Interelectrode Spacing Research Articles

Fabrication and Characterization of Ag-Sr-Substituted Hydroxyapatite/Chitosan Coatings Deposited via Electrophoretic Deposition: A Design of Experiment Study.

In this study, silver–strontium-doped hydroxyapatite (AgSr-HA)/chitosan composite coatings were deposited on a 316L stainless steel (SS) substrate via electrophoretic deposition (EPD). The Taguchi design of experiment (DoE) approach was used to optimize the EPD parameters such as the applied voltage, interelectrode spacing, and deposition time. Furthermore, the concentration of AgSr-HA particles in the suspension was also optimized via the DoE approach. DoE results demonstrated that the “homogeneous” coatings were obtained at the deposition time of 7 min, deposition voltage of 20 V, and at a concentration of 5 g/L AgSr-HA particles in the suspension. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), antibacterial studies, contact angle, and roughness measurements were performed to characterize the optimized coatings. SEM images confirmed the deposition of chitosan/AgSr-HA on the SS substrate. The wettability studies indicated the hydrophilic nature of the chitosan/AgSr-HA composite coatings, which confirmed that the developed coatings are suitable for biomedical applications, e.g., orthopedics. The average surface roughness of the chitosan/AgSr-HA composite coatings was in a suitable range used to attach the bone marrow stromal cells. Chitosan/AgSr-HA composite coatings showed an effective antibacterial effect against Gram-positive and Gram-negative bacteria. Moreover, the coatings developed apatite crystals on their surface upon immersion in simulated body fluid.

Degradation of distillery effluent by twisted-type Iron electrodes: experimental with ANN approach

ABSTRACT The distillery spent wash consists of extremely high COD values, high content of pollutants and has an objectionable dark colour. These properties mark the effluent as one of the challenging tasks to treat ahead of exculpating into the surroundings. In this original research work, the raw distillery effluent was electrochemically treated using twisted-type Iron electrodes. Electrochemical treatment was performed for 2 hours and the treated effluent was sampled at defined periods to evaluate the efficiencies of spent wash degradation in terms of colour removal. Optimisation studies were conducted to evaluate the impact of various process parameters viz., applied electric current intensity, pH, mixing speed, electrolysis time and the inter-electrode space on the colour removal efficiencies. The maximum degradation of colour achieved by twisted-type Iron electrodes was found to be 83.75%. Operating conditions at which maximum colour removal efficiencies were achieved at current intensity 1.9 A, pH 3, 2 cm of inter-electrode distance, mixing speed of 100 rpm and for an electrolysis time of 2 h. The experimental results obtained were validated and evaluated using an Artificial Neural Network for modelling and predicting the electrocoagulation process for the degradation of distillery effluent employing twisted-type Iron electrodes.

Enhanced electrospinning: Multi-level fiber alignment by control of electrohydrodynamic jet motion for tissue engineering

This paper proposes a novel electrospinning method for controllable fiber alignment and deposition on a dielectric substrate by the electric field manipulation using nanosecond rise time high-voltage pulse generators. A peculiarity of the proposed technical solution is the ability to control polymer jet localization in the interelectrode space with the possibility of stabilization and retention of the jet at an arbitrary point. A preliminary numerical simulation shows electric field distribution in proposed geometry with a syringe and two cylindrical collectors. Samples of oriented materials based on a polyamide 6/66 copolymer with 2–4° degrees of disorientation were obtained. The study of thermal and mechanical behavior of oriented materials based on polyamide was carried out, and macromolecular orientation was established by X-ray diffraction in small and wide angles. The possibility to create material by stacking multiple layers with given fiber orientation at 65° and 90° and polymer spinning on various dielectric materials by means of the reverse polarity operating principle is demonstrated. The ability to control fiber alignment in electrospinning will expand the possibilities of high-performance production of polymeric nonwoven materials with a given architecture and unique physicochemical characteristics required for solving a whole range of medical and technological challenges of a different profile.

