Pub Date : 2026-01-13DOI: 10.1016/j.elstat.2026.104239
Zhihao Zhang , Jiao Wang , Yang Liu
Triboelectric nanogenerators (TENGs), characterized by pulsed output, high voltage, and high internal impedance, enable efficient energy storage via passive power management circuits (PMCs). While switches are commonly used to shape pulses for impedance matching, prior research has largely treated the pulse as a monolithic event, overlooking the differential impact of its specific temporal parameters (e.g., rise time, pulse width). This study focuses on the impact mechanism of temporal modulation on PMC performance, and improves the energy storage efficiency of PMC by dynamically adjusting the time dimension parameters of TENG output signals. At constant pulse height, shorter pulse durations correlate with higher efficiency, with maximum simulated efficiency reaching 48.4 %. Crucially, the change rate of the rising edge—not pulse width—governs efficiency: higher change rates improve efficiency and reduce TENG internal impedance. Experimental validation using a needle-plate discharge switch confirms that PMC with larger impedance inductors achieve 47.6 % efficiency. Multi-load tests further characterize output voltage dynamics of PMC. The proposed strategy, successfully applied in a self-powered agricultural monitoring system, advances sustainable agricultural efficiency, offering critical technological support for smart agriculture.
{"title":"Temporal modulation of triboelectric nanogenerator pulsed output and its application in agricultural environmental monitoring systems","authors":"Zhihao Zhang , Jiao Wang , Yang Liu","doi":"10.1016/j.elstat.2026.104239","DOIUrl":"10.1016/j.elstat.2026.104239","url":null,"abstract":"<div><div>Triboelectric nanogenerators (TENGs), characterized by pulsed output, high voltage, and high internal impedance, enable efficient energy storage via passive power management circuits (PMCs). While switches are commonly used to shape pulses for impedance matching, prior research has largely treated the pulse as a monolithic event, overlooking the differential impact of its specific temporal parameters (e.g., rise time, pulse width). This study focuses on the impact mechanism of temporal modulation on PMC performance, and improves the energy storage efficiency of PMC by dynamically adjusting the time dimension parameters of TENG output signals. At constant pulse height, shorter pulse durations correlate with higher efficiency, with maximum simulated efficiency reaching 48.4 %. Crucially, the change rate of the rising edge—not pulse width—governs efficiency: higher change rates improve efficiency and reduce TENG internal impedance. Experimental validation using a needle-plate discharge switch confirms that PMC with larger impedance inductors achieve 47.6 % efficiency. Multi-load tests further characterize output voltage dynamics of PMC. The proposed strategy, successfully applied in a self-powered agricultural monitoring system, advances sustainable agricultural efficiency, offering critical technological support for smart agriculture.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"140 ","pages":"Article 104239"},"PeriodicalIF":2.1,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980858","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 : 2026-01-10DOI: 10.1016/j.elstat.2025.104230
Navraj S. Lalli, Andrea Giusti
Injecting fuel as a dispersion of charged droplets and applying electric fields has been proposed as a mechanism to improve the fuel flexibility of aviation engines. Modelling such systems requires computationally efficient methods that can predict when droplet instability occurs due to electrical forces overcoming surface tension. Therefore, two methods are developed to provide the maximum charge a droplet can hold before instability. Taylor’s approach of assuming prolate spheroidal droplet shapes up until instability is generalised to charged linear dielectric droplets in an insulating linear dielectric fluid and subject to a uniform electric field. Additionally, an analytical charge limit expression is derived by considering a spherical droplet and analysing the stresses acting at the point of maximum surface charge density. Both methods predict that the charge limit increasingly falls below the Rayleigh limit as the electric field intensity is increased, with the electric field effect increasing with increasing droplet diameter and permittivity. Taylor’s generalised method provides accurate electric field limits for uncharged dielectric droplets, while the analytical expression overestimates these limits. For conducting droplets in reasonably strong electric fields, the generalised method underestimates the charge limits by overestimating droplet elongation, while the analytical expression provides more accurate charge limits. The analytical expression is also expected to provide accurate charge limits when the droplet diameter, droplet permittivity, and/or electric field intensity are not large. Ultimately, the derived methods provide a computationally efficient approach for simulating the fragmentation of charged droplets in electric fields.
