Pub Date : 2026-02-03DOI: 10.1016/j.elstat.2026.104255
L. Gonzalez , C. Biscara , J.-M. Roux , L. Davoust
Enhancing molecular transport in microfluidic systems remains challenging because of the very low Reynolds numbers involved. Here, we demonstrate efficient microscale stirring by coupling an electroosmotic flow with an externally applied non-uniform magnetic field. An axial electroosmotic flow is generated in a saline solution-filled microchannel by an applied voltage, while magnetic field inhomogeneity is introduced using a wall-mounted permanent magnet, without modifying the device architecture. Experiments and numerical simulations reveal the formation of upstream and downstream recirculating flows in the resulting electro-magneto-hydrodynamic (EMHD) regime. The localized magnetic induction thus acts as an effective online vorticity generator in the presence of electroosmotic flow, enabling simple and flexible stirring-on-demand. Beyond practical applications such as biological manipulation, this work provides fundamental insight into EMHD flows at low hydrodynamic, electric, and magnetic Reynolds numbers.
{"title":"Magneto-electroosmotic stirring-on-demand: A pathway to enhanced molecular transport in microfluidics applications","authors":"L. Gonzalez , C. Biscara , J.-M. Roux , L. Davoust","doi":"10.1016/j.elstat.2026.104255","DOIUrl":"10.1016/j.elstat.2026.104255","url":null,"abstract":"<div><div>Enhancing molecular transport in microfluidic systems remains challenging because of the very low Reynolds numbers involved. Here, we demonstrate efficient microscale stirring by coupling an electroosmotic flow with an externally applied non-uniform magnetic field. An axial electroosmotic flow is generated in a saline solution-filled microchannel by an applied voltage, while magnetic field inhomogeneity is introduced using a wall-mounted permanent magnet, without modifying the device architecture. Experiments and numerical simulations reveal the formation of upstream and downstream recirculating flows in the resulting electro-magneto-hydrodynamic (EMHD) regime. The localized magnetic induction thus acts as an effective online vorticity generator in the presence of electroosmotic flow, enabling simple and flexible stirring-on-demand. Beyond practical applications such as biological manipulation, this work provides fundamental insight into EMHD flows at low hydrodynamic, electric, and magnetic Reynolds numbers.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"140 ","pages":"Article 104255"},"PeriodicalIF":2.1,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.elstat.2026.104257
J. Ricardo de Sousa
We revisit the classic electrostatic problem of a point charge between two grounded, parallel conducting plates. While the potential in the slab is standard, extracting the total induced charges directly from the real-space image hierarchy leads to non-absolutely convergent series whose naive partial sums oscillate unless a summation prescription consistent with the grounded Dirichlet boundary conditions is made explicit. We provide a transparent, distributionally well-defined evaluation of the image series by combining the principal-value Fourier representation of the sign function with Poisson summation, which reorganizes the hierarchy into a discrete spectral (Dirac-comb) structure and yields closed-form induced charges on both plates. The resulting expressions agree with the classical separation-of-variables solution and offer a practical template for handling similar convergence issues in parallel-plate and pixelated detector geometries.
