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There are two parts to this manuscript. In the first part, thin films were prepared by doping carboxymethyl cellulose with Polyanionic cellulose low viscosity, with a concentration of 73% CMCHV and 27% PACLV, then CMC HV/PAC LV thin films were exposed to different X-ray photon doses (0, 200, 400, 600, and 800 cGy). But second Part were prepared the thin films by dissolving 8 g of CMCHV in 50 ml of distilled water, then adding NaCl and ZnONPs in concentrations (0.00, 11, 20, 27, 33 and 38%). The intensity of the direct current I was measured for all samples by changing the potential difference V at different temperatures (T). The measurement results of all samples studied in this research indicate that the conductivity and current density increase with an increase in the X-ray photon doses in the irradiated samples or with an increase in the concentrations of NaCl, ZnOPNs and also increases with increasing temperature, but the conductivity and current density increase more when NaCl is added than when ZnO PNs are added. By using these results, several areas can benefit, such as industry, scientific research, etc.

2023 Descuento SCOAP, We provide a reinterpretation of the quantum vacuum ambiguities that one encounters when studying particle creation phenomena due to an external and time-dependent agent. We propose a measurement-motivated understanding: Each way of measuring the number of created particles selects a particular vacuum. This point of view gives a clear and physical meaning to the time evolution of the number of particles produced by the agent as the counts in a specific detector and, at the same time, relates commonly used quantization prescriptions to particular measurement setups., Ministerio de Ciencia e Innovación (España), Agencia Estatal de Investigación (España), Fondo Europeo de Desarrollo Regional (FEDER), European Commission, European Cooperation in Science and Technology, Ministerio de Universidades (España), Centro de Excelencia Severo Ochoa (España), Depto. de Física Teórica, Fac. de Ciencias Físicas, Instituto de Física de Partículas y del Cosmos (IPARCOS), TRUE, pub, Descuento UCM

High voltage is essential in power grids, but it inevitably leads to high electrical stress and the associated risk of electrical discharges. Due to the complexity of the phenomena involved in electrical discharges, there are no analytical formulas for predicting the electric field strength at which they initiate, so experimental data and numerical methods are required for this purpose. According to many sources, electrical discharges can occur in air at normal pressure and temperature when the electric field strength is approximately 3 kV/mm or greater. This paper analyzes and discusses this threshold in detail by examining relevant electrode geometries used in high voltage applications from experimental data found in the scientific literature and using 2D finite element analysis (FEA) simulations. Uniform, quasi-uniform, and non-uniform field gaps are analyzed to help students draw conclusions and gain insight into the nature of gas breakdown and the applicability of the 3 kV/mm threshold. The approach proposed in this paper is well suited for a practical session or group project for undergraduate or even graduate courses. Despite the important effects and design implications of electrical discharges on high voltage devices, apparatus and systems, this topic is rarely covered in regular courses., This work was partially supported by Ministerio de Ciencia e Innovación de España, grant number PID2020-114240RB-I00 and by the Generalitat de Catalunya, grant number 2021 SGR 967., Peer Reviewed, Postprint (author's final draft)

Bipolar charge transport (BCT) models have been used for the past few decades to simulate and analyze charge transport and its associated phenomena in polymeric insulation materials. Whilst in this method primarily, electronic charge carriers are used, recent studies show that there has been a high interest in the addition of ionic charge carriers and their physical processes in the model. Among the byproducts in the crosslinked XLPE, acetophenone is speculated to have deep electron traps and therefore can contribute to the electrical conduction processes in XLPE insulation, leading to charge and field dynamics in XLPE insulation. In this paper, a new model is attempted considering acetophenone for modelling the ions originating from acetophenone molecules, which demonstrates the charge and field dynamics in the insulation. Using the BCT model, combining with the electronic species, the impact of the presence of the ions is discussed. The ionic charge carrier and the neutral molecule are modelled based on Marcus theory. The results reported in this paper draw attention to the charge and field distribution for different ionic concentrations, the effect of thermal gradient and mobilities of the ions. A comparison between the experimental conductivity values from various literature and the proposed model has been done., Part of ISBN 9798350308976QC 20240924

Bij elektriciteit hoort spanning. Spanningsvariatie, zoals door een frequentieregelaar, heeft in de stal mogelijk ook effect op het welzijn, de weerstand, het gedrag en de gezondheid van dieren. Een groep veehouders kijkt hiernaar.

Joule heating is generally acknowledged as the main driving force behind Flash Sintering. However, this view is challenged by the presence of athermal phenomena and the similarities between the flash process and dielectric breakdown. This work offers new insights into flash as an electrical runaway. Using current ramps to perform flash experiments on zinc oxide, two distinct stages within the process were revealed by electrical, thermal and microstructural measurements: a field-dominated regime where the flash event is triggered and a subsequent current-dominated regime associated with power dissipation. The contribution of each regime to the whole flash process was found to be determined by the initial resistivity of the sample. Furthermore, impedance spectroscopy data confirmed field-induced enhancement of conductivity at the flash-onset without significant Joule heating.