{"title":"Modelling the onset of instability for charged droplets in an external electric field","authors":"Navraj S. Lalli, Andrea Giusti","doi":"10.1016/j.elstat.2025.104230","DOIUrl":"10.1016/j.elstat.2025.104230","url":null,"abstract":"<div><div>Injecting fuel as a dispersion of charged droplets and applying electric fields has been proposed as a mechanism to improve the fuel flexibility of aviation engines. Modelling such systems requires computationally efficient methods that can predict when droplet instability occurs due to electrical forces overcoming surface tension. Therefore, two methods are developed to provide the maximum charge a droplet can hold before instability. Taylor’s approach of assuming prolate spheroidal droplet shapes up until instability is generalised to charged linear dielectric droplets in an insulating linear dielectric fluid and subject to a uniform electric field. Additionally, an analytical charge limit expression is derived by considering a spherical droplet and analysing the stresses acting at the point of maximum surface charge density. Both methods predict that the charge limit increasingly falls below the Rayleigh limit as the electric field intensity is increased, with the electric field effect increasing with increasing droplet diameter and permittivity. Taylor’s generalised method provides accurate electric field limits for uncharged dielectric droplets, while the analytical expression overestimates these limits. For conducting droplets in reasonably strong electric fields, the generalised method underestimates the charge limits by overestimating droplet elongation, while the analytical expression provides more accurate charge limits. The analytical expression is also expected to provide accurate charge limits when the droplet diameter, droplet permittivity, and/or electric field intensity are not large. Ultimately, the derived methods provide a computationally efficient approach for simulating the fragmentation of charged droplets in electric fields.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"140 ","pages":"Article 104230"},"PeriodicalIF":2.1,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941313","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 : 2026-01-01DOI: 10.1016/j.elstat.2025.104229
S. Rahman Pejman , Madhuri Deb , Ayman Rouf , Han Almekinders , Jonathan P. Singer
Self-limiting electrospray deposition (SLED) enables conformal coatings by allowing surface charge buildup to reshape local electric fields, redirecting spray toward uncoated regions. This requires droplets to travel non-inertially, so they respond to near-field electric changes, which break down at high flow rates when droplet inertia dominates. Here, we demonstrate that high-flow emitters maintain SLED behavior up to 5 mL/h per tip, an order of magnitude increase in throughput, producing uniform 4–5 m PMMA films and conformal coatings on 3D objects. Beyond this, anisotropic deposition arises due to high Stokes numbers. Applying a same-polarity secondary bias softens droplet landing, mitigating inertial overdeposition and restoring uniform deposition at rates up to 12 mL/h. Simulations further show that increased air pressure can achieve similar effects. These results frame SLED as a Stokes-number-dependent regime and offer a scalable strategy to extend conformal electrospray coatings to large areas, complex geometries, and industrially relevant throughputs.
