Capacitance Values Research Articles

Ecoflex-assisted quasi-solid-state flexible hybrid supercapacitors based on binder-free nanoflower-like CoxMo3-xS3 and Te-infused radish-derived bio-carbon for sensing and healthcare applications

Advancements in electronic devices have driven the fabrication of flexible supercapacitors (SCs) to power electronic devices in twisted or bent states. In this regard, we report the fabrication of nanoflower-like arrays of cobalt molybdenum sulfide (CoxMo3-xS3) on flexible and conductive carbon cloth via a facile single-step electrodeposition technique as a positive electrode. The morphological, physiochemical, and electrochemical characteristics of the corresponding electrodes are evaluated. For optimization, the CoxMo3-xS3 electrodes with various stoichiometric ratios of Co/Mo in the precursor solution are fabricated. The optimized CoxMo3-xS electrode shows a maximum areal capacitance value of 1008.7 mF cm−2 at 2 mA cm−2 and an excellent life duration with areal capacitance retention value of ~ 100% over 10,000 galvanostatic charge–discharge (GCD) cycles. Furthermore, Te-infused carbon derived from radish is explored as a green negative electrode. A flexible hybrid SC (FHSC) device is fabricated using optimized CoxMo3-xS3 and Te-infused radish-derived bio-carbon as the positive and negative electrodes, respectively. The corresponding FHSC device exhibits excellent electrochemical properties with power and energy density values of 7500 W kg−1 and 19.2 Wh kg−1, respectively, followed by outstanding long-term durability with a specific capacitance retention value of ~ 100% over 10,000 GCD cycles. Finally, the FHSC device successfully powers various electronic gadgets in contorted states, thereby demonstrating its practical feasibility. The ecoflex-packaged FHSC device is also employed to power temperature and humidity sensors in the wearable condition for wireless internet of things applications.

Magnetic field probe-based co-simulation method for irregular volume-type inductively coupled wireless MRI radiofrequency coils.

Inductively coupled wireless coils are increasingly used in MRI due to their cost-effectiveness and simplicity, eliminating the need for expensive components like preamplifiers, baluns, coil plugs, and coil ID circuits. Existing tools for predicting component values and electromagnetic (EM) fields are primarily designed for cylindrical volume coils, making them inadequate for irregular volume-type wireless coils. The aim of this study is to introduce and validate a novel magnetic (H-) field probe-based co-simulation method to accurately predict capacitance values and EM fields for irregular volume-type wireless coils, thereby addressing the limitations of current prediction tools. The proposed method involves several key steps: modeling the coil in EM simulation software, replacing lumped components with 50-Ω ports, placing well-decoupled double pick-up sniffer probes within the wireless coil, conducting full-wave EM simulations, and exporting the S-parameter matrix to an RF circuit simulation tool for optimization. The RF circuit simulation optimizes component values by maximizing the average magnitude of the root square of Sxys (mean_√Sxy) of double probes and minimizing the normalized standard deviation of √Sxy (normStd_√Sxy). The optimized capacitance values are validated through re-performing EM simulations, and hardware prototypes are fabricated and tested in MRI experiments. The method was validated using bottle-shaped and dome-shaped Litzcage coils designed for 1.5T MRI. Consistent resonant peaks and magnetic field distributions were observed across different coil designs. The optimized capacitance values obtained from circuit-level simulations were confirmed through EM simulations. Significant SNR enhancements were observed in MRI experiments, with the wireless hand and wrist/head coil showing an overall SNR enhancement of 12.8/3.4-fold in EM simulation and 13.4/3.8-fold in MRI experiments, compared to the body coil alone. The H-field probe-based co-simulation method provides an efficient and accurate solution for designing and optimizing irregular wireless RF coils in MRI. By integrating EM simulation, H-field probes, and RF circuit optimization, this method reduces the need for extensive full-wave EM simulations and accurately predicts capacitance values and EM fields. The validation using irregular Litzcage coils demonstrated the method's efficacy, contributing to improved imaging quality in MRI applications. This approach offers a valuable tool for coil developers and researchers, facilitating the development of high-quality irregular wireless coils for enhanced MRI performance.

