Charge Characteristics Research Articles

Ionic liquid-triggered charge regulation of polydopamine-based surface for antibacterial nanofiltration

The charged surfaces with desirable performance are of high concern in membrane separation but there exist challenges to tailor them over a task-specific range. Herein, we propose an ionic liquid (IL)-triggered charge regulation strategy for polydopamine (PDA)-based surfaces by tuning the number and position of amino groups of ILs. By strategically manipulating the location of amino groups in either the anion, cation, or both, we realize a complete inversion in the surface charge nature of PDA coatings from highly negative to negative and even highly positive (zeta potential: −25 mV to +25 mV). This charge inversion triggered by IL is attributed to both the number of protonable groups and shielding effect provided by counter ions. Such charge flip enhances Donna effect when the PDA/IL coatings serve as the skin layer of nanofiltration membranes, thereby enabling high rejection to both negative and positive target molecules (i.e., chlorogenic acids at various pH). Despite charge regulation, ILs with dual amino groups cross link the PDA aggregates, largely narrowing the pore size distribution of the skin layer. The IL cross-linked PDA skin layer with uniform pores thus shows a nearly 100 % rejection to the target solutes. Meanwhile, the IL synchronously endow the PDA coatings with tunable charge characteristics, imidazolium functional groups and exceptional superoleophobicity, compensating for the originally inferior antibacterial activity of membranes in a wide pH range.

Numerical simulation of interior ballistics two-phase flow in modular charge based on the particle element method

The full combustibility and strong discontinuity characteristics of module charge result in significant differences from conventional mode, making it challenging for traditional two-fluid methods to effectively reveal its particle dispersion mechanism. In this study, the particle element method for module charge were developed and applied for modeling the interior ballistics to overcome above drawback. Firstly, based on the characteristics of module charge and particle aggregation, criteria for dividing particle elements and methods for motion calculation are proposed. Next, particle element solver and CFD solver are constructed and mutually coupled for solution. Finally, validation is conducted under the condition of three modules charging. The computational results show that the particle element method can effectively predict the pressure and velocity inside the chamber, consistent with experimental results, the pressure error is 5.55 % and the velocity error is 0.79 %. The particle element method reproduces the combustion process with variable particle mass, accurately presenting the distribution of the flow field and temperature. Moreover, it fundamentally explains that pressure fluctuations occur due to the presence of free space and changes in the flow field caused by the movement of the propellant bed. The particle element method can provide scientific research methods and technical support for the development of module charge technology.

Observation of monotonic surface charging at polycrystalline platinum-electrolyte interface using streaming current method

Surface charging characteristics at polycrystalline Pt-electrolyte interfaces were studied using a novel combination of electrochemical techniques and electrokinetic streaming current methods developed by our group [Saha et al., 2019]. Surface charge typically increases with increasing electric potential on a metal, and this trend is commonly referred to as monotonic charging. Based on theoretical models, it was suggested that the Pt-electrolyte interface might deviate from this trend and have negative charge above the potential of zero charge (PZC) due to the metal's strong chemisorption properties [Huang et al., 2016]. We attempted to experimentally determine the validity of this claim using our method. In addition to the surface charging relations, we also quantified the effect of anion adsorption (oxide, chloride, sulfate) on surface charging. The experimental method also allowed us to observe the slow time-dependent growth of oxides on Pt surface. Since our first publication in 2019 [Saha et al., 2019], we were able to develop the setup to be more efficient that enabled us to apply higher potential on the metal, observe stronger ion adsorption effects on surface charging, and obtain more reliable data. Our recent experimental study shows that Pt charging remains monotonic and does not reverse due to chemisorption of oxides nor strong anion adsorption in the potential window where the charge reversal was theoretically shown to occur.