{"title":"Exact induced charges from an infinite image-charge system: A rigorous resolution of a classical problem","authors":"J. Ricardo de Sousa","doi":"10.1016/j.elstat.2026.104257","DOIUrl":"10.1016/j.elstat.2026.104257","url":null,"abstract":"<div><div>We revisit the classic electrostatic problem of a point charge between two grounded, parallel conducting plates. While the potential in the slab is standard, extracting the total induced charges directly from the real-space image hierarchy leads to non-absolutely convergent series whose naive partial sums oscillate unless a summation prescription consistent with the grounded Dirichlet boundary conditions is made explicit. We provide a transparent, distributionally well-defined evaluation of the image series by combining the principal-value Fourier representation of the sign function with Poisson summation, which reorganizes the hierarchy into a discrete spectral (Dirac-comb) structure and yields closed-form induced charges on both plates. The resulting expressions agree with the classical separation-of-variables solution and offer a practical template for handling similar convergence issues in parallel-plate and pixelated detector geometries.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"140 ","pages":"Article 104257"},"PeriodicalIF":2.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-30DOI: 10.1016/j.elstat.2026.104259
Abdelhafid Bouchelkha , Miloud Kachi
This paper presents a detailed investigation into how the magnitude and polarity of an initial electrostatic charge influence the subsequent charging of dielectric particles as they pass through a coaxial corona electrode. High-density polyethylene (HDPE) particles with diameter 2.5 – 4 mm were pre-charged to various levels, using both positive and negative polarities, before being introduced into a DC corona discharge region. To encompass all relevant configurations, the corona discharge was operated with either the same or opposite polarity as the particles’ initial charge. The charging capability of the particle–corona system was assessed through the relationship between the charge acquired by the particles and the charge released by the corona discharge, while also considering the limitations imposed by particle saturation and self-discharge. The relationship between the corona charge released and the amount of charge captured by a single particle during its residence time in the ionized region is determined through analysis of the discharge current and particle charge measurements. The results reveal a strong dependence of the final particle charge on the ratio of the initial charge to the saturation charge. Two distinct behaviors were identified: (i) when the initial charge is below the saturation level or of opposite polarity, particles continue to accumulate charge until reaching saturation; (ii) when the initial charge has the same polarity but exceeds the saturation level, particles lose charge until converging to the saturation value. This latter, less frequently observed scenario is examined in depth. To further interpret these findings, the induced charge on the metallic components of the electrode—specifically the wire and the cylindrical collector—was analyzed in attempt to elucidate the mechanisms responsible for charge reduction when the initial charge substantially exceeds the saturation limit. Several mechanisms are considered, whose relative contributions may vary depending on the initial charge magnitude.
{"title":"Influence of the initial charge on the charging and neutralization states of dielectric particles crossing a corona discharge","authors":"Abdelhafid Bouchelkha , Miloud Kachi","doi":"10.1016/j.elstat.2026.104259","DOIUrl":"10.1016/j.elstat.2026.104259","url":null,"abstract":"<div><div>This paper presents a detailed investigation into how the magnitude and polarity of an initial electrostatic charge influence the subsequent charging of dielectric particles as they pass through a coaxial corona electrode. High-density polyethylene (HDPE) particles with diameter 2.5 – 4 mm were pre-charged to various levels, using both positive and negative polarities, before being introduced into a DC corona discharge region. To encompass all relevant configurations, the corona discharge was operated with either the same or opposite polarity as the particles’ initial charge. The charging capability of the particle–corona system was assessed through the relationship between the charge acquired by the particles and the charge released by the corona discharge, while also considering the limitations imposed by particle saturation and self-discharge. The relationship between the corona charge released and the amount of charge captured by a single particle during its residence time in the ionized region is determined through analysis of the discharge current and particle charge measurements. The results reveal a strong dependence of the final particle charge on the ratio of the initial charge to the saturation charge. Two distinct behaviors were identified: (i) when the initial charge is below the saturation level or of opposite polarity, particles continue to accumulate charge until reaching saturation; (ii) when the initial charge has the same polarity but exceeds the saturation level, particles lose charge until converging to the saturation value. This latter, less frequently observed scenario is examined in depth. To further interpret these findings, the induced charge on the metallic components of the electrode—specifically the wire and the cylindrical collector—was analyzed in attempt to elucidate the mechanisms responsible for charge reduction when the initial charge substantially exceeds the saturation limit. Several mechanisms are considered, whose relative contributions may vary depending on the initial charge magnitude.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"140 ","pages":"Article 104259"},"PeriodicalIF":2.1,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bench-scale shake tests were conducted using linear low-density polyethylene (LLDPE) resin in controlled environments of argon, nitrogen, and ambient air to investigate how gas type (argon vs. nitrogen), relative humidity (10–75 % RH), and temperature (23 and 65 °C) affect charge buildup. Tests involved single and multiple particles shaken in an aluminum cup, and a stainless-steel cup coated with LLDPE resin. Under low-humidity (RH < 3 %) conditions, charge accumulation with nitrogen was 50 % higher than with argon, due to differences in the gases' dielectric strengths. Ambient air with an RH of ∼38 % resulted in a saturation charge like argon, as increased moisture diminished charge buildup. Across an RH range of 10–75 %, minimal variation in average particle charge was observed below 40 %, but higher relative humidities caused a notable decline in charge accumulation. Elevated temperatures decreased charge buildup under nitrogen, while argon showed no significant change, highlighting a gas-dependent response to temperature.
