Spiral Electrode Research Articles

Soft Human–Machine Interface with Triboelectric Patterns and Archimedes Spiral Electrodes for Enhanced Motion Detection

AbstractThe rapid development of electronic skins has allowed novel multifunctional human–machine interaction interfaces, especially in motion interaction sensors. Although motion sensing is widely used in advanced flexible electronic devices through the integration of single sensing units, the number of electrodes has increased with the increase in integration by the square multiple. This paper presents a self‐powered electronic skin based on the Archimedes spiral structure design, which can detect the multi‐directional movement of the slider without external energy supply. As the rotation angle of the Archimedes spiral increases from 2π to 4π, the maximum resolvable movement direction of the device increases from 24 to 280, and the number of electrodes is kept at 4. Through the exploration of the principle of triboelectricity, the inherent electronegativity of the triboelectric materials is used as the basis for signal discrimination, which not only increases the reliability of the device, but also solves the problem of energy supply during device operation. A reduced number of electrodes and its battery‐free nature enables this electronic skin to be easily integrated into portable electronic devices, such as laptops, smart phones, healthcare devices, etc.

Design and simulation of silicon detector cells with spiral ring electrode structures

Traditional pixel detectors are neatly arranged rectangular or square electrodes that cover almost the entire surface. Large electrode areas lead to high capacitance, and capacitance is the primary factor affecting detector noise. A large noise signal will reduce detector detection performance and the system S/N ratio. We have designed a spiral ring electrode silicon detector cell with n-type silicon bulk and systematically studied its electrical properties, including electric potential distribution, electric field distribution, electron concentration distribution, leakage current, full depletion voltage, and detector capacitance. It has been verified that the spiral ring electrode silicon detector has a smaller capacitance than the traditional detector and a smaller depletion voltage compared with the previously designed structures such as the inner circle broom-shaped structure. At the same time, high position resolution pixel detectors can be made by the array of these detector cells.

REFRACTORY EPILEPSY AND VAGUS NERVE STIMULATION: THE WAY FORWARD

Vagus Nerve Stimulation (VNS) an efficacious neurophysiological modality of treatment for both medically & surgically refractory epilepsy was first implanted in 1988 & later approved by US FDA in 1997. In clinical practice, trains of current are applied intermittently to the left vagus using a pacemaker or AICD like device 'the VNS device'. The device has four components pulse generator, lead, spiral electrodes & a magnet. The pulse generator is implanted beneath left clavicle by a simple surgical method & attached to left vagus nerve via lead & spiral electrodes.[1] The magnet provides an extra edge to control the aura or impending seizure by providing 'On Demand' stimulations. The poor cardiac innervation by left vagus helps to minimize the unwanted or at time dangerous side effects like severe bradycardia, brady arrythmia, or even cardiac asystole.[2]

Identifying Cochlear Implant Channels With Relatively Poor Electrode-Neuron Interfaces Using the Electrically Evoked Compound Action Potential.

