Thread Electrode Research Articles

The effects of inner electrode shape on the performance of dielectric barrier discharge reactor for oxidative removal of NO and SO2

Seagoing vessels are responsible for more than 90% of global freight traffic, but meanwhile, emission pollutants (NO x and SO x ) of seagoing vessels also cause serious air pollution. Nonthermal plasma (NTP) combined with wet scrubbing technology is considered to be a promising technology. In order to improve the oxidation efficiency and energy efficiency of the NTP reactor, the screw and rod inner electrodes of dielectric barrier discharge (DBD) reactor were investigated. To analyze the mechanism, the optical emission spectra (OES) of NTP were measured and numerical calculation was applied. The experiment results show that the NO oxidation removal efficiency of screw electrode is lower than that of rod electrode. However, the SO2 removal efficiency of screw electrode is higher. According to the OES experiment and numerical calculation, the electric field intensity of the screw electrode surface is much higher than that of the rod electrode surface, and it is easier to generate N radicals to form NO. For the same energy density condition, the OH radical generation efficiency of the screw electrode reactor is similar to that of the rod electrode, but the gas temperature in the discharge gap is higher. Therefore, the SO2 oxidation efficiency of the thread electrode is higher. This study provides guidance for the optimization of oxidation efficiency and energy consumption of DBD reactor.

Modified Ultra Micro-Carbon Electrode for Efficient Ammonia Sensing for Water Quality Assessment.

Ammonia is one of the most prominent and hazardous water pollutants; hence its selective and sensitive detection in water is crucial for monitoring water quality and determining its usability. In the present work, a simple, cost-effective electrochemical sensor for the detection of ammonia is presented. Multi-walled carbon nanotubes modified ultra-micro-carbon thread electrode (UME/MWCNT) has been realized. The electro-catalytic activity of ammonia is studied by voltammetry and amperometry techniques and the results are presented. The microscopic characterization of UME/MWCNT for surface morphology analysis was also carried out. Further, the UME/MWCNT based electrochemical sensor was tested for its practical application by exploring various parameters like the effect of scan rate, pH and interference from co-existing bio-chemicals like nitrate, nitrite, phosphate, hydrazine, H2 [Formula: see text] uric acid, ascorbic acid and dopamine along with real sample analysis. The developed sensor can efficiently detect ammonia in a linear range of [Formula: see text] to 1 mM which is well within the permissible safe drinking water limit. The limit of detection (LoD) and limit of quantification (LoQ) obtained for the developed sensor were [Formula: see text] and [Formula: see text] respectively. The negligible interference, good reproducibility, and appreciable recovery values indicated the potential of the developed UME for real-time ammonia detection. As a flexible electrode, UME can be further modified and fabricated as a microfluidic or a miniaturized device for a portable electrochemical sensing platform in future.

Flexible polyamide-based dental floss sensor for pH monitoring

• Use of polyamide-based dental flosses as novel sensing material. • Silver plated polyamide conductive thread electrodes as working and counter electrodes. • EIS in the frequency range from 1 Hz to 100 kHz to detect pH change. • Linear trend between pH change and resistance at 1 kHz. In the present work, we present a novel resistive pH sensor prototype comprising of disposable polyamide-based dental flosses which act as a sensing layer connected to the conductive silver-plated polyamide thread-based electrodes. Without a reference electrode, the prepared dental floss-based sensor was able to detect the pH change of different buffer media by analyzing the variation in the electrical resistance using electrochemical impedance spectroscopy in 1 Hz-100 kHz frequency range. Utilizing dental flosses and thread-based electrode set up, fabricated sensor offers a miniaturized, flexible and promising pH sensing interface suitable for developing implantable and wearable devices for in-vivo applications to ensure oral health.

Energy Yield and Removal Efficiency of NO x Curtailment Process With High Voltage Pulse Powered DBD Electrode Configurations

Experimental investigation on the NO_<i>x</i> removal efficiency and energy yield (EY) of eight dielectric barrier discharge (DBD) reactor configurations is done in this work. A high voltage pulsed power supply developed in the laboratory is used to generate nonthermal plasma (NTP) in the reactors with eight types of electrodes varying in shape and dimensions. Simulated NO_<i>x</i> gas with a concentration of 350 ppm is passed at a flow rate of 8 l/min through the reactors. Different pulse voltage amplitude and repetition rate are applied to the reactors for generating NTP in the confined airgap. Gas concentrations at the inlet and outlet, applied voltage, and voltage across the monitoring capacitance were measured at each of these operating points. Corresponding discharge power, specific energy density (SED), NO_<i>x</i> removal efficiency, and EY were calculated. NTP treatment without any catalysts/adsorbents attained NO_<i>x</i> removal efficiency of 95&#x0025; and above using screw thread electrode, 5 mm rod electrode, pipe electrode and coiled wire electrode configurations. But considering the discharge power, SED, and hence the EY of the process, DBDs with pipe electrode and wire electrode were found to be effective with lower energy consumption. Based on this observation, the selection of appropriate DBD configuration and electrical input parameters can be made according to the intended EY for a specific process.