Innovative Organic Electrolytes for Enhanced Energy Density and Performance in Supercapacitors

ABSTRACTSupercapacitors, known for their high‐power energy storage capabilities, have garnered significant attention due to their rapid charge–discharge cycles and extended life span. To expand their application in fields such as electric vehicles, renewable energy systems, and portable electronic devices, the development of advanced electrolytes that can boost energy density, power density, and overall performance is crucial. This study introduces a novel electrolyte formulation comprising lithium chloride in ethylene glycol and Magnesium Acetate in methanol. These formulations are designed to address existing challenges and enhance supercapacitor efficiency. The study reports impressive specific capacitance values (Csp = 582, 360, and 224 F/g), specific energy (SE = 323, 200, and 124 Wh/kg), and specific power (SP = 11 628, 7200, and 1322 W/kg) for lithium chloride, magnesium acetate, and zinc chloride electrolytes, respectively. These findings open new avenues for developing optimal and sustainable energy storage solutions in an increasingly electrified world. Continued research in this domain is expected to unlock the full potential of supercapacitors, contributing to a cleaner and more energy‐efficient future.

Cerium oxide nanoparticles decorated on graphene oxide nanosheets as battery-type cathode material for supercapacitors.

Designing advanced materials that effectively mitigate the poor cycle life of battery-type electrodes with high specific capacities is crucial for next-generation energy storage systems. Herein, graphene oxide-ceria (GO-CeO2) nanocomposite synthesized via a facile wet chemical route is explored as cathode for high-performance supercapacitors. The morphological analysis suggests fine ceria (CeO2) nanoparticles dispersed over ultrathin graphene oxide (GO) sheets while structural studies reveal face-centered cubic phase of CeO2 in the nanocomposite. In-depth electrochemical performance investigation of the nanocomposite in 6M KOH aqueous electrolyte demonstrated its excellent battery-type behavior with least ion diffusion resistance and a superior cycle life resulting from the synergistic effect of redox-active CeO2 and 2D GO with abundant oxygen functionalities. Specifically, GO-CeO2 composite electrode delivered a maximum specific capacitance of 625.9F/g (52.2mAh/g) at 3 A/g current density, which is substantially higher than the capacitance values obtained for GO and CeO2 electrodes, and demonstrated an excellent cycling stability with∼100% capacitance retention after 10,000 CV cycles. Furthermore, a novel aqueous asymmetric supercapacitor (ASC) is explored with GO-CeO2 as positive and iron(III) oxyhydroxide (FeOOH) as negative electrode material in 6M KOH electrolyte which has also displayed good energy-power density combination along with excellent cycle stability. The study thus endorses rational design of nanocomposite materials with suitable functionalities as an excellent strategy in augmenting the performance of futuristic energy storage devices.

Enhancing fine-tuning efficiency and design optimization of an eight-channel 3T transmit array via equivalent circuit modeling and Eigenmode analysis.

Radiofrequency (RF) transmit arrays play a crucial role in various MRI applications, offering enhanced field control and improved imaging capabilities. Designing and optimizing these arrays, particularly in high-field MRI settings, poses challenges related to coupling, resonance, and construction imperfections. Numerical electromagnetic simulation methods effectively aid in the initial design, but discrepancies between simulated and fabricated arrays often necessitate fine-tuning. Fine-tuning involves iteratively adjusting the array's lumped elements, a complex and time-consuming process that demands expertise and substantial experience. This process is particularly required for high-Q-factor arrays or those with decoupling circuitries, where the impact of construction variations and coupling between elements is more pronounced. In this context, our study introduces and validates an accelerated fine-tuning approach custom RF transmit arrays, leveraging the arrays equivalent circuit modeling and eigenmode analysis of the scattering (S) parameters. This study aims to streamline the fine-tuning process of lab-fabricated RF transmit arrays, specifically targeting an eight-channel degenerate birdcage coil designed for 3T MRI. The objective is to minimize the array's modal reflected power values and address challenges related to coupling and resonance. An eight-channel 3T transmit array is designed and simulated, optimizing capacitor values via the co-simulation strategy and eigenmode analysis. The resulting values are used in constructing a prototype. Experimental measurements of the fabricated coil's S-parameters and fitting them into an equivalent circuit model, enabling estimation of self/mutual-inductances and self/mutual-resistances of the fabricated coil. Capacitor adjustments in the equivalent circuit model minimize mismatches between experimental and simulated results. The simulated eight-channel array, optimized for minimal normalized reflected power, exhibits excellent tuning and matching and an acceptable level of decoupling (|Snn|≤-23dB and |Smn|≤-11dB). However, the fabricated array displays deviations, including resonances at different frequencies and increased reflections. The proposed fine-tuning approach yields an updated set of capacitor values, improving resonance frequencies and reducing reflections. The fine-tuned array demonstrates comparable performance to the simulation (|Snn|≤-15dB and |Smn|≤-9dB), mitigating disparities caused by construction imperfections. The maximum error between the calculated and measured S-parameters is -7dB. This accelerated fine-tuning approach, integrating equivalent circuit modeling and eigenmode analysis, effectively optimizes the performance of fabricated transmit arrays. Demonstrated through the design and refinement of an eight-channel array, the method addresses construction-related disparities, showcasing its potential to enhance overall array performance. The approach holds promise for streamlining the design and optimization of complex RF coil systems, particularly for high Q-factor arrays and/or arrays with decoupling circuitry.