The primary objective of this study was to quantify local (within ear) and global (between ear) variation in the cochlear implant (CI) electrode-neuron interface (ENI) using the electrically evoked compound action potential (ECAP). We tested the hypothesis that, within an ear, ECAP measures can be used to identify channels with presumed good and poor ENIs, which may be influenced by a combination of spiral ganglion neuron (SGN) density, electrode position, and cochlear resistivity. We also hypothesized that ECAP responses would reflect age-related differences in the global quality of the ENI between younger and older listeners who theoretically differ in SGN density. Data were obtained from 18 implanted ears (13 individuals) with Advanced Bionics HiRes 90K devices. Six participants (8 ears) were adolescents or young adults (age range: 14-32 years), and 7 participants (10 ears) were older adults (age range: 54-88 years). In each ear, single-channel auditory detection thresholds were measured on channels 2 through 15 in response to a spatially focused electrode configuration (steered quadrupolar; focusing coefficient = 0.9). ECAP amplitudes, amplitude growth function (AGF) slopes, and thresholds were assessed on a subset of channels in each ear in response to three interphase gaps (0, 7, and 30 µs). ECAP peak amplitudes were assessed on all channels between 2 and 15. AGFs and ECAP thresholds were measured on the two nonadjacent channels with the lowest and highest focused behavioral thresholds in each ear. ECAP responses were compared across low- and high-threshold channels and between younger and older CI listeners. Channels that were estimated to interface poorly with the auditory nerve (i.e., high-focused-threshold channels) had steeper ECAP AGF slopes, smaller dynamic ranges, and higher ECAP thresholds than channels with low focused thresholds. Younger listeners had steeper ECAP AGF slopes and larger ECAP peak amplitudes than older listeners. Moreover, younger listeners showed greater interphase gap sensitivity for ECAP amplitude than older listeners. ECAP responses may be used to quantify both local (within ear) and global (between ear) variation in the quality of the ENI. Results of this study support future investigation into the use of ECAP responses in site-selection CI programming strategies. The present results also support a growing body of evidence suggesting that adolescents and young adults with CIs may have denser populations of functional SGNs relative to older adults. Potential differences in global SGN integrity between younger and older listeners warrant investigation of optimal CI programming interventions based on their divergent hearing histories.

A Stretchable Inductor With Integrated Strain Sensing and Wireless Signal Transfer

Objective: A soft and stretchable inductive sensor is presented with the ability to wirelessly transmit large strain measurements without the need for directly connected circuitry. Methods: The sensor is fabricated using a scaffold-removal technique to create microfluidic channels within an elastomer sheet (0.07 MPa modulus), which are injected with a non-toxic liquid metal alloy electrode. An analytical model is derived to predict the static inductance of the sensor while being uniaxially stretched and experimental characterisation of the sensor's dynamic response to axial and biaxial deformation is conducted, as well as wireless measurements within ex-vivo porcine tissue. Results: Experimental validation showed that the sensor's inductance change is linear with uniaxial and biaxial strains up to twice its original length. Strain-rate dependent hysteresis was negligible during slow deformation (<; 5s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> ) and below 10% during more rapid changes in length (15 s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> ). For wireless strain sensing, the variation of inductance in the sensor induced an increase in the transmitting voltage from 3.1 V to 5.7 V for strains up to 83%. While implanted within different layers of porcine tissue, the transmitter voltage linearly increased by 750 mV on average under bending deformation. Conclusion: Large stretching (83%) and bending (8 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> ) deformations in the inherently soft sensor can be wirelessly captured, including through biological tissue. Significance: The wireless sensor's simplified structure, where the antenna and sensor are integrated into a single soft spiral electrode with modulus comparable to biological tissue, means that this novel design shows significant potential for implantable and wearable biomedical devices to monitor dynamic deformation.

Design and Electrochemical Characterization of Spiral Electrochemical Notification Coupled Electrode (SENCE) Platform for Biosensing Application.

C-reactive protein (CRP) is considered to be an important biomarker associated with many diseases. During any physiological inflammation, the level of CRP reaches its peak at 48 h, whereas its half-life is around 19 h. Hence, the detection of low-level CRP is an important task for the prognostic management of diseases like cancer, stress, metabolic disorders, cardiovascular diseases, and so on. There are various techniques available in the market to detect low-level CRP like ELISA, Western blot, etc. An electrochemical biosensor is one of the important miniaturized platforms which provides sensitivity along with ease of operation. The most important element of an electrochemical biosensor platform is the electrode which, upon functionalization with a probe, captures the selective antibody–antigen interaction and produces a digital signal in the form of potential/current. Optimization of the electrode design can increase the sensitivity of the sensor by 5–10-fold. Herein, we come up with a new sensor design called the spiral electrochemical notification coupled electrode (SENCE) where the working electrode (WE) is concentric in nature, which shows better response than the market-available standard screen-printed electrode. The sensor is thoroughly characterized using a standard Ferro/Ferri couple. The sensing performance of the fabricated platform is also characterized by the detection of standard H2O2 using a diffusion-driven technique, and a low detection limit of 15 µM was achieved. Furthermore, we utilized the platform to detect a low level (100 ng/mL) of CRP in synthetic sweat. The manuscript provides emphasis on the design of a sensor that can offer good sensitivity in electrochemical biosensing applications.

