scholarly journals Estimating the Volume of Unknown Inclusions in an Electrically Conducting Body with Voltage Measurements

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 637 ◽  
Author(s):  
Antonio Affanni ◽  
Ruben Specogna ◽  
Francesco Trevisan
Keyword(s):  
Current Density ◽  
Low Cost ◽  
Region Of Interest ◽  
Density Field ◽  
Impedance Tomography ◽  
Electrically Conducting ◽  
Conducting Body ◽  
Micro Channels ◽  
Blood Clots ◽  
A Current

We propose a novel technique to estimate the total volume of unknown insulating inclusions in an electrically conducting body from voltage measurements. Unlike conventional Electrical Impedance Tomography (EIT) systems that usually exhibit low spatial resolution and accuracy, the proposed device is composed of a pair of driving electrodes which, supplied with a known sinusoidal voltage, create a current density field inside a region of interest. The electrodes are designed to generate a current density field in the region of interest that is uniform, to a good approximation, when the inclusions are not present. A set of electrodes with a polygonal geometry is used for four-wires resistance measurements. The proposed technique has been tested designing a low cost prototype, where all electrodes are on the bottom of the conducting body, showing good performances. Such a device may be used to monitor the volume of biological cells inside cell culture dishes or the volume of blood clots in micro-channels in lab-on-a-chip biosensors.

scholarly journals A Ni(OH)2 nanopetals network for high-performance supercapacitors synthesized by immersing Ni nanofoam in water

2019 ◽  
Vol 10 ◽  
pp. 281-293 ◽  
Author(s):  
Donghui Zheng ◽  
Man Li ◽  
Yongyan Li ◽  
Chunling Qin ◽  
Yichao Wang ◽  
...  
Keyword(s):  
Power Density ◽  
Current Density ◽  
High Performance ◽  
Low Cost ◽  
Electrode Reaction ◽  
Commercial Application ◽  
Ion Diffusion ◽  
Symmetric Supercapacitor ◽  
Red Led ◽  
A Current

Developing a facile and environmentally friendly approach to the synthesis of nanostructured Ni(OH)2 electrodes for high-performance supercapacitor applications is a great challenge. In this work, we report an extremely simple route to prepare a Ni(OH)2 nanopetals network by immersing Ni nanofoam in water. A binder-free composite electrode, consisting of Ni(OH)2 nanopetals network, Ni nanofoam interlayer and Ni-based metallic glass matrix (Ni(OH)2/Ni-NF/MG) with sandwich structure and good flexibility, was designed and finally achieved. Microstructure and morphology of the Ni(OH)2 nanopetals were characterized. It is found that the Ni(OH)2 nanopetals interweave with each other and grow vertically on the surface of Ni nanofoam to form an “ion reservoir”, which facilitates the ion diffusion in the electrode reaction. Electrochemical measurements show that the Ni(OH)2/Ni-NF/MG electrode, after immersion in water for seven days, reveals a high volumetric capacitance of 966.4 F/cm3 at a current density of 0.5 A/cm3. The electrode immersed for five days exhibits an excellent cycling stability (83.7% of the initial capacity after 3000 cycles at a current density of 1 A/cm3). Furthermore, symmetric supercapacitor (SC) devices were assembled using ribbons immersed for seven days and showed a maximum volumetric energy density of ca. 32.7 mWh/cm3 at a power density of 0.8 W/cm3, and of 13.7 mWh/cm3 when the power density was increased to 2 W/cm3. The fully charged SC devices could light up a red LED. The work provides a new idea for the synthesis of nanostructured Ni(OH)2 by a simple approach and ultra-low cost, which largely extends the prospect of commercial application in flexible or wearable devices.

scholarly journals Low-cost CoFe2O4/biomass carbon hybrid from metal-enriched sulfate reducing bacteria as an electrocatalyst for water oxidation

