Faraday Cage Research Articles

Recent modeling for the ITER ion cyclotron range of frequency antennas with the TOPICA code

This paper documents the analysis of the ITER ion cyclotron resonance heating (ICRF) launcher using the TOPICA code, throughout recent years’ design activities. The ability to simulate the detailed geometry of an ICRF antenna in front of a realistic plasma and to obtain the antenna input parameters, the electric currents on conductors and the radiated field distribution next to the antenna is of significant importance to evaluate and predict the overall system performances. Starting from a reference geometry, we first investigated the impact of some geometrical and numerical factors, such as the Faraday Screen geometry or the mesh quality. Then a final geometry was the object of a comprehensive analysis, varying the working frequency, the plasma conditions and the poloidal and toroidal phasings between the feeding lines. The performance of the antenna has been documented in terms of input parameters, power coupled to plasma and electric fields. Eventually, the four-port junction has also been included in TOPICA models.

Synergistic effect in simultaneous removal of cationic and anionic heavy metals by nitrogen heteroatom doped hydrochar from aqueous solutions

Industrial wastewater typically contains both cationic and anionic heavy metals; therefore, their simultaneous removal must be considered to ensure environmental sustainability. Herein, nitrogen heteroatom (N) doped hydrochar derived from corncob was prepared via facile NH4Cl-aided hydrothermal carbonization and used for the simultaneous adsorption of divalent copper (Cu(II)) and hexavalent chromium (Cr(VI)) in aqueous solutions. During hydrothermal carbonization, NH4Cl played a vital role as the porogen and N dopant, which contributed to the efficient adsorption affinity toward coexisting Cu(II) and Cr(VI). The theoretical maximum adsorption capacities of the N-doped hydrochar were determined to be 1.223 mmol/g for Cu(II) and 1.995 mmol/g for Cr(VI), which were much better than those of the pristine hydrochar. Furthermore, in the binary-component system, the synergistic effect between Cu(II) and Cr(VI) significantly promoted the adsorption affinity of N-doped hydrochar, resulting in adsorption capacities for Cu(II) and Cr(VI) 9.48 and 1.92 times higher than those of the single-component system, respectively. A series of adsorption experiments and spectroscopic analyses demonstrated that multiple mechanisms, including electrostatic shielding, cation bridging, and redox reactions, mutually contributed to the synergistic effect in the adsorption of coexisting Cu(II) and Cr(VI). Overall, the N-doped hydrochar proved to be effective in simultaneously removing both cationic and anionic heavy metal pollutants.

Ammonium and Tetraalkylammonium Salts as Additives for Li Metal Electrodes

Lithium metal batteries are considered a promising technology to implement high energy density rechargeable systems beyond lithium-ion batteries. However, the development of dendritic morphology is the basis of safety and performance issues and represents the main limiting factor for using lithium anodes in commercial rechargeable batteries. In this study, the electrochemical behaviour of Li metal has been investigated in organic carbonate-based electrolytes by electrochemical impedance spectroscopy measurements and deposition/stripping galvanostatic cycling. Low amounts of tetraalkylammonium hexafluorophosphate salts have been added to the electrolytes with the aim of regulating the lithium deposition/stripping process through the electrostatic shielding effect that improves the lithium deposition. The use of NH4PF6 also determined good lithium deposition/stripping performance due to the chemical modification of the native solid electrolyte interphase via direct reaction with lithium.

Preparation of sludge–cyanobacteria composite carbon for synergistically enhanced co-removal of Cu(II) and Cr(VI)