Simulation and measurement of charged particle trajectory with ionic flow in a wire-to-plate type electrostatic precipitator

The purpose of this study is to simulate charged particle trajectory in a wire-to-plate type electrostatic precipitator (ESP). The analyzed corona current value was fitted to the experimental value, whereby the negative ion density on the surface of the wire electrode as the boundary condition was determined. The gas flow distribution with the ionic flow and the charged particle trajectory in the ESP were simulated. The particle charge was calculated by the diffusion charging and the field charging theories. The particle trajectory in the gas with ionic flow was also measured using a particle image velocimetry (PIV) to show the validity of the analysis result. As a result, it was shown that the analysis result of particle migration velocity in the ESP increased and eddies parallel to the xy plane were generated between the wire electrode and the grounded plate electrode as the applied voltage increased. The tendency and the values of the x component of the analyzed particle velocity agreed with the experimental result. The y component of the analyzed particle velocity in the inter-electrode space was in good agreement with the experiment. The validity of the analysis result was indicated from these results.

Band Electrodes Reduce Simulated Calf Bioimpedance Measurement Errors Due to Muscle Anisotropy.

Remote monitoring of fluid status via calf bioimpedance measurements could improve the experience of patients with congestive heart failure and reduce readmission rates. Most measurements today use conventional Ag/AgCl electrodes and a short inter-electrode spacing, resulting in current flowing primarily near the electrodes, preventing deeper current penetration and in turn accurate volume estimation. Textile band electrodes may more evenly distribute current throughout the calf. In the present study, simulations were conducted to investigate the impact of inter-electrode spacing/placement and fat tissue on bioimpedance using both Ag/AgCl electrodes and textile band electrodes. Simulation results showed that increasing the inter-electrode spacing can improve current distribution in the tissue, but there are still errors that increase with fat thickness (14.3% error at 10 cm spacing down to 1.7% error at 20 cm spacing for a "nominal" fat thickness, vs. -0.3% and -0.5% error for band electrodes). Band electrodes most closely matched the expected resistance and seem the most suitable regardless of inter-electrode spacing.

The Influence of Supersonic Gas Stream on Spatial Structure of Glow Discharge

This work investigates into the properties of longitudinal glowing discharge in supersonic gas stream between central body and reducer. It has been established that the properties of discharge spatial localization, intensity of radiation, formation of near-electrode areas directly depend on arrangement of supersonic stream. This work analyzes the properties of gas stream in expanding area of supersonic nozzle, pressure recovery in reducer. It has been experimentally established that gas circulation at supersonic speed in the area of glowing discharge makes it possible to control the distribution of concentration of neutral particles in interelectrode space as well as localization of near-electrode zones and positive glow.

Optimized parameters of the electrocoagulation process using a novel reactor with rotating anode for saline water treatment

In this study, a novel rotating anode-based reactor (RAR) was designed to investigate its effectiveness in removing dissolved salts (i.e., Br−, Cl−, TDS, and SO42−) from saline water samples. Two configurations of an impeller’s rotating anode with various operation factors, such as operating time (min), rotating speed (rpm), current density (mA/cm2), temperature (°C), pH, and inter-electrode space (cm), were used in the desalination process. The total cost consumed was calculated on the basis of the energy consumption and aluminum (Al) used in the desalination. In this respect, operating costs were calculated using optimal operating conditions. Salinity was removed electrochemically from saline water through electrocoagulation (EC). Results showed that the optimal adjustments for treating saline water were carried out at the following conditions: 150 and 75 rpm rotating speeds for the impeller’s rod anode and plate anode designs, respectively; 2 mA/cm2 current density (I), 1 cm2 inter-electrode space, 25 °C temperature, 10 min operation time, and pH 8. The results indicated that EC technology with impeller plates of rotating anode can be considered a very cost-effective technique for treating saline water.

The influence of external electrostatic field on the combustion of hexamine

In scientific work investigates the impact of electric fields on combustion of hexamine. The experimental setup has been developed to study the interaction of an electric field with a low-temperature flame. The optimal spatial configuration of the electrodes for extinguishing the flame was established; the dynamics of airflows caused by the ion wind was studied; the threshold value of the electric field leading to flame extinguishing was determined. An expression is proposed based on the equation of motion that connects the speed of motion of partially ionized gas particles, the viscosity and degree of ionization of the gas, and the intensity of the external electric field. It is shown that the strength of the external electric field, leading to extinguishing of hexamine combustion, increases with decreasing inter-electrode space. The values of corresponding electric field strength lied in range from 80 to 135 kV/m at interelectrode distances of 0.4 and 0.1 m, respectively. The results of the study can be used for effective fire extinguishing in compact devices running on dry fuel.