RSC Advances ◽  
2018 ◽  
Vol 8 (40) ◽  
pp. 22799-22805 ◽  
Author(s):  
Songhu Bi ◽  
Jingde Li ◽  
Qin Zhong ◽  
Chuntan Chen ◽  
Qiyi Zhang ◽  
...  
Keyword(s):  
Current Density ◽  
Water Oxidation ◽  
Low Cost ◽  
Sulfate Reducing Bacteria ◽  
Biomass Carbon ◽  
Tafel Slope ◽  
Sulfate Reducing ◽  
Reducing Bacteria ◽  
A Current

A low-cost CoFe2O4/biomass carbon (CFO@BC/Zn) hybrid from Co-enriched Sulfate Reducing Bacteria (Co-SRB) as an electrocatalyst for OER. The electrocatalyst exhibits a low potential of 1.53 V at a current density 10 mA cm−2 and Tafel slope of 86 mV dec−1.

scholarly journals Bimetallic Co-Based (CoM, M = Mo, Fe, Mn) Coatings for High-Efficiency Water Splitting

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 92
Author(s):  
Jadranka Milikić ◽  
Aldona Balčiūnaitė ◽  
Zita Sukackienė ◽  
Dušan Mladenović ◽  
Diogo M. F. Santos ◽  
...  
Keyword(s):  
Current Density ◽  
Potassium Hydroxide ◽  
Electroless Deposition ◽  
High Efficiency ◽  
Low Cost ◽  
Copper Substrate ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Current ◽  
Scanning Electron

Bimetallic cobalt (Co)-based coatings were prepared by a facile, fast, and low-cost electroless deposition on a copper substrate (CoFe, CoMn, CoMo) and characterized by scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray diffraction analysis. Prepared coatings were thoroughly examined for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline solution (1 M potassium hydroxide, KOH) and their activity compared to that of Co and Ni coatings. All five coatings showed activity for both reactions, where CoMo and Co showed the highest activity for HER and OER, respectively. Namely, the highest HER current density was recorded at CoMo coating with low overpotential (61 mV) to reach a current density of 10 mA·cm−2. The highest OER current density was recorded at Co coating with a low Tafel slope of 60 mV·dec−1. Furthermore, these coatings proved to be stable under HER and OER polarization conditions.

scholarly journals Development and evaluation of a low cost 8-electrode Electrical Impedance Tomography system

2021 ◽  
Vol 2008 (1) ◽  
pp. 012002
Author(s):  
C E Castillo ◽  
A E Álvarez
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Imaging Modality ◽  
Low Cost ◽  
Region Of Interest ◽  
Electrical Current ◽  
Maximum Error ◽  
Impedance Tomography ◽  
Homogeneous Test ◽  
Electrical Properties Of Tissues

Abstract Electrical impedance tomography (EIT) is a medical imaging modality that considers the electrical properties of tissues to obtain a conductivity distribution of a region of interest using the level of resistance it presents to the passage of a small electrical current. This work describes the design of an 8-electrode EIT prototype that offers the possibility of changing the excitation parameters and freedom of movement of the demodulation synchrony by means of conventional electronics. The image reconstruction obtained can locate disturbances in the study medium using the adjacent electrode method. A comparison of the voltage measurements acquired on a homogeneous test medium in two different collection cycles was implemented to determine the precision of the system. The data obtained indicate a maximum error percentage of 2.6% between measurements, which represents an acceptable first approach towards the design of a device with greater stability and precision.

Prototype of a Low-Cost Impedance Tomography Based on the Open-Hardware Paradigm

2021 ◽  
pp. 1-15
Author(s):  
David Edson Ribeiro ◽  
Valter Augusto de Freitas Barbosa ◽  
Clarisse Lins de Lima ◽  
Ricardo Emmanuel de Souza ◽  
Wellington Pinheiro dos Santos
Keyword(s):  
Ionizing Radiation ◽  
Low Cost ◽  
Region Of Interest ◽  
Surface Region ◽  
Data Acquisition System ◽  
Impedance Tomography ◽  
Open Hardware ◽  
Low Intensity ◽  
Electrical Potentials ◽  
Alternating Electric Current

Electrical Impedance Tomography (EIT) is a noninvasive, painless, and ionizing radiation-free technique for image acquisition of a region of interest. It is performed through electrical parameters. The method is based on the application of an alternating electric current pattern of low intensity through electrodes arranged around the surface region in order to obtain the image and also to measure the excitation electrical potentials. The aim of this study is to develop a device based in open hardware. Furthermore, the authors aim to build a prototype of a data acquisition system based on EIT. This device is the first step to obtain a complete and portable tomography equipment at a low cost.