Национальные певческие голоса Советского Союза в 1920-х годах

The aim of the study is to determine the ways of describing the national voice in the 1920s. With all the multiple functions of the voice, it is most clearly manifested in singing, and, accordingly, in relation to singing, it undergoes the greatest theorization among music critics of that time. The body of the Soviet singer is marked through social class, topos and ethnicity and is endowed with multiple emotionally charged characteristics. Ultimately, many singers of that time, precisely due to their voice features, often were marked by contemporaries with the ethnographic clichés of ‘nature’ or ‘naturalness’ and formed a musical fashion for many decades. Others, though, despite possessing similar characteristics, were persecuted. The study will be devoted to the analysis of these characteristics. The novelty of the work is determined by the use of approaches to the voice characteristic of cultural studies and Western philosophy of sound, coming from the works of R. Barthes, J. Derrida and M. Dolar, in relation to the problems and tasks of the field of soviet studies. As a result, several clusters of national voices were identified: the first of them are Jewish, Gypsy and Ukrainian voices, marked mainly through class and political affiliation with previous era. The second cluster is represented by Caucasus and Central Asian voices, which possessed, on the contrary, purely colonial-ethnographic characteristics. Conclusions are made about the high level of theorization and politization of the human voice in the early Soviet period.

CPred: Charge State Prediction for Modified and Unmodified Peptides in Electrospray Ionization.

The mass-to-charge ratio serves as a critical parameter in peptide identification via mass spectrometry, enabling the precise determination of peptide masses and facilitating their differentiation based on unique charge characteristics, especially when peptides are ionized by tools like electrospray ionization, which produces multiply charged ions. We developed a neural network called CPred, which can accurately predict the charge state distribution from +1 to +7 for the modified and unmodified peptides. CPred was trained on the large-scale synthetic training data, consisting of tryptic and non-tryptic peptides, and various fragmentation methods. The model was further evaluated on independent, external test data sets. Results were evaluated through the Pearson correlation coefficient and showed high correlations of up to 0.9997117 between the predicted and acquired charge state distributions. The effect of specifying modifications in the neural network and feature importance was further investigated, revealing the value of modifications and vital peptide properties in holding on to protons. CPreds' accurate predictions of the charge state distribution can play an essential role in boosting confidence in peptide identifications during rescoring as a novel feature.

Facile synthesis of magnetic ionic covalent organic framework and dispersive magnetic solid phase extraction of aromatic amino acid oxidation products in thermally processed foods

Aromatic amino acid oxidation products (AAAOPs) are newly discovered risk substances of thermal processes. Due to its significant polarity and trace level in food matrices, there are no efficient pre-treatment methods available to enrich AAAOPs. Herein, we proposed a magnetic cationic covalent organic framework (Fe3O4@EB-iCOF) as an adsorbent for dispersive magnetic solid-phase extraction (DMSPE). Benefiting from the unique charged characteristics of Fe3O4@EB-iCOF, AAAOPs can be enriched through electrostatic interaction and π-π interactions. Under the optimal DMSPE conditions, the combined HPLC-MS/MS method demonstrated good linearity (R2 ≥ 0.990) and a low detection limit (0.11–7.5 μg·kg−1) for AAAOPs. In addition, the method was applied to real sample and obtained satisfactory recoveries (86.8 % ∼ 109.9 %). Especially, we applied this method to the detection of AAAOPs in meat samples and conducted a preliminarily study on its formation rules, which provides a reliable basis for assessing potential dietary risks.

A fully superconducting magnetic bearing with a jointless coil excited by a superconducting dynamo

Abstract Superconducting magnetic bearings usually combine a setup of permanent magnets (PMs) and superconducting bulks. The bearing size is typically scaled up to increase the levitation force as the force density is limited in such setups due to the magnetic flux density and its spatial gradient. As alternative, the PMs might be replaced by a superconducting coil. To test this, jointless coils were prepared by a wind and flip technology using coated conductors of different tape manufacturers. The realized pancake coils were studied at liquid nitrogen temperature. Numerical simulations yielded a magnetic field of up to 0.5 T at 77 K for coils with a inner diameter of 20 mm. The prepared coils were charged with a superconducting dynamo, in which two magnet configurations were tested. A clear dependence on the magnet size and frequency was found for the charging characteristics. A magnetic field of about 0.3 T at 77 K was imprinted in one of the coils. However, a degradation of the coils was found over time indicated by some delamination at the cutted edges, which reduced the maximum achievable magnetic field after a few weeks. Nevertheless, a fully superconducting bearing was realized with by combining the jointless coil with an additional YBCO bulk. After charging the coil with the dynamo, a levitation force of up to 10 N at 77 K was measured under zero-field cooling conditions. The generated levitation force decayed only slightly after charging indicating low losses in the coil.