Driver Status Monitoring System with Body Channel Communication Technique Using Conductive Thread Electrodes

Driver Status Monitoring System with Body Channel Communication Technique Using Conductive Thread Electrodes

Thread‐Based Wristwatch Sensing Device for Noninvasive and Simultaneous Detection of Glucose and Lactate

AbstractAn electrochemical sensing device based on a cotton‐thread electrode for real‐time and simultaneous detection of sweat glucose and sweat lactate is reported. The cotton thread surfaces are simply modified by cellulose nanofibers/carbon nanotube ink‐Prussian blue/chitosan to enhance liquid adsorption, bioreceptor immobilization, and sensor performance in addition to minimize potential irritation and allergies on the wearer's skin. The modified thread surfaces are characterized by laser scanning confocal microscopy, scanning electron microscopy, and Fourier transform Raman spectroscopy. Amperometry is carried out via hydrogen peroxide detection for electrochemical characterization of the modified thread electrodes. A circuit and digital readout of this wearable sensor are customized designed to be integrated with thread electrodes for real‐time and simultaneous detection of sweat glucose and sweat lactate. The wristwatch sensing device provides a linear range of 0.025–3 × 10−3 m with a detection limit of 0.025 × 10−3 m for glucose and a linear range of 0.25–35 × 10−3 m with a detection limit of 0.25 × 10−3 m for lactate. This device can effectively determine the cut‐off levels of both glucose and lactate, which can distinguish between a normal individual and one with a diabetic condition. This platform opens a new avenue for noninvasive and real‐time detection of other sweat biomarkers.

Non-invasive electrochemical immunosensor for sweat cortisol based on L-cys/AuNPs/ MXene modified thread electrode

Thread-based electrochemical immunosensor is fabricated for non-invasive detection of cortisol in sweat by immobilization of anti-cortisol on L-cys/AuNPs/MXene modified conductive thread electrode. MXene and AuNPs increase the surface area of conductive thread electrode and facilitate anti-cortisol immobilization leading to enhanced sensor sensitivity. Anti-cortisol is immobilized on L-cys/AuNPs/MXene modified electrode by using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysulfosuccinimide coupling agents. The electrochemical detection of cortisol is based on the decrease of oxidation current towards the antigen-antibody binding interaction owing to blocking of electron transfer process by cortisol. Under the optimal conditions, this immunosensor offers high sensitivity, a wide linearity of 5–180 ng mL−1 and a detection limit of 0.54 ng mL−1 with negligible effect from interferences. Furthermore, this immunosensor provides high reproducibility and long-term storage stability (≥6 weeks). Ultimately, this system is successfully applied for the detection of cortisol in artificial sweat with satisfactory results. Hence, this platform might be suitable to apply as a wearable electrochemical sensor for sweat cortisol by integrating on a wristband.

A Low-Voltage Dielectrophoretic System Using Thread Based Electrodes for Cell Viability Assessment

We present a disposable low-voltage thread-based electrode system that can differentiate live and dead Saccharomyces cerevisiae cells via field-induced assembly. Our system consists of a silver nanoparticle based conductive thread electrodes embedded in a rubber o-ring. The three-dimensional conductive thread with high aspect ratios were found to facilitate high electric field regions at low voltages. Rapid assembly of biological cells into highly ordered pearl chains was observed at voltages as low as 4V.Thread based devices create DEP forces that are larger by two orders of magnitude for the same applied voltage when compared to most microfluidic e-DEP designs in literature, which rely on planar electrodes to produce the DEP forces. Numerical simulations of electric field intensity in the device using a representative thread geometry also confirmed our experimental findings. The dead cells probed at a voltage of 4V @2.5 MHz was found to aggregate in low electric field regions. The percentage of live and dead cells are estimated using an image recognition algorithm that analyze cells that are viable in a given sample within 60 seconds. The area occupied by the dead-cell aggregate is a direct indicator of cell viability.We are currently exploring the possibilities of three-dimensional assembly of microparticles for point-of-care applications. Figure 1

Electroanalytical Paper-Based Nucleic Acid Amplification Biosensors with Integrated Thread Electrodes.

