Electrostatic Capacity Research Articles

Adsorption and desorption of parachlormetaxylenol by aged microplastics and molecular mechanism

The addition of active ingredients such as antibacterial agent and non-active ingredients such as plastic microspheres (MPs) in personal care products (PCPs) are the common pollutants in the aquatic environment, and their coexistence poses potential threat to the aquatic ecosystem. As a substitute for the traditional antibacterial ingredients triclosan and triclocarban, the usage of parachlormetaxylenol (PCMX) is on the rise and is widely used in PCPs. In this study, the adsorption and desorption behaviors of PCMX were investigated with two typical MPs, polyvinyl chloride (PVC) and polyethylene (PE), and the effects of different aging modes and molecular mechanisms were explored through batch experiments and density functional theory calculation. Both laboratory aging and field aging resulted in surface wrinkles of MPs, along with an increased proportion of oxygen-containing functional groups (CO, -OH). At the same aging time, the degree of laboratory aging was stronger than that of field aging, and the aging degree of PVC was greater that of PE. The aging process enhanced the adsorption capacity of MPs for PCMX. The equilibrium adsorption capacity of PVC increased from 3.713 mg/g (virgin) to 3.823 mg/g (field aging) and 3.969 mg/g (laboratory aging), while that of PE increased from 3.509 mg/g to 3.879 mg/g and 4.109 mg/g, respectively. Meanwhile, aging also resulted in an increase in the desorption capacity of PCMX from PVC and PE. Oxygen-containing functional groups in aged MPs could serve as adsorption sites for PCMX and improved the electrostatic adsorption capacity. Oxygen-containing groups generated on the surface of aged MPs formed hydrogen bonding with the phenolic hydroxyl groups of PCMX, which became the main driving force for adsorption. Our results reveal the potential impact and mechanism of aging on the adsorption of PCMX by MPs, which provides new insights for the interaction mechanism between environmental MPs and associated contaminants.

Magnetic graphene oxide and vertically-ordered mesoporous silica film for universal and sensitive homogeneous electrochemiluminescence aptasensor platform

Herein, we demonstrated a convenient and highly sensitive homogeneous electrochemiluminescence (ECL) aptasensor platform by combination of magnetic composite probe and vertically-ordered mesoporous silica films (VMSF). Magnetic composite probe composed of biorecognition element (target-specific aptamer), ECL signal reporter (Ru(bpy)32+) and large-scale magnetic graphene oxide (M−GO), can be prepared by simple incubation, magnetic separation and redispersion prior to use. High-affinity and specific binding between target and aptamer can detach aptamer from M−GO and simultaneously release the slight amount of Ru(bpy)32+ into a solution, which can be sensitively detected by VMSF modified indium tin oxide (VMSF/ITO) due to the excellent electrostatic preconcentration capacity of VMSF. In this sensing system, detectable signal of Ru(bpy)32+ can be remarkably amplified by VMSF/ITO and meanwhile background signal can be reduced by the adsorption capacity of M−GO and size exclusion property of VMSF/ITO, effectively promoting the analytical performance of the present homogeneous ECL aptasensor. The applicability and universality of this sensing platform was confirmed by employing alpha fetoprotein (AFP) and prostate specific antigen (PSA) as the target models and their detection limits were 0.08 pg/mL and 9.6 pg/mL, respectively. Furthermore, the designed homogeneous ECL aptasensor platform is label-free, immobilization-free, low-cost, and free of additional electrode modification and sample pretreatment procedures, rendering a simple sensing strategy for quantitative determination of various biomarkers in clinical diagnosis by adapting the specific aptamer.