Study on the Relationship between Electron Transfer and Electrical Properties of XLPE/Modification SR under Polarity Reversal.

The insulation of high-voltage direct-current (HVDC) cables experiences a short period of voltage polarity reversal when the power flow is adjusted, leading to sever field distortion in this situation. Consequently, improving the insulation performance of the composite insulation structure in these cables has become an urgent challenge. In this paper, SiC-SR (silicone rubber) and TiO2-SR nanocomposites were chosen for fabricating HVDC cable accessories. These nanocomposites were prepared using the solution blending method, and an electro-acoustic pulse (PEA) space charge test platform was established to explore the electron transfer mechanism. The space charge characteristics and field strength distribution of a double-layer dielectric composed of cross-linked polyethylene (XLPE) and nano-composite SR at different concentrations were studied during voltage polarity reversal. Additionally, a self-built breakdown platform for flake samples was established to explore the effect of the nanoparticle doping concentration on the breakdown field strength of double-layer composite media under polarity reversal. Therefore, a correlation was established between the micro electron transfer process and the macro electrical properties of polymers (XLPE/SR). The results show that optimal concentrations of nano-SiC and TiO2 particles introduce deep traps in the SR matrix, significantly inhibiting charge accumulation and electric field distortion at the interface, thereby effectively improving the dielectric strength of the double-layer polymers (XLPE/SR).

Preparation of thermally stable egg white protein microgel particles as assisted by differently charged polysaccharides: A comparatively study

Egg white proteins (EWP) were prone to thermal aggregation under heat sterilization conditions, thereby limiting their application in the field of protein beverages. In this study, EWP were microgel particleized via polysaccharide-protein phase separation to enhance their resistance to thermal aggregation during processing. Results indicated that the charge characteristics of polysaccharides were crucial factors influencing their interaction with EWP. Microstructural and physicochemical properties indicated that egg white protein microgel particles (EMGP) with the bilayer structure formation (polysaccharide shell layer and dense protein core) could only be formed in the phase separation system of EWP and anionic polysaccharides (carboxymethyl cellulose sodium salt (low viscosity), carboxymethyl cellulose sodium salt (high viscosity), High-methoxyl pectin). Additionally, the EMGP exhibited uniform size, high denaturation extent and dense structure that effectively prevented structural unfolding and exposure of active sites upon reheating of the EWP. The thermal denaturation temperatures of the EMGP were significantly higher (up to 155.8 °C, 163.5 °C, 165.7 °C), compared to natural proteins (88.8 °C). Thermal stability experiments confirmed that the suspension of 5% w/v microgel particles maintained good flow ability after heating at 100 °C for 30 min, demonstrating excellent thermal stability suitable for high-temperature pasteurization conditions. Moreover, its uniform particle size and adsorption of polysaccharides improved storage stability. In contrast, groups other than anionic polysaccharides exhibited aggregation and gelation upon heating. Overall, this study demonstrated that preparing heat-stable EMGP effectively reduces aggregation in EWP beverages during heat-pasteurization, enhanced product sensory attributes, extended shelf-life, and expanded the application scope of EWP.

Contact electrification characteristics of solid oxygen particle-laden flows in liquid hydrogen transportation