Radio frequency powered spiral hollow cathodes

Potential usage of the radio frequency (RF) spiral hollow electrodes in comparison with the compact hollow cathodes was examined for coating and other surface processing treatments. Most properties were found similar to the compact RF hollow cathodes. The non-conventional shapes of spiral hollow cathodes can be suitable for the inner coating in narrow tubes and pipes. Small diameter spiral cathodes can generate focused high-density ion flux capable of rapid etching of the substrate.

Epicardial left ventricular lead implantation in cardiac resynchronization therapy patients via a video-assisted thoracoscopic technique: Long-term outcome.

BackgroundEpicardial placement of the left ventricular (LV) lead via a video‐assisted thoracoscopic (VAT) approach is an alternative to the standard transvenous technique.HypothesisLong‐term safety and efficacy of VAT and transvenous LV lead implantation are comparable. To test it, we reviewed our experience and we compared the outcomes of patients who underwent implantation with the two techniques.MethodsThe VAT procedure is performed under general anesthesia, with oro‐tracheal intubation and right‐sided ventilation, and requires two 5 mm and one 15 mm thoracoscopic ports. After pericardiotomy at the spot of the epicardial target area, pacing measurements are taken and a spiral screw electrode is anchored at the final pacing site. The electrode is then tunneled to the pectoral pocket and connected to the device.Results105 patients were referred to our center for epicardial LV lead implantation. After pre‐operative assessment, 5 patients were excluded because of concomitant conditions precluding surgery. The remaining 100 underwent the procedure. LV lead implantation was successful in all patients (median pacing threshold 0.8 ± 0.5 V, no phrenic nerve stimulation) and cardiac resynchronization therapy was established in all but one patient. The median procedure time was 75 min. During a median follow‐up of 24 months, there were no differences in terms of death, cardiovascular hospitalizations or device‐related complications vs the group of 100 patients who had undergone transvenous implantation. Patients of both groups displayed similar improvements in terms of ventricular reverse remodeling and functional status.ConclusionsOur VAT approach proved safe and effective, and is a viable alternative in the case of failed transvenous LV implantation.

Study of ionic wind based on dielectric barrier discharge of carbon fiber spiral electrode

Based on the idea that a large number of charged particles can be generated by a high-frequency alternating current (AC) dielectric barrier discharge (DBD), and charged particles can be accelerated directionally by a direct current (DC) electric field, a new type of ionic wind formation method is proposed in this paper. To this end, a carbon fiber spiral electrode serves as the generation electrode and a metal rod electrode as the collection electrode, with AC and DC potentials applied respectively to the generation electrode and the collection electrode to form an AC–DC coupled electric field. Under the action of the coupled electric field, a dielectric barrier discharge is formed on the carbon fiber spiral electrode, and the electrons generated by the discharge move from the generation electrode to the collection electrode in the opposite direction of the electric field vectors. During the movement, energy is transferred to the gas molecules by their colliding with neutral gas molecules, thereby forming a directional gas stream movement, i.e. ionic wind. In the research process, it is verified through electric field simulation analysis and discharge experiment that this method can effectively increase the number of charged particles in the discharge process, and the velocity of the ionic wind is nearly doubled. On this basis, the addition of a third electrode forms a distinct discharge region and an electron acceleration region, which further increases its velocity. The experimental result shows that the ionic wind speed reaches up to 2.98 m s−1. Thanks to the ability of the electrode structure to generate an atmospheric pressure DBD plasma and form an ionic wind, we can create a noise-free air purification device without resorting to a fan, with this device having good application prospects in the field of air purification.