The modeling of transcranial magnetic stimulation (TMS)–induced electric fields (E-fields) is a versatile technique for evaluating and refining brain targeting and dosing strategies, while also providing insights into dose–response relationships in the brain. This review outlines the methodologies employed to derive E-field estimations, covering TMS physics, modeling assumptions, and aspects of subject-specific head tissue and coil modeling. We also summarize various numerical methods for solving the E-field and their suitability for various applications. Modeling methodologies have been optimized to efficiently execute numerous TMS simulations across diverse scalp coil configurations, facilitating the identification of optimal setups or rapid cortical E-field visualization for specific brain targets. These brain targets are extrapolated from neurophysiological measurements and neuroimaging, enabling precise and individualized E-field dosing in experimental and clinical applications. This necessitates the quantification of E-field estimates using metrics that enable the comparison of brain target engagement, functional localization, and TMS intensity adjustments across subjects. The integration of E-field modeling with empirical data has the potential to uncover pivotal insights into the aspects of E-fields responsible for stimulating and modulating brain function and states, enhancing behavioral task performance, and impacting the clinical outcomes of personalized TMS interventions., The modeling of transcranial magnetic stimulation (TMS)–induced electric fields (E-fields) is a versatile technique for evaluating and refining brain targeting and dosing strategies, while also providing insights into dose–response relationships in the brain. This review outlines the methodologies employed to derive E-field estimations, covering TMS physics, modeling assumptions, and aspects of subject-specific head tissue and coil modeling. We also summarize various numerical methods for solving the E-field and their suitability for various applications. Modeling methodologies have been optimized to efficiently execute numerous TMS simulations across diverse scalp coil configurations, facilitating the identification of optimal setups or rapid cortical E-field visualization for specific brain targets. These brain targets are extrapolated from neurophysiological measurements and neuroimaging, enabling precise and individualized E-field dosing in experimental and clinical applications. This necessitates the quantification of E-field estimates using metrics that enable the comparison of brain target engagement, functional localization, and TMS intensity adjustments across subjects. The integration of E-field modeling with empirical data has the potential to uncover pivotal insights into the aspects of E-fields responsible for stimulating and modulating brain function and states, enhancing behavioral task performance, and impacting the clinical outcomes of personalized TMS interventions.

Received 5 April 2017, revised 20 August 2017; Accepted for publication 29 August 2017; Published 19 September 2017., In this work, Doppler-free two photon optogalvanic spectroscopy is used to measure the electric field strength in the cathode fall region of a hollow cathode discharge, operated in pure hydrogen, via the Stark splitting of the 2S level of atomic hydrogen. The cathode fall characteristics are analysed for various pressures and in a wide range of discharge currents. Tungsten is used as the cathode material, because it allows for reliable measurements in a fairly wide range of discharge conditions and because of its minimal sputtering. Two cathode diameters (10 mm and 15 mm) are used to study the dependence of the cathode fall on discharge geometry. The measurements reveal that the cathode fall characteristics are quite independent on the cathode diameter for equal cathode current density; hence the measurements can be used to test one dimensional modelling of the cathode fall region for low pressure hydrogen discharges using e.g. plane parallel electrodes., Ministerio de Economía y Competitividad, Depto. de Óptica, Fac. de Óptica y Optometría, TRUE, pub

We describe a construction of random meromorphic functions with prescribed simple poles with unit residues at a given stationary point process. We characterize those stationary processes with finite second moment for which, after subtracting the mean, the random function becomes stationary. These random meromorphic functions can be viewed as random analogues of the Weierstrass zeta function from the theory of elliptic functions, or equivalently as electric fields generated by an infinite random distribution of point charges., QC 20231128

It is critical to develop new insulating materials that can improve the performance of next generation high voltage cables for creating future electrical networks. The high electric field reduces the resistance of solid insulation and produces partial discharge through imperfections in a dielectric, causing the dielectric to age and eventually fail. Thus, this project seeks to analyse the electric field intensity of High Density Polyethylene (HDPE) in breakdown condition when added with 10g, 20g and 30g of different types of bio-filler such as coconut coir fibre, pineapple leaves fibre, and oil palm empty fruit bunch. This can be achieved by creating a two-dimensional (2D) axisymmetric electrostatic model by using the Finite Element Method Magnetics (FEMM) 4.2 software. The results showed that the unfilled HDPE biocomposites have a higher electric field intensity than 10g, 20g, and 30g biocomposite. This indicates that the maximum electric field intensity changes according to the permittivity and voltage of the bio-filler under breakdown conditions. As a result, the maximum electric field intensity was much lower for HDPE added with a 20g of the pineapple leaves fibre. Hence, pineapple leaves fibre was the best composition as it tends to improve the dielectric properties since it has a lower electric field intensity at the top electrode as compared to other compositions.

During thermal annealing at 1425 °C nominal electric field strengths of 50 V/mm and 150 V/mm were applied along the grain boundary planes of a near 45° (100) twist grain boundary in SrTiO3. Electron microscopy characterization revealed interface expansions near the positive electrode around 0.8 nm for either field strength. While the interface width decreased to roughly 0.4 nm after annealing at 50 V/mm, the higher field strength caused decomposition of the boundary structure close to the negative electrode. Electron energy-loss and X-ray photoelectron spectroscopies demonstrated an increased degree of oxygen sublattice distortion at the negative electrode side, and enhanced concentrations of Ti3+ and Ti2+ compared to bulk for both single crystals and bicrystals annealed with an external electric field, respectively. Oxygen migration due to the applied electric field causes the observed alteration of grain boundary structures. At sufficiently high field strength the agglomeration of anion vacancies may lead to the decomposition of the grain boundary.

The lateral migration of colloidal particles inside a microfluidic channel has gained attention due to being both fundamentally intriguing and applicable for particle separation, such as cancer cell isolation or extracellular vesicle purification. Applying an external electric field combined with a pressure-driven flow induces such lateral migrations. In this study, new modes of lateral particle migration have been found by experimentally investigating 6 µm particles in the co-presence of electric field and pressure-driven flow. The experiments revealed the importance of the relative strengths of electric field and pressure gradient in determining particle lateral positioning. We hypothesize that the nonuniformity of the polarization caused by the external electric field and the rotation of the particle due to the background pressure-driven flow result in these modes of transverse migration. These new migration patterns are further utilized to perform microparticle separation and, more importantly, present a novel separation modality.