Traditional sludge disposal is currently restricted by the risk of secondary pollution. Sludge carbon material has gained widespread attention because of its low cost and environmentally sustainable properties. However, owing to the high ash content and low–energy density of sludge, sludge pyrolysis alone has certain limitations, and the performance of carbon materials needs to be improved. Herein, a sludge–cyanobacteria composite carbon (SCC) was easily synthesized, and the adsorption process of Cu(II) and Cr(VI) by SCC was examined. SCC-700-2-50% exhibited a high SBET (1047.54 m2/g) and developed pore structure rich in functional groups (such as –NH, –OH, and C–O). The combination of pore structure and functional groups improved the adsorption performance of SCC. The adsorption processes exhibited a synergistic effect in a binary system: the qm of Cu(II) and Cr(VI) were 386 mg/g and 341 mg/g, respectively, and the selectivity of Cu(II) adsorption by SCC was greater than Cr(VI). The adsorption process, examined by SEM-EDS, FTIR, and XPS analysis, indicated that Cu(II) as a cationic interface strengthens Cr(VI) adsorption through electrostatic interaction, and the anion Cr(VI) created a valid electrostatic shield against the electrostatic repulsion between H+ and Cu(II), facilitating Cu(II) adsorption. SCC had great reusability: Cu(II) and Cr(VI) adsorption capacity were 90% and 84%, of the initial adsorption capacity, respectively, after six cycles. This study demonstrates the prospect of SCC as a valid adsorbent for multiple heavy metal contaminations removal.

2D VS2 @MXene Based Zinc Ion Batteries with SPANI-Contained Electrolyte Enables Dendrite-Free Anode for Stable Cycling.

Regarded as one of the popular cathode materials in aqueous zinc ion batteries (ZIBs), VS2 has unsatisfied cycling stability and relatively low capacity owing to its poor conductivity and low mechanical properties. To this regard, compositing VS2 with high-conductive 2D transition metal carbide (MXene) has been an effective method recently. However, the Zn dendrite on the anode electrode derived from the uncontrollable sluggish migration of solvated Zn2+ /H2 O ions seriously threatens the application safety of ZIB batteries. To effectively regulate the diffusion of zinc ions, in this work a conductive polymeric electrolyte of sulfonated polyaniline (SPANI) is added in the electrolyte solution. Under the Zn2+ /SPANI interactions confirmed by X-ray diffraction, Raman, and zeta potential experiments, the Zn2+ /H2 O combination is weakened, and the deposition rate of Zn2+ is increased evaluated by the galvanostatic intermittent titration technique. Theoretical simulation shows that the electrostatic shielding by SPANI combining Zn2- at the zinc/electrolyte interface has important contribution to the significant suppression of Zn dendrite. Accordingly, the fabricated VS2 @MXene||ZnSO4 +SPANI||Zn battery shows high capacity (368.0 mAh g-1 at 0.1 A g-1 ), which remains 96% after 5000 cyclic charge-discharge operations. This work develops an available strategic idea for suppressing growth of metallic dendrites to improve the ZIB performances.

The structure, antioxidant activity, and stability of fish gelatin/chitooligosaccharide nanoparticles loaded with apple polyphenols.

Apple polyphenols (APs) with multiple biological effects have attracted extensive attention due to their broad opportunities for application. However, the use of APs is hampered by their instability in the face of environmental changes. Designing efficient carriers to improve the bioavailability of APs is the key to solving these problems. In this study, gelatin-chitooligosaccharide nanoparticles produced by the Maillard reaction (GCM) were fabricated to encapsulate AP, and the structure, antioxidant activity, and stability of the GMM-AP nanoparticle system were evaluated. The results of endogenous fluorescence spectrum, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction, and simultaneous thermal analysis confirmed structural changes and interactions between GCM and AP. Combination with GCM did not adversely affect the antioxidant properties of AP, and the GCM-AP nanoparticles possessed superior temperature and storage stability. In comparison with fish gelatin-apple polyphenol nanoparticles, the GCM-AP nanoparticles were more stable at a wider pH range, and were more resistant to the electrostatic shielding effect of NaCl. After simulating gastric digestion, the particle size and polydispersity index (PDI) of GCM-AP nanoparticles were almost unchanged. The findings suggest that GCM nanoparticles loaded with AP could be used as good carriers with good antioxidant activity and stability. This study therefore provides a theoretical foundation for the development and industrial application of food functional factors. © 2023 Society of Chemical Industry.

