhanced powder concentration within the GAD region. Additionally, powder located beneath the gliding arc experiences downward resistance caused by the opposing gas flow and arc. Excessive gas flow rate notably hampers the powder concentration within the discharge region, and the velocity of powder motion in the upper part of the GAD region is reduced. Under the condition of electrode-to-sieve-plate distance of 30 mm, gas flow rate of 1.5 L/min, and peak-to-peak voltage of 31 kV, the best combination of arc gliding and powder spark discharge phenomena can be achieved with the addition of Al2O3 powder.

Calibrations, Validations, and Checks of a Dual 23 nm and 10 nm Diffusion Charger-Based Portable Emissions Measurement System (PEMS).

The upcoming Euro 7 vehicle exhaust emissions regulation includes particle number (PN) limits for all vehicles, not only those with direct fuel injection. It also sets the lower detection particle size of the PN methodology to 10 nm from 23 nm. Recently, a commercial diffusion charger-based PEMS added the possibility of switching the lower size between 23 nm and 10 nm. In this study, we assessed the dual PEMS in the calibration laboratory using diffusion flame soot or spark discharge graphite particles following the regulated procedures. Furthermore, we compared the dual PEMS with a laboratory grade system (LABS) using soot, graphite, and vehicle exhaust particles. To put the results into perspective, we added comparisons (validations) of two additional 23 nm PEMSs with LABSs over a three-year period. The results showed that the differences of the 23 nm PEMSs remained the same (around 35% underestimation) over the years and were similar to the dual PEMS. This difference is still well within the permissible tolerance from the regulation (50%). We argued that the reason is the calibration material used by the manufacturer (spark discharge graphite). We demonstrated that calibrating with combustion soot could reduce the differences. The 10 nm PEMS gave similar results but with much smaller differences, indicating that the calibration material is of less importance for the Euro 7 step. The results showed that the measurement uncertainty has not increased but rather decreased for the specific PEMS switching from 23 nm to 10 nm.

An Experimental Murine Model to Study Lipoatrophia Semicircularis.

Lipoatrophia semicircularis is a benign pathology characterized by subcutaneous tissue atrophy that affects the skin and related structures. Its etiology remains unclear; however, in the recent few years, it has been proposed that electrostatic charges could be a potential factor. Based on this hypothesis, the aim of this work is to study the cause-effect relation between electrostatic energy and LS, providing insights into the molecular mechanisms. For this purpose, an experimental murine model was created using obese mice. One group served as a control and the other groups involved charging clothes with varying connections to the ground: through the skin, through the clothes or not connected to the ground). Skin biopsies showed that the most significant lesions, including lipophagic granulomas with inflammatory infiltrate, were found in the first group (connected to the ground through the skin). Lipophagic reactions without an inflammatory infiltrate were observed in the other groups subjected to electrical discharges. In the control mice, no histological changes were observed. Oxidative processes were also measured in lower limbs tissue. Malondialdehyde levels significantly increased in the lower limbs after electrostatic discharges. However, the presence of ground through a wire attached to highly conductive clothes around the thigh significantly reduced the effect of electrostatic charges on lipid peroxidation. To our knowledge, this is the first study in which an experimental model has been used to reproduce LS induced by electrostatic energy, suggesting a cause-effect relationship between electrostatic charge and discharge with fat tissue lesion.

Cold Nitrogen Plasma: A Groundbreaking Eco-Friendly Technique for the Surface Modification of Activated Carbon Aimed at Elevating Its Carbon Dioxide Adsorption Capacity

The commercially available activated carbon was modified using barrier and spark discharge low-temperature nitrogen plasma treatment. The samples were investigated using nitrogen sorption at a temperature of −196 °C, XRD, SEM, and FTIR methods, and elemental analysis. The nitrogen content on the surface was increased, but other properties, such as specific surface area, total pore volume, pseudocrystallite height, and pseudocrystallite width, remained unchanged. The activated carbons after nitrogen plasma treatment indicated higher CO2 adsorption than the pristine ones. Since the investigated materials only differed in their nitrogen content, it has been unequivocally demonstrated that the increased presence of nitrogen is responsible for the enhanced adsorption of CO2. The low-temperature nitrogen plasma treatment of activated carbon is a promising method for enhancing CO2 capture.

Decreasing the electrostatic discharge generated from friction of polyester and polyamide sing carbon fiber

AbstractThe present work discusses the voltage difference as a measure for electrostatic charge generated from the contact‐separation and sliding of polymeric textiles on polyamide textile. It is proposed to blend polyester by carbon fiber to decrease the electrostatic charge generated on the contact surfaces. Because polyester acquires a negative charge and polyamide gains a positive one, carbon fiber is proposed to conduct the negative electrostatic charge from polyester to polyamide and conducts the positive one from polyamide to polyester, so that the resultant electrostatic charge decreased. The effect of carbon fiber to decrease the electrostatic charge depends on its area of contact, interaction, and distribution with polyester. Polyester double weaved by carbon fiber showed the lowest voltage. Based on those observations, it can be recommended to use double weaves of carbon fiber with polyester. The reduction in voltage was relatively lower for braided polyester by carbon fiber than that detected for double‐weaved polyester by carbon fiber.