{"title":"Secondary bias-assisted high-throughput electrospray for uniform and self-limiting coatings at elevated flow rates","authors":"S. Rahman Pejman , Madhuri Deb , Ayman Rouf , Han Almekinders , Jonathan P. Singer","doi":"10.1016/j.elstat.2025.104229","DOIUrl":"10.1016/j.elstat.2025.104229","url":null,"abstract":"<div><div>Self-limiting electrospray deposition (SLED) enables conformal coatings by allowing surface charge buildup to reshape local electric fields, redirecting spray toward uncoated regions. This requires droplets to travel non-inertially, so they respond to near-field electric changes, which break down at high flow rates when droplet inertia dominates. Here, we demonstrate that high-flow emitters maintain SLED behavior up to <span><math><mo>∼</mo></math></span>5<!--> <!-->mL/h per tip, an order of magnitude increase in throughput, producing uniform <span><math><mo>∼</mo></math></span>4–5<!--> <span><math><mi>μ</mi></math></span>m PMMA films and conformal coatings on 3D objects. Beyond this, anisotropic deposition arises due to high Stokes numbers. Applying a same-polarity secondary bias softens droplet landing, mitigating inertial overdeposition and restoring uniform deposition at rates up to 12<!--> <!-->mL/h. Simulations further show that increased air pressure can achieve similar effects. These results frame SLED as a Stokes-number-dependent regime and offer a scalable strategy to extend conformal electrospray coatings to large areas, complex geometries, and industrially relevant throughputs.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"139 ","pages":"Article 104229"},"PeriodicalIF":2.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925082","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 : 2025-12-24DOI: 10.1016/j.elstat.2025.104224
Petr Kostin, Vladimir Chirkov, Karina Poluektova
This study investigates the behavior of water droplets suspended in oil under pulsed electric fields, focusing on the electrodeformation of a single droplet and the electrocoalescence of a droplet pair. Numerical simulations were performed using the arbitrary Lagrangian–Eulerian (ALE) method, which allows for accurate tracking of sharp interfaces between the droplet and the surrounding medium. A key objective was to determine the threshold electric field required for irreversible droplet deformation and coalescence across a range of frequencies, droplet sizes, viscosities, and interfacial tensions. The main contribution of this work is the introduction of a dimensionless time-scale parameter that effectively captures the transition from low-to high-frequency regimes. The parameter is defined in terms of the pulse frequency , the natural oscillation period , and the Ohnesorge number as . This parameter allows for the collapse of threshold–frequency curves for different system properties, providing a unified framework for predicting the frequency-dependent behavior of droplets under pulsed electric fields. Regarding the dependence of the threshold field on frequency, single-droplet electrodeformation occurs in a quasi-static regime for , in a high-frequency regime for , and in a transitional region between these values. For the electrocoalescence of two droplets, analogous boundaries may be taken as and . The proposed parameter also offers a practical tool for interpreting experimental observations and planning further studies in electrohydrodynamic processes.
{"title":"Threshold electric field for pulsed electrodeformation and electrocoalescence of conducting droplets: A dimensionless approach to the low-to-high frequency transition","authors":"Petr Kostin, Vladimir Chirkov, Karina Poluektova","doi":"10.1016/j.elstat.2025.104224","DOIUrl":"10.1016/j.elstat.2025.104224","url":null,"abstract":"<div><div>This study investigates the behavior of water droplets suspended in oil under pulsed electric fields, focusing on the electrodeformation of a single droplet and the electrocoalescence of a droplet pair. Numerical simulations were performed using the arbitrary Lagrangian–Eulerian (ALE) method, which allows for accurate tracking of sharp interfaces between the droplet and the surrounding medium. A key objective was to determine the threshold electric field required for irreversible droplet deformation and coalescence across a range of frequencies, droplet sizes, viscosities, and interfacial tensions. The main contribution of this work is the introduction of a dimensionless time-scale parameter that effectively captures the transition from low-to high-frequency regimes. The parameter is defined in terms of the pulse frequency <span><math><mrow><mi>f</mi></mrow></math></span>, the natural oscillation period <span><math><mrow><msub><mi>t</mi><mn>1</mn></msub></mrow></math></span>, and the Ohnesorge number <span><math><mrow><mi>O</mi><mi>h</mi></mrow></math></span> as <span><math><mrow><msub><mi>P</mi><mrow><mi>t</mi><mi>y</mi></mrow></msub><mo>=</mo><mi>f</mi><mspace></mspace><msub><mi>t</mi><mn>1</mn></msub><mspace></mspace><mi>O</mi><msup><mi>h</mi><mrow><mo>−</mo><mn>0.7</mn></mrow></msup></mrow></math></span>. This parameter allows for the collapse of threshold–frequency curves for different system properties, providing a unified framework for predicting the frequency-dependent behavior of droplets under pulsed electric fields. Regarding the dependence of the threshold field on frequency, single-droplet electrodeformation occurs in a quasi-static regime for <span><math><mrow><msub><mi>P</mi><mrow><mi>t</mi><mi>y</mi></mrow></msub><mo><</mo><mn>0.01</mn></mrow></math></span>, in a high-frequency regime for <span><math><mrow><msub><mi>P</mi><mrow><mi>t</mi><mi>y</mi></mrow></msub><mo>></mo><mn>1</mn></mrow></math></span>, and in a transitional region between these values. For the electrocoalescence of two droplets, analogous boundaries may be taken as <span><math><mrow><msub><mi>P</mi><mrow><mi>t</mi><mi>y</mi></mrow></msub><mo>=</mo><mn>0.01</mn></mrow></math></span> and <span><math><mrow><msub><mi>P</mi><mrow><mi>t</mi><mi>y</mi></mrow></msub><mo>=</mo><mn>10</mn></mrow></math></span>. The proposed parameter also offers a practical tool for interpreting experimental observations and planning further studies in electrohydrodynamic processes.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"139 ","pages":"Article 104224"},"PeriodicalIF":2.1,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839923","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 : 2025-12-23DOI: 10.1016/j.elstat.2025.104227
Jean Nugel , Thomas Gmeinwieser , Georg Suter , Martina Scotton
Models for estimating electric field strength in silos and containers typically focus on the maximum field value occurring along the container wall (Glor (2023) and Nugel, Scotton and Suter (Nugel et al., 2025) [8], often located within the bulk powder. While this approach ensures conservative estimations, it does not align with the physical location where ignition is most likely to occur. According to TRGS 727 [10], the relevant field for assessing cone discharge hazards is that at the powder-air interface, where an explosive atmosphere may simultaneously occur with a cone discharge during filling of containers or silos.
This study extends and prolongs the analytical model previously developed by Nugel, Scotton, and Suter (Nugel et al., 2025) [8], by specifically targeting the electric field at the upper surface of the powder bed, where ignition is most likely to occur, and by integrating the influence of bulk heap geometry, in line with the findings of Zhou and al. (Zhou et al., 2019) [11], who demonstrated that conical heap shape is the most constraining parameter governing the magnitude of the electric field along the silo walls.
By combining both approaches, a refined methodology is proposed that evaluates the electric field directly above the powder bed while explicitly accounting for the geometrical influence of conical heap configurations.
Unlike the model by Nugel, Scotton and Suter (Nugel et al., 2025) [8], which evaluates the electric field assuming a flat bulk surface and therefore results in less conservative estimates, and which identifies the maximum electric field within the powder volume without assessing whether an explosive atmosphere is present at that location, the present approach offers a conservative analytical formulation that remains valid for any cone angle formed by the bulk heap. It explicitly focuses on the powder–air interface, which represents the physically relevant zone for cone discharge hazards. Although the study by Zhou and al. (Zhou et al., 2019) [9] highlights the influence of bulk heap geometry, it does not offer a generalized expression that can be directly implemented in industrial risk assessment, as it remains confined to specific conical shapes and fixed angles.
To characterize the field at this interface, newly defined dimensionless correction factors are introduced. These allow a more realistic estimation of the electric field strength at the powder-air interface, without requiring full numerical integration for each specific container geometry or filling condition.
估计筒仓和容器中的电场强度的模型通常侧重于沿容器壁（Glor(2023)）和Nugel， Scotton和Suter (Nugel等人，2025)[8]的最大电场值，通常位于散装粉末中。虽然这种方法保证了保守的估计，但它与最可能发生点火的物理位置不一致。根据TRGS 727[10]，评估锥筒放电危害的相关领域是在粉末-空气界面，在容器或筒仓填充过程中，爆炸性大气可能同时发生锥筒放电。本研究扩展和延长了Nugel， Scotton和Suter (Nugel et al., 2025)[8]先前开发的分析模型，具体针对最可能发生着火的粉末床上表面的电场，并通过整合堆积几何形状的影响，与Zhou等人的发现一致（Zhou et al., 2019）[11]。他证明了圆锥形堆形是控制沿筒仓壁电场大小的最具限制性的参数。通过结合这两种方法，提出了一种改进的方法，该方法可以评估粉末床直接上方的电场，同时明确考虑锥形堆构型的几何影响。Nugel， Scotton和Suter （Nugel et al., 2025）的模型（假设一个平坦的体表面评估电场，因此得出的保守估计较少）[8]不同，该模型确定了粉末体积内的最大电场，而不评估该位置是否存在爆炸性气氛，本方法提供了一个保守的分析公式，适用于任何由体堆形成的锥角。它明确地侧重于粉末-空气界面，它代表了锥体放电危险的物理相关区域。虽然Zhou等人的研究（Zhou et al., 2019）[9]强调了堆堆几何形状的影响，但它并没有提供一个可以直接用于工业风险评估的广义表达式，因为它仍然局限于特定的圆锥形状和固定的角度。为了描述该界面处的场，引入了新定义的无量纲校正因子。这样可以更真实地估计粉末-空气界面处的电场强度，而不需要对每个特定容器几何形状或填充条件进行完整的数值积分。
