Journal articles on the topic 'Electrochemical analyzer system'
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Velusamy, Vijayalakshmi, Khalil Arshak, Olga Korostynska, and Ahmed Al-Shamma'a. "A Novel Handheld Electrochemical Analyzer System Interfaced to a Smartphone." Key Engineering Materials 543 (March 2013): 47–50. http://dx.doi.org/10.4028/www.scientific.net/kem.543.47.
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Detailed in this paper is the design of a novel handheld electrochemical analyzer system interfaced to a smart phone, which provides versatile and cost-effective solution for real-time sensing applications. It was characterised for electron transfer events associated with chemical and biological samples. The presented design is implemented based on the Arduino nanoopen source electronics prototyping platform. The versatility of the instrument is further demonstrated by employing the electrochemical analyser to a modified electrochemical cell which formed the basis of a DNA biosensor. Cyclic voltammetry technique was used to impose a triangular waveform on an electrochemical cell and the resulting current through the cell was then monitored. The DNA biosensor generated unique electrical signals in real-time between complementary and non-complementary oligonucleotides sequences of the Bacillus cereus DNA. The effects of hybridization and non-specific binding were compared when the probe DNA molecules were immobilized on a conducting polymer matrix. The results showed that the probe DNA immobilized using electrochemical adsorption yielded better hybridization signals compared to other immobilization methods. The performance of the DNA sensor proved to be effective in terms of selectivity, sensitivity and reproducibility of hybridization events. Analysis of these DNA probes showed that the minimum level of detection was 33.3 pg/ml.
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Bubela, Tetiana, Vasyl Yatsuk, Tetiana Fedyshyn, and Hristo Krachunov. "STUDY OF THE PRIMARY CONVERTER-OBJECT SYSTEM FOR ELECTROCHEMICAL DEVICES." Measuring Equipment and Metrology 82, no. 4 (2021): 18–25. http://dx.doi.org/10.23939/istcmtm2021.04.018.
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The problem of creating electrochemical devices and the issues that arise in the system of the primary converterobject of control are considered. Low-resistance (salt solutions) and high-resistance (sugar solutions) objects were selected as the subject of study. To solve the problem, we have applied the method of impedance spectrum analysis with EIS Spectrum Analyzer software, which performs modeling on the Levenberg-Marquardt algorithm. Substitution schemes in different frequency and concentration ranges of studied objects were synthesized. This enables appropriate corrective action to minimize the impact of adverse events in the system while monitoring the quality of solutions - non-electrical nature objects – by electrochemical devices.
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Silva, Manori J., and John L. Wong. "Electrochemical bioassay system. Redox measurements of Escherichia coli growth by multichannel analyzer." Bioelectrochemistry and Bioenergetics 34, no. 2 (September 1994): 177–84. http://dx.doi.org/10.1016/0302-4598(94)80033-2.
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Jacobs, E., M. Nowakowski, and N. Colman. "Performance of Gem Premier blood gas/electrolyte analyzer evaluated." Clinical Chemistry 39, no. 9 (September 1, 1993): 1890–93. http://dx.doi.org/10.1093/clinchem/39.9.1890.
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Abstract We evaluated a new analyzer designed for point-of-care testing of blood gases, sodium, potassium, ionized calcium, and hematocrit. The Gem Premier (Mallinckrodt) system has two components: the analyzer and a disposable cartridge. Analysis takes place in the cartridge, which contains the electrochemical sensors, the calibrants, the reagents, the sampling stylus, and the waste container. The system was evaluated for imprecision and accuracy. With aqueous control materials, total imprecision (CV) was: pH, 0.10-0.18%; PCO2, 3.16-5.78%; PO2, 2.92-4.85%; sodium, 0.82-1.44%; potassium, 1.35-1.48%; ionized calcium, 0.75-1.45%; and hematocrit, 1.13-1.83%. Accuracy of the system was assessed by split-sample comparison with the Radiometer ABL 330 blood gas analyzer for pH and blood gases, the Nova Stat Profile 5 for whole-blood electrolyte and hematocrit analysis, and the IL Phoenix for plasma electrolyte analysis. After outlier correction, regression statistics were excellent for all analytes except sodium, which demonstrated Sy[x values between 1.80 and 2.30 mmol/L and 0.85 < or = r < 0.90.
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Schmidt, Wolfram, Carsten Tautorat, Klaus-Peter Schmitz, Niels Grabow, Frank Kamke, Sylvia Pfensig, and Stefan Siewert. "Multi-channel impedance analyzer for automated testing of networks and biomaterials." Current Directions in Biomedical Engineering 6, no. 3 (September 1, 2020): 414–17. http://dx.doi.org/10.1515/cdbme-2020-3107.