{"title":"Bench-scale tribocharging of polyethylene: Role of gas type, temperature and relative humidity","authors":"Talha Mukarram Syed, Grissel Myrtle Fernandes, Nikhil Sridhar, Poupak Mehrani","doi":"10.1016/j.elstat.2026.104254","DOIUrl":"10.1016/j.elstat.2026.104254","url":null,"abstract":"<div><div>Bench-scale shake tests were conducted using linear low-density polyethylene (LLDPE) resin in controlled environments of argon, nitrogen, and ambient air to investigate how gas type (argon vs. nitrogen), relative humidity (10–75 % RH), and temperature (23 and 65 °C) affect charge buildup. Tests involved single and multiple particles shaken in an aluminum cup, and a stainless-steel cup coated with LLDPE resin. Under low-humidity (RH < 3 %) conditions, charge accumulation with nitrogen was 50 % higher than with argon, due to differences in the gases' dielectric strengths. Ambient air with an RH of ∼38 % resulted in a saturation charge like argon, as increased moisture diminished charge buildup. Across an RH range of 10–75 %, minimal variation in average particle charge was observed below 40 %, but higher relative humidities caused a notable decline in charge accumulation. Elevated temperatures decreased charge buildup under nitrogen, while argon showed no significant change, highlighting a gas-dependent response to temperature.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"140 ","pages":"Article 104254"},"PeriodicalIF":2.1,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-28DOI: 10.1016/j.elstat.2026.104251
Abdulkerim Karabiber
This study investigates the effect of metal oxide fillers on the electrical, morphological, and output characteristics of rubber silicone-based triboelectric nanogenerators (TENGs). TENGs were fabricated using glass fiber as the common tribo-positive layer and silicone matrices doped with various metal oxides (Aluminum oxide, cobalt oxide, manganese oxide, molybdenum oxide, nickel oxide, and tungsten oxide) at 1, 2.5, and 5 wt% as tribo-negative layers. The devices were mechanically driven under controlled impact forces and frequencies, and their performance was evaluated under both ohmic and capacitive loads. Metal oxide doping generally increased internal resistance and decreased internal capacitance, leading to a cross-effect: enhanced output under ohmic loads due to suppressed leakage currents, but reduced performance under capacitive loads owing to diminished charge storage capacity. Among the fillers, cobalt oxide at 2.5 wt% yielded the highest voltage and maximum power output, whereas optimal compositions for other oxides were typically around 1 wt%. Excessive filler contents caused aggregation, air-gap formation, and loss of effective contact area, which degraded performance despite favorable changes in internal resistance and capacitance. Overall, the results demonstrate that metal oxide fillers offer an effective means to tune TENG performance, but optimal design requires simultaneous optimization of filler type and content, surface morphology, and load impedance.
{"title":"Energy harvesting performance of metal oxide doped TENGs based on load impedance characterization","authors":"Abdulkerim Karabiber","doi":"10.1016/j.elstat.2026.104251","DOIUrl":"10.1016/j.elstat.2026.104251","url":null,"abstract":"<div><div>This study investigates the effect of metal oxide fillers on the electrical, morphological, and output characteristics of rubber silicone-based triboelectric nanogenerators (TENGs). TENGs were fabricated using glass fiber as the common tribo-positive layer and silicone matrices doped with various metal oxides (Aluminum oxide, cobalt oxide, manganese oxide, molybdenum oxide, nickel oxide, and tungsten oxide) at 1, 2.5, and 5 wt% as tribo-negative layers. The devices were mechanically driven under controlled impact forces and frequencies, and their performance was evaluated under both ohmic and capacitive loads. Metal oxide doping generally increased internal resistance and decreased internal capacitance, leading to a cross-effect: enhanced output under ohmic loads due to suppressed leakage currents, but reduced performance under capacitive loads owing to diminished charge storage capacity. Among the fillers, cobalt oxide at 2.5 wt% yielded the highest voltage and maximum power output, whereas optimal compositions for other oxides were typically around 1 wt%. Excessive filler contents caused aggregation, air-gap formation, and loss of effective contact area, which degraded performance despite favorable changes in internal resistance and capacitance. Overall, the results demonstrate that metal oxide fillers offer an effective means to tune TENG performance, but optimal design requires simultaneous optimization of filler type and content, surface morphology, and load impedance.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"140 ","pages":"Article 104251"},"PeriodicalIF":2.1,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-27DOI: 10.1016/j.elstat.2026.104231