The issue of electrostatic safety in liquid hydrogen systems has garnered increasing attention, especially concerning the potential threat of electrostatic explosions due to the collision-electrification phenomenon of solid oxygen particles formed after air leakage in liquid hydrogen pipelines. To delve into the contact electrification characteristics of solid oxygen particle-laden flows in liquid hydrogen transportation, a mathematical model based on the computational fluid dynamics-discrete element method (CFD-DEM) two-phase flow dynamics has been developed. This model integrates the Hertz contact theory for describing particle collision processes and the condenser model for describing particle collision-electrification. The reliability of this model has been validated in existing literature through its ability to capture the flow characteristics of two-phase flow and the electrification characteristics of particle groups. Using density functional theory to compute the solid oxygen work function and considering the low-temperature properties of liquid hydrogen, a series of numerical studies on the flow sedimentation and electrification characteristics of solid oxygen particle-laden flows in liquid hydrogen pipelines have been conducted. The results indicate that particles carry negative charges after colliding with stainless steel pipe walls, with single charge exchange magnitudes of approximately 10−12C for particle-wall continuous collision processes and 10−14C for particle-particle collision processes, resulting in particle charge-to-mass ratios on the order of tens of μC/kg at the outlet interface. The impact of electrostatic forces on particle motion is significant and cannot be overlooked. Furthermore, the effects of velocity, particle diameter, and pipe diameter on particle charge characteristics have been thoroughly analyzed. At low flow velocities, severe particle settlement occurs, leading to increased collision frequency between particles and walls and significant charge accumulation. Increasing flow velocity can mitigate particle settlement and reduce charge levels. Changes in particle and pipe diameters have a minor impact on particle settlement but can increase single charge amounts with larger particle diameters and intensify particle charging with reduced pipe diameters due to shortened radial travel distances, leading to increased collision frequency. Our study meticulously illustrates the charge characteristics of individual particles and particle groups, providing a theoretical basis for assessing the electrostatic safety of liquid hydrogen transportation systems under extreme conditions.

Effect of heat treatment on charge states, thermophysical and mechanical properties of polypropylene doped with ZrO2 nanoparticles

Charge states, thermophysical and mechanical properties of polypropylene doped with zirconium oxide nanoparticles, and their changes during heat treatment at temperatures 60 °C, 100 °C, and 140 °C are studied. The methods used are thermal stimulated depolarization (TSD), scanning differential calorimetry (SDC), and mechanical life assessment. It is shown that with an increase in the concentration of the filler, the intensity of the TSD peaks increases up to 3 vol.%. A further increase in concentration leads to a decrease in the intensity of the peaks. The activation energy of charge release from traps, temperature of maximum of the peaks, and the magnitude of the accumulated charge in the traps have also maximal value at nanoparticle concentration of 3 vol.%. The study of charge characteristics of the nanocomposite with concentration of 3 vol.% after heat treatment shows that the intensity of TSD peaks, the temperature of peak maxima, and the activation energy of charge release increase with increasing pretreatment temperature. The magnitude of the charge accumulated in traps has a maximal value at treatment temperature of 140 °C owing to the increase in the number of traps. The melting point of the composite is 149.38 °C and shifts to 146.88 °C after heat treatment at 140 °C. It indicates that the high temperature of heat treatment leads to partial destruction of polymer chains, leading to a decrease in the critical melting temperature. The mechanical durability of PP + 3%ZrO2 nanocomposite decreases with increase in pretreatment temperature.

Monotonic Surface Charging at Polycrystalline Platinum-Electrolyte Interface in the Presence of Chemisorbed Species Using Streaming Current Method

Surface charging characteristics at a polycrystalline Pt-electrolyte interface were studied using electrokinetic streaming current method integrated with in-situ electrochemical cell, which was developed by our group [1-3]. Experimentally, surface charging relations are determined from the potential-dependent capacitance data. For catalytic surfaces (e.g., platinum), this method is challenging to apply due to the strong chemisorption properties of the metal [4]. We developed a method to measure surface charge of a metal in presence of strong chemisorption of ions by incorporating electrokinetic streaming current technique with traditional electrochemical 3-electrode setup (Figure 1a).Generally, the metal charge increases monotonically with applied potential. Based on theoretical models, it was suggested that the Pt-electrolyte interface might deviate from this trend and have negative charge above the potential of zero charge (PZC) due to the metal’s strong chemisorption properties [5,6]. We attempted to experimentally determine the validity of this claim using our method. In addition, we also observed the effect of anion adsorption (oxide, chloride, sulfate, etc.) on surface charging. The experimental method also allowed us to observe the slow time-dependent growth of oxides on Pt surface.Since our first publication in 2019 [1], we were able to develop the setup to be more efficient by reducing noise, electrolyte resistance, current fluctuations, etc. that enabled us to apply higher potential on the metal, observe stronger ion adsorption effects on surface charging, and obtain more reliable data. Our recent experimental study shows that Pt charging remains monotonic and does not reverse due to chemisorption of oxides in the potential window where the charge reversal was speculated to occur (Figure 1b). Figure 1c shows that metal charge (at 1.2 V vs SHE) grows slowly over time to settle down to an equilibrium value. We hypothesize that it was caused by the slow growth of oxides at the interface. The time-dependent growth of oxides has already been observed [7]. The electrolyte used in our experiments was HClO4 where the anion (ClO4 -) is less adsorbing than Cl-, SO4 2-, Br- etc. The only adsorbing anions in this electrolyte solution are OH- and O2-. In this work, we will present a brief description of the improvements of the electrokinetic-electrochemical method and our experimental results showing monotonic charging behavior for Pt in the presence of ion adsorption and oxide growth.