Nucleic acid amplification tests (NAATs) are very sensitive and specific methods, but they mainly rely on centralized laboratories and therefore are not suitable for point-of-care testing. Here, we present a 3D microfluidic paper-based electrochemical NAAT. These devices use off-the-shelf gold plasma-coated threads to integrate electroanalytical readouts using ex situ self-assembled monolayer formation on the threads prior to assembling into the paper device. They further include a sandwich hybridization assay with sample incubation, rinsing, and detection steps all integrated using movable stacks of filter papers to allow time-sequenced reactions. The devices use glass fiber substrates for storing recombinase polymerase amplification reagents and conducting the isothermal amplification. We used the paper-based device for the detection of the toxic microalgae Ostreopsis cf. ovata. The NAAT, completed in 95 min, attained a limit of detection of 0.06 pM target synthetic DNA and was able to detect 1 ng/μL O. cf. ovata genomic DNA with negligible cross-reactivity from a closely related microalgae species. We think that the integration of thread electrodes within paper-based devices paves the way for digital one-time use NAATs and numerous other advanced electroanalytical paper- or textile-based devices.

Flexible cotton-AuNP thread electrode for non-enzymatic sensor of uric acid in urine

We report on the development of an electrochemical sensor platform based on modified cotton fibers for the non-enzymatic detection of uric acid (UA), an important biomarker for gout disease. To create the flexible electrode, a cotton thread was coated with carbon ink as a pre-conductive layer prior to direct electrodeposition of AuNPs. Then, differential pulse voltammetry (DPV) was used to evaluate the sensor performances, and a linear detection range between 10 µM and 5.0 mM of uric acid was obtained. The sensor has a detection limit of 0.12 µM, which is sufficient for use in the patients suffering from gout disease which uric acid is higher than 4.46 mM. Furthermore, we found that the detection sensitivity of the platform was not affected by the presence of other physiological compounds present in human urine. The described platform has the potential for integration in a diaper hence enabling rapid detection and screening for gout disease.Graphic abstract

Sensorized tissue analogues enabled by a 3D-printed conductive organogel

State-of-the-art tissue analogues used in high-fidelity, hands-on medical simulation modules can deliver lifelike appearance and feel but lack the capability to provide quantified, real-time assessment of practitioner performance. The monolithic fabrication of hybrid printed/textile piezoresistive strain sensors in a realistic Y/V plasty suture training pad is demonstrated. A class of 3D-printable organogels comprised of inexpensive and nonhazardous feedstocks is used as the sensing medium, and conductive composite threads are used as the electrodes. These organogels are comprised of a glycol-based deep-eutectic solvent (DES) serving as the ionic conductor and 3-trimethoxysilylmethacrylate-capped fumed silica particles serving as the gelating agent. Rheology measurements reveal the influence of fumed silica particle capping group on the mixture rheology. Freestanding strain sensors demonstrate a maximum strain amplitude of 300%, negligible signal drift, a monotonic sensor response, a low degree of hysteresis, and excellent cyclic stability. The increased contact resistance of the conductive thread electrodes used in place of wire electrodes do not make a significant impact on sensor performance. This work showcases the potential of these organogels utilized in sensorized tissue analogues and freestanding strain sensors for widespread applications in medical simulation and education.

Au-catalyzed electrochemical oxidation of alcohols using an electrochemical column flow cell

A novel green system for the electrochemical oxidation of alcohols is demonstrated using a column flow cell. Voltammetric analysis revealed that the oxidation of 1-phenylethanol and benzaldehyde are promoted by using both an Au-electrode and an alkaline medium. To conduct such reaction with a column flow cell, we developed a method to modify a carbon-fiber thread with Au nanoparticles. The column carbon-fiber thread electrode modified with Au nanoparticles showed a high surface area, enabling the efficient electrochemical oxidation of various alcohols.

Byproducts Generation Characteristics of Non-thermal Plasma for NO Conversion: Effect of Reaction Conditions

Over the years, the combined Non-thermal Plasma (NTP) denitrification process which is used for decomposition of NOx has have become an application technology with great potential. And the formation of byproducts, such as N2O and O3, which is an important factor that interfere with NO removal efficiency, has a high research value. In present study, HZSM-5 molecular sieve was selected as the packed material in dielectric barrier discharge reactor to investigate the effect of reaction conditions, such as with/without packed bed, discharge power, inner electrode diameter, electrode shape and operation time, on formation and conversion characteristics of byproducts (N2O and O3). Results showed that the presence of HZSM-5 pellets in discharge zone increases the discharge power, NO removal efficiency and the concentration of the byproducts in the outlet. The optimization of electrode diameter and the utilization of screw thread electrode increased the NO removal efficiency and the yield of N2O and O3. The pellets temperature increases with the operation time and the enhancement of input energy, which has different effects on O3 and N2O. These results provide some new methods for improving the NTP-assisted catalytic denitrification process.