Hui Fu , Shaokang Meng , Xiaonan Luo , Qinzhen Zheng , Shuran Li , Zhen Liu , Keping Yan
A heat-exchange-assisted wire-tube electrostatic precipitator (HEAT-ESP) is proposed to mitigate wet plumes and improve PM2.5 capture in conventional ESPs. By cooling the collection electrode, the system enables simultaneous flue gas purification and heat recovery. Flue gas temperature and humidity significantly enhance discharge performance, increasing dust removal efficiency by up to 12.5 %, water recovery by 30.2 %, and heat transfer by 17.2 %. Particle concentration slightly reduces discharge current but improves overall performance, with gains of 10.0–16.5 % at 45 kV. The system exhibits strong synergy among dust removal, water recovery, and heat transfer. At the relative humidity of 90 % and a voltage of 22.5 kV, the maximum water harvesting efficiency and latent heat recovery-to-input ratio reach 772.78 kg/kWh and 489, respectively. With energy costing 0.1–0.3 CNY/kWh and water priced at 5–8 CNY/ton, this technology offers strong potential for energy and water conservation applications.
{"title":"Investigation on heat exchange assisted wet electrostatic precipitator in dust removal, heat transfer enhancement process and water collection","authors":"Hui Fu , Shaokang Meng , Xiaonan Luo , Qinzhen Zheng , Shuran Li , Zhen Liu , Keping Yan","doi":"10.1016/j.elstat.2026.104231","DOIUrl":"10.1016/j.elstat.2026.104231","url":null,"abstract":"<div><div>A heat-exchange-assisted wire-tube electrostatic precipitator (HEAT-ESP) is proposed to mitigate wet plumes and improve PM<sub>2.5</sub> capture in conventional ESPs. By cooling the collection electrode, the system enables simultaneous flue gas purification and heat recovery. Flue gas temperature and humidity significantly enhance discharge performance, increasing dust removal efficiency by up to 12.5 %, water recovery by 30.2 %, and heat transfer by 17.2 %. Particle concentration slightly reduces discharge current but improves overall performance, with gains of 10.0–16.5 % at 45 kV. The system exhibits strong synergy among dust removal, water recovery, and heat transfer. At the relative humidity of 90 % and a voltage of 22.5 kV, the maximum water harvesting efficiency and latent heat recovery-to-input ratio reach 772.78 kg/kWh and 489, respectively. With energy costing 0.1–0.3 CNY/kWh and water priced at 5–8 CNY/ton, this technology offers strong potential for energy and water conservation applications.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"140 ","pages":"Article 104231"},"PeriodicalIF":2.1,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-22DOI: 10.1016/j.elstat.2026.104249
I.F. Spivak-Lavrov, T. Zh Shugayeva, A.B. Seiten, A. Sh Amantaeva
This study presents the analytical derivation of potential functions characterizing the electrostatic fields of multipole systems based on a conducting circular cylinder, utilizing methods from the theory of complex variable functions.
Explicit analytical expressions for the field potentials and their derivatives have been obtained, enabling the computational modeling of equipotential lines for various multipolar configurations, including quadrupole, sextupole and octupole systems. The presented results were obtained under the assumption of infinitely narrow insulating gaps between electrodes. Furthermore, an algorithm and a suite of application software were developed to compute the potentials and electric field intensities of multipole systems constructed on the basis of a conducting circular cylinder.
The results obtained in study can be applied to the design and calculation of charged particle beam transport systems, anti-resonance mass analyzers, and various electrostatic multipole traps, as well as multipole aberration correction in electron microscopy.