Enabling Highly Reversible Zn Anode by Multifunctional Synergistic Effects of Hybrid Solute Additives

Aqueous zinc ion batteries are promising secondary batteries for next-generation electrochemical energy storage. In this work, we report a hybrid electrolyte system with 3 M Zn(OTf)2 as zinc salt and 1 M urea + 0.3 M LiOAc as hybrid solute additives for highly reversible aqueous zinc ion batteries. In this electrolyte system, partial coordinated water molecules of Zn2+ are replaced, and the original hydrogen bond network of the bulk electrolyte also suffers from interruption. Moreover, the introduction of lithium acetate solves the aggravated self-corrosion caused by urea on the one hand and inhibits the growth of dendrites through the electrostatic shielding effect on the other. Benefiting from this multifunctional synergistic effect, dendrite-free Zn plating/stripping for 600 h at 4.8 mA cm–2 (20% depth of discharge) and highly reversible plating/stripping at ∼99.7% Coulombic efficiency with a high cumulative plating capacity of 1600 mAh is achieved.

Nitrogen-Doped and Sulfonated Carbon Dots as a Multifunctional Additive to Realize Highly Reversible Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries (ZIBs) using the Zn metal anode have been considered as one of the next-generation commercial batteries with high security, robust capacity, and low price. However, parasitic reactions, notorious dendrites and limited lifespan still hamper their practical applications. Herein, an eco-friendly nitrogen-doped and sulfonated carbon dots (NSCDs) is designed as a multifunctional additive for the cheap aqueous ZnSO4 electrolyte, which can overcome the above difficulties effectively. The abundant polar groups (-COOH, -OH, -NH2 , and -SO3 H) on the CDs surfaces can regulate the solvation structure of Zn2+ through decreasing the coordinated active H2 O molecules, and thus redistribute Zn2+ deposition to avoid side reactions. Some of the negatively charged NSCDs are adsorbed on Zn anode surface to isolate the H2 O/SO4 2- corrosion through the electrostatic shielding effect. The synergistic effect of the doped nitrogen species and the surface sulfonic groups can induce a uniform electrolyte flux and a homogeneous Zn plating with a (002) texture. As a result, the excellent cycle life (4000h) and Coulombic efficiency (99.5%) of the optimized ZIBs are realized in typical ZnSO4 electrolytes with only 0.1mgmL-1 of NSCDs additive.

Three-in-One Detector by 3D Printing: Simultaneous Contactless Conductivity, Ultraviolet Absorbance, and Laser-Induced Fluorescence Measurements for Capillary Electrophoresis.

We describe a 3-in-1 detector for simultaneous contactless conductivity (C4D), ultraviolet absorbance (UV-AD), and laser-induced fluorescence (LIF) measurements on a single detection point for capillary electrophoresis (CE). A key component of the detector was a rectangular detector head that was assembled with four 3D-printed parts. Two parts covering the detector head to function as a Faraday cage were fused deposition modeling printed using an electrically conductive material. The other two parts in between the conductive parts were stereolithography (SLA) printed with high-resolution (50 μm) constructions on the surface. After assembling the two SLA printed parts, several cavities were built with the surface constructions. Two electrodes and a Faraday shield for C4D were cast by injecting molten Wood's metal into the cavities. For UV-AD, a slit (100 μm width) was created by putting together two grooves (50 μm depth) on the surface of the SLA printed parts. A 255 nm UV-LED was used as the light source. The effective path length and stray light for a 50 μm id capillary were 39 μm and 13%, which were superior to those of other reported 3D-printed AD detectors. Confocal LIF detection was conducted by using an objective lens to focus the laser on the capillary via a through-hole. The detector was used to detect model analytes, including inorganic and organic ions, and fluorescein isothiocyanate labeled amino acids in a signal-run CE separation. In detecting fluorescein, LODs were 1.3 μM (C4D), 2.0 μM (UV-AD), and 1 nM (LIF). The calibration ranges covered from 0.01 μM to 500 μM.