Study on the tribocharging properties of MgCO3 particles based on LFN-en-A model

Abstract As an efficient and environment-friendly method, electrostatic separation has gradually replaced flotation methods in the separation of magnesite in recent years. In the process of triboelectrostatic separation, the mineral particles are tribocharged driven by the air flow, then the trajectory is shifted under the action of the electric field, so as to realize the separation. The useful mineral in magnesite is MgCO3, but the theoretical research related to the charge characteristics of MgCO3 is not sufficient. Particle image velocimetry (PIV), as an indirect measurement technique, is able to obtain the velocity field of the fluids from images. However, the particles moving in the air have the issues such as excessive speed and small particle size, which make the traditional PIV has low accuracy in estimating the motion of particles. In this paper, a high-speed camera is used to capture the motion trajectory of tribocharged MgCO3 particles in a parallel electric field. A new optical flow method LFN-en-A network based on LiteFlowNet-en network is proposed to compute the particle motion trajectory by combining the deep learning method with the traditional PIV, which realizes the displacement estimation of particles moving in the air. It ultimately realizes the calculation of the charge-to-mass ratio on single particles. Analyzing the accuracy of the LFN-en-A network’s estimation in the experiments, the estimation of LiteFlowNet-en was compared. Changing the shooting frame rate analyzes the optimal one required by the LFN-en-A network. Combining the estimation results of LFN-en-A to calculate the particle charge-to-mass ratio (Q/m), the Q/m of MgCO3 particle was analyzed by changing the experimental conditions in the process of particles’ tribocharging, which provided a new method for particle-to-charge ratio measurement.

Enabling Fast Charging of High Loading Batteries Via Operando Microscopy Diagnosis of Lithium Plating Limits

While lithium-ion batteries have undergone substantial development, enabling their widespread adoption in consumer electronics, a critical need persists—achieving faster charging even at lower temperatures. This realization is hindered by lithium plating, which reduces capacity and cycle life.A possible strategy involves engineering the electrolyte to improve the ionic transport across/into the graphitic anode. Based on recent studies and simulation results, the traditional carbonate-based electrolyte was replaced with a more promising ether-based electrolyte and tested in our specially designed operando capillary full cells. Here the axial lithiation of graphite could be monitored in real-time and lithium plating precisely correlated to the voltage response. Lithium-ion transport at the face of the electrode was further evaluated with our in-plane imaging setup. The demonstrated performance improvements were then investigated in larger high loading cells at different temperatures and cycling conditions.Our results reveal significantly better charging characteristics for the ether-based electrolyte, not only showing better particle activation but also increasing the capacity (as much as 40%) before the onset of lithium plating. This prompts a compelling inquiry into the roles played by ether driven solid electrolyte interface (SEI) formation and possible co-intercalation processes. How might these mechanisms contribute to the observed enhancements, and what implications could they have for the broader landscape for fast charging batteries. Figure 1