Micro-machining of Monel K500 using electrical discharge drilling: insights into hole tapering mechanism and surface morphology

Abstract Monel K500, a corrosion-resistant nickel-copper alloy, presents machining difficulties because of its hardness and toughness. Consequently, the efficacy of non-conventional machining processes on this material demands investigation. Substantial research on micro-feature manufacturing on Monel K500 utilizing the micro-electrical discharge drilling (MEDD) technique remains unreported. This investigation is an attempt to study the micro-machining performance of Monel K500 while fabricating through-micro-holes using MEDD process. The one-factor-at-a-time (OFAT) approach was adopted to arrive at the optimal combination of voltage (V), capacitance (C), tool speed (TS), and pulse duration (PD) for the best output responses. There is a scarcity of extensive investigations on the tapering mechanism in Monel K500 MEDD, such as the one conducted in this study. The value of material removal rate (MRR) at 160 volts was 7.73 × 10−5 g min−1 with 100 pF capacitance, 200 rpm tool speed, and 5 μs pulse duration. At 220 volts, the MRR increased by 50.06% with the same capacitance, tool speed, and pulse length values, reaching 11.60 × 10−5 g min−1. The values of V, C, TS, and PD corresponding to the optimal combination of MRR (35.68 × 10−5 g min−1) and machining time (MT) (16.19 min) were 220 volts, 10000 pF, 400 rpm, and 20 μs respectively. The micrographs of the machined specimens depicted deviation in hole diameter and the presence of tapering in the though-micro-holes. The study revealed that a micro-hole, machined at low discharge energy (DE), has a smoother surface and more uniform size than one machined at higher DE. Monel K500 is extensively utilized in the aerospace, marine, and chemical sectors because to its superior mechanical qualities and corrosion resistance. A standard set of efficient machining conditions can aid in the accurate manufacturing of Monel K500 components with intricate features via the MEDD process.

An Integrated Microfluidic Microwave Array Sensor with Machine Learning for Enrichment and Detection of Mixed Biological Solution.

In this work, an integrated microfluidic microwave array sensor is proposed for the enrichment and detection of mixed biological solution. In individuals with urinary tract infections or intestinal health issues, the levels of white blood cells (WBCs) and Escherichia coli (E. coli) in urine or intestinal extracts can be significantly elevated compared to normal. The proposed integrated chip, characterized by its low cost, simplicity of operation, fast response, and high accuracy, is designed to detect a mixed solution of WBCs and E. coli. The results demonstrate that microfluidics could effectively enrich WBCs with an efficiency of 88.3%. For WBC detection, the resonance frequency of the sensing chip decreases with increasing concentration, while for E. coli detection, the capacitance value of the sensing chip increases with elevated concentration. Furthermore, the measurement data are processed using machine learning. Specifically, the WBC measurement data are subjected to a further linear fitting. In addition, the prediction model for E. coli concentration, employing four different algorithms, achieves a maximum accuracy of 95.24%. Consequently, the proposed integrated chip can be employed for the clinical diagnosis of WBCs and E. coli, providing a novel approach for medical and biological research involving cells and bacteria.