250Efficacy of multi-electrode linear irreversible electroporation

Abstract Background We investigated the efficacy of linear irreversible electroporation (IRE) ablation in a porcine model. Methods The study was performed in 6 pigs (weight 60-75kg). After median sternotomy and opening of the pericardium, a pericardial cradle was formed and filled with blood. A linear 7 polar 7F electrode catheter with 2.5mm electrodes and 2.5mm inter-electrode spacing was placed in good epicardial contact. A single IRE application was delivered using 50 Joules (J) at 1 site and 100 J at 2 other sites, in random sequence, using a standard monophasic defibrillator connected to all 7 electrodes connected in parallel. The pericardium and thorax were closed and after 3 weeks survival animals were euthanized. 82 histological sections from all 18 electroporation lesions were analyzed. Results A total of seven 50 J and fourteen 100 J epicardial IRE applications were performed. Mean peak voltages at 50 J and 100 J were 1079.2 V ± 81.1 and 1609.5 V ± 56.8, with a mean peak current of 15.4 A ± 2.3 and 20.2 A ± 1.7, respectively. Median depth of the 50J and 100J lesions were 3.2 mm (interquartile range [IQR], 3.1 – 3.6) and 5.5 mm (IQR, 4.6 – 6.6) (P < 0.001), respectively. Median lesion width of the 50J and 100J lesions were 3.9 mm (IQR, 3.7 – 4.8) and 5.4 mm (IQR, 5.0 - 6.3), respectively(P < 0.001). Longitudinal sections showed continuous lesions for 100J lesions. Conclusion Epicardial linear application of IRE pulses is effective in creating continuous deep lesions. Ablation characteristics and lesion size Peak voltageV Peak currentA Peak resistanceΩ SlicesN Depthmm Widthmm 50 J 1079.2 ± 81.1 14.5 ± 2.3 71.8 ± 15.6 26 3.2 (3.1 - 3.6) 3.9 (3.7 - 4.8) 100J 1609.5 ± 56.8 20.2 ± 1.7 80.0 ± 9.5 56 5.5 (4.6 - 6.6) 5.4 (5.0 - 6.3) P-value† <0.001 <0.001 Data is displayed as mean ± SD or median (interquartile range) where appropriate.†assessed by general linear mixed models Abstract Figure. Transversal histological sections

Deposition of thin films of nanoscale carbon onto solid samples as a method of suppressing surface colonization of bacteria

The paper presents preliminary results demonstrating the bactericidal properties of surface coatings created on metal and dielectric samples by evaporation of a colloidal solution of nanostructured carbon. A colloidal solution of nanocarbon was obtained using a high-voltage pulsed multi-spark discharge in ethanol with argon injection into the interelectrode space. The main properties of a colloidal solution and the parameters of its constituent nanoparticles are given. Bactericidal activity was assessed by seeding Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive) bacterial cultures on prepared slides. Results on suppression of bacterial colonization on samples coated with carbon nanoparticles are presented.

Analysis of electrohydrodynamic air flow induced by DC corona field in wire-to-plane electrode system

Method of the electrohydrodynamic (EHD) air flow induced by DC corona field calculation is proposed. Computation based upon the finite-element method is performed using Comsol Multiphysics commercial program. EHD air flow velocities field distribution in inter-electrode space is presented. Two-dimensional numerical model for computation of the air flow induced by corona field in wire-to-plane electrode system is presented. Results have been obtained using mathematical model and compared with experimental ones. Results analyses consist of EHD flow distribution in inter electrode space and integrated total flow dependence from corona electrode voltage. Comparison of corona discharge electric and air flow mechanic powers is presented.

Melanopsin Driven Light Responses Across a Large Fraction of Retinal Ganglion Cells in a Dystrophic Retina.

Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin and project to central targets, allowing them to contribute to both image-forming and non-image forming vision. Recent studies have highlighted chemical and electrical synapses between ipRGCs and neurons of the inner retina, suggesting a potential influence from the melanopsin-born signal to affect visual processing at an early stage of the visual pathway. We investigated melanopsin responses in ganglion cell layer (GCL) neurons of both intact and dystrophic mouse retinas using 256 channel multi-electrode array (MEA) recordings. A wide 200 μm inter-electrode spacing enabled a pan-retinal visualization of melanopsin’s influence upon GCL activity. Upon initial stimulation of dystrophic retinas with a long, bright light pulse, over 37% of units responded with an increase in firing (a far greater fraction than can be expected from the anatomically characterized number of ipRGCs). This relatively widespread response dissipated with repeated stimulation even at a quite long inter-stimulus interval (ISI; 120 s), to leave a smaller fraction of responsive units (<10%; more in tune with the predicted number of ipRGCs). Visually intact retinas appeared to lack such widespread melanopsin responses indicating that it is a feature of dystrophy. Taken together, our data reveal the potential for anomalously widespread melanopsin responses in advanced retinal degeneration. These could be used to probe the functional reorganization of retinal circuits in degeneration and should be taken into account when using retinally degenerate mice as a model of disease.

Electrochemiluminescence (ECL)-Based Electrochemical Imaging Using a Massive Array of Bipolar Ultramicroelectrodes.

In this report, we describe the fabrication, characterization, and use of a massive array of closed bipolar ultramicroelectrodes (UMEs) in electrochemical imaging applications. The bipolar UME array is 1 cm2 in size and contains >146 000 carbon electrodes embedded in a 15 μm thick insulating and freestanding membrane of Parylene C. Structural characterization with optical and electron microscopies shows that the carbon UMEs are highly uniform in size, shape, and interelectrode spacing. The bipolar UME array was used in electrochemical imaging to probe highly dynamic redox processes in which the reduction of redox molecules on one side the array is electrically coupled to an oxidative electrochemilumescence (ECL) process on the opposite side. This allows one to simultaneously monitor electrochemical reactions on hundreds of thousands of individual electrodes with millisecond temporal resolution. Our results suggest that microfabricated closed bipolar UME arrays can be useful for imaging fast and transient electrochemical processes in which scanning probe methods are inapplicable due to their limited temporal resolution.

2019 APHRS expert consensus statement on three-dimensional mapping systems for tachycardia developed in collaboration with HRS, EHRA, and LAHRS.

2019 APHRS expert consensus statement on three-dimensional mapping systems for tachycardia developed in collaboration with HRS, EHRA, and LAHRS.

Unified modelling of non-equilibrium microarcs in atmospheric pressure argon: potentials and limitations of one-dimensional models in comparison to two-dimensional models

A recently developed modelling approach is applied in one and two dimensions in order to obtain the plasma properties of direct current microarcs in atmospheric pressure argon under non-equilibrium conditions. The configuration includes a cylindrical cathode made of tungsten and a cooled copper anode. The one-dimensional (1D) description represents the situation on the axis of the two-dimensional (2D) axially symmetric arrangement. The models solve equations for species and energy conservation of electrons and heavy particles and the Poisson equation, which are coupled to the heat conduction in the thermionic cathode. The results obtained show very good agreement between the one- and 2D models provided that the microarc plasma fills and solely occupies the inter-electrode space. When the arc attachment spreads to the lateral surface of the cathode, the 1D model can be applied at a reduced current density to explore the plasma in the inter-electrode region.

Synthesis of Nanostructured Cadmium Sulphide and Fabrication of High Response Photo Sensor

The light dependent resistor (LDR) are prepared using bulk CdS material and using conventional thick film technique. But bulk CdS and this conventional thick film technique gives lower inter-electrode spacing resulting poor response. In the present work, the CdS nanostructure was synthesized using hydrothermal reaction technique and with the help of screen printing technique, the CdS pattern having lower inter-electrode spacing resulting larger length of the CdS was prepared. As the inter electrode spacing increases the photocurrent also increases resulting enhancement of the sensor response. The work reported in the present paper provides the photo-sensor having higher sensitivity.

Temperature Gradient Method for Alleviating Bonding-Induced Warpage in a High-Precision Capacitive MEMS Accelerometer.

Capacitive MEMS accelerometers with area-variable periodic-electrode displacement transducers found wide applications in disaster monitoring, resource exploration and inertial navigation. The bonding-induced warpage, due to the difference in the coefficients of thermal expansion of the bonded slices, has a negative influence on the precise control of the interelectrode spacing that is essential to the sensitivity of accelerometers. In this work, we propose the theory, simulation and experiment of a method that can alleviate both the stress and the warpage by applying different bonding temperature on the bonded slices. A quasi-zero warpage is achieved experimentally, proving the feasibility of the method. As a benefit of the flat surface, the spacing of the capacitive displacement transducer can be precisely controlled, improving the self-noise of the accelerometer to 6 ng/√Hz @0.07 Hz, which is about two times lower than that of the accelerometer using a uniform-temperature bonding process.