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AbstractImpedance spectroscopy represents a basic operating principle for biomedical sensors, bioimpedance spectroscopy, electrochemical analyses and for characterization of functional biomaterials. For automated long-term investigations, an impedance analyzer for multi-channel testing of up to eight passive two-pole networks is presented in this paper. Its operating system is application-specific adapted to the required test functionalities and measuring ranges. Measurements are based on a commercially available integrated impedance converter circuit. Our current analyzer setup is capable of measuring impedance values from 50 kΩ up to 10 MΩ with automated range selection for most accurate results. The impedance under test is excited with a single frequency of 1 kHz. An impedance accuracy of 1.5 % was determined in reference measurements. The presented impedance analyzer is a low cost system ready for use particularly in long-term characterization of dielectric networks, such as material properties, with multiple samples.
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Manová, A., E. Beinrohr, and F. Čacho. "Atomic absorption spectrometry with electrothermal atomization to determine trace amounts of arsenic." Acta Chimica Slovaca 10, no. 2 (October 26, 2017): 175–79. http://dx.doi.org/10.1515/acs-2017-0029.
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AbstractThe aim of this work was to develop an on-line coupling of electrochemical preconcentration to atomic absorption spectrometry method and to apply the developed system in the determination of ultra-trace amounts of As in water samples. A flow-through electrochemical analyzer EcaFlow (Istran Ltd, Bratislava, Slovakia) was used as the preconcentration unit with a two-electrode cell. The working electrode was a reticular vitreous carbon electrode coated with gold. An atomic absorption spectrometer SP9 with a graphite furnace atomizer (Pye Unicam) was used to determine the preconcentrated As species. Preconcentration parameters were optimized for the electrochemical process.
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Chung, Yi-Chen, Ade Julistian, Lakshmanan Saravanan, Peng-Ren Chen, Bai-Cheng Xu, Pei-Jie Xie, and An-Ya Lo. "Hydrothermal Synthesis of CuO/RuO2/MWCNT Nanocomposites with Morphological Variants for High Efficient Supercapacitors." Catalysts 12, no. 1 (December 26, 2021): 23. http://dx.doi.org/10.3390/catal12010023.
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In this study, we develop the optimum composition of copper oxide/ruthenium oxide and multi-walled carbon nanotubes (CuO/RuO2/MWCNTs) ternary nanocomposite via a hydrothermal method as an efficient electrode material for supercapacitor applications. The ratio between CuO and RuO2 varied to improve the electrochemical performance of the electrode. The synthesized nanocomposites are analyzed by high-resolution scanning electron microscopy (HR-SEM), thermo gravimetric analyzer (TGA) and electrochemical impedance spectroscopy (EIS). Furthermore, the elemental composition is analyzed by energy dispersive X-ray (EDX) spectroscopy and the specific capacitance was analyzed by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) methods. The electrochemical investigations is conducted in a three-electrode system and the sample is attached on a stainless steel plate as the working electrode; platinum wire works as the counter electrode and Ag/AgCl electrode as the reference electrode, adopting 3 M (NH4)2SO4 as the electrolyte. The resultant of CuO/RuO2/MWCNT nanocomposite with 7 wt% Cu and 20 wt% Ru was found to perform the highest specific capacitance of 461.59 F/g in a current density of 1 A/g.
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López-Lozano, Lina Marcela, Cesar Augusto Quiñones-Segura, and Oscar Rodríguez-Bejarano. "Electrochemical monitoring of a photocatalytic desulfurization process of a model liquid fuel." CT&F - Ciencia, Tecnología y Futuro 9, no. 2 (November 11, 2019): 73–78. http://dx.doi.org/10.29047/01225383.180.
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Thiophene is a sulfur compound found mostly in gasoline and contributor to air pollution. This paper analyzes UV light photocatalytic desulfurization of model oil using Ag/TiO2. Thiophene concentration in the oil phase was determined by the electrochemical analyzer using Differential Pulse Voltammetry (DPV).
The electrochemical experimental works were performed by two methodologies. First, aliquots of the oleic mixture were taken every 30 minutes and the thiophene concentration was measured over 7 hours of degradation. The concentration of thiophene decreased by 37.94%. In the second methodology, the in situ thiophene concentration was determined by DPV, where the reaction mixture was altered by the addition of acetonitrile and a quaternary ammonium salt as solvent-supporting electrolyte system. In this medium, the thiophene concentration was reduced by 43.88% after 4 hours of photocatalytic degradation.
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Matsaridis, Efstathios, Varban Savov, Alexandre Gritzkov, Nelie Zheleva, and Stoyan Gutzov. "Transport of Carbon Dioxide through a Biomimetic Membrane." Advances in Physical Chemistry 2011 (September 5, 2011): 1–5. http://dx.doi.org/10.1155/2011/210802.
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Biomimetic membranes (BMM) based on polymer filters impregnated with lipids or their analogues are widely applied in numerous areas of physics, biology, and medicine. In this paper we report the design and testing of an electrochemical system, which allows the investigation of CO2 transport through natural membranes such as alveoli barrier membrane system and also can be applied for solid-state measurements. The experimental setup comprises a specially designed two-compartment cell with BMM connected with an electrochemical workstation placed in a Faraday cage, two PH meters, and a nondispersive infrared gas analyzer. We prove, experimentally, that the CO2 transport through the natural membranes under different conditions depends on pH and displays a similar behavior as natural membranes. The influence of different drugs on the CO2 transport process through such membranes is discussed.