Direct laser writing of planar and stretchable supercapacitors based on a graphene oxide and manganese dioxide nanoparticle composite on a paper substrate

Paper-based supercapacitors (P-SCs) exhibit superior electrochemical performance owing to the flexibility and unique surface properties of paper substrates. Currently, most P-SCs adopt a sandwich structure that is limited by electrode fabrication methods. However, the development of planar paper-based devices is crucial to satisfy the tremendous demand for wearable electronics. Herein, based on the mechanism of interaction between the laser and material, we used direct laser writing (DLW) techniques to fabricate in-plane P-SCs based on graphene oxide (GO) and manganese dioxide (MnO2) composite-covered paper substrates. Owing to the in-plane device structure and pseudocapacitive MnO2, the acquired rGO-MnO2-based planar P-SCs possessed a much higher specific capacitance value (17.7 mF/cm2) than that based on sandwich-structured reduced GO (rGO) (1.71 mF/cm2). In addition, three in-series integrated devices can be easily achieved via the DLW fabrication method, which shows potential for practical applications such as powering a light emitting diode. In addition, by carefully designing the paper substrate structure, the paper-based device exhibited excellent stretching stability. A specific capacitance retention of 86.8% remained after 5000 stretch cycles. Therefore, this study provides valuable insights into the design and fabrication of wearable paper-based electronics.

Deposition of VS2/MoS2 bilayer layers of 2D material on nickel inverse opal structural substrates by SILAR and ECD processes as supercapacitor electrodes

The composition, microstructure, and electrochemical properties of the two kinds of thin film electrode materials, namely VS2/MoS2/Ni-IOS and VS2/MoS2/Ni-foam, were analyzed. The research results indicate that the self-assembled photonic crystal (PhC) templates with adjusted electrophoretic self-assembly processing parameters (100 V cm-1; 7 min) would lead the specimen to a face-centered closely packed structure. Metallic nickel inverse opal structure (IOS) PhCs whose thickness can be freely regulated simply by electrochemical deposition time. VS2and MoS2are 2D materials with excellent electrochemical properties. We employed them as the electroactive material in this study and deposited them onto nickel IOS (Ni-IOS) surfaces to form a composite of The specimens exhibited an excellent specific capacitance (2180 F g-1) at a charge-discharge current density of 5 A g-1. After the 2000 cycles during the life test, the sample can still retain the original specific capacitance value by 72.3%. The IOS PhC substrate produced in this work is designed as VS2/MoS2/Ni-IOS supercapacitor electrode materials, which is proved to offer a significant technical contribution to the application of 2D materials in high-performance supercapacitors currently.

ЕЛЕКТРОСТАТИЧНЕ ПОЛЕ В ПОВІТРЯНОМУ ПРОМІЖКУ СИСТЕМИ ПЛОСКО-ПАРАЛЕЛЬНИХ ЕЛЕКТРОДІВ ДЛЯ ОБРОБКИ КРАПЕЛЬ ВОДИ БАР’ЄРНИМ РОЗРЯДОМ

This study investigates the electrostatic field in a discharge chamber (DC) designed for water purification from organic pollutants using pulsed barrier discharge (PBD) technology. The DC consists of vertical plane-parallel electrodes, with an air gap containing water droplets between them, and one of the electrodes is insulated from the air gap by a dielectric (barrier). The research employs computer modeling in both two-dimensional and three-dimensional setups. Therefore, the aim of this work is to compare the distribution of the electrostatic field intensity of PBD in the air gap and the electrical capacitance of the DC to establish the optimal distance between droplets and to determine the calculation error using the two-dimensional DC model. Electrostatic field modeling was performed using the Poisson equation and the finite element method. Calculations were performed for two-dimensional and three-dimensional models with conditions of a droplet diameter of 1 mm, a gas gap length of 3.36 mm, and an applied voltage of 3 kV. The influence of droplet conductivity and the distance between them on the characteristics of the electrostatic field in the gas medium and in the droplets was investigated. A comparison of the calculated capacitance values of the DC in the two-dimensional and three-dimensional models depending on the distance between the droplets was conducted. The research results can be used in the application of electro-discharge technology based on pulsed barrier discharges in water treatment systems, specifically in selecting the parameters for the movement of the treated liquid in the plasma zone. References 10, figures 7.

A Decoupling Method for Multimode Flexible Capacitive Sensors to Decouple Spatial Forces and Dynamic Humidity.