Overall collaborative contribution of electrodeposited NiFe2O4@Ni0.75Fe0.25S2 composites for high performance supercapacitors

In this work, a three-dimensional layered NiFe2O4@Ni0.75Fe0.25S2 composite has been synthesised by a two-step electrodeposition process. In the 3 M KOH aqueous solution system, the NiFe2O4@Ni0.75Fe0.25S2 composite exhibits good electrochemical properties due to the overall synergistic effect of the two components. The layered nanostructures provide a high surface area, which increases the specific capacity of NiFe2O4@Ni0.75Fe0.25S2@NF. The current density is 1 A g−1 and the maximum specific electrostatic capacity is 734 C g−1. The construction of an asymmetric supercapacitor (ASC) involves the assembly of NiFe2O4@Ni0.75Fe0.25S2@NF//AC@NF. Operating at a current density of 1 A g−1, this ASC achieves an impressive maximum specific electrostatic capacity of 734 C g−1. In particular, the assembled NiFe2O4@Ni0.75Fe0.25S2 @NF//AC@NF ASC exhibits exceptional electrochemical performance. In particular, it demonstrates an ultra-high specific capacitance of 463 C g−1 at a current density of 1 A g−1, coupled with excellent cycle stability. Even after 10,000 charge-discharge cycles at a current density of 10 A g−1, only 3.6 % of the initial specific capacitance is lost. These impressive results show that NiFe2O4@Ni0.75Fe0.25S2@NF electrodes offer a new solution for the design of high performance aqueous supercapacitors.

Flower-shaped Ni(OH)2 decorated with biomass-derived carbon TPB-1 for asymmetric supercapacitors

In recent years, notable headway has been made in augmenting supercapacitor functioning through employment of pioneering components, exceptional nanostructures and additional investigation of electrolytes. Nonetheless, achieving superior performance with straightforward techniques remains a significant hurdle. In order to surmount this, an experimental three-dimensional nanospherical pore structure (TPB-20@Ni(OH)2) was designed and prepared. TPB-1 was obtained through carbonisation and activation. TPB-20@Ni(OH)2 nanoparticles were synthesized using TPB-1 as the carbon source and nickel chloride hexahydrate as the nickel source. Furthermore, the TPB-20@Ni(OH)2//AC supercapacitor displayed an impressive energy density of 22.1 Wh kg−1. The TPB-20@Ni(OH)2 composites exhibited a specific capacity of 978 F−1, which is noteworthy. The exceptional output exhibited by the TPB-20@Ni(OH)2 composite derives from its innovative structure, presenting an extensive specific surface area of 237.4 m2 g−1 and porosity of roughly 4.0 nm. Following 20 000 cycles (at a current density of 1 A g−1), asymmetric supercapacitors assembled from TPB-20@Ni(OH)2//AC retained 80.0% of its initial specific electrostatic capacity, indicating superior electrochemical stability and high electrochemical reversibility.

Study on flocculation performance and mechanism of cationic polyacrylamide on montmorillonite: Insights from experiments and molecular simulations

To achieve efficient flocculation of fine montmorillonite particles, molecular simulation and flocculation test were investigated to explore the influence of cationic monomer on the performance of cationic polyacrylamide (CPAM) flocculating montmorillonite particles. Three cationic monomers including methylacryloxyethyl trimethyl ammonium chloride (DMC), acrylamide propyl trimethyl ammonium chloride (ATMAC), and methylacrylamide propyl trimethyl ammonium chloride (MAPTAC) were copolymerized with acrylamide (AM) to produce CPAM copolymers. The simulation results suggested the electrostatic interaction was the primary internal propelling force for the stable adsorption of three distinct CPAM copolymers on the montmorillonite/water interface, followed by hydrogen bonding. Flocculation test indicated that CPAM has better flocculation effect on fine montmorillonite particles only when it has strong electrostatic adsorption and bridging capacity. This research establishes a theoretical foundation for the structural design of new flocculants for fine clay minerals.