Measurements of independent fission yield distributions in neutron-induced fission at high neutron energies are important for our fundamental understanding of the fission process, and are also relevant for reactor physics applications. So far, measurements of independent fission yields in proton-induced fission have been performed at the IGISOL facility at the University of Jyväskylä, using the Penning trap as a high resolving-power mass-filter. In order to also facilitate measurements of neutron-induced fission, a dedicated ion guide and a proton-to-neutron converter was developed. However, the first measurement indicates that fewer fission products than expected reach the Penning trap. To explore potential reasons and possible improvements, a simulation model was also developed and benchmarked. The benchmark showed that the model is able to reproduce the performance of the ion guide remarkably well and that the main reason for the low yield of fission products is the low collection efficiency of the ion guide. Based on the benchmark, a new ion guide is being designed. In the new design, the positions of the uranium targets and volume of the ion guide have been changed to increase the collection of fission products. This results in a five-fold increase of the yield. However, the collection efficiency of the new ion guide still needs to be improved in order to achieve intensities of the extracted fission products that are large enough to allow for reasonable measurement times. Because the volume of the ion guide is increased significantly, the extraction time of the ions is expected to be longer than that from the previous ion guide. Therefore, an electric field guidance system that consists of a combination of a stationary electric field and an RF-carpet is considered to be deployed. The stationary field, produced from a set of DC-ring electrodes, accelerates the ions towards the RF-carpet at end plate of the ion guide. The RF-carpet consists of a time-dependent fi

The antiferromagnetic (AFM) CrI3 bilayer is a particularly interesting representative of van der Waals 2D semiconductors, which are currently being studied for their magnetism and for their potential in spintronics. Using ab initio density-functional theory calculations, we investigate the spin texture in momentum space of the states of the (doubly degenerate) highest valence band of the AFM CrI3 bilayer with Cr-spin moments perpendicular to the layers. We find the existence, in the main central part of the Brillouin zone, of a Rashba in-plane spin texture of opposite signs on the two layers, resulting from the intrinsic local electric fields acting on each layer. To study the layer segregation of the wavefunctions, we apply a small electric field that splits the degenerate states according to their layer occupancy. We find that the wavefunctions of the highest valence band are layer-segregated, belonging to only one of the two layers with opposite in-plane spin textures, and the segregation occurs over nearly the whole Brillouin zone. The corresponding layer locking of the in-plane -canted spin is related to the separation in energy of the highest AFM band from the rest of the valence bands. We explain how the band interactions destroy the layer locking at the K, K ', and Gamma points. Furthermore, we compare the layer locking of the in-plane-canted spin in our AFM bilayer system with the hidden spin polarization in centrosymmetric nonmagnetic materials, pointing out the differences in segregation mechanisms and their consequences for the layer locking. We note that a similar Rashba effect with layer locking of in -plane-canted spin could occur in other van der Waals AFM bilayers with strong spin-orbit coupling and an isolated energy band.

Since energy efficiency in comminution of ores is as small as 1% using a mechanical crushing process, it is highly demanded to improve its efficiency. Using electrical impulses to selectively liberate valuable minerals from ores can be a solution of this problem. In this work, we developed a simulation method using equivalent circuits of granite to better understand the crushing process with high-voltage (HV) electrical pulses. From our simulation works, we calculated the electric field distributions in granite when an electrical pulse was applied. We also calculated other associated electrical phenomena such as produced heat and temperature changes from the simulation results. A decrease in the electric field was observed in the plagioclase with high electrical conductivity and void space. This suggests that the void volume in each mineral is important in calculating the electrical properties. Our equivalent circuit models considering both the electrical conductivity and dielectric constant of a granite can more accurately represent the electrical properties of granite under HV electric pulse application. These results will help us better understand the liberation of minerals from granite by electric pulse application.

Although ICRF heating has achieved the high heating efficiency necessary to achieve high-performance plasmas, it has not overcome the reliability and economic problems associated with the antenna structure inside the vacuum vessel in fusion reactors. We suggested a slit ICRF antenna that uses the blanket surface as a transmission line to solve these problems. With a single slit ICRF antenna with a width of 3 m and a height of 15 cm, the electric field strength to the magnetic field direction was successfully suppressed to 5 kV/cm when 20 MW of power radiation was achieved from the single slit. The slit ICRF antenna had a bending angle in the electromagnetic wave transmission path to prevent direct neutron impact on the first wall and a vacuum gate from rapidly preventing water or air leakage accidents. The slit ICRF antenna has a simple structure that allows heating at high power density while minimizing blanket volume reduction., source:https://doi.org/10.1016/j.fusengdes.2023.113453, identifier:0000-0001-6075-1146

A wisely applied external electric field could effectively develop the optoelectronic properties of single-layer materials. The optical and electronic characteristics of monolayer molybdenum diselenide (ML-MoSe2) are deeply studied by means of density functional computations (DFT) to pinpoint the effect of the out-of-plane applied electric field (F//Oz). In fact, variations in the applied electric field strength gradually increase the energy of the electronic band gap (Eg) from 1.44 eV at 0V/& ANGS; to 1.51 eV at & PLUSMN;0.6V/& ANGS;. We also probed a sharp drop in the energy gap at high intensities. However, dielectric function, reflectivity, and loss function are studied for unpolarized and polarized incident light. Interestingly, the 001-polarization of the incident light affects the dielectric function's magnitude and position; this effect is more emphasized in the presence of an electric field with positive strengths. Furthermore, we found that the applied negative/positive electric field enhances the UV-visible reflectivity. Also, blue shifts of the ML-MoSe2 optical properties spectrum appear when subjected to the 001-polarized incident light. However, the loss function exhibits a weak response to the applied F. Additionally, we obtain that the 001-light polarization improves a plasmonic peak around 100 nm. Our results will provide a new view to understanding the controllable optical and electronic properties of MoSe2 monolayer, which is valuable for the design of new optoelectronic and plasmonic devices under development.