This paper focuses on a four-capacitor flexible sensor composed of two electrode materials; also, the decoupling method and sensing performance for multimodal sensing of spatial forces and dynamic humidity are described. In previous work, decoupling of multimode sensors is mostly done by monitoring the types of signals, numerical differences of the same signal, and stacking multiple parameter-sensitive materials. This paper mainly uses the different characteristics of the two electrode materials; in the simulation and experiment of humidity, the moisture-sensitive electrode quickly wets from the outside to the inside and expands, and the contact angle quickly decreases from 58.5 to 3.7° within 12.04 s, while the copper electrode has no obvious change; in the simulation and experiment of force, the capacitance value of the capacitor composed of the two electrodes changes steadily with the magnitude of the force. That is, the moisture-sensitive electrode can respond to both force and humidity, while the copper electrode responds only to force. So, we use the copper electrode to decouple the spatial force information and calculate the capacitance value of the moisture-sensitive electrode under the influence of only spatial force. The capacitance value of the moisture-sensitive electrode only affected by humidity can be obtained by the difference between the measured capacitance value and the capacitance value under the influence of only spatial force, and then, the humidity value can be obtained according to the material properties. When a single physical quantity changes, the built-in test platform of the experiment verifies that the decoupling accuracy of the force in the dual-mode sensor is as high as 0.95, and the decoupling accuracy of humidity is as high as 0.97. When the two physical quantities change synchronously, the decoupling accuracy of the force is relatively uniformly distributed within the range, and the decoupling accuracy of humidity can reach as high as 0.99 within the range of 31%RH-56%RH. As a humidity sensor, the sensitivity gradually decreases as the humidity increases. During the repeated changes from low humidity to high humidity, the dynamic characteristics, stability, and repeatability have very good performance. The repetition rate is 97.64%, the response time is 11.3 s, the recovery time is 6.8 s, and the capacitance value for 24 days remains basically unchanged. All of these provide some insight into the application of multimode sensors.

Analytical computation of arm inductor for minimizing MMC circulating current using passive method

The study of circulating currents in modular multilevel converters is vital for improving their efficiency and reliability. The circulating current may arise from capacitor voltage unbalancing, modulation imperfections, load variations, and transient conditions. Such currents typically induce distortions in arm currents, exhibiting second-order harmonics that lead to power losses and negatively impact the ratings of converter components as well as the amplitudes of capacitor voltage ripples. Despite ongoing research, effective strategies to mitigate circulating currents are limited. This paper aims to systematically address this issue by selecting key design parameters specifically arm inductance and capacitor values, to suppress circulating currents. The methodology incorporates harmonic analysis and instantaneous power theory to derive expressions for arm inductance. Initial modelling includes common mode and differential mode analyses, leading to an examination of harmonic content. Analysis reveals that the selection of the arm inductor value is mainly influenced by the second-order harmonic component, whereas the capacitor value is determined by the fundamental harmonic component. By adopting this methodology, the boundary limit for arm inductor selection can be determined. This article proposes a novel expression for arm inductor selection. The proposed expression mainly depends on factors such as load, submodule capacitor voltages, submodule capacitor, and differential current. By selecting an appropriate inductor value based on converter-rated parameters, circulating current within the system can be effectively suppressed. The methodology offers a practical framework for arm inductor selection. Simulation results validation shows strong alignment with analytical results with the error margin of less than 1%, hereby the MMC parameter can be determined with better accuracy through analytic method.

Modeling and Suppression Method of Low Order Harmonics for Three-Level Inverter With Small Capacitance Value

Modeling and Suppression Method of Low Order Harmonics for Three-Level Inverter With Small Capacitance Value

Fully printed non-contact touch sensors based on GCN/PDMS composites: enabling over-the-bottom detection, 3D recognition, and wireless transmission