Imidazolium functionalized polysulfone/DTPA-chitosan composite beads for simultaneous removal of Cr(VI) and Cu(II) from aqueous solutions

Simultaneous removal of chromium(VI) oxyanions and heavy metal cations from contaminated water body is of great significance. In this work, a novel and bifunctional sorbent, imidazolium functionalized polysulfone/DTPA-chitosan composite bead (IMPSF/DACS) was successfully constructed by phase inversion method and applied for co-removal of Cr(VI) and Cu(II) from aqueous solutions. The maximum adsorption capacities for Cr(VI) and Cu(II) on IMPSF/DACS in single system at pH 5 were 56.72 and 43.05 mg g−1, respectively. In binary system, the removal of Cr(VI) could be further enhanced by the presence of Cu(II) due to the electrostatic shielding effect, while Cu(II) sorption was not significantly affected by the coexistence of Cr(VI). Moreover, IMPSF/DACS could simultaneously reduce low concentrations of Cu(II) and Cr(VI) in simulated contaminated lake water below the limit, while also showing good reusability in co-removal of Cr(VI) and Cu(II). The order of inhibitory effect of competing anions on Cr(VI) removal was as follows: H2PO4− < Cl− < NO3− < SO42−, while the competing hardness cations had a little effects on the adsorption of Cu(II), implying that the Cr(VI) removal was mainly depended on the electrostatic attraction between Cr(VI) and imidazolium ions modified on IMPSF/DACS, and Cu(II) uptake was associated with chelation of DACS encapsulated in IMPSF/DACS beads. These assumptions were confirmed by XPS, FTIR and EDS-mapping techniques.

A cationic polymeric interface enabling dendrite-free and highly stable aqueous Zn-metal batteries

Recently, aqueous rechargeable zinc-ion batteries (AZIBs) have attracted much attention owing to their low cost and intrinsic safety. However, the reversibility of AZIBs is limited by dendrite growth on the Zn anode, which leads to low Coulombic efficiency and potential short circuit during cycling. Herein, we develop a new strategy using electrostatic shielding to enable a highly reversible Zn anode. Specifically, a cationic polymeric ionic liquid (PIL) coating layer with a strong positive charge evens out the charge distribution on the surface of the Zn electrode, enabling uniform stripping and deposition of Zn. As a result, a symmetric Zn–Zn cell can sustain stripping-plating for over 2000 h at 1 mA cm−2 with a capacity limit of 1 mAh cm−2, far exceeding the performance of bare Zn electrode. A highly reversible Zn stripping-plating on Cu substrate is also achieved with an average coulombic efficiency of 99.5% over 1100 cycles. PILZ layer can even allow a uniform Zn deposition of up to 30 μm thick, allowing large utilization of the Zn foil. Moreover, the coating layer enables the stable cycling of a MnO2–Zn full cell with a high areal capacity of 1 mAh cm−2.

Electromyography biofeedback system with visual and vibratory feedbacks designed for lower limb rehabilitation