{"title":"A realistic generalized model for the electric field in containers: Evaluation at the powder-air interface","authors":"Jean Nugel , Thomas Gmeinwieser , Georg Suter , Martina Scotton","doi":"10.1016/j.elstat.2025.104227","DOIUrl":"10.1016/j.elstat.2025.104227","url":null,"abstract":"<div><div>Models for estimating electric field strength in silos and containers typically focus on the maximum field value occurring along the container wall (Glor (2023) and Nugel, Scotton and Suter (Nugel et al., 2025) [8], often located within the bulk powder. While this approach ensures conservative estimations, it does not align with the physical location where ignition is most likely to occur. According to TRGS 727 [10], the relevant field for assessing cone discharge hazards is that at the powder-air interface, where an explosive atmosphere may simultaneously occur with a cone discharge during filling of containers or silos.</div><div>This study extends and prolongs the analytical model previously developed by Nugel, Scotton, and Suter (Nugel et al., 2025) [8], by specifically targeting the electric field at the upper surface of the powder bed, where ignition is most likely to occur, and by integrating the influence of bulk heap geometry, in line with the findings of Zhou and al. (Zhou et al., 2019) [11], who demonstrated that conical heap shape is the most constraining parameter governing the magnitude of the electric field along the silo walls.</div><div>By combining both approaches, a refined methodology is proposed that evaluates the electric field directly above the powder bed while explicitly accounting for the geometrical influence of conical heap configurations.</div><div>Unlike the model by Nugel, Scotton and Suter (Nugel et al., 2025) [8], which evaluates the electric field assuming a flat bulk surface and therefore results in less conservative estimates, and which identifies the maximum electric field within the powder volume without assessing whether an explosive atmosphere is present at that location, the present approach offers a conservative analytical formulation that remains valid for any cone angle formed by the bulk heap. It explicitly focuses on the powder–air interface, which represents the physically relevant zone for cone discharge hazards. Although the study by Zhou and al. (Zhou et al., 2019) [9] highlights the influence of bulk heap geometry, it does not offer a generalized expression that can be directly implemented in industrial risk assessment, as it remains confined to specific conical shapes and fixed angles.</div><div>To characterize the field at this interface, newly defined dimensionless correction factors are introduced. These allow a more realistic estimation of the electric field strength at the powder-air interface, without requiring full numerical integration for each specific container geometry or filling condition.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"139 ","pages":"Article 104227"},"PeriodicalIF":2.1,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839924","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}
This study investigates the dynamics of conducting droplets impacting hydrophobic substrates under externally applied electric fields using high-fidelity numerical simulations. A modified OpenFOAM solver is developed that integrates Kistler’s dynamic contact angle model with a coupled electrohydrodynamic module to capture the combined effects of inertia, surface tension, viscosity and Maxwell stresses. Validation against experimental data confirmed that the solver reproduces inertia-capillary oscillations and spread–recoil behavior with good accuracy. The simulations reveal that electric fields change the energy distribution of an impacting droplet. Increasing electric Bond number reduces lateral spreading, delays recoil and enhances vertical elongation, producing rebound even on hydrophobic substrates that normally suppress it. At the maximum rebound height increases by nearly fifty percent compared to the case without electric field, demonstrating the strong role of Maxwell stresses. Analysis of flow fields and interfacial distributions shows that this behavior is due to decrease in curvature-driven pressure gradients, increase in tangential velocities and distribution of surface electrical charge. Regression-based correlations are derived to quantify equilibrium rise and spread, damping ratios and oscillation frequencies as functions of , and . These predictive laws reproduce simulations consistently below margin of error, confirming their usefulness as surrogates for droplet electrohydrodynamics.