Electric machines are widely used in for instance the automotive industry in electric vehicles and in wind turbines. The electrical machines have mechanical bearings as an integral part used to transmit power and load. In addition, the main function includes reducing friction between interacting surfaces. However, it is one of the most failing machine elements in these machines. To improve operational sustainability and reduce maintenance costs, understanding bearing failure mechanisms under electrical influence is important. One of the main reasons of bearing failure is linked to high frequency power switches typically used to enhance electric machines’ efficiency. The increase in switching rate induces more frequent common mode voltage fluctuations making the system vulnerable to bearing currents. A small voltage difference of a few ten volts can induce significant electric stress on the bearing depending on the lubricant film thickness and related tribological parameters. The electric charge build-up leads to electric current conduction (arc discharge which happens when the voltage exceeds the breakdown voltage) ultimately damaging the bearing. There are different mitigation strategies which are used to restrict bearing currents through grounding or using completely insulative bearings such as ceramic ones. However, at the moment, there are no satisfactory solutions and there is a need for efficient and economical solutions to the problem. On the other hand, various filters are used to reduce the amplitude and its frequency of bearing currents, but they only partly solve the problem. Similarly, the insulative surface coatings provides high electrical resistance but start acting as capacitors. At a sufficiently high voltage difference, the current passes through the system. Therefore, mitigation strategies are still being explored to improve system performance and service-life. To understand the bearing discharge activity and electrical breakdowns, an electrified

This paper presents a comparative analysis of the propagation models Hata Extended, SUI with a frequency correction factor, and Ericsson 9999 in mobile telephony systems operating in the 1900 MHz band (LTE). The study is carried out by measuring the electric field to establish a recommendation for an existing propagation model that fits the characteristics of the urban area of Ambato City. First, five base stations were located. Then, two base stations working in the band and technology mentioned above are chosen. Subsequently, four radial limits were drawn in the surroundings of the base stations, and four electric field measurement campaigns were carried out with the Narda SRM-3006 equipment for a total of 48 points for 6 minutes per point. In addition, the coordinates of the measurement points were determined using the Spectra Precision Mobile Mapper 50 equipment, obtaining the distances and heights of the terrain with great precision. With the data collected, the propagation losses are calculated to bring the theoretical electric field of each propagation model. Next, comparing the measured electric field values concerning each model's theoretical electric field values is performed to evaluate which model best fits the measurements. Also, a comparison of the RMSE is made. Finally, it is concluded that the SUI model with frequency correction factor is the best fit for the urban environment of the city of Ambato., El presente artículo ofrece un análisis comparativo de los modelos de propagación Hata Extendido, SUI con factor de corrección de frecuencia y Ericsson 9999, en los sistemas de telefonía móvil que operan en la banda de 1900 MHz (LTE) a través de mediciones de campo eléctrico con la finalidad de establecer una recomendación de un modelo de propagación existente que se ajuste a las características del casco urbano de la ciudad de Ambato. Inicialmente se ubicaron cinco estaciones base, luego se escogieron dos estaciones base que trabajan en la banda y tecnología antes mencionada. Posteriormente se trazaron 4 limites radiales en los alrededores de las estaciones base y se realizaron 4 campañas de mediciones de campo eléctrico con el equipo Narda SRM-3006 en un total de 48 puntos por 6 minutos por punto. Además, se determinó las coordenadas de los puntos de medición mediante el equipo Spectra Precision Mobile Mapper 50 donde se obtiene las distancias y alturas de terreno con gran precisión, con los datos recolectados se realizó el cálculo de las pérdidas de propagación para la obtención del campo eléctrico teórico de cada modelo de propagación. Para evaluar qué modelo se ajusta más a las mediciones se realizó una comparación de valores de campo eléctrico medido con respecto a los valores de campo eléctrico teórico de cada modelo, mediante una comparación del RMSE. Finalmente se concluyó que el modelo SUI con factor de corrección de frecuencia es el que tiene mejor ajuste al entorno urbano de la ciudad de Ambato.

It is critical to develop new insulating materials that can improve the performance of next-generation high-voltage cables used in the construction of future electrical networks. The high electric field reduces solid insulation resistance and causes partial discharge through imperfections in a dielectric, causing the dielectric to age and eventually fail. Moisture is one of the most serious factors the effect the high voltage insulation status of High-Density Polyethylene (HDPE) composites. The main goal of this project is to investigate the electric field intensity of HDPE due to moisture content condition when mixed with 10g, 20g, and 30g of various bio-fillers such as coconut coir fibre, pineapple leaves fibre, and oil palm empty fruit bunch. This can be accomplished by using the Finite Element Method Magnetics (FEMM) 4.2 software to create a two-dimensional (2D) axisymmetric electrostatic model. When compared to unfilled HDPE, the inclusion of bio-filler in HDPE increased the maximum electric field intensity due to moisture content condition. The intensity of the electric field varied with the different percentages of biocomposite loading and their permittivity due to moisture content condition. The results showed, due to moisture content condition, the maximum electric field intensity was significantly lower when HDPE was added with a 10% loading of the oil palm empty fruit bunch (EFB). As a result, EFB bio-filler was the best composition because it tends to improve dielectric properties by having a lower maximum electric field intensity which is 4.214Mv/m due to moisture content condition at the top sphere electrode when compared to other compositions.