ABSTRACT The rapid advancement in intelligent bionics has elevated electronic skin to a pivotal component in bionic robots, enabling swift responses to diverse external stimuli. Combining wearable touch sensors with IoT technology lays the groundwork for achieving the versatile functionality of electronic skin. However, most current touch sensors rely on capacitive layer deformations induced by pressure, leading to changes in capacitance values. Unfortunately, sensors of this kind often face limitations in practical applications due to their uniform sensing capabilities. This study presents a novel approach by incorporating graphitic carbon nitride (GCN) into polydimethylsiloxane (PDMS) at a low concentration. Surprisingly, this blend of materials with higher dielectric constants yields composite films with lower dielectric constants, contrary to expectations. Unlike traditional capacitive sensors, our non-contact touch sensors exploit electric field interference between the object and the sensor’s edge, with enhanced effects from the low dielectric constant GCN/PDMS film. Consequently, we have fabricated touch sensor grids using an array configuration of dispensing printing techniques, facilitating fast response and ultra-low-limit contact detection with finger-to-device distances ranging from 5 to 100 mm. These sensors exhibit excellent resolution in recognizing 3D object shapes and accurately detecting positional motion. Moreover, they enable real-time monitoring of array data with signal transmission over a 4G network. In summary, our proposed approach for fabricating low dielectric constant thin films, as employed in non-contact touch sensors, opens new avenues for advancing electronic skin technology.

Effect of functionalization on the energy storage performance of super capacitors derived from wood charcoal

AbstractThe electrochemical performance of wood charcoal is investigated with respect to the disorders in the system after subjecting to oxidation and exfoliation conditions. The Cyclic voltammetry and galvanostatic charge discharge curves indicate an improvement in the electrochemical behavior, resulting in a marginal increase in the specific capacitance values at higher exfoliation temperatures. The improvement is predominantly due to the change in the structural disorder in the system accompanied by the incorporation of oxygen functional groups which act as electrochemical active species. The exfoliation of wood charcoal at 160 and 200°C yield a specific capacitance of 6.23 and 12.24 F/g at a current density of 0.01 A/g. The ESR values representing the overall resistance of the system are observed to be 6.07 Ω for 200°C as opposed to 10.41 Ω of the bare material, making the material more conducting. The drastic change in the structural morphology along with the optimal amount of oxygen functional groups can be the reason for this behavior. The acquired results offer useful information for investigating the possibilities of fabricating supercapacitors with wood charcoal by tuning the defects of the system.

Synthesis and characterisation of calcium magnesium aluminate nanomaterials using neem plant extract: its photocatalytic and supercapacitor application

ABSTRACT The synthesis of Calcium Magnesium Aluminate nanoparticles (CMA NPs) using Azadirachta indica (neem) leaf extract is presented in this paper. The photochemical and electrochemical properties of green CMA NPs also studied. PXRD data indicate a hexagonal phase with space group P63/mmc with average crystallite size of approximately 19.05 nm. SEM analysis shows a homogeneous, flower-like morphology and UV-DRS investigations reveal an energy gap (Eg) of 4.377 eV. The dye degradation tests on Fast Orange (FO) and Fast Blue (FB) dyes under UV (0–120 min) show the highest photocatalytic activity for FO. Cyclic Voltammetry (CV) in 1 M KOH electrolyte shows excellent redox potential with a graphite electrode. Electrochemical Impedance Spectroscopy (EIS) reveals reduced charge transfer resistance, and enhanced electrochemical performance. Specific capacitance values were 48 Fg−1. Galvanostatic charge-discharge tests confirm excellent capacitance for battery and supercapacitor applications.

Design and Fabrication of MoCuOx Bimetallic Oxide Electrodes for High-Performance Micro-Supercapacitor by Electro-Spark Machining.

Transition metal oxides, distinguished by their high theoretical specific capacitance values, inexpensive cost, and low toxicity, have been extensively utilized as electrode materials for high-performance supercapacitors. Nevertheless, their conductivity is generally insufficient to facilitate rapid electron transport at high rates. Therefore, research on bimetallic oxide electrode materials has become a hot spot, especially in the field of micro-supercapacitors (MSC). Hence, this study presents the preparation of bimetallic oxide electrode materials via electro-spark machining (EM), which is efficient, convenient, green and non-polluting, as well as customizable. The fabricated copper-molybdenum bimetallic oxide (MoCuOx) device showed good electrochemical performance under the electrode system. It provided a high areal capacity of 50.2 mF cm-2 (scan rate: 2 mV s-1) with outstanding cycling retention of 94.9% even after 2000 cycles. This work opens a new window for fabricating bimetallic oxide materials in an efficient, environmental and customizable way for various electronics applications.