A Na-Rich Nanocomposite of Na1.83Ni0.12Mn0.88Fe(CN)6/RGO as Cathode for Superior Performance Sodium-Ion Batteries

NANO ◽  
2018 ◽  
Vol 13 (06) ◽  
pp. 1850064 ◽  
Author(s):  
Shimeng Yu ◽  
Danting Li ◽  
Yan Zhang ◽  
Hui Wang ◽  
Junjie Quan ◽  
...  
Keyword(s):  
Current Density ◽  
Low Cost ◽  
Storage System ◽  
Electronic Conductivity ◽  
Synthesis Method ◽  
Rate Capability ◽  
Energy Storage System ◽  
Superior Performance ◽  
Precipitation Method ◽  
A Current

Prussian blue analogs are receiving intense attention due to their high theoretical energy density and low cost, but their real applications are still hampered by poor electronic conductivity and cycling stability. Here, Na[Formula: see text]Ni[Formula: see text]Mn[Formula: see text]Fe(CN)6 wrapped with graphene was synthesized by a facile co-precipitation method. The existence of RGO not only significantly increases the conductivity of the cathode, but also makes the framework much more robust during long cycling process. As the cathode, the Na[Formula: see text]Ni[Formula: see text]Mn[Formula: see text]Fe(CN)6/RGO is able to deliver a high initial discharge capacity of 120[Formula: see text]mA[Formula: see text]h[Formula: see text]g[Formula: see text] at a current density of 20[Formula: see text]mA[Formula: see text]g[Formula: see text] with superior capacity retention of 96.7% after 100 cycles. Even at a current density of 1000[Formula: see text]mA[Formula: see text]g[Formula: see text], the cell still delivers a capacity of 86[Formula: see text]mA[Formula: see text]h[Formula: see text]g[Formula: see text], indicating outstanding rate capability. The results and the facile synthesis method enable Na[Formula: see text]Ni[Formula: see text]Mn[Formula: see text]Fe(CN)6/RGO to the competitive for a future energy storage system.

scholarly journals Experimental demonstration of an arbitrary shape dc electric concentrator

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hooman Barati Sedeh ◽  
Mohammad Hosein Fakheri ◽  
Ali Abdolali ◽  
Fei Sun
Keyword(s):  
Numerical Simulations ◽  
Electric Fields ◽  
Arbitrary Shape ◽  
Printed Circuit Board ◽  
Low Cost ◽  
Circuit Board ◽  
Impedance Tomography ◽  
Electrically Conducting ◽  
Resistor Networks ◽  
Theoretical Predictions

Abstract Coordinate transformation (CT) theory has shown great potentials in manipulating both time-varying and static fields for different physics ranging from electromagnetism and acoustics to electrostatic and thermal science. Nevertheless, as inhomogeneous and anisotropic materials are required to be realized for the implementation of CT-based devices, the applicability of this method is restricted due to difficulties in the fabrication process. In this paper, based on transformation electrostatic (TE) methodology, the design principle of an arbitrary shape dc electric concentrator is established which yields the enhancement of static electric fields in a predefined region with only one homogeneous conductivity, named as dc null medium (DNM). It is shown that one constant DNM is sufficient for localizing steady electric current in any arbitrary shape region, which in turn obviates the tedious mathematical calculations that conventional methods suffer from. In other words, the same DNM can be used for different concentrators regardless of their cross-section geometries, which makes the presented approach suitable for scenarios where reconfigurability is of utmost importance. Several numerical simulations are performed in order to demonstrate the capability of the proposed dc electric concentrator in localizing steady electric fields into the desired region. Moreover, by utilizing the analogy between electrically conducting materials and resistor networks, the attained DNM is realized with low-cost resistors and then exploited for fabricating a square shape dc electric concentrator on a printed circuit board (PCB). It is demonstrated that the measurement results agree well with the theoretical predictions and numerical simulations, which corroborate the effectiveness of the propounded method. The presented idea of this paper could find applications in scenarios where highly confined electric fields/currents are of critical importance such as electronic skin devices and electrical impedance tomography.