{"title":"Numerical investigation revealing droplet electrohydrodynamic response on hydrophobic substrate","authors":"Aaditya Rampal , Yash Agrawal , Shebaz Memon , Tejas Patel , Absar Lakdawala","doi":"10.1016/j.elstat.2025.104225","DOIUrl":"10.1016/j.elstat.2025.104225","url":null,"abstract":"<div><div>This study investigates the dynamics of conducting droplets impacting hydrophobic substrates under externally applied electric fields using high-fidelity numerical simulations. A modified OpenFOAM solver is developed that integrates Kistler’s dynamic contact angle model with a coupled electrohydrodynamic module to capture the combined effects of inertia, surface tension, viscosity and Maxwell stresses. Validation against experimental data confirmed that the solver reproduces inertia-capillary oscillations and spread–recoil behavior with good accuracy. The simulations reveal that electric fields change the energy distribution of an impacting droplet. Increasing electric Bond number reduces lateral spreading, delays recoil and enhances vertical elongation, producing rebound even on hydrophobic substrates that normally suppress it. At <span><math><mrow><msub><mrow><mi>B</mi></mrow><mrow><mi>o</mi><mi>e</mi></mrow></msub><mo>=</mo><mn>0</mn><mo>.</mo><mn>25</mn></mrow></math></span> the maximum rebound height increases by nearly fifty percent compared to the case without electric field, demonstrating the strong role of Maxwell stresses. Analysis of flow fields and interfacial distributions shows that this behavior is due to decrease in curvature-driven pressure gradients, increase in tangential velocities and distribution of surface electrical charge. Regression-based correlations are derived to quantify equilibrium rise and spread, damping ratios and oscillation frequencies as functions of <span><math><msub><mrow><mi>B</mi></mrow><mrow><mi>o</mi><mi>e</mi></mrow></msub></math></span>, <span><math><mrow><mi>W</mi><mi>e</mi></mrow></math></span> and <span><math><msub><mrow><mi>θ</mi></mrow><mrow><mi>E</mi></mrow></msub></math></span>. These predictive laws reproduce simulations consistently below margin of error, confirming their usefulness as surrogates for droplet electrohydrodynamics.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"139 ","pages":"Article 104225"},"PeriodicalIF":2.1,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839922","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 : 2025-12-22DOI: 10.1016/j.elstat.2025.104223
Xiaofen Wu , Yunyi Ding , Ru Wang , Kai Lin , Yichen Luo , Cai Lin
Wearable self-powered sensors show great potential for continuous motion monitoring and next-generation intelligent systems. In this work, a silicone paper-based triboelectric nanogenerator (SP-TENG) was developed to efficiently harvest biomechanical energy from human motion while enabling real-time sensing for gait and posture analysis. The device achieved a peak open-circuit voltage of ∼350.8 V, a short-circuit current of ∼46.3 μA, and a transferred charge of ∼71.9 nC, demonstrating excellent energy conversion efficiency. A maximum instantaneous power of 1.3 mW was obtained under matched load conditions. Compared to conventional paper-based TENGs, the SP-TENG exhibited significantly enhanced output due to the superior triboelectric properties of silicone paper. Its water-resistant structure ensures durability in humid environments, supporting reliable performance in practical applications. The stacked design enables the device to power low-power electronics and LED arrays. With its flexible and lightweight structure, the SP-TENG effectively detects joint bending angles, lower-limb movements, and postural changes. These features make it a promising candidate for integration into wearable electronics for mobility assessment, motion recognition, and adaptive human–machine interfacing, with potential relevance in activity tracking, rehabilitation, and health-related monitoring.