Green combustion synthesised Zn/NiO nanocomposite for photocatalytic and supercapacitor applications

ABSTRACT In the present research study, a Zn:NiO nanocomposite (NC) was extracted using Tulsi leaf extract via a bio-mediated solution combustion method. The composite material is characterised by XRD, DRS, SEM, EDAX and TEM spectral methods. The XRD shows that the average crystallite size of Zn:NiO NC is ~28 nm. The SEM images exhibit a hexagonal shape and an average particle size of about 80 nm. The TEM images provide information that Zn diffraction spots typically correspond to the hexagonal structure, while NiO shows diffraction rings/spots consistent with its cubic structure. The DRS spectra give an energy band gap value for Zn:NiO NC of 3.34 eV. The NC photocatalytic activity (PCA) was measured using the photodegradation of Fast Orange Red (FOR) dye, and it shows that a maximum absorption was observed at 495 nm with 84.46% degradation under UV light irradiation. The Zn:NiO NC is also used as an electrode in Cyclic Voltammetric (CV) studies, it exhibits surface redox mechanism of Ni2+ to Ni3+, which emerged at 0.13 V (cathodic) and −0.07 V (anodic) at 10 mV/s in 1 M KOH solution. The GCD shows the highest specific capacitance value of 239.8 F/g at a current density of 1 A/g. The Zn:NiO NC also shows excellent outstanding cycle stability, retaining 81.5% of its starting value after 3000 cycles. This suggests that the electrode is appropriate for use in supercapacitors.

Reduced voltage-activated Ca2+ release flux in muscle fibers from a rat model of Duchenne dystrophy

The potential pathogenic role of disturbed Ca2+ homeostasis in Duchenne muscular dystrophy (DMD) remains a complex, unsettled issue. We used muscle fibers isolated from 3-mo-old DMDmdx rats to further investigate the case. Most DMDmdx fibers exhibited no sign of trophic or morphology distinction as compared with WT fibers and mitochondria and t-tubule membrane networks also showed no stringent discrepancy. Under voltage clamp, values for holding current were similar in the two groups, whereas values for capacitance were larger in DMDmdx fibers, suggestive of enhanced amount of t-tubule membrane. The Ca2+ current density across the channel carried by the EC coupling voltage sensor (CaV1.1) was unchanged. The maximum rate of voltage-activated sarcoplasmic reticulum (SR) Ca2+ release was reduced by 25% in the DMDmdx fibers, with no change in voltage dependency. Imaging resting Ca2+ revealed rare spontaneous local SR Ca2+ release events with no sign of elevated activity in DMDmdx fibers. Under current clamp, DMDmdx fibers generated similar trains of action potentials as WT fibers. Results suggest that reduced peak amplitude of SR Ca2+ release is an inherent feature of this DMD model, likely contributing to muscle weakness. This occurs despite a preserved amount of releasable Ca2+ and with no change in excitability, CaV1.1 channel activity, and SR Ca2+ release at rest. Although we cannot exclude that fibers from the 3-mo-old animals do not yet display a fully developed disease phenotype, results provide limited support for pathomechanistic concepts frequently associated with DMD such as membrane fragility, excessive Ca2+ entry, or enhanced SR Ca2+ leak.

PRODUCTION OF HIGH-PERFORMANCE SUPERCAPACITOR ELECTRODES BASED ON GRAPHENE-LIKE CARBON OBTAINED FROM TEA WASTE

This article presents the results of a study on the production of active material for supercapacitor electrodes from graphene-like carbon obtained from tea waste, carbonization at a temperature of 550°C, followed by thermochemical activation using potassium hydroxide in a ratio of 1:4 at a temperature of 850°C in a quartz tube furnace. The structure and morphology of the resulting porous graphene-like carbon based on tea waste were investigated using scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), X-ray diffraction, and Raman spectroscopy. The surface area of activated porous graphene-like carbon from tea waste was 2407 m2/g. Electrochemical characterization of the assembled supercapacitor using GLC-TW was performed on an Elins P-40X electrochemical workstation and showed high specific capacitance values of 182 F/g, as well as a Coulombic efficiency of 96% at a current density of 1 A/g and the material also demonstrated a low charge transfer resistance of about 1.5 Ohms. These results highlight the effectiveness of using graphene-like carbon derived from tea waste, demonstrating its potential as a promising material for supercapacitors.