Ultrasensitive and selective detection of ciprofloxacin in milk based on organic photoelectrochemical transistor aptasensor enhanced by high capacitance Ti3C2/TiO2

Ciprofloxacin (CIP) in milk has a harmful effect on human health, it’s important to conduct ultra-sensitive selective detection of ciprofloxacin. Herein, an ultrasensitive and selective organic photoelectrochemical transistor (OPECT) CIP aptasensor was constructed using Ti3C2/TiO2 composites as gate photoactive materials. Compared with Ti3C2, TiO2, and Ti3C2/TiO2 mixed by physical, Ti3C2/TiO2 composites exhibits larger capacitance and the OPECT intensity is 3 times of Ti3C2, 2 times of Ti3C2/TiO2 mixed by physical and TiO2, which attributed to higher capacitance of Ti3C2/TiO2 composites provides high electrostatic charge storage capacity and leads to effective gating, induces more electronic charge in the channel and larger drain currents. Exemplified by CIP as target, the developed sensor achieves sensitive detection with linear range from 3 ng/L to 3 mg/L, detection limit is 1 ng/L. This work completed the detection in real samples, which lays a foundation for the construction of OPECT food safety analysis and detection platform.

Copper Nanoparticles Confined in a Silica Nanochannel Film for the Electrochemical Detection of Nitrate Ions in Water Samples.

The nitrate ion (NO3-) is a typical pollutant in environmental samples, posing a threat to the aquatic ecosystem and human health. Therefore, rapid and accurate detection of NO3- is crucial for both the aquatic sciences and government regulations. Here we report the fabrication of an amino-functionalized, vertically ordered mesoporous silica film (NH2-VMSF) confining localized copper nanoparticles (CuNPs) for the electrochemical detection of NO3-. NH2-VMSF-carrying amino groups possess an ordered perpendicular nanochannel structure and ultrasmall nanopores, enabling the confined growth of CuNPs through the electrodeposition method. The resulting CuNPs/NH2-VMSF-modified indium tin oxide (ITO) electrode (CuNPs/NH2-VMSF/ITO) combines the electrocatalytic reduction ability of CuNPs and the electrostatic attraction capacity of NH2-VMSF towards NO3-. Thus, it is a rapid and sensitive electrochemical method for the determination of NO3- with a wide linear detection range of 5.0-1000 μM and a low detection limit of 2.3 μM. Direct electrochemical detection of NO3- in water samples (tap water, lake water, seawater, and rainwater) with acceptable recoveries ranging from 97.8% to 109% was performed, demonstrating that the proposed CuNPs/NH2-VMSF/ITO sensor has excellent reproducibility, regeneration, and anti-interference abilities.

Insights into polystyrene nanoplastics adsorption mechanisms onto quartz sand used in drinking water treatment plants

The widespread production and use of plastics with poor recycling practices have resulted in higher discharge of plastic waste into the aquatic systems. Nanoplastics (NPLs) resulting from the fragmentation of microplastics, are considered as the most hazardous fraction. Adsorption to mineral surfaces is considered as one of the most important processes controlling the fate and transport of nanomaterials both in the natural environment and conventional filtration systems. However, adsorption mechanisms, influencing physicochemical parameters, and adsorption capacities of different porous media are still poorly known. In this study, the adsorption process of polystyrene (PS) NPLs to quartz sand, used as a filter medium in the drinking water treatment plant in Geneva (Switzerland), is investigated. Contrasting conditions are considered: ultrapure water and Geneva Lake water. Results indicate that PS NPLs dispersed in ultrapure water are adsorbed to the sand surface mainly due to the electrostatic interactions and adsorption capacity of the sand grains varies from 0.05 ± 0.01 mg g−1 to 0.10 ± 0.02 mg g−1 for PS NPLs concentrations comprised between 10 and 50 mg L−1. The adsorption process is successfully described by Langmuir isotherm, therefore indicating the formation of a monolayer on the sand grain surfaces. SEM micrography confirms PS NPLs monolayer formation and image analysis indicates a maximum surface coverage ranging from 9 to 12 %. Adsorption mechanisms of PS NPLs are significantly modified under environmental conditions (i.e., pH, ionic composition, presence of DOM). The adsorption capacity of sand grains for the removal of PS NPLs increased and varies from 0.05 ± 0.01 mg g−1 to 0.7 ± 0.2 mg g−1 for PS NPLs concentrations ranging from 10 to 50 mg L−1. Increased adsorption capacity is due to heteroaggregation and cation bridging processes. SEM micrography shows aggregates attached to smooth sand surfaces and deposited in the vicinity of surface irregularities.