Acoustic Vortex Beam Generation by a Piezoelectric Transducer Using Spiral Electrodes**Supported by the National Natural Science Foundation of China under Grant Nos 11772349, 11472299, 51704015, 11972354 and 11972365 and the China Agricultural University Education Foundation under Grant No 1101-240001.

We propose an innovative method to generate acoustic vortex waves based on a disc piezoelectric transducer that is coated with multi-arm coiled electrodes. Finite element simulation results for single-arm to four-arm coiled electrodes indicate that the method could modulate amplitude and phase spatial distribution of the acoustic waves near the acoustic axis by acoustic field synthesis principle, making the waves rotate spirally in space and form stable focused vortex beams. Compared with the traditional method that requires electronic control of an array consisting of a large number of transducers, this method provides a more effective and compact solution.

Optical properties of a liquid-crystal microlens with an arrayed planar non-uniform spiral micro-coil electrode

A new type of liquid-crystal (LC) microlens with an arrayed planar non-uniform spiral micro-coil electrode is proposed. Arrayed cylindrical microbeam focusing and spherical microbeam focusing corresponding to a circular and an elliptical micro-coil are realized, respectively. By applying driving voltage signals over only one electrode plate of the proposed LC microlens, an orderly inclining of LC directors can be achieved in response to the generated electric field, and this is the first time such a method has been proposed to the best of our knowledge. Through adjusting driving voltage signals, the electrically tunable focusing properties are evaluated experimentally. Typical focusing performances such as an arrayed focal line with ${\sim} 1.75\,\,{\rm mm}$∼1.75mm focal length corresponding to a signal voltage of ${\sim}{45.6\,\,{\rm V}_{\rm rms}}$∼45.6Vrms and a focal point with ${\sim} 2.35\,\,{\rm mm}$∼2.35mm focal length corresponding to ${\sim}{55.0\,\,{\rm V}_{\rm rms}}$∼55.0Vrms are given, as well as several typical intermediate states. This research lays a solid basis for continuously developing LC microlens technology.

Experimental Investigation on Rotating Electrochemical Etching of a Micro Spiral Cylindrical Electrode.

To realize the electrochemical etching of a micro spiral cylindrical electrode, a new method of rotating electrochemical etching is proposed, and its process is further studied. First, according to the electrochemical etching principle, the machining mechanism of rotating electrochemical etching of a micro spiral cylindrical electrode is introduced. Second, based on the spiral vortex theory in the Taylor-Couette system, the effect of the high-speed rotating cylindrical microelectrode on its external flow field is analyzed. Third, the effects of rotation direction, rotation speed, machining voltage, and machining time on the thread structure are analyzed by experiments. Finally, a spiral cylindrical microelectrode with good surface thread shape is fabricated within two minutes by using the optimized machining parameters. It is proved that the rotating electrochemical etching method is an easy way to fabricate a micro spiral cylindrical electrode with high efficiency and low cost.

Field test and electrode optimization of electrodynamic cleaning systems for solar panels

AbstractSoiling is the major cause of power loss of photovoltaics (PV) and concentrated solar power (CSP) in desert areas. Electrodynamic cleaning system (EDS) is an automatic and water‐free integrated cleaning system for mirrors or solar panels, which uses pulsed electric fields to remove dust off their surface. The first EDS field test over a long period on PV modules is reported here and shows a clear effect on soiling reduction in real conditions in Saudi Arabia. A total of 458 days of measurements is analyzed, and depending on the considered periods, performance losses due to soiling (soiling rate) can vary from −0.06%/day to −0.41%/day for a reference module, while the relative soiling rate reduction using an EDS can be up to 95.7% with an average of 32.1%. Cost calculations demonstrate an added value of the modules equipped with the EDS between 2.6 and 5.2 ¢/Wp compared with usual cleaning system, which is nearly between 10% and 20% of the module price.In addition, extended indoor tests of various electrode designs of EDS for heliostat dedicated to CSP or PV applications show a high cleaning efficiency of up to 98% with front glass thickness of more than 1 mm. A good specular reflectivity, only 4% lower than the bare reference mirror, is obtained with patterned sputtered silver in a spiral electrode design. High reliability of two types of electrode deposition is demonstrated after 200 cycles between −40°C and +85°C.