In this work, the high- and low-frequency precursors discovered by Sommerfeld and analyzed by Sommerfeld and Brillouin are further examined using numerical integration techniques on a modern computer. It builds on the techniques and results found by Jakobsen and Mansuripur, who extended Sommerfeld and Brillouin's work by investigating finite-bandwidth electric fields and analyzing the use of the steepest descent approximation for integration of the Fourier integral. To that method is added two others: the method of stationary phase and an alternate approach to the method of steepest descent using path integrals. The behavior of the saddle-points described in detail by Jakobsen and Mansuripur is reproduced. Then, taking advantage of the numerical techniques to calculate the integral results for over a million points, the original field used by Sommerfeld is examined in greater detail, confirming the results he sketched out for the behavior of the field and expanding upon them to reveal more details of the spectral and intensity behavior of the field. Additionally, two of the limited-bandwidth fields proposed by Jakobsen and Mansuripur are examined, showing the similarities and differences of their behavior compared to those of Sommerfeld's. Finally, since the results for the three different fields were each computed using all three numerical integration methods, the characteristics of the outputs and computation speeds for all three methods are compared, finding advantages and disadvantages of each.

Recent use of ion currents as a sensing strategy in the mechanized oxyfuel cutting process motivated a series of studies which revealed that the steel work piece contributes secondary ions in addition to the primary ions classically identified in the oxyfuel flame. In this work, we present a computational model that has linked carbon-related chemi-ions as a source of secondary ions in preheating stage of oxyfuel cutting process subject to electric bias voltages. The flames' response to the electric field at different positive and negative polarities manifested a better understanding of the physical behavior of current-voltage (i-v) relationship. While copper surface exhibits stable and repeatable i-v characteristics, sporadically enhanced current was observed in positive saturation regime for steel surface, and this is believed to be due to the presence of secondary chemi-ions. To this extent, a source term of gaseous carbon has been assigned to mimic the 'work surface' reactions. The hypothesis is that since carbon is an important element, it will be diffusing out of the steel surface and evaporate into the flame.

The piezoelectric response in polycrystalline films of doped ferroelectric HfO2 has been explored so far; however, the lack of texture in most of the studied films prevents its full understanding. By selecting the appropriate substrate orientation, the ferroelectric orthorhombic phase ratio and crystallographic orientation can be modified in epitaxial films. We exploit this possibility to get further insight into the ferroelectric hafnium oxide piezoelectric response. While characterizing in-plane and out-of-plane piezoelectric responses, it is observed that their magnitude is mainly ruled by the presence of the orthorhombic phase and the polar axis of the polarization along the probing direction. It is also found for the as-grown state that along the out-of-plane direction a single ferroelectric domain is formed, and instead the in-plane response reveals a rich domain structure with a domain size of ≈10-30 nm. By characterizing the in-plane piezoelectric response, it is observed that it is anisotropic if the specific orientation, (110), of the SrTiO3 substrate is used. We propose that an out-of-plane single domain is formed due to the presence of an imprint electric field, whereas in-plane domains are formed by non-purely electrostatic interactions as revealed by their relatively large size. Besides, the small but sizeable in-plane anisotropic response is found to result from the in-plane crystallographic configuration, ultimately determined by the selected substrate.

This course runs parallel to 8.02, but assumes that students have some knowledge of vector calculus. The class introduces Maxwell's equations, in both differential and integral form, along with electrostatic and magnetic vector potential, and the properties of dielectrics and magnetic materials. This class was taught by an undergraduate in the Experimental Study Group (ESG). Student instructors are paired with ESG faculty members, who advise and oversee the students' teaching efforts.

The dataset used to generate plots for the manuscript "The Role of the Atmospheric Electric Field and Downdrafts in the Surface Ozone Concentration in the Amazon." It contains data of the electric field, downdrafts, ozone, GLM events, and ultrafine particle concentration. All files are in CSV format.

Electrostatic forces can be used to control the motion of charged particles. In this article, particle charging and motion in an electric field under ultraviolet (UV) irradiation were investigated. When the particle layers deposited on an insulating substrate were irradiated with UV light in a downward electric field, photoelectrons were emitted, and positive charges moved to the bottom of the particle layers. Subsequently, by reversing the direction of the electric field, the positive charges in the bottom moved upward; thus, the particles in the top layer were positively charged and levitated by Coulomb forces. The flux of the levitated particles increased with an increase in the strength of the electric field (downward and upward). As the upward electric field strength increased, the number of agglomerated particles in the levitation increased; however, the particle charge decreased. As the thickness of the particle layers increased, the time delay for particle levitation increased; however, the flux of the levitated particles decreased. The ratio of agglomerated particles to the total levitated particles increased. These results can be explained by the mechanisms of charge transfer and particle levitation.

Alloy-type anodes are promising next-generation electrodes for Li-ion batteries because of their high specific capacity, but the severe volume expansion causes fast capacity decay. Here, two methods were explored to improve alloy-type anodes. First, a thermodynamically driven grain boundary engineering was proposed as a potential strategy. SnSb with Bi addition fabricated through ball milling and annealing was selected as a model system. The Bi-doped SnSb demonstrated improved cycling performance with < 1% porosity. Transmission electron microscopy shows grain boundaries Bi segregation, and thermodynamic modeling further indicates the stabilization of a nanoscale liquid-like interfacial phase. In situ X-ray microscopy shows the crack suppression effect for the Bi-doped sample, suggesting a potential grain boundary sliding as a stress relief mechanism. Second, cryogenic milling was demonstrated as a novel method to engineer alloy-type anodes. This process can suppress cold welding, exfoliate bulk graphite into multilayer graphene, and evenly disperse them between the grains to form nanostructured electrodes. Based on the cross-section electron microscopy and X-ray microscopy, the dispersed graphene between the nanosized grains can effectively alleviate the volume expansion upon lithiation. Compared to the traditional ball milling methods under room temperature, the cryomilled SnSb-C composite anode showed improved cycling stability and rate capability. For ceramic processing methods, electric field assisted sintering process can have a lower sintering temperature and faster sintering time compared to conventional sintering. For the second part of the thesis, nonthermal electric field effects on ZnO polycrystalline specimen was investigated. In undoped ZnO, electric field can induce defect polarization and subsequently alter the grain boundary structure. We also demonstrated the possibility of creating and controlling graded microstructure via electric fields. In B