Improving the Electrostatic Capacity and Efficiency of UVC LEDs by Embedded Anti-Parallel Diode

Improving the Electrostatic Capacity and Efficiency of UVC LEDs by Embedded Anti-Parallel Diode

Integration fabrication of polyimide composite films for aerospace applications

AbstractPolyimides externally deployed in spacecraft or satellites extensively have various aerospace hazards, including atomic oxygen (AO) erosion, irradiation degradation, and electrostatic charge/discharge (ESC/ESD). To cope with these challenges, we fabricate a ZnO/CuNi‐polyimide composite film with augmented permanence. Using spectroscopy and microscopy techniques, we have shown that the combination of chelation and cross‐linking in the interfacial architecture leads to enhanced interfacial compatibility and mechanical robustness. Besides, due to the positive AO diffusion barrier ability of the wurtzite ZnO, our composite film shows remarkable AO resistance and a very small Ey value of 6.88 × 10−26 cm3/atom, which is merely 2.29% of that of pristine polyimide. Moreover, the well‐defined nanocrystalline state with minimal lattice swelling (0.3%–0.7%) of the Fe+‐irradiated ZnO/CuNi‐polyimide at a damaging dose of 353.4 dpa demonstrates its excellent irradiation resistance. Finally, the ZnO/CuNi‐polyimide also shows sufficient electrostatic dissipation capacity to cope with the ESC/ESD events. Our fabrication approach for composite films based on multi‐technology integration shows potential for aerospace applications and deployment.

Impact of Flaxseed Gums on the Colloidal Changes and In Vitro Digestibility of Milk Proteins.

Flaxseed (Linum usitatissimum L.) mucilage is one of the most studied plant seed gums in terms of its techno-functional and health-promoting properties. Nonetheless, the interplay of flaxseed gum (FG) with other food biopolymers, such as milk proteins, under in vitro digestion conditions remains underexplored. The aim of the present work was to investigate the colloidal interplay between flaxseed gum (golden or brown) and milk proteins (sodium caseinate or whey protein isolate) under simulated in vitro digestion conditions and its relationship with the attained in vitro protein digestibility. The presence of flaxseed gum in the milk protein food models and in the oral food boluses obtained was associated with the occurrence of segregative microphase separation. Flaxseed gum exhibited a prominent role in controlling the acid-mediated protein aggregation phenomena, particularly in the sodium caseinate gastric chymes. The addition of FG in the food models was associated with a higher amount of intact total caseins and β-lactoglobulin at the end of the gastric processing step. Monitoring of the intestinal processing step revealed a very advanced cleavage of the whey proteins (>98%) and caseins (>90%). The degree of the milk protein hydrolysis achieved at the end of the intestinal processing was significantly higher in the systems containing flaxseed gum (i.e., 59-62%) than their gum-free protein counterparts (i.e., 46-47%). It was postulated that the electrostatic milk protein complexation capacity and, to a lesser extent, the thickening effect of flaxseed gum influenced the in vitro digestibility of the milk proteins.

Experimental study on particulate matter removal using packed-bed dielectric barrier discharge plasma reactor

In this study, a packed-bed dielectric barrier discharge (DBD) reactor was developed for particulate matter (PM) removal. The effects of operating conditions such as the packing materials, applied power, and discharging gap were systematically investigated. The results revealed that Zeolite 13X exhibited the highest PM removal efficiency based on its high electrostatic adsorption capacity. A narrow discharge gap (2.4 mm) and increased power density resulted in an enhancement of the PM removal efficiency in the system. Further, these operating conditions increased the electric field strength, which was proportional to the current density in the system. The energy yield decreased with an increase in the specific energy input into the packed-bed DBD reactor. Among the tested operating parameters, maintaining a narrow discharging gap was determined to be the most important for achieving high energy efficiency and PM removal in the system. Moreover, an air cleaning procedure was applied for the regeneration of the packing materials, resulting in a high recovery rate of over 80%.