Advances in Spin‐Modulated Electrocatalysis of Oxygen Evolution Reaction

AbstractElectrochemical splitting of water for hydrogen generation has emerged as a potential strategy for transitioning towards renewable energy sources and mitigating the environmental impact of fossil fuel dependence. However, the efficiency of water splitting is mainly hindered by oxygen evolution reaction (OER) at the anode side, which involves kinetically sluggish four proton‐coupled electron‐transfer steps. Recent studies on OER demonstrate that a spin‐dependent mechanism governs the reaction kinetics, wherein the electronic exchange interactions in the catalytic activity of transition metals can provide a spin‐selective channel to filter out electron spins with the right orientation during the formation of O2. Maximizing efficiency and stability of such catalysts require optimization the geometric and electrical structures of transition metal systems. In addition, it is vital to understand the OER mechanism with spin considerations to be familiar with the connection between spin, charge, orbital, and lattice characteristics. This review focuses on current developments in understanding and the use of the spin‐related effect in the OER mechanism.

Theoretical and Molecular Dynamics Simulation Approaches to Praseodymium Content Effect on Radiation Shielding and Time Dependent Volume‐Collapse for a Newly Produced Borate Glass

AbstractGamma‐ray, fast neutron and charged particle shielding characteristics of Praseodymium (Pr3+) activated glasses with composition 10ZnF2‐(10‐x)SrO‐15Li2O‐65H3BO3‐xPr2O3(where x = 0.1, 0.5, 1.0, 1.5, and 2.0) are investigated. For this, the radiation shielding parameters are estimated by using Photon Shielding and Dosimetry (Phy‐X/PSD), Interaction of Proton, Alpha, Gamma rays, Electrons, and X‐rays with matter (PAGEX), Stopping Powers and Ranges for Electrons (ESTAR), and The Stopping and Range of Ions in Matter (SRIM) codes. Furthermore, the results are compared comprehensively and comparatively. The glasses with increasing Pr3+ content exhibited higher shielding potential. It can be said that the ZFLHBPr2.0 sample could be used as a shielding material in various applied fields. Additionally, the effect of Pr composition on structural transitions and time‐dependent volume‐collapse of this new family of borate glass doped with Pr is analyzed by molecular dynamics study (MD) based density functional tight binding method. The simulation results show that the addition of Pr led to the cubic‐orthorhombic transformation of simulation cell at determined temperature and 1 atm pressure. Also, a sudden decrease in volume are observed within a short time at 8% Pr composition (x = 2.0) atmospheric pressure. This result provides a strong connection between Pr composition and volume change with time and at constant low pressure.

3D printing for constructing biocarriers using sodium alginate/ε-poly-l-lysine ink: Enhancing microbial enrichment for efficient nitrogen removal in wastewater

The microbial enrichment of traditional biocarriers is limited due to the inadequate consideration of spatial structure and surface charging characteristics. Here, capitalizing on the ability of 3D printing technology to fabricate high-resolution materials, we further designed a positively charged sodium alginate/ε-poly-l-lysine (SA/ε-PL) printing ink, and the 3D printed biocarriers with ideal pore structure and rich positive charge were constructed to enhance the microbial enrichment. The rheological and mechanical tests confirmed that the developed SA/ε-PL ink could simultaneously satisfy the smooth extrusion for printing process and the maintenance of 3D structure. The utilization of the ε-PL secondary cross-linking strategy reinforced the 3D mechanical structure and imparted the requisite physical properties for its application as a biocarrier. Compared with traditional sponge carriers, 3D printed biocarrier had a faster initial attachment rate and a higher biomass of 14.58 ± 1.18 VS/cm3, and the nitrogen removal efficiency increased by 53.9 %. Besides, due to the superior electrochemical properties and biocompatibility, the 3D printed biocarriers effectively enriched the electroactive denitrifying bacteria genus Trichococcus, thus supporting its excellent denitrification performance. This study provided novel insights into the development of new functional biocarriers in the wastewater treatment, thereby providing scientific guidance for practical engineering.

Self-Assembly of Three-Dimensional Hyperbranched Magnetic Composites and Application in High-Turbidity Water Treatment.