The technology of focus in this paper, the applied-field magnetoplasmadynamic (MPD) thruster (AF-MPDT), was developed in the 1960s. However, little research has been conducted for this thruster. There is still the need for an accurate model describing the thruster's functioning, its thrust and the physical phenomenons inside. This project was conducted together with the Neutron Star Systems start-up, who are developing the SUPREME AF-MPDT. This thruster incorporates new technologies making the older simulation codes less suitable. Thus, the need for the very expensive AF-MPDT laboratory testing is reduced, new plasma models are tested faster and the operation parameters are optimised. Therefore, the goal of this project was to identify the most suitable plasma simulation software for SUPREME that can be used in the Digital Twin of an AF-MPD thruster, supported by a set of requirements and a number of important parameters., Aerospace Engineering

In the present work, the interactions between neutral molecular systems subject to external static electric fields are studied. To comprehensively explore the effects of external fields on intermolecular interactions, the two most reliable frameworks in the subject, namely molecular quantum mechanics and quantum electrodynamics are employed while atomic and molecular responses are modeled using quantum Drude oscillators (QDO). In the first part of the work, the focus is to understand the interplay between dispersion and field-induced forces in two-body systems for both nonretarded and retarded ranges of inter-species distances. To identify the origin and the mechanism responsible for different field-induced interactions, a complementary approach based on classical electrodynamics with a zero-point radiation field, namely stochastic electrodynamics, is employed. The results show that neglecting higher-order contributions coming from field-induced hyperpolarizabilities of atoms, the dispersion interaction remains unchanged by the external uniform static field, for both regimes. However, using an external static field one can control the magnitude and characteristics of intermolecular interactions. The second part of the work is devoted to the extension of the study to many-body interacting systems. There, the total interaction energy in systems with many interacting atoms or molecules is obtained by extending the well-established theory of many-body dispersion (MBD) interactions to the presence of external static electric fields. Diagonalization of the Hamiltonian of the system in the nonretarded regime and in the framework of quantum mechanics yields the total energy of the interacting system in terms of the corresponding normal mode frequencies. Subtraction of the energy of the non-interacting QDOs-in-fields from the total energy of the interacting system results in the many-body interaction energy. The impact of the field-induced many-body contributions is investig

Two-dimensional materials are excellent candidates for effective gas detection due to the large surface-volume ratio, however the controllability to adsorb/desorb the gas molecules for recycling use is still a big challenge. In this study, different from previous strategies to modulate gas adsorption behavior via strain and external electric field, a novel approach to achieve gas adsorption control via ferroelectric (FE) switching is proposed. From first principle simulations, it is found that gas molecule adsorptions on Fe and Mn doped defective graphene can be well controlled when it is placed on the surface of FE In2Se3. The adsorption energies and charge transfer can be significantly modulated when the polarization is reversed, due to the polarization dependent electron redistribution and band state shifts near the Fermi level. The hypothesis of the FE controlled gas adsorption is further supported by the adsorption variations under the electric field. These findings provide feasible approaches and design principles for the next generation gas sensors.

Non-thermal atmospheric pressure plasma jets (NAPPJs) using ambient air as the inducer are of particular and desirable interest but with significant challenges. In this study, we report an air APPJ driven by ionization in the afterglow region, resembling noble gas APPJs. A pin-to-nozzle electrode is used for the air plasma jet with a nanosecond-pulsed DC high voltage as the power supply. Results show that the nozzle diameter plays an essential role in forming the air plasma jet. When the nozzle diameter is 3 mm, the air APPJ is driven by ionization in the afterglow region which is proved by the following three phenomena. First, with an exposure time of 0.1 s, an obvious shiny line (the narrow channel plasma) formed by electron accumulation is observed in the jet. The narrow channel becomes much brighter with a grounding pin approaching the nozzle vertically. In comparison, there is no such phenomenon with a 1-mm diameter nozzle. Second, the afterglow region discharge current of the ionization-driven processes is hundreds of mA distinguished from airflow-driven processes, the afterglow region current of which is typically zero. By using E-FISH to measure the electric field in the afterglow region, it can detect the electric field which has a maximum value of 10.5 kV/cm. Third, the intensity of the N2+ band is much stronger with a 3-mm diameter nozzle than with a 1-mm diameter nozzle, indicating that the local electric field plays an important role in the discharge. We expect this study can offer useful guidelines on the design and understanding of ionization-driven air plasma jets.