Structure and Circuit Engineering Features of Stand- Alone Photovoltaic System with a Battery-Capacitive Energy Storage Device

The purpose of this research is to analyze the structure and circuit design of stand-alone photovoltaic system with a battery-capacitive energy storage device to ensure voltage stability under peak voltage and a variable nature of the power generated by a solar panel. There is an original active control scheme for a hybrid drive. The peak power of the solar panel was 100 W. The battery part of the energy storage device was represented by a 12 V gel lead-acid battery with a charging capacity of 11 Ah, and the capacitive part consisted of a battery of supercapacitors with an electrostatic capacity of 80 F, an operating voltage of 15.5 V. A rheostat was used as a load during a stationary discharge of the storage device with a resistance of 12 Om, and the pulsed nature of the discharge was simulated using an automobile air compressor. The analysis of circuit design variants that implement the charging process the capacitive part of the energy storage device from a solar panel directly or with a shunt DC/DC converter is performed. Charging and discharging of the battery part was controlled by the ProStar-15 controller. In both cases, charging buffer modes the battery and capacitive parts of the energy storage device were used. The research results have identified ways to increase the stability of the output voltage under peak voltage and the variable nature of electricity generation conditions while increasing the resource of an expensive battery.

Electrospun PAN-HNTs composite nanofiber membranes for efficient electrostatic capture of particulate matters

The fine particulate matter (PM) pollution has become a serious concern to public health. As the core part of PM air filters, high-performance electrostatic nanofiber membranes are urgently needed. However, the existing air filters remain challenging to further decrease the pressure drop to improve the wearer comfort. On the other hand, the rapidly disappearing static electricity of the existing electrostatic nanofiber inevitably gives rise to a relatively short service life. Here, we demonstrate a novel and enhanced electrostatic nanofiber membrane by introducing the halloysite nanotubes (HNTs) to the traditional electrospun PAN nanofiber membrane. The optimal PAN-HNTs nanofiber membrane shows a high removal efficiency of 99.54%, a low pressure drop of 39 Pa, and a high quality factor of 0.89 Pa−1. This greatly improved filtration performance can be attributed to the increased surface area and diameter of nanofiber after introducing the HNTs as additives with suitable doping concentrations. More importantly, compared with the pure PAN nanofiber membrane, the electrostatic capacity of the PAN-HNTs nanofiber membrane is significantly enhanced, which is confirmed by the leaf electroscope. After introducing the HNTs as additives, the surface of the PAN-HNTs nanofiber membrane becomes hydrophilic, which benefits for preventing foulants from attaching to the surface. We anticipate that the PAN-HNTs nanofibers as high-performance membrane air filters will bring great benefits to public health.

Charging and Discharging Characteristics of a Battery-Capacitive Energy Storage Device for Stand-Alone Photovoltaic System

The purpose of the research is to study the charging-discharging characteristics of a hybrid energy storage device which consists of two parallel connected battery and capacitive parts to assess the work efficiency of its circuit design as a part of standalone photovoltaic system. The charge current kinetics of a hybrid storage device from a solar panel was carried out under natural conditions at a specific power of incident solar radiation of 800–850 W/m2. The discharge current kinetics of battery and capacitive storages were obtained with a resistive load and disconnected solar battery. The dynamics of charging and discharging processes of the battery and capacitive parts of the energy storage device were monitored by the voltage rise/fall rate. The battery part of the drive is charging and starting the device based on a lead-acid gel battery with a charging capacity of 11 A·h, 12.8 V maximum voltage, and 15 A maximum discharge current. The capacitive part consisted of a new generation INSPECTOR Booster supercapacitor starting the device with an electrostatic capacity of 80 F, 15.5 V voltage, and 800 A starting current. As the energy source a solar battery was used, with a 12 V nominal voltage and 100 W peak power. A 6 Om rheostat with 15 A consumption current was used as a load during the storage device discharge. A Morningstar ProStar-15 charging/discharging controller with a pulse-width modulation function was used to monitor and control the photovoltaic system. Quantitative charging and discharging characteristics of a battery-capacity energy storage device were obtained for the use in the development of standalone photovoltaic system.