{"title":"High output flexible triboelectric nanogenerator for biomechanical energy harvesting and wearable body joints monitoring","authors":"Xiaofen Wu , Yunyi Ding , Ru Wang , Kai Lin , Yichen Luo , Cai Lin","doi":"10.1016/j.elstat.2025.104223","DOIUrl":"10.1016/j.elstat.2025.104223","url":null,"abstract":"<div><div>Wearable self-powered sensors show great potential for continuous motion monitoring and next-generation intelligent systems. In this work, a silicone paper-based triboelectric nanogenerator (SP-TENG) was developed to efficiently harvest biomechanical energy from human motion while enabling real-time sensing for gait and posture analysis. The device achieved a peak open-circuit voltage of ∼350.8 V, a short-circuit current of ∼46.3 μA, and a transferred charge of ∼71.9 nC, demonstrating excellent energy conversion efficiency. A maximum instantaneous power of 1.3 mW was obtained under matched load conditions. Compared to conventional paper-based TENGs, the SP-TENG exhibited significantly enhanced output due to the superior triboelectric properties of silicone paper. Its water-resistant structure ensures durability in humid environments, supporting reliable performance in practical applications. The stacked design enables the device to power low-power electronics and LED arrays. With its flexible and lightweight structure, the SP-TENG effectively detects joint bending angles, lower-limb movements, and postural changes. These features make it a promising candidate for integration into wearable electronics for mobility assessment, motion recognition, and adaptive human–machine interfacing, with potential relevance in activity tracking, rehabilitation, and health-related monitoring.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"139 ","pages":"Article 104223"},"PeriodicalIF":2.1,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839993","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 : 2025-12-18DOI: 10.1016/j.elstat.2025.104228
Zoltán Ádám Tamus , Lorenzo Villani , Simone Vincenzo Suraci , Davide Fabiani
The -irradiation initiates several degradation mechanisms in insulating polymers, including cross-linking, chain scission, and oxidation, thereby degrading both the mechanical and electrical properties of the materials. Traditionally, the elongation properties are used to qualify the functionality of polymers in radiation environments; however, there is a growing need for non-destructive material testing. One of the substantial advantages of testing electrical properties is that they can be non-destructively measured. Therefore, the conductive properties of -irradiated EPR insulation were investigated in this study. The subject of the research, EPR-insulated cable samples, was investigated using current and extended voltage response (EVR) measurements. The samples were irradiated at a dose rate of 0.8 kGy/h. The total absorbed dose was 1.2 MGy. The results showed that the conductive current and the slope of decay voltage increased steadily with absorbed dose. The activation energies of conductivity increased from the initial 0.8 eV to 2 eV after the total dose. From the trap distribution data, the de-trapping rates were calculated for shallow and deep traps. The de-trapping rate showed a strong correlation with conductivity; however, the de-trapping rate was greater for shallow traps, indicating the dominant role of shallow traps in conduction.
{"title":"Investigation of conduction processes of γ-irradiated EPR insulation by conduction current and extended voltage response measurements","authors":"Zoltán Ádám Tamus , Lorenzo Villani , Simone Vincenzo Suraci , Davide Fabiani","doi":"10.1016/j.elstat.2025.104228","DOIUrl":"10.1016/j.elstat.2025.104228","url":null,"abstract":"<div><div>The <span><math><mi>γ</mi></math></span>-irradiation initiates several degradation mechanisms in insulating polymers, including cross-linking, chain scission, and oxidation, thereby degrading both the mechanical and electrical properties of the materials. Traditionally, the elongation properties are used to qualify the functionality of polymers in radiation environments; however, there is a growing need for non-destructive material testing. One of the substantial advantages of testing electrical properties is that they can be non-destructively measured. Therefore, the conductive properties of <span><math><mi>γ</mi></math></span>-irradiated EPR insulation were investigated in this study. The subject of the research, EPR-insulated cable samples, was investigated using current and extended voltage response (EVR) measurements. The samples were irradiated at a dose rate of 0.8 kGy/h. The total absorbed dose was 1.2 MGy. The results showed that the conductive current and the slope of decay voltage increased steadily with absorbed dose. The activation energies of conductivity increased from the initial 0.8 eV to 2 eV after the total dose. From the trap distribution data, the de-trapping rates were calculated for shallow and deep traps. The de-trapping rate showed a strong correlation with conductivity; however, the de-trapping rate was greater for shallow traps, indicating the dominant role of shallow traps in conduction.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"139 ","pages":"Article 104228"},"PeriodicalIF":2.1,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790722","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 : 2025-12-17DOI: 10.1016/j.elstat.2025.104222
V. Jankuj , P. Lepik , E. Salzano , M. Mynarz
Hydrogen is a promising energy carrier with wide-ranging applications, but its safe storage and handling remain critical challenges. This study investigates the conditions that lead to the accidental self- (or spontaneous) ignition of hydrogen during controlled release from a pressurized cylinder. In the experimental setup, a hydrogen cylinder pressurized to 200 bar was penetrated by a bullet to simulate an accidental release. Thermocouples were strategically placed to measure the temperature of the escaping gas, while the event was monitored with high-speed cameras and drones equipped with thermal imaging.