Triboelectric proximity and contact detection using soft planar spiral electrodes

In this study, planar spiral electrodes for triboelectric contact and proximity detection are investigated. The spiral electrodes are created using liquid metal in a soft elastomer in order to make the sensor flexible and stretchable. When the metallic object to be detected comes in contact with the silicon elastomer surrounding the electrodes, charge transfer occurs, and this can be utilized for contact and noncontact sensing of the metallic object in flat or curved geometries. An equivalent electrical circuit model for the noncontact system is proposed and found to be in good agreement with the experimental data. A comparison between triboelectric proximity detection and eddy current resonance frequency proximity detection, using the same electrode geometry, shows that the two methods have comparable sensitivity. An added advantage of the triboelectric system is that it transforms mechanical into electrical energy and thereby allows one to monitor the triboelectrical signal upon impact of a metal object, and the experimental data show that the generated current scales with the impact force.

Analysis on Machining Performance of Nickel-Base Superalloy by Electrochemical Micro-milling with High-Speed Spiral Electrode

As one of the most promising micro-machining methods, electrochemical micro-machining is widely used in the field of metal micro-structures. The electrochemical micro-milling on Nickel-base superalloy by using high-speed spiral electrode was studied in detail. Firstly, the electric field and flow field models of micro-electrochemical milling are established and analyzed by the finite element method. Then, the milling profile was predicted and the effect of high-speed rotation of electrodes on electrolyte promotion and secondary electrolysis prevention were analyzed. Secondly, the influence of the main machining parameters, such as rotating speed, electrical parameters, and feed rate on machining precision and efficiency was analyzed experimentally. Finally, by optimizing the machining parameters, a series of micro-graphic structures with a width of about 150 μm were obtained on Nickel-base superalloy 718 by using the spiral electrode with a diameter of 100 μm. The experimental and simulation results show that the high-speed rotation of electrodes can greatly improve the machining efficiency and stability. It was proved that micro-electrochemical milling with the high-speed rotating electrode technique is an effective method for machining micro-metal parts.

The formation of ultrafine polyamide 6 nanofiber membranes with needleless electrospinning for air filtration

Particulate matter (PM) is a major air pollutant, which has a significant impact on public health. Filtration of PM through filters is a common method to protect the environment. However, the effective removal of PM with conventional filters still remains a challenge because of its small sizes. Here, we reported the formation of ultrafine polyamide 6 (PA‐6) nanofiber membranes formed with needleless electrospinning, in which both relative humidity condition and electrode type were included in the discussion. The PA‐6S nanofibers formed by using spiral electrode as a spinneret at 60% RH had the diameter of 33 nm, while the PA‐6C nanofibers formed by using cylindrical electrode had the diameter of 120 nm. With the integration of fine diameter, small pore size, and high porosity, the resultant PA‐6S nanofiber membrane exhibits high filtration efficiency of 99.42% and low pressure drop of 85.5 Pa under a face velocity of 85 L/min. Besides, it took only 10 minutes to reduce the concentration of PM2.5 from 999 to 34.1 μg/m3 when used to filter real PM particles.