PurposeOne of the main causes of long-term prosthetic abandonment is the lack of ownership over the prosthesis, which was caused mainly by the absence of sensory information regarding the lost limb. The period where the patient learns how to interact with a prosthetic device is critical in rehabilitation. This ideally happens within the first months after amputation, which is also a period associated with the consolidation of brain changes. Different studies have shown that the introduction of feedback mechanisms can be crucial to bypass the lack of sensorial information. To develop a biofeedback system for the rehabilitation of transfemoral amputees – controlled via electromyographic (EMG) activity from the leg muscles – that can provide real-time visual and/or vibratory feedback for the user.Design/methodology/approachThe system uses surface EMG to control two feedback mechanisms, which are the knee joint of a prosthetic leg of a humanoid avatar in a virtual reality (VR) environment (visual feedback) and a matrix of 16 vibrotactile actuators placed in the back of the user (vibratory feedback). Data acquisition was inside a Faraday Cage using an OpenEphys® acquisition board for the surface EMG recordings. The tasks were performed on able-bodied participants, with no amputation, and for this, the dominant leg of the user was immobilized using an orthopedic boot fixed on the chair, allowing only isometric contractions of target muscles, according to the Surface EMG for Non-Invasive Assessment of Muscles (SENIAM) standard. The authors test the effectiveness of combining vibratory and visual feedback and how task difficulty affects overall performance.FindingsThe authors' results show no negative interference combining both feedback modalities and that performance peaked at the intermediate difficulty. These results provide powerful insights of what can be accomplished with the population of amputee people. By using this biofeedback system, the authors expect to engage another sensory modality in the process of spatial representation of a virtual leg, bypassing the lack of information associated with the disruption of afferent pathways following amputation.Research limitations/implicationsThe authors developed a showcase with a new protocol and feedback mechanisms showing the protocol's safety, efficiency and reliability. However, since this system is designed for patients with leg amputation, the full extent of the effects of the biofeedback training can only be assessed after the evaluation with the amputees, and the results obtained so far establish a safe and operational protocol to accomplish this.Practical implicationsIn this study, the authors proposed a new biofeedback device intended to be used in the preprosthetic rehabilitation phase for people with transfemoral amputation. With this new system, the authors propose a mechanism to bypass the lack of sensory information from a virtual prosthesis and help to assimilate visual and vibrotactile stimuli as a cue for movement representation.Social implicationsWith this new system, the authors propose a mechanism to bypass the lack of sensory information from a virtual prosthesis and help to assimilate visual and vibrotactile stimuli as a cue for movement representation.Originality/valueThe authors' results show that all users were capable of recognizing both feedback modalities, both separate and combined, being able to respond accordingly throughout the tasks. The authors also show that for a one-session protocol, the last difficulty level imposed a greater challenge for most users, explained by the significant drop in performance disregarding the feedback modality. Lastly, the authors believe this paradigm can provide a better process for the embodiment of prosthetic devices, fulfilling the lack of sensory information for the users.

Enabling uniform Li deposition behavior with dynamic electrostatic shield by the single effect of potassium cation additive for dendrite-free lithium metal batteries

The introduction of optimized amounts (0.010 M) of KTFSI additives results in preferential adsorption at the tip areas to form an electrostatic shielding effect, so that Li+ grows uniformly on other flat regions.

Solubilized LiNO3by the cationic size effect of CsF for lithium metal anode protection and dendrite formation prevention in carbonate electrolyte

CsF solubilized LiNO3 to optimize solvated shell of Li+ in carbonate electrolyte. LiF-rich SEI was generated to prevent severe side reactions of Li metal. Cs+ can inhibit lithium dendrite formation by self-healing electrostatic shield mechanism.

Electrostatic shielding effect and dynamic process of potential energy of metallic and nonmetallic elements

The ground-state energy is crucial for studying the properties of a material. In this study, we computed both the Hartree–Fock and random phase approximations of the ground state energy of metals and nonmetals. Considering the effect of the electrostatic shielding potential, we utilized the Thomas–Fermi dielectric function to obtain the Thomas–Fermi formula for the total potential energy. We calculated the total potential energy of the elements using the Wigner and Hedin–Lundqvist correlation energies, considering the changes in them after the electrostatic shielding effect. The exchange correlation potential, including electrostatic shielding effect, can be used in the measurement of scanning impedance microscopy experiments. Furthermore, we consider the dynamic process with respect to the change in the potential energy.

An advanced Ca/Zn hybrid battery enabled by the dendrite-free zinc anode and a reversible calcification/decalcification NASICON cathode

The proposal of hybrid ion batteries, which can integrate the advantages of the single ion battery, opens up a new route for developing high-performance secondary batteries. Herein, we successfully constructed an aqueous hybrid battery comprised of polyanionic-type cathode material (Na3V2(PO4)3, NVP), Zn metal anode, and aqueous Ca2+/Zn2+ hybrid electrolyte. This exciting combination gives full play to not only the excellent diffusion dynamics of Ca2+ in the NASICON (sodium super ion conductors) structure but also the electrostatic shielding effect of Ca2+ with low reduction potential that inhibits the formation of zinc dendrites. As results, the NVP//Zn Zn/Ca hybrid battery delivers favorable specific capacity with outstanding rate performance (85.3 mAh g−1 capacity at 1 C, 60.5 mAh g−1 capacity at 20 C), and excellent cycle stability (74 % capacity retention after 1300 cycles).