Effect of electrolyte pH value on microstructure and corrosion resistance of black MAO coating on 6063 aluminum alloy

Black micro-arc oxidation (MAO) coatings were obtained on the surface of 6063 aluminum alloy by using the MAO technique in silicate electrolyte with colorant NH4VO3. The work aimed to study the effect of adjusting the electrolyte pH (pH10, pH11, pH12, and pH13) on the microstructure, mechanical properties, and corrosion resistance of black MAO coatings on 6063 aluminum alloy. The experimental results showed that the electrolyte pH had an important effect on the macroscopic morphology of the MAO coatings. As the electrolyte pH value increased, the process voltage of the sample decreased, the duration of the anodic oxidation stage and the spark discharge stage were shortened, while the duration of the micro arc oxidation stage was prolonged. Reasonable adjustment of the electrolyte pH could reduce the poriness and defects of the coatings, decrease the surface roughness of the coatings, and improve the quality and wear resistance of the coatings. The corrosion resistance of the black MAO coating obtained in the electrolyte with pH12 was superior and the corrosion current density was only 3.207×10−7 A/cm2. The immersion corrosion test further demonstrated the same results of corrosion resistance.

Dynamics of high-speed electrical tree growth in electron-irradiated polymethyl methacrylate.

Dielectric materials are foundational to our modern-day communications, defense, and commerce needs. Although dielectric breakdown is a primary cause of failure of these systems, we do not fully understand this process. We analyzed the dielectric breakdown channel propagation dynamics of two distinct types of electrical trees. One type of these electrical trees has not been formally classified. We observed the propagation speed of this electrical tree type to exceed 10 million meters per second. These results identify substantial gaps in the understanding of dielectric breakdown, and filling these gaps is paramount to the design and engineering of dielectric materials that are less susceptible to electrostatic discharge failure.

Anticancer transmission effects induced by hybrid plasma bubble-activated medium

As an indirect application of cold atmospheric plasma, the use of plasma-activated solutions has recently attracted significant attention for intracavity tumor perfusion therapy. Here, an underwater plasma-bubble reactor with three discharge modes was applied to activate a cell culture medium, with the aim of inhibiting the growth of bladder cancer T24 cells in vitro. The results showed that although the reactive species in cell culture medium generated by the underwater bubble plasma varied between the dielectric barrier discharge (DBD) mode, spark mode, and hybrid mode, the plasma-activated cell culture medium (PAM) corresponding to all three discharge modes effectively decreased the viability of T24 cells. However, after co-culturing the PAM-pretreated T24 cells with normal T24 cells, it was observed that normal T24 cells were not affected by either the DBD or spark mode; however, the hybrid mode PAM-pretreated T24 cells further induced inactivation and apoptosis of normal T24 cells. Further studies suggested that the aqueous reactive species generated by the underwater bubble plasma in hybrid mode not only induced the apoptosis of T24 cells directly but also triggered PAM-pretreated T24 cell-derived exosome-mediated anticancer activity toward cancer cells. These results may provide a strategy for enhancing the anticancer extent and effect of PAM as well as advancing its clinical application.

Formation of diffuse and spark discharges between two needle electrodes with the scattering of particles

The development of a nanosecond discharge in a pin-to-pin gap filled with air at atmospheric pressure has been studied with high temporal and spatial resolutions from a breakdown start to the spark decay. Positive and negative nanosecond voltage pulses with an amplitude of tens of kilovolts were applied. Time-resolved images of the discharge development were taken with a four-channel Intensified Charge Coupled Device (ICCD) camera. The minimum delay between the camera channels could be as short as ≈ 0.1 ns. This made it possible to study the gap breakdown process with subnanosecond resolution. It was observed that a wide-diameter streamer develops from the high-voltage pointed electrode. The ionization processes near the grounded pin electrode started when the streamer crossed half of the gap. After bridging the gap by the streamer, a diffuse discharge was formed. The development of spark leaders from bright spots on the surface of the pointed electrodes was observed at the next stage. It was found that the rate of development of the spark leader is an order of magnitude lower than that of the wide-diameter streamer. Long thin luminous tracks were observed against the background of a discharge plasma glow. It has been established that the tracks are adjacent to brightly glowing spots on the electrodes and are associated with the flight of small particles.

Centimeter-level 2D ultra-small interdigital sensor for ESD detection of spacecraft

The spacecraft in geosynchronous orbit interacts with the space plasma environment, which is prone to electrostatic discharge and affects the safe operation of the spacecraft. In order to realize simple, accurate and reliable electrostatic discharge detection in space environment, based on the energy spectrum characteristics of spacecraft electrostatic discharge electromagnetic radiation electromagnetic pulse and the electromagnetic pulse sensing principle of interdigital electrode, a centimeter-level two-dimensional planar ultra-small interdigital sensor with a size of only 4 cm × 3 cm × 0.01 cm is developed. The impedance matching circuit is established to greatly improve the transmission efficiency of electromagnetic pulse, which is 59.34 % higher than that before the matching circuit is added. Finally, a spacecraft vacuum electrostatic discharge simulation experiment platform is built to test the frequency response characteristics of the sensor. The results show that the frequency response characteristics of the electromagnetic pulse signal perceived by the sensor developed in this paper are consistent with the main frequency characteristics of the spacecraft electrostatic discharge radiation electromagnetic pulse energy spectrum, which can be used for spacecraft electrostatic discharge detection in space environment.