{"title":"Analytical description of the electrostatic field of multiple system based on a conducting circular cylinder","authors":"I.F. Spivak-Lavrov, T. Zh Shugayeva, A.B. Seiten, A. Sh Amantaeva","doi":"10.1016/j.elstat.2026.104249","DOIUrl":"10.1016/j.elstat.2026.104249","url":null,"abstract":"<div><div>This study presents the analytical derivation of potential functions characterizing the electrostatic fields of multipole systems based on a conducting circular cylinder, utilizing methods from the theory of complex variable functions.</div><div>Explicit analytical expressions for the field potentials and their derivatives have been obtained, enabling the computational modeling of equipotential lines for various multipolar configurations, including quadrupole, sextupole and octupole systems. The presented results were obtained under the assumption of infinitely narrow insulating gaps between electrodes. Furthermore, an algorithm and a suite of application software were developed to compute the potentials and electric field intensities of multipole systems constructed on the basis of a conducting circular cylinder.</div><div>The results obtained in study can be applied to the design and calculation of charged particle beam transport systems, anti-resonance mass analyzers, and various electrostatic multipole traps, as well as multipole aberration correction in electron microscopy.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"140 ","pages":"Article 104249"},"PeriodicalIF":2.1,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-18DOI: 10.1016/j.elstat.2026.104241
Chau-Shing Wang , Yuan-Jen Chang , Chau-Ming Tsai
Laser micro-drilling is essential in precision manufacturing, yet its extremely high processing speed makes real-time monitoring challenging. Plasma detection using an externally applied electric field has emerged as a promising solution, as laser-induced plasma generates measurable electrical signals under an applied voltage. This study systematically investigates the effects of electrode geometry, size, internal resistance, and spatial configuration on plasma detection performance. Experimental results show that thick copper electrodes with very low internal resistance can detect plasma signal peaks up to 72.9 V, significantly exceeding previously reported values. The goal of this work is to optimize electrode design to enhance plasma detection sensitivity for real-time monitoring of laser micro-drilling processes.
{"title":"Electrode design and analysis for improving laser-induced plasma detection in laser micro-drilling","authors":"Chau-Shing Wang , Yuan-Jen Chang , Chau-Ming Tsai","doi":"10.1016/j.elstat.2026.104241","DOIUrl":"10.1016/j.elstat.2026.104241","url":null,"abstract":"<div><div>Laser micro-drilling is essential in precision manufacturing, yet its extremely high processing speed makes real-time monitoring challenging. Plasma detection using an externally applied electric field has emerged as a promising solution, as laser-induced plasma generates measurable electrical signals under an applied voltage. This study systematically investigates the effects of electrode geometry, size, internal resistance, and spatial configuration on plasma detection performance. Experimental results show that thick copper electrodes with very low internal resistance can detect plasma signal peaks up to 72.9 V, significantly exceeding previously reported values. The goal of this work is to optimize electrode design to enhance plasma detection sensitivity for real-time monitoring of laser micro-drilling processes.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"140 ","pages":"Article 104241"},"PeriodicalIF":2.1,"publicationDate":"2026-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-16DOI: 10.1016/j.elstat.2026.104246
Panich Intra
This study investigates the critical influence of particle charge neutralization on the particle filtration efficiency (PFE) of surgical mask media and N95 respirator media across various inhalation face velocities. Surgical masks rely heavily on electrostatic attraction from charged electret fibers to achieve high filtration ratings. We compared the PFE of both mask types under three aerosol charge conditions—highly charged (Non-Neutralizer), X-ray neutralized, and Corona Discharge neutralized—at three face velocities (15.9 cm/s, 10.6 cm/s, and 5.3 cm/s) using 100 nm test particles. Results confirmed that the X-ray neutralizer achieved the closest state to the theoretical Boltzmann charge equilibrium for 100 nm particles (∼19 % charged fraction), establishing the lowest baseline for mechanical filtration efficiency. Filtration efficiency was highest in the Non-Neutralizer condition (up to ∼ 98 %). For surgical masks, the electrostatic contribution was maximized at the high face velocity of 15.9 cm/s, accounting for a drop of up to 20 % in PFE upon neutralization. In contrast, the N95 respirator media maintained an FE of≥95 % even when the challenge aerosol was completely neutralized by the X-ray Neutralizer, fulfilling the minimum requirements of the TIS 2480–2563 standard. The Corona Discharge neutralizer consistently yielded higher PFE values than the X-ray neutralizer for both mask types, suggesting it fails to completely establish a neutral equilibrium. This work quantitatively demonstrates that while surgical mask performance is critically dependent on electrostatic forces, N95 compliance is guaranteed by its inherently robust mechanical filtration.