Design, Modeling and Simulation of a Capacitive Size-Discriminating Particulate Matter Sensor for Personal Air Quality Monitoring

We applied the well-established thermophoretic effect to air quality monitoring. We developed a novel method for particulate matter distribution analysis in an in-flow capacitive detection device. The proposed Multiphysics model combines fluid dynamics of particulate matter influenced by thermophoresis with electric field variations in the active volume space of a charged coplanar interdigitated electrodes. The model allows to anticipate the effect of thermophoresis in separating particles of PM10 and PM2.5 size ranges into different streams from a single particle-entrained flow and provides an estimated value of sensitivity for capacitive PM detection. The model is described through the Finite Element Method from the main equations to the simulation run using COMSOL Multiphysics and validated by comparing the results with literature. We obtained high sensor sensitivity of up to 0.48 zF/particle as far as $18~\mu \text{m}$ from coplanar electrode surface using the Computational Fluid Dynamics and Heat Transfer, Electrostatics and Particle tracing modules. We compare results of the simulations for different particle positions, electrode width and inter-electrode spacing, then we use the results to identify optimal design parameters for a novel architecture of a PM detection system with high sensitivity down to PM2.5 single particles and embedded particle size discrimination by using $10~\mu \text{m}$ electrode width and $1\mu \text{m}$ inter-electrode spacing.

Investigation of flow regimes in arc plasma–gas interactions using a two-temperature arc in crossflow model

The perpendicular impingement of a gas stream on an electric arc, a configuration known as the arc in crossflow, is of primary relevance in the study of plasma–gas interactions as well as in industrial applications such as circuit breakers and wire-arc spraying. The flow dynamics in the arc in crossflow are the result of coupled fluid-thermal-electromagnetic phenomena accompanied by large property gradients, which can produce significant deviations from Local Thermodynamic Equilibrium (LTE) among electrons and gas species. These characteristics can lead to the establishment of distinct flow regimes depending on the relative values of the controlling parameters of the system, such as inflow velocity, arc current, and inter-electrode spacing. A two-temperature non-LTE model is used to investigate the arc dynamics and the establishment of flow regimes in the arc in crossflow. The plasma flow model is implemented within a nonlinear Variational Multiscale (VMS) numerical discretization approach that is less dissipative and, hence, better suited to capture unstable behavior than traditional VMS methods commonly used in computational fluid dynamics simulations. The Reynolds and the Enthalpy dimensionless numbers, characterizing the relative flow strength and arc strength, respectively, are chosen as the controlling parameters of the system. Simulation results reveal the onset of dynamic behavior and the establishment of steady, periodic, quasi-periodic, and chaotic or potentially turbulent regimes, as identified by distinct spatiotemporal fluctuations. The computational results reveal the role of increasing the relative arc strength on enhancing flow stability by delaying the growth of fluctuating and unstable flow behavior.

Effect of Accelerated Electrons on the Glow Structure of Nanosecond Diffuse Discharge in the Rod–Plane Air Gap

A diffuse discharge in a rod (cathode)–plane gap with an interelectrode spacing of 10 cm is studied in air at atmospheric pressure. The cathode voltage is 370–390 kV at a pulse FWHM of about 70 ns. It is shown that a pulse-to-pulse variation in delay time of the discharge formation in an interval of 3–15 ns leads to variations in the discharge current and X-ray pulse amplitude in intervals of 100–200 A and 20–250 relative units, respectively. A relationship of the amplitude of the X-ray pulse and structural parameters of the discharge glow is obtained. It is shown that fast electrons with energies of less 30 keV that are accelerated by strong electric field in the vicinity of the cathode play the key role in the formation of the longitudinal structure of glow at relatively large delay times of the discharge formation. Fast electrons ionize peripheral regions of the discharge, increase its cross section, and, hence, provide a decrease in the current density, specific energy deposition, and radiation intensity at a distance from the cathode that corresponds to electron path in air.