The Brunn-Minkowski Inequality and A Minkowski Problem for Nonlinear Capacity

In this article we study two classical potential-theoretic problems in convex geometry. The first problem is an inequality of Brunn-Minkowski type for a nonlinear capacity, Cap A , \operatorname {Cap}_{\mathcal {A}}, where A \mathcal {A} -capacity is associated with a nonlinear elliptic PDE whose structure is modeled on the p p -Laplace equation and whose solutions in an open set are called A \mathcal {A} -harmonic. In the first part of this article, we prove the Brunn-Minkowski inequality for this capacity: \[ [ Cap A ⁡ ( λ E 1 + ( 1 − λ ) E 2 ) ] 1 ( n − p ) ≥ λ [ Cap A ⁡ ( E 1 ) ] 1 ( n − p ) + ( 1 − λ ) [ Cap A ⁡ ( E 2 ) ] 1 ( n − p ) \left [\operatorname {Cap}_\mathcal {A} ( \lambda E_1 + (1-\lambda ) E_2 )\right ]^{\frac {1}{(n-p)}} \geq \lambda \, \left [\operatorname {Cap}_\mathcal {A} ( E_1 )\right ]^{\frac {1}{(n-p)}} + (1-\lambda ) \left [\operatorname {Cap}_\mathcal {A} (E_2 )\right ]^{\frac {1}{(n-p)}} \] when 1 > p > n , 0 > λ > 1 , 1>p>n, 0 > \lambda > 1, and E 1 , E 2 E_1, E_2 are convex compact sets with positive A \mathcal {A} -capacity. Moreover, if equality holds in the above inequality for some E 1 E_1 and E 2 , E_2, then under certain regularity and structural assumptions on A , \mathcal {A}, we show that these two sets are homothetic. In the second part of this article we study a Minkowski problem for a certain measure associated with a compact convex set E E with nonempty interior and its A \mathcal {A} -harmonic capacitary function in the complement of E E . If μ E \mu _E denotes this measure, then the Minkowski problem we consider in this setting is that; for a given finite Borel measure μ \mu on S n − 1 \mathbb {S}^{n-1} , find necessary and sufficient conditions for which there exists E E as above with μ E = μ . \mu _E = \mu . We show that necessary and sufficient conditions for existence under this setting are exactly the same conditions as in the classical Minkowski problem for volume as well as in the work of Jerison in \cite{J} for electrostatic capacity. Using the Brunn-Minkowski inequality result from the first part, we also show that this problem has a unique solution up to translation when p ≠ n − 1 p\neq n- 1 and translation and dilation when p = n − 1 p = n-1 .

BiFeO3-Based Relaxor Ferroelectrics for Energy Storage: Progress and Prospects.

Dielectric capacitors have been widely studied because their electrostatic storage capacity is enormous, and they can deliver the stored energy in a very short time. Relaxor ferroelectrics-based dielectric capacitors have gained tremendous importance for the efficient storage of electrical energy. Relaxor ferroelectrics possess low dielectric loss, low remanent polarization, high saturation polarization, and high breakdown strength, which are the main parameters for energy storage. This article focuses on a timely review of the energy storage performance of BiFeO3-based relaxor ferroelectrics in bulk ceramics, multilayers, and thin film forms. The article begins with a general introduction to various energy storage systems and the need for dielectric capacitors as energy storage devices. This is followed by a brief discussion on the mechanism of energy storage in capacitors, ferroelectrics, anti-ferroelectrics, and relaxor ferroelectrics as potential candidates for energy storage. The remainder of this article is devoted to reviewing the energy storage performance of bulk ceramics, multilayers, and thin films of BiFeO3-based relaxor ferroelectrics, along with a discussion of strategies to address some of the issues associated with their application as energy storage systems.