We investigate the response characteristics of a two-dimensional neuron model exposed to an externally applied extremely low frequency (ELF) sinusoidal electric field and the synchronization of neurons weakly coupled with gap junction. We find, by numerical simulations, that neurons can exhibit different spiking patterns, which are well observed in the structure of the recurrence plot (RP). We further study the synchronization between weakly coupled neurons in chaotic regimes under the influence of a weak ELF electric field. In general, detecting the phases of chaotic spiky signals is not easy by using standard methods. Recurrence analysis provides a reliable tool for defining phases even for noncoherent regimes or spiky signals. Recurrence-based synchronization analysis reveals that, even in the range of weak coupling, phase synchronization of the coupled neurons occurs and, by adding an ELF electric field, this synchronization increases depending on the amplitude of the externally applied ELF electric field. We further suggest a novel measure for RP-based phase synchronization analysis, which better takes into account the probabilities of recurrences., Peer Reviewed

Plasma jets are sources of repetitive and stable ionization waves, meant for applications where they interact with surfaces of different characteristics. As such, plasma jets provide an ideal testbed for the study of transient reproducible streamer discharge dynamics, particularly in inhomogeneous gaseous mixtures, and of plasma-surface interactions. This topical review addresses the physics of plasma jets and their interactions with surfaces through a pedagogical approach. The state-of-the-art of numerical models and diagnostic techniques to describe helium jets is presented, along with the benchmarking of different experimental measurements in literature and recent efforts for direct comparisons between simulations and measurements. This exposure is focussed on the most fundamental physical quantities determining discharge dynamics, such as the electric field, the mean electron energy and the electron number density, as well as the charging of targets. The physics of plasma jets is described for jet systems of increasing complexity, showing the effect of the different components (tube, electrodes, gas mixing in the plume, target) of the jet system on discharge dynamics. Focussing on coaxial helium kHz plasma jets powered by rectangular pulses of applied voltage, physical phenomena imposed by different targets on the discharge, such as discharge acceleration, surface spreading, the return stroke and the charge relaxation event, are explained and reviewed. Finally, open questions and perspectives for the physics of plasma jets and interactions with surfaces are outlined.

Aerobic life is powered by membrane-bound enzymes that catalyze the transfer of electrons to oxygen and protons across a biological membrane. Cytochrome c oxidase (CcO) functions as a terminal electron acceptor in mitochondrial and bacterial respiratory chains, driving cellular respiration and transducing the free energy from O2 reduction into proton pumping. Here we show that CcO creates orientated electric fields around a nonpolar cavity next to the active site, establishing a molecular switch that directs the protons along distinct pathways. By combining large-scale quantum chemical density functional theory (DFT) calculations with hybrid quantum mechanics/ molecular mechanics (QM/MM) simulations and atomistic molecular dynamics (MD) explorations, we find that reduction of the electron donor, heme a, leads to dissociation of an arginine (Arg438)–heme a3 D-propionate ion-pair. This ion-pair dissociation creates a strong electric field of up to 1 V Å-1 along a water-mediated proton array leading to a transient proton loading site (PLS) near the active site. Protonation of the PLS triggers the reduction of the active site, which in turn aligns the electric field vectors along a second, “chemical,” proton pathway. We find a linear energy relationship of the proton transfer barrier with the electric field strength that explains the effectivity of the gating process. Our mechanism shows distinct similarities to principles also found in other energy-converting enzymes, suggesting that orientated electric fields generally control enzyme catalysis.

A black hole x-ray binary (XRB) system forms when gas is stripped from a normal star and accretes onto a black hole, which heats the gas sufficiently to emit x-rays. We report a polarimetric observation of the XRB Cygnus X-1 using the Imaging X-ray Polarimetry Explorer. The electric field position angle aligns with the outflowing jet, indicating that the jet is launched from the inner x-ray-emitting region. The polarization degree is 4.01 ± 0.20% at 2 to 8 kiloelectronvolts, implying that the accretion disk is viewed closer to edge-on than the binary orbit. These observations reveal that hot x-ray-emitting plasma is spatially extended in a plane perpendicular to, not parallel to, the jet axis.

Featured Application Electric fields produced by lightning subsequent stroke leaders are sufficiently high for acceleration of electrons to relativistic speeds, leading to generation of X-rays/gamma-rays as a result of Bremsstrahlung emissions. Leaders of subsequent strokes in negative cloud-to-ground lightning are known to produce X-ray/gamma-ray emissions detectable at distances of a few kilometers or less from the lightning channel. These leaders usually develop in decayed but still warm channels of preceding strokes. We computed electric field waveforms at different points along the path of subsequent leader as those points are traversed by the leader tip. For a typical subsequent leader, the electric field peak is a few MV/m, which is sufficient for production of energetic radiation in a warm (reduced air density) channel. We examined the dependence of electric field peak on the leader model input parameters, including the prospective return-stroke peak current (a proxy for the leader tip potential) and leader propagation speed, and compared model predictions with measurements.

Geospace plasma simulations have progressed toward more realistic descriptions of the solar wind-magnetosphere interaction from magnetohydrodynamic to hybrid ion-kinetic, such as the state-of-the-art Vlasiator model. Despite computational advances, electron scales have been out of reach in a global setting. eVlasiator, a novel Vlasiator submodule, shows for the first time how electromagnetic fields driven by global hybrid-ion kinetics influence electrons, resulting in kinetic signatures. We analyze simulated electron distributions associated with reconnection sites and compare them with Magnetospheric Multiscale (MMS) spacecraft observations. Comparison with MMS shows that key electron features, such as reconnection inflows, heated outflows, flat-top distributions, and bidirectional streaming, are in remarkable agreement. Thus, we show that many reconnection-related features can be reproduced despite strongly truncated electron physics and an ion-scale spatial resolution. Ion-scale dynamics and ion-driven magnetic fields are shown to be significantly responsible for the environment that produces electron dynamics observed by spacecraft in near-Earth plasmas.