Low Current Density Cathode Plasma Electrolytic Deposition of Aluminum Alloy Based on a Bipolar Pulse Power Supply

The present paper reported a novel bipolar-pulse cathodic plasma electrolytic deposition (BP-CPED) technique with a low current density. This newly developed CPED technique can break down the barriers of the existing CPED technique with higher current density. In this report, ceramic coatings were successfully prepared on aluminum alloy via the BP-CPED technique in an aqueous carbamide-based electrolyte. Data recording results in the reacting process show that there is the current density of the cathode below 0.15 A/cm2 and that of the anode below 0.035 A/cm2, which approximately reaches the level of conventional MAO technique. Interestingly, the addition of PEG into the electrolyte can further reduce the current density and effectively improve the coating quality. The kinetic of the BP-CPED process was discussed based on the evolution of current density/voltage-time curves and spark discharge phenomena. SEM observations illustrate that BP-CPED coatings possess a typical porous-surface feature. XRD analysis indicates that the coating was mainly composed of Al2O3 and Al4C3. Al2O3/Al4C3/ZrO2 composite coatings fabricated after Zr-doping reflected the successful Zr-incorporation into the coating, which demonstrated that the BP-CPED technique can be used to design the coating composition by the doping modification. The direct pull-off and thermal shock tests confirmed that new BP-CPED coatings obtained under the cathodic plasma discharge have excellent bonding strength. It is possible that this novel BP-CPED technique can provide a promising choice in developing the large-area CPED surface treatment for the industrial application.

Characterization of Some Functional Polymeric Composites in a Synergistic Regime of Protection at Electromagnetic Shielding and Electrostatic Transfer

The paper presents the characterization of 5 polymer composite materials with a poly-propylene (PP) matrix obtained with different (mass) concentrations of strontium ferrite (Fe12SrO19) reinforcement that have synergistic protective properties against electrostatic discharges (ESD) and electromagnetic impulses (EMI). These types of composites can be used to protect electronic equipment. To this purpose, suitable polymer composites were developed using SrFe12O19 type filler in two forms (powder and concentrate). The weight ratio of the PP/SrFe12O19 composites obtained by the extrusion process and injection from the melt is 75/25 and 70/30. The characterization of these composite materials consisted of carrying out some physico-chemical tests to determine the hydrostatic density and the resistance to the action of water, as well as FTIR, UV-Vis analyzes and dielectric, magnetic and functional tests to identify the simultaneous protection performance at electromagnetic shielding and electrostatic discharges, which can occur in the electro-technical, electronics and automotive industries. It is also found that all composite materials presented reflection shielding properties (SER) in the range: -71.5 dB...to -56.7 dB, indicating very low absorption shielding. The best performing material was the PP/SrFe12O19 powder composite with a weight ratio of 70/30. At the same time, EDS tests were also carried out on these materials. For these applications, the surface resistance Rs and the point-to-point resistance Rp were tested. Recommended composites for simultaneous EMI and sensitivity to electrostatic discharges (ESD) functionality, in order of their performance, are M2 (with 30% ferrite powder) and M1 (with 25% ferrite powder). M4 composite (with 30% ferrite powder concentrate) can also be used at the limit. Following the research carried out, the obtained results recommend the composite with promising simultaneous operations as M2 (with 30% ferrite powder). The element of originality consists of obtaining polymer composites with simultaneous properties of protection against electromagnetic impulses and electrostatic discharges.

Machine learning for parameters diagnosis of spark discharge by electro-acoustic signal

Discharge plasma parameter measurement is a key focus in low-temperature plasma research. Traditional diagnostics often require costly equipment, whereas electro-acoustic signals provide a rich, non-invasive, and less complex source of discharge information. This study harnesses machine learning to decode these signals. It establishes links between electro-acoustic signals and gas discharge parameters, such as power and distance, thus streamlining the prediction process. By building a spark discharge platform to collect electro-acoustic signals and implementing a series of acoustic signal processing techniques, the Mel-Frequency Cepstral Coefficients (MFCCs) of the acoustic signals are extracted to construct the predictors. Three machine learning models (Linear Regression, k-Nearest Neighbors, and Random Forest) are introduced and applied to the predictors to achieve real-time rapid diagnostic measurement of typical spark discharge power and discharge distance. All models display impressive performance in prediction precision and fitting abilities. Among them, the k-Nearest Neighbors model shows the best performance on discharge power prediction with the lowest mean square error (MSE = 0.00571) and the highest -squared value ( ). The experimental results show that the relationship between the electro-acoustic signal and the gas discharge power and distance can be effectively constructed based on the machine learning algorithm, which provides a new idea and basis for the online monitoring and real-time diagnosis of plasma parameters.