Electrostatic Shielding Boosts Electrochemical Performance of Alloy-Type Anode Materials of Sodium-Ion Batteries.

The applications of alloy-type anode materials for Na-ion batteries are always obstructed by enormous volume variation upon cycles. Here, K+ ions are introduced as an electrolyte additive to improve the electrochemical performance via electrostatic shielding, using Sn microparticles (μ-Sn) as a model. Theoretical calculations and experimental results indicate that K+ ions are not incorporated in the electrode, but accumulate on some sites. This accumulation slows down the local sodiation at the "hot spots", promotes the uniform sodiation and enhances the electrode stability. Therefore, the electrode maintains a high specific capacity of 565 mAh g-1 after 3000 cycles at 2 A g-1 , much better than the case without K+ . The electrode also remains an areal capacity of ≈3.5 mAh cm-2 after 100 cycles. This method does not involve time-consuming preparation, sophisticated instruments and expensive reagents, exhibiting the promising potential for other anode materials.

Electrostatic Shielding Boosts Electrochemical Performance of Alloy‐Type Anode Materials of Sodium‐Ion Batteries

AbstractThe applications of alloy‐type anode materials for Na‐ion batteries are always obstructed by enormous volume variation upon cycles. Here, K+ ions are introduced as an electrolyte additive to improve the electrochemical performance via electrostatic shielding, using Sn microparticles (μ‐Sn) as a model. Theoretical calculations and experimental results indicate that K+ ions are not incorporated in the electrode, but accumulate on some sites. This accumulation slows down the local sodiation at the “hot spots”, promotes the uniform sodiation and enhances the electrode stability. Therefore, the electrode maintains a high specific capacity of 565 mAh g−1 after 3000 cycles at 2 A g−1, much better than the case without K+. The electrode also remains an areal capacity of ≈3.5 mAh cm−2 after 100 cycles. This method does not involve time‐consuming preparation, sophisticated instruments and expensive reagents, exhibiting the promising potential for other anode materials.

Measures for attenuation of interference at the level of design of the measuring system of spacecraft

One of the primary tasks in the development of temperature control interface modules used as part of onboard equipment for measuring systems on spacecraft for various purposes is to justify a set of measures to ensure their noise immunity, taken at the levels design of the measuring system, measuring device and temperature control interface module. Such a justification involves an assessment of the effectiveness of possible methods for attenuating various types of interference affecting the measuring system, which determine the electromagnetic environment on the spacecraft. The article is devoted to the consideration of interference mitigation measures at the design level of the measuring system, which should be taken to ensure the required noise immunity of the temperature control interface module in combination with measures taken at other design levels. It is shown that in order to ensure the required noise immunity of the temperature control interface modules, it is necessary at the level of the measuring system design to provide for measures to mitigate interference in the power cable and in the measuring cables. In the power cable, it is possible to attenuate interference by reducing the impedance of the common electrostatic shield and the resistance of the connection of the wires of the on-board power buses, as well as by twisting the wires in the form of a twisted pair. In measuring cables, it is possible to attenuate interference by reducing the impedance of the common electrostatic shield and the resistance of communication wires of communication lines, introducing an additional electrostatic shield for individual groups of wires of communication lines, and using pair or quadruple twist in individual groups of wires.

Homogenization of Helmholtz equation in a periodic layer to study Faraday cage-like shielding effects

The work is motivated by the Faraday cage effect. We consider the Helmholtz equation over a 3D domain containing a thin heterogeneous interface of thickness . The layer has a δ-periodic structure in the in-plane directions and is cylindrical in the third direction. The periodic layer has one connected component and a collection of isolated regions. The isolated region in the thin layer represents air or liquid, and the connected component represents a solid metal grid with a δ thickness. The main issue is created by the contrast of the coefficients in the air and in the grid and that the zero-order term has a complex-valued coefficient in the connected faze while a real-valued in the complement. An asymptotic analysis with respect to is provided, and the limit Helmholtz problem is obtained with the Dirichlet condition on the interface. The periodic unfolding method is used to find the limit.