In order to improve dispersibility, polymerization characteristics, chemical stability, and magnetic flocculation performance, magnetic Fe3O4 is often assembled with multifarious polymers to realize a functionalization process. Herein, a typical three-dimensional configuration of hyperbranched amino acid polymer (HAAP) was employed to assemble it with Fe3O4, in which we obtained three-dimensional hyperbranched magnetic amino acid composites (Fe3O4@HAAP). The characterization of the Fe3O4@HAAP composites was analyzed, for instance, their size, morphology, structure, configuration, chemical composition, charged characteristics, and magnetic properties. The magnetic flocculation of kaolin suspensions was conducted under different Fe3O4@HAAP dosages, pHs, and kaolin concentrations. The embedded assembly of HAAP with Fe3O4 was constructed by the N-O bond according to an X-ray photoelectron energy spectrum (XPS) analysis. The characteristic peaks of -OH (3420 cm-1), C=O (1728 cm-1), Fe-O (563 cm-1), and N-H (1622 cm-1) were observed in the Fourier transform infrared spectrometer (FTIR) spectra of Fe3O4@HAAP successfully. In a field emission scanning electron microscope (FE-SEM) observation, Fe3O4@HAAP exhibited a lotus-leaf-like morphological structure. A vibrating sample magnetometer (VSM) showed that Fe3O4@HAAP had a relatively low magnetization (Ms) and magnetic induction (Mr); nevertheless, the ferromagnetic Fe3O4@HAAP could also quickly respond to an external magnetic field. The isoelectric point of Fe3O4@HAAP was at 8.5. Fe3O4@HAAP could not only achieve a 98.5% removal efficiency of kaolin suspensions, but could also overcome the obstacles induced by high-concentration suspensions (4500 NTU), high pHs, and low fields. The results showed that the magnetic flocculation of kaolin with Fe3O4@HAAP was a rapid process with a 91.96% removal efficiency at 0.25 h. In an interaction energy analysis, both the UDLVO and UEDLVO showed electrostatic repulsion between the kaolin particles in the condition of a flocculation distance of <30 nm, and this changed to electrostatic attraction when the separation distance was >30 nm. As Fe3O4@ HAAP was employed, kaolin particles could cross the energy barrier more easily; thus, the fine flocs and particles were destabilized and aggregated further. Rapid magnetic separation was realized under the action of an external magnetic field.

Analysis of the dynamic characteristics of XLPE pellet space charge

Analysis of the dynamic characteristics of XLPE pellet space charge

National 22-year epilepsy surgery landscape shows increasing open and minimally invasive pediatric epilepsy surgery.

A surgical "treatment gap" in pediatric epilepsy persists despite the demonstrated safety and effectiveness of surgery. For this reason, the national surgical landscape should be investigated such that an updated assessment may more appropriately guide health care efforts. In our retrospective cross-sectional observational study, the National Inpatient Sample (NIS) database was queried for individuals 0 to <18 years of age who had an International Classification of Diseases (ICD) code for drug-resistant epilepsy (DRE). This cohort was then split into a medical group and a surgical group. The former was defined by ICD codes for -DRE without an accompanying surgical code, and the latter was defined by DRE and one of the following epilepsy surgeries: any open surgery; laser interstitial thermal therapy (LITT); vagus nerve stimulation; or responsive neurostimulation (RNS) from 1998 to 2020. Demographic variables of age, gender, race, insurance type, hospital charge, and hospital characteristics were analyzed between surgical options. Continuous variables were analyzed with weight-adjusted quantile regression analysis, and categorical variables were analyzed by weight-adjusted counts with percentages and compared with weight-adjusted chi-square test results. These data indicate an increase in epilepsy surgeries over a 22-year period, primarily due to a statistically significant increase in open surgery and a non-significant increase in minimally invasive techniques, such as LITT and RNS. There are significant differences in age, race, gender, insurance type, median household income, Elixhauser index, hospital setting, and size between the medical and surgical groups, as well as the procedure performed. An increase in open surgery and minimally invasive surgeries (LITT and RNS) account for the overall rise in pediatric epilepsy surgery over the last 22 years. A positive inflection point in open surgery is seen in 2005. Socioeconomic disparities exist between medical and surgical groups. Patient and hospital sociodemographics show significant differences between the procedure performed. Further efforts are required to close the surgical "treatment gap."