High-performance anion exchange membrane water electrolyzers with a current density of 7.68 A cm-2 and durability of 1000 h

2021 ◽  
Author(s):  
Nanjun Chen ◽  
Sae Yane Baek ◽  
Ju Yeon Lee ◽  
Jong Hyeong Park ◽  
So Young Lee ◽  
...  
Keyword(s):  
Anion Exchange ◽  
Current Density ◽  
High Performance ◽  
Low Cost ◽  
New Technology ◽  
Anion Exchange Membrane ◽  
Proton Exchange ◽  
Exchange Membrane ◽  
A Current ◽  
High Purity Hydrogen

Low-cost anion exchange membrane (AEM) water electrolyzers (AEMWEs) are a new technology to produce high-purity hydrogen; however, their current density and durability are far lower than those of proton exchange...

scholarly journals Flax-Derived Carbon: A Highly Durable Electrode Material for Electrochemical Double-Layer Supercapacitors

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2229
Author(s):  
Petr Jakubec ◽  
Stanislav Bartusek ◽  
Josef Jan Dvořáček ◽  
Veronika Šedajová ◽  
Vojtěch Kupka ◽  
...  
Keyword(s):  
Surface Area ◽  
Double Layer ◽  
Current Density ◽  
Activated Carbons ◽  
High Current Density ◽  
Low Cost ◽  
High Specific Surface Area ◽  
High Rate ◽  
Electrochemical Double Layer ◽  
A Current

Owing to their low cost, good performance, and high lifetime stability, activated carbons (ACs) with a large surface area rank among the most popular materials deployed in commercially available electrochemical double-layer (EDLC) capacitors. Here, we report a simple two-step synthetic procedure for the preparation of activated carbon from natural flax. Such ACs possess a very high specific surface area (1649 m2 g–1) accompanied by a microporous structure with the size of pores below 2 nm. These features are behind the extraordinary electrochemical performance of flax-derived ACs in terms of their high values of specific capacitance (500 F g–1 at a current density of 0.25 A g–1 in the three-electrode setup and 189 F g–1 at a current density of 0.5 A g–1 in two-electrode setup.), high-rate stability, and outstanding lifetime capability (85% retention after 150,000 charging/discharging cycles recorded at the high current density of 5 A g–1). These findings demonstrate that flax-based ACs have more than competitive potential compared to standard and commercially available activated carbons.

A Novel Capacitive Negative Electrode Material of Fe3N

NANO ◽  
2018 ◽  
Vol 13 (01) ◽  
pp. 1850002 ◽  
Author(s):  
Zhi-Yun Zhao ◽  
Wei-Bin Zhang ◽  
Xue-Jing Ma ◽  
Kai Li ◽  
Yue Zhao ◽  
...  
Keyword(s):  
Current Density ◽  
Electrode Material ◽  
Preparation Method ◽  
Low Cost ◽  
Negative Electrode ◽  
Initial Value ◽  
Capacitive Energy Storage ◽  
Simple Preparation ◽  
Negative Electrode Material ◽  
A Current

A capacitive negative electrode material of Fe3N has been synthesized via a simple precursor ammoniation treatment. Electrochemical measure shows that the electrode exhibits a specific capacitance of 270[Formula: see text]F[Formula: see text]g[Formula: see text] at a current density of 0.5[Formula: see text]A[Formula: see text]g[Formula: see text] in 6[Formula: see text]M KOH, 66% of the initial value remains at a specific current density of 5[Formula: see text]A[Formula: see text]g[Formula: see text]. Capacitance retention after 5000 cycles is about 61.5% of the initial capacitance. The electrochemical performance is relatively great in comparison with the literature reports of some Fe-based compounds. Because of the low cost and simple preparation method of Fe3N, the material is promising in electrochemical capacitive energy storage applications.

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