Domains rich in different blend components phase-separate during deposition, creating a film morphology that determines the performance of active layers in organic electronics. However, morphological control either relies on additional fabrication steps or is limited to a small region where an external interaction is applied. Here, we show that different semiconductor-insulator polymer composites can be rapidly dip-coated with the film structure electrically switched between distinct morphologies during deposition guided by the meniscus formed between the stationary barrier and horizontally drawn solid substrate. Reversible and repeatable changes between the morphologies used in devices, e.g., lateral morphologies and stratified layers of semiconductors and insulators, or between phase-inverted droplet-like structures are manifested only for one polarity of the voltage applied across the meniscus as a rectangular pulse. This phenomenon points to a novel mechanism, related to voltage-induced doping and the doping-dependent solubility of the conjugated polymer, equivalent to an increased semiconductor content that controls the composite morphologies. This is effective only for the positively polarized substrate rather than the barrier, as the former entrains the nearby lower part of the coating solution that forms the final composite film. The mechanism, applied to the pristine semiconductor solution, results in an increased semiconductor deposition and 40-times higher film conductance.

The mechanism of proton motion in a LaScO3 perovskite crystal was studied by ab initio molecular dynamics. The calculations were performed at different temperatures, locations, and initial velocity of the proton. Different magnitudes and directions of the external electric field were also considered. It is shown that initial location and interaction between proton and its nearest environment are of great importance to the character of the proton movement, while the magnitude and direction of the initial velocity and electric field strength are secondary factors characterizing its movement through the LaScO3 crystal. Four types of proton-jumping between oxygen atoms are determined and the probability of each of them is established. Energy barriers and characteristic times of these jumps are determined. The probable distances from a proton to other types of atoms present in perovskite are calculated. It is shown that the temperature determines, to a greater extent, the nature of the motion of a proton in a perovskite crystal than the magnitude of the external electric field. The distortion of the crystal lattice and its polarization provoke the formation of a potential well, which determines the path for the proton to move and its mobility in the perovskite crystal. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

Microporous materials (MPMs) are sponge-like solids with pore diameters less than 20 angstrom. They have been used in various industries and technologies, such as clean energy, healthcare, and environmental protection. Gas adsorption is one of the most important applications of MPMs and is the basis of gas separation, storage, and detection. Active regulation of pore accessibility in MPMs by external stimuli has aroused great attention in recent years. Numerous MPMs undergo structural changes in response to physical or chemical stimulation, such as guest accommodation, temperature change, light absorption, etc., which enables selective molecular adsorption. Compared to other stimuli, the electric field (E-field) can be a faster and more energy-efficient alternative. However, to date, the feasibility of using an E-field to regulate molecule adsorption in MPMs has been mainly limited to computational studies, while the experimental demonstration is still very rare. Here, for the first time, we demonstrate that the adsorption of small gas molecules in dielectric MPMs can be regulated by an external E-field. The adsorption capacity of CO2 in the metal-organic framework (MOF) MIL-53 was significantly reduced by applying an external direct current E-field gradient at adsorption. Gas separation selectivities of zeolite molecular sieves were also improved by pre-activating the zeolites with an external E-field. Our findings demonstrate the feasibility of regulating molecular adsorption in MPMs using E-fields. It proves that E-fields can be exploited to sharpen the molecular sieving capability and opens up new avenues for regulating pore accessibility in porous materials. This thesis comprehensively describes the E-field-controlled gas adsorptions in various MPMs: Chapter 1 is an extensive literature review on the gating effect of gas adsorption, which reflects existing approaches to regulate guest admission in MPMs. Chapter 2 describes the E-field-controlled CO2 adsorption

The electronic properties of 2-Dimensional Van der Waals heterostructure of MX2(M:Mo, X:S, Se) and graphenelike ZnO by applying an external electric field(EF) in the range -0.50V/angstrom to 1.0V/angstrom is studied using first principles calculations. The effect of the transverse electric field is measured in terms of modulation of the electronic energy bandgap and change in the band alignment properties. The bandstructure of MoS2/ZnO heterostructure(HS) shows an indirect bandgap of 1.61eV with a type-II band alignment and a large built-in electric field of 7.42eV with a valence band offset of 1.22eV across the interface. The bandstructure of MoSe2/ZnO shows a direct bandgap of 1.81eV with type-I alignment and a built-in electric field of 3.64eV with a band offset of 0.31eV. The charge density is localized on MoS2 and ZnO in VBM and CBM respectively in MoS2/ZnO HS, whereas in MoSe2/ZnO, both VBM and CBM are localized on MoSe2. With a perpendicular electric field applied across the HS, re-alignment of bandstructure and modulation of bandgap in both the HSs occurs. The energy bandgap increases linearly with the applied electric field for MoS2/ZnO(1.1-2.2eV) and remains almost constant (1.81eV) in the range -0.50V/angstrom to 0.50V/angstrom followed by a small decrease with an increase in electric field (1.60 for EF=+/- 1.0V/angstrom). A cross-over in the bandgap type from indirect(type-II)-> direct(type-I) in MoS2-ZnO and direct(type-I) to indirect(type-II) in MoSe2/ZnO has been observed at a critical value of electric field EF=0.75V/ angstrom. The cross-over in band structure is consistent with the charge transfer pattern observed on the application of electric field. Tuning the electronic bandgap and changing the band-alignment with an external electric field opens a way to design futuristic electronic and optical devices.

We introduce TUPÃ, a Python-based algorithm to calculate and analyze electric fields in molecular simulations. To demonstrate the features in TUPÃ, we present three test cases in which the orientation and magnitude of the electric field exerted by biomolecules help explain biological phenomena or observed kinetics. As part of TUPÃ, we also provide a PyMOL plugin to help researchers visualize how electric fields are organized within the simulation system. The code is freely available and can be obtained at https://mdpoleto.github.io/tupa/.