Temperature measurements of the escaping gas showed minimal variation. However, ignition was observed a few meters from the release point, a surprising result suggesting the involvement of external factors, such as electrostatic discharge or environmental interactions, rather than direct ignition by hydrogen itself. These findings highlight the complexity of hydrogen behavior during high-pressure releases and underline the need for further research to understand and mitigate such risks.
{"title":"Accidental self-ignition of hydrogen released from pressurized cylinder","authors":"V. Jankuj , P. Lepik , E. Salzano , M. Mynarz","doi":"10.1016/j.elstat.2025.104222","DOIUrl":"10.1016/j.elstat.2025.104222","url":null,"abstract":"<div><div>Hydrogen is a promising energy carrier with wide-ranging applications, but its safe storage and handling remain critical challenges. This study investigates the conditions that lead to the accidental self- (or spontaneous) ignition of hydrogen during controlled release from a pressurized cylinder. In the experimental setup, a hydrogen cylinder pressurized to 200 bar was penetrated by a bullet to simulate an accidental release. Thermocouples were strategically placed to measure the temperature of the escaping gas, while the event was monitored with high-speed cameras and drones equipped with thermal imaging.</div><div>Temperature measurements of the escaping gas showed minimal variation. However, ignition was observed a few meters from the release point, a surprising result suggesting the involvement of external factors, such as electrostatic discharge or environmental interactions, rather than direct ignition by hydrogen itself. These findings highlight the complexity of hydrogen behavior during high-pressure releases and underline the need for further research to understand and mitigate such risks.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"139 ","pages":"Article 104222"},"PeriodicalIF":2.1,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790721","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 : 2025-12-16DOI: 10.1016/j.elstat.2025.104226
Constantine Yerin , Inna Es'kova , Dmitry Kudinov
An optical method for measuring the conductivity of low-conductivity dielectric liquids is proposed. The method is based on measuring the electric field relaxation times in a cell containing low-conductivity liquid dielectrics, with one electrode coated with a non-conductive dielectric film. The electric field relaxation time in the cell is estimated from the magnitude of the electro-optical Kerr effect, which depends on the field strength. The results of electro-optical conductivity measurements are in good agreement with those obtained using the classical method based on the analysis of current-voltage curves. The effectiveness of the method is confirmed by computer modelling of electric field relaxation using the Nernst-Planck-Poisson equations.
{"title":"A new method for measuring the conductivity of a low-conducting dielectric liquid based on optical experiments","authors":"Constantine Yerin , Inna Es'kova , Dmitry Kudinov","doi":"10.1016/j.elstat.2025.104226","DOIUrl":"10.1016/j.elstat.2025.104226","url":null,"abstract":"<div><div>An optical method for measuring the conductivity of low-conductivity dielectric liquids is proposed. The method is based on measuring the electric field relaxation times in a cell containing low-conductivity liquid dielectrics, with one electrode coated with a non-conductive dielectric film. The electric field relaxation time in the cell is estimated from the magnitude of the electro-optical Kerr effect, which depends on the field strength. The results of electro-optical conductivity measurements are in good agreement with those obtained using the classical method based on the analysis of current-voltage curves. The effectiveness of the method is confirmed by computer modelling of electric field relaxation using the Nernst-Planck-Poisson equations.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"139 ","pages":"Article 104226"},"PeriodicalIF":2.1,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790743","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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