Highly self-healable and flexible cable-type pH sensors for real-time monitoring of human fluids

Development of sensing technology with wearable chemical sensors is realizing non-invasive, real-time monitoring healthcare and disease diagnostics. The advanced sensor devices should be compact and portable for use in limited space, easy to wear on human body, and low-cost for personalized healthcare markets. Here, we report a highly sensitive, flexible, and autonomously self-healable pH sensor cable developed by weaving together two carbon fiber thread electrodes coated with mechanically robust self-healing polymers. The pH sensor cable showed excellent electrochemical performances of sensitivity, repeatability, and durability. Spontaneous and autonomous sensor healing efficiency of the pH sensor cable was demonstrated by measuring sensitivity during four cycles of cutting and healing process. The pH sensor cable could measure pH in small volumes of real human fluid samples, including urine, saliva, and sweat, and the results were similar to those of a commercial pH meter. Taken together, successful real-time pH monitoring for human sweat was demonstrated by fabricating a wearable sensing system in which the pH sensor cable was knitted into a headband integrated with wireless electronics.

Learning the signatures of the human grasp using a scalable tactile glove.

Humans can feel, weigh and grasp diverse objects, and simultaneously infer their material properties while applying the right amount of force-a challenging set of tasks for a modern robot1. Mechanoreceptor networks that provide sensory feedback and enable the dexterity of the human grasp2 remain difficult to replicate in robots. Whereas computer-vision-based robot grasping strategies3-5 have progressed substantially with the abundance of visual data and emerging machine-learning tools, there are as yet no equivalent sensing platforms and large-scale datasets with which to probe the use of the tactile information that humans rely on when grasping objects. Studying the mechanics of how humans grasp objects will complement vision-based robotic object handling. Importantly, the inability to record and analyse tactile signals currently limits our understanding of the role of tactile information in the human grasp itself-for example, how tactile maps are used to identify objects and infer their properties is unknown6. Here we use a scalable tactile glove and deep convolutional neural networks to show that sensors uniformly distributed over the hand can be used to identify individual objects, estimate their weight and explore the typical tactile patterns that emerge while grasping objects. The sensor array (548 sensors) is assembled on a knitted glove, and consists of a piezoresistive film connected by a network of conductive thread electrodes that are passively probed. Using a low-cost (about US$10) scalable tactile glove sensor array, we record a large-scale tactile dataset with 135,000 frames, each covering the full hand, while interacting with 26 different objects. This set of interactions with different objects reveals the key correspondences between different regions of a human hand while it is manipulating objects. Insights from the tactile signatures of the human grasp-through the lens of an artificial analogue of the natural mechanoreceptor network-can thus aid the future design of prosthetics7, robot grasping tools and human-robot interactions1,8-10.

Wearable woven supercapacitor fabrics with high energy density and load-bearing capability

Flexible power sources with load bearing capability are attractive for modern wearable electronics. Here, free-standing supercapacitor fabrics that can store high electrical energy and sustain large mechanical loads are directly woven to be compatible with flexible systems. The prototype with reduced package weight/volume provides an impressive energy density of 2.58 mWh g−1 or 3.6 mWh cm−3, high tensile strength of over 1000 MPa, and bearable pressure of over 100 MPa. The nanoporous thread electrodes are prepared by the activation of commercial carbon fibers to have three-orders of magnitude increase in the specific surface area and 86% retention of the original strength. The novel device configuration woven by solid electrolyte-coated threads shows excellent flexibility and stability during repeated mechanical bending tests. A supercapacitor watchstrap is used to power a liquid crystal display as an example of load-bearing power sources with various form-factor designs for wearable electronics.

Carbon Nanotube Thread Electrochemical Cell: Detection of Heavy Metals.

In this work, all three electrodes in an electrochemical cell were fabricated based on carbon nanotube (CNT) thread. CNT thread partially insulated with a thin polystyrene coating to define the microelectrode area was used as the working electrode; bare CNT thread was used as the auxiliary electrode; and a micro quasi-reference electrode was fabricated by electroplating CNT thread with Ag and then anodizing it in chloride solution to form a layer of AgCl. The Ag|AgCl coated CNT thread electrode provided a stable potential comparable to the conventional liquid-junction type Ag|AgCl reference electrode. The CNT thread auxiliary electrode provided a stable current, which is comparable to a Pt wire auxiliary electrode. This all-CNT thread three electrode cell has been evaluated as a microsensor for the simultaneous determination of trace levels of heavy metal ions by anodic stripping voltammetry (ASV). Hg2+, Cu2+, and Pb2+ were used as a representative system for this study. The calculated detection limits (based on the 3σ method) with a 120 s deposition time are 1.05, 0.53, and 0.57 nM for Hg2+, Cu2+, and Pb2+, respectively. These electrodes significantly reduce the dimensions of the conventional three electrode electrochemical cell to the microscale.