{"title":"The critical influence of particle charge neutralization on surgical mask and N95 respirator filtration efficiency","authors":"Panich Intra","doi":"10.1016/j.elstat.2026.104246","DOIUrl":"10.1016/j.elstat.2026.104246","url":null,"abstract":"<div><div>This study investigates the critical influence of particle charge neutralization on the particle filtration efficiency (PFE) of surgical mask media and N95 respirator media across various inhalation face velocities. Surgical masks rely heavily on electrostatic attraction from charged electret fibers to achieve high filtration ratings. We compared the PFE of both mask types under three aerosol charge conditions—highly charged (Non-Neutralizer), X-ray neutralized, and Corona Discharge neutralized—at three face velocities (15.9 cm/s, 10.6 cm/s, and 5.3 cm/s) using 100 nm test particles. Results confirmed that the X-ray neutralizer achieved the closest state to the theoretical Boltzmann charge equilibrium for 100 nm particles (∼19 % charged fraction), establishing the lowest baseline for mechanical filtration efficiency. Filtration efficiency was highest in the Non-Neutralizer condition (up to ∼ 98 %). For surgical masks, the electrostatic contribution was maximized at the high face velocity of 15.9 cm/s, accounting for a drop of up to 20 % in PFE upon neutralization. In contrast, the N95 respirator media maintained an FE of≥95 % even when the challenge aerosol was completely neutralized by the X-ray Neutralizer, fulfilling the minimum requirements of the TIS 2480–2563 standard. The Corona Discharge neutralizer consistently yielded higher PFE values than the X-ray neutralizer for both mask types, suggesting it fails to completely establish a neutral equilibrium. This work quantitatively demonstrates that while surgical mask performance is critically dependent on electrostatic forces, N95 compliance is guaranteed by its inherently robust mechanical filtration.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"140 ","pages":"Article 104246"},"PeriodicalIF":2.1,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-16DOI: 10.1016/j.elstat.2026.104242
Swe Zin Linn Htet, Takuya Kondo, Takuma Miyake, May Thin Khaing, Tatsuya Sakoda
Partial discharge (PD) is a precursor to insulation breakdown in cast resin transformers. This study investigates PD behavior in epoxy resin containing insulation paper which is commonly used in cast resin transformers to enhance dielectric strength. If there are voids between epoxy and insulation paper, PDs may occur. Measuring PDs in this configuration helps reproduce actual PD phenomena such as PD magnitude, PD occurrence frequency, and degradation in cast resin transformers. In order to grasp the PD behavior, we fabricated a plane-to-plane epoxy electrode and a wire-wound epoxy electrode. Each epoxy electrode contained a void and insulation paper and was arranged in a cubicle. PDs were detected using two transient earth voltage (TEV) sensors and a current transformer (CT) sensor. TEV sensors on the inner cubicle wall captured higher frequency components than those on the outer wall. Additionally, higher frequency components more than 100 MHz became larger after PDs made pits or electrical trees, which is useful for evaluating state of development of PD activities.
{"title":"Partial discharge behavior in epoxy resin including insulation paper","authors":"Swe Zin Linn Htet, Takuya Kondo, Takuma Miyake, May Thin Khaing, Tatsuya Sakoda","doi":"10.1016/j.elstat.2026.104242","DOIUrl":"10.1016/j.elstat.2026.104242","url":null,"abstract":"<div><div>Partial discharge (PD) is a precursor to insulation breakdown in cast resin transformers. This study investigates PD behavior in epoxy resin containing insulation paper which is commonly used in cast resin transformers to enhance dielectric strength. If there are voids between epoxy and insulation paper, PDs may occur. Measuring PDs in this configuration helps reproduce actual PD phenomena such as PD magnitude, PD occurrence frequency, and degradation in cast resin transformers. In order to grasp the PD behavior, we fabricated a plane-to-plane epoxy electrode and a wire-wound epoxy electrode. Each epoxy electrode contained a void and insulation paper and was arranged in a cubicle. PDs were detected using two transient earth voltage (TEV) sensors and a current transformer (CT) sensor. TEV sensors on the inner cubicle wall captured higher frequency components than those on the outer wall. Additionally, higher frequency components more than 100 MHz became larger after PDs made pits or electrical trees, which is useful for evaluating state of development of PD activities.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"140 ","pages":"Article 104242"},"PeriodicalIF":2.1,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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