Co-immobilization of clinoptilolite and nanostructured hydrated ferric-zirconium binary oxide via polyvinyl alcohol-alginate covalent cross-linking for simultaneous deep removal of aqueous low-level nitrogen and phosphorus

A novel absorbent, PVA/SA-CFZ, was developed by jointly enveloping nanostructured hydrated ferric-zirconium binary oxide and clinoptilolite in the cross-linking of polyvinyl alcohol (PVA)/sodium alginate (SA). As a result, the cation exchange capacity of clinoptilolite and electrostatic attraction capacity of hydrated ferric-zirconium binary oxide can be integrated for the simultaneous removal of nitrogen and phosphorus from wastewater. The adsorption behavior of PVA/SA-CFZ for the co-existing ammonium and phosphate was primarily investigated by batch experiments. Over a wide pH range (4 ~ 11), PVA/SA-CFZ always showed the excellent adsorption performance both for the low-concentration ammonium (<5 mg/L) and phosphate (<0.5 mg/L), which reflected the well adaptability towards unfavorable environmental conditions. The kinetic analysis indicated that the pseudo-second-order kinetic model could quantitatively describe the adsorption process optimally. The mechanistic investigation revealed that ammonium was captured through the cation exchange reaction with clinoptilolite. The electrostatic attraction, inner sphere complexation with Fe/Zr-O-OH groups, and formation of phosphate precipitation jointly contributed to the fixation of phosphate by PVA/SA-CFZ. Generally, it is believed that PVA/SA-CFZ can serve as a promising composite absorbent for the simultaneous deep removal of nitrogen and phosphorus, and support for the advanced treatment of wastewater containing low-level nutrients.

IMPACT OF THE GRAPHENE SYNTHESIS AND CONCENTRATION CONDITIONS ON ELECTRICAL PARAMETERS OF GRAPHENE — GRAPHITE SYSTEM

Electrochemical impedance spectroscopy was used to study the electrical parameters of graphite-graphene systems with different mass concentrations of graphene. Graphene was synthesized using two methods of plasma arc discharge from aqueous and non-aqueous medium (water and liquid nitrogen) to determine the impact of graphite concentration, water, and heat treatment of graphene on electrical parameters (conductivity and electrostatic capacity) of the graphite-graphene mixture. The average va­lues ​​of active resistance and electrostatic capacity of these systems are obtained. The optimal ratio of components with high capacitance and conductivity, which was 1: 1. The influence of heat treatment adsorbed on the graphene surface of the water and mass fraction of graphite on the change of electrical parameters of the system is shown. Comparison of the values ​​of capacity and active resistance of the samples showed that the presence of water in graphene reduces the average values ​​of capacity relative to graphene without water by 10 times and symbolically increases the active resistance at a mass ratio of graphene to graphite 1: 3, and at a ratio of 1: 1 values ​​are proportional. Comparison of resistance, capacitance, and charge distribution calculations in a graphite-graphene mixture in the frequency range 10–2 ÷ 103 Hz established the effect of heat treatment on increasing the values ​​of capacitance and active resistance. Heat treatment at 2500C of graphene, synthesized from an aqueous medium, leads to an increase in the values ​​of capacitance and conductivity, which occurs due to a different distribution of charges on the surface. Analysis of charge distribution maps shows that water adsorbed on the surface of graphene in the presence of a signi­ficant amount of graphite can be a factor in interfering with the distribution of charge carriers and significantly reduce the conductivity and electrostatic capacity of the system.

Robot end effector based on electrostatic adsorption for manipulating garment fabrics

To improve the effectiveness of industrial robots in the textile and garment industry, it is necessary to expand the application range of electrostatic adsorption end effectors and solve the problem of automatically grasping and transferring fabrics during garment processing. Taking weft-knit fabric as an example, this paper begins by analyzing the factors that influence the electrostatic adsorption capacity, and then constructing an electrostatic adsorption capacity model based on the fabric characteristics. Next, the shape arrangement and structural parameters of the electrode plate are optimized by taking the electrostatic adsorption force model and maximizing the adsorption force per unit area. Finally, the adsorption effect of the electrostatic adsorption end effector is verified by simulation and experiment. The verification results show that the electrode with a comb-shaped arrangement and optimized structural parameters can adsorb clothing fabric well and meets the requirements of clothing automated production lines. This study provides a new method for solving the problem of automatically grasping and transferring fabrics and provides technical support for improving automation in the garment industry.