Identification of myoelectric signals of pregnant rat uterus: new method to detect myometrial contraction.

AimTo develop an electromyography method for pregnant rat uterus in vivo and to separate myometrial signals from the gastrointestinal tract signals.MethodsPregnant Sprague-Dawley rats (n = 8) were anaesthetized and their stomach, small intestine, and large intestine were removed from the abdomen. A pair of thread electrodes was inserted into the uterus, while a pair of disk electrodes was placed subcutaneously above the myometrium. Additionally, a strain gauge sensor was fixed on the surface of the myometrium and cecum for the parallel detection of mechanical contractions in rats (n = 18) with intact gastrointestinal tract. The filtered electric signals were amplified and recorded by an online computer system and analyzed by fast Fourier transformation. The frequency of the electric activity was characterized by cycle per minute (cpm), the magnitude of the activity was described as power spectrum density maximum (PsDmax).ResultsThe frequency of the pregnant uterine activity was 1-3 cpm, which falls within the same range as that of cecum. Measuring by both electrodes, oxytocin (1 µg/kg) increased and terbutaline (50 µg/kg) decreased the PsDmax by 25%-50% (P < 0.001) and 25%-40% (P < 0.01), respectively. We found a strong positive correlation between the alterations of PsDmax values and the strain gauge sensor-detected mechanical contractions (area under curve). The GI specific compounds (neostigmine, atropine) mainly affected the cecal activity, while myometrium specific drugs (oxytocin, terbutaline) influenced the myometrial signals only.ConclusionOur method proved to be able to detect the myoelectric activity that reflects the mechanical contraction. The overlapping myometrial and cecal signals are not separable, but they can be distinguished based on the much higher activity and different pharmacological reactivity of the pregnant uterus. Thus, the early signs of contractions can be detected and labor may be predicted in a fast and sensitive way.

Evaluation of Bismuth Modified Carbon Thread Electrode for Simultaneous and Highly Sensitive Cd (II) and Pb (II) Determination

AbstractBismuth film modified and chemically activated carbon micro‐thread electrodes were investigated for the simultaneous determination of Cd(II) and Pb(II) using square wave anodic stripping voltammetry. The carbon thread electrode was characterised using both surface and electrochemical techniques. Electrochemical impedance spectroscopy (EIS) studies demonstrated that the H2SO4/IPA‐treated carbon thread electrode showed a much improved resistance response (Rct=23 Ω) compared to the IPA‐untreated carbon thread (Rct=8317 Ω). Furthermore, parameters such as the effect of deposition potential, deposition time and Bi(III) concentration were explored using square wave voltammetry. Detection limits (S/N=3) for Cd(II) and Pb(II) were found to be 1.08 µg L−1 and 0.87 µg L−1, respectively and response was found to be linear over the range 5–110 µg L−1. The proposed Bi/IPA‐treated carbon thread electrode exhibited a high selectivity towards Cd(II) and Pb(II) even in the presence of a range of heavy metals and is capable of repetitive and reproducible measurements, being attributed to the high surface area, geometry and electrode treatment characteristics. The proposed metal ion sensor was employed to determine cadmium and lead in river water samples and % RSD was found to be 5.46 % and 5.93 % for Cd(II) and Pb(II) respectively (n=3). Such facile sensing components favour the development of cost effective portable devices for environmental sample analysis and electrochemical applications.

Platinum black electrodeposited thread based electrodes for dielectrophoretic assembly of microparticles.

We report dielectrophoretic (DEP) assembly of biological cells and microparticles using platinum-black electrodeposited conductive textile fiber. The three-dimensional conductive structures with high aspect ratios were found to facilitate high electric field regions, as revealed by scanning electron microscope characterization. The effective conducting area (Aeff) and its stability of thread electrodes were estimated using electrochemical methods. Potential of platinum black electrodeposited thread as 3-D electrodes for creating high gradient electrical field for dielectrophoretic assembly of microspheres and Saccharomyces cerevisiae (yeast cells) into 1D and two-dimensional structures over long ranges under the application of low voltages (4-10 Vpp) has been demonstrated. The formation of highly ordered pearl chains of microparticles using thread electrodes when subjected to dielectrophoresis (DEP) has been discussed in detail.