Picosecond laser-direct fabrication of graphene-based electrodes for a gas sensor module with wireless circuits

This paper proposes an ultrafast-laser process for ablating multilayer graphene film to form the conductive electrodes for a gas sensor module with wireless circuits. In this study, a picosecond laser source was directly used to perform double scanning for precisely fabricating the spiral electrode pattern as the sensing test region. The ablated surface of multilayer graphene structures fabricated using sufficiently strong pulses with a pulse width of 7 ps and a wavelength of 532 nm was investigated through scanning electron microscopy. The graphene-based electrode was integrated with wireless circuits to form a gas sensor module. The relationship between the spiral electrode design and sensitivity to gas detection was analyzed. Electrical detection of gas was studied by employing different electrode designs, and change in the detection limit at room temperature with change in resistance was examined. Furthermore, the role of graphene-based devices comprising spiral electrodes fabricated using the laser process and integrated with wireless circuits to form a module in gas detection was analyzed.

Synthesis of polyvinyl acetate (PVAc) fibers using needleless electrospinning technique with straight wire electrode

Low production rate has become a major problem for conventional electrospinning method that uses a needle as the single route for the ejected solution. Multi-needles have then been employed to overcome the problem, but there is a primary problem in its process. The needleless electrospinning method can be used to make nanofiber. There are several types of electrodes on needleless electrospinning methods, such as the cylinder, spiral and wire electrodes. In this research, the straight wire electrode was utilized to synthesize polyvinyl acetate (PVAc) fibers. Several process parameters were varied such as polymer solution concentration, voltage, and wire-collector distance. The results have shown that polymer solution concentration and wire-collector distance affected the fibers morphology, while the voltage did not significantly affect a diameter of fibers. The higher the polymer solution concentration, the average diameter of fibers became bigger. On the other hand, the average diameter of fibers decreased with increasing the wire-collector distance.

Simulation and experimental investigation on micro electrochemical drilling of micro-holes with ultra short pulse voltage

This paper introduces an electrochemical drilling process which is efficient in fabricating micro-holes, in order to study the influences of ultra short pulse voltage and high speed spiral micro electrode on the machining accuracy and machining efficiency of micro electrochemical drilling, the simulation of the gap electric field and the gap flow field are carried out. Firstly, the model of ultra short pulse gap electric field was established, by simulating the process of the drilling, the shape change of the anode workpiece surface was analysed and predicted with the ultra short pulse voltage. The results show that the ultra short pulse voltage can greatly improve the machining accuracy. Secondly, by using CFX to simulate the gap flow field, with the increase of the electrode rotating speed, the gas film generated with good insulation effect can greatly reduce the taper of the micro-holes. Finally, the simulation results above were verified by the experiments, a series of micro-holes was fabricated successfully; the diameter of the micro-holes was less than 200 μm, which proved that the micro electrochemical drilling for fabricating micro-holes has a widespread application prospect. [Submitted 3 November 2016; Accepted 5 December 2017]

Simulation and experimental investigation on micro electrochemical drilling of micro-holes with ultra short pulse voltage

This paper introduces an electrochemical drilling process which is efficient in fabricating micro-holes, in order to study the influences of ultra short pulse voltage and high speed spiral micro electrode on the machining accuracy and machining efficiency of micro electrochemical drilling, the simulation of the gap electric field and the gap flow field are carried out. Firstly, the model of ultra short pulse gap electric field was established, by simulating the process of the drilling, the shape change of the anode workpiece surface was analysed and predicted with the ultra short pulse voltage. The results show that the ultra short pulse voltage can greatly improve the machining accuracy. Secondly, by using CFX to simulate the gap flow field, with the increase of the electrode rotating speed, the gas film generated with good insulation effect can greatly reduce the taper of the micro-holes. Finally, the simulation results above were verified by the experiments, a series of micro-holes was fabricated successfully; the diameter of the micro-holes was less than 200 μm, which proved that the micro electrochemical drilling for fabricating micro-holes has a widespread application prospect. [Submitted 3 November 2016; Accepted 5 December 2017]