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Markova, Ivania, Valentina Milanova, Tihomir Petrov, Ivan Denev, and Olivier Chauvet. "New Porous Nanocomposite Materials for Electrochemical Power Sources." Key Engineering Materials 644 (May 2015): 129–32. http://dx.doi.org/10.4028/www.scientific.net/kem.644.129.
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Intermetallic (Cu-Sn) nanoparticles are synthesized through a borohydride reduction with NaBH4 in a mixture of aqueous solutions of CuCl2.2H2O and SnCl2.2H2O at mass ratio Cu:Sn = 3:2 applying a template technique with a support such as carbon foam. The ratio is chosen in accordance with the Cu-Sn binary system phase diagram. The reductive precipitation is carried out at room temperature and atmospheric pressure. Porous nanocomposites are obtained and studied by scanning and transmission electron microscopy (SEM/TEM), and X-ray diffraction (XRD) analysis. The electrochemical behavior of the synthesized Cu-Sn alloy and the C-based composites (С-foam/Cu-Sn alloy) as positive electrodes is also investigated in a Li-ion battery) using a computer controlled laboratory cycling equipment BA500 Series Battery Analyzer.
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Jang, A., Z. Zou, E. MacKnight, P. M. Wu, I. S. Kim, C. H. Ahn, and P. L. Bishop. "Development of a portable analyzer with polymer lab-on-a-chip (LOC) for continuous sampling and monitoring of Pb(II)." Water Science and Technology 60, no. 11 (December 1, 2009): 2889–96. http://dx.doi.org/10.2166/wst.2009.727.
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A new portable analyzer with polymer lab-on-a-chip (LOC) has been designed, fabricated and fully characterized for continuous sampling and monitoring of lead (Pb(II)) in this work. As the working electrodes of the sensor, bismuth (Bi (III)) which allowed the advantage of being more environmentally friendly than traditional mercury drop electrodes was used, while maintaining similar sensitivity and other desirable characteristics. The size of a portable analyzer was 30 cm × 23 cm × 7 cm, and the weight was around 3 kg. The small size gives the advantage of being portable for field use while not sacrificing portability for accuracy of measurement. Furthermore, the autonomous system developed in coordination with the development of new polymer LOC integrated with electrochemical sensors can provide an innovative way to monitor surface waters in an efficient, cost-effective and sustainable manner.
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Yuan, Yang, Shilun Feng, Md Alahi, Anindya Nag, Nasrin Afsarimanesh, Hong Zhang, and Shan He. "Development of an Internet of Things Based Electrochemical Microfluidic System for Free Calcium Detection." Applied Sciences 8, no. 8 (August 13, 2018): 1357. http://dx.doi.org/10.3390/app8081357.
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This paper represents the design, fabrication, and implementation of an Internet of Things (IoT)-based electrochemical microfluidic system for free calcium concentration detection with a 3D printing technique. Free calcium solutions with desired concentrations between 0 and 40 µM can be obtained. The solutions were used to calibrate the system by using an impedance analyzer for monitoring the impedance change to determine the operating frequency. Continuously, an IoT enabled point of care device was used for real-time detection and to send signals to the cloud for sharing. The relationship between the concentration and reactance are y = − 1.3812 Lgx + 0.9809 at a wavelength of 450 Hz, with an R2 of 0.9719. We measured the calcium concentration changing from 39.8 µM to 1.35 µM (nearly real-time) by the PoC device and showed the concentration changes resulting with time on the cell phone app. The results depicted in this paper provide a strong platform for the precise and real-time monitoring of different biomedical samples.
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Brainina, Khiena, Aleksey Tarasov, Ekaterina Khamzina, Yan Kazakov, and Natalia Stozhko. "Disposable Potentiometric Sensory System for Skin Antioxidant Activity Evaluation." Sensors 19, no. 11 (June 6, 2019): 2586. http://dx.doi.org/10.3390/s19112586.
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The skin is a natural barrier between the external and internal environment. Its protective functions and the relationship of its state with the state of health of the organism as a whole are very important. It is known that oxidant stress (OS) is a common indicator of health status. This paper describes a new sensory system for monitoring OS of the skin using antioxidant activity (AOA) as its criteria. The contact hybrid potentiometric method (CHPM) and new electrochemical measuring scheme were used. A new sensory system, including disposable modified screen-printed carbon and silver electrodes covered by membrane impregnated by mediator, was developed. Its informative ability was demonstrated in the evaluation of the impact of fasting, consumption of food and food enriched by vitamins (antioxidants) on skin AOA. This device consisting of a sensory system and potentiometric analyzer can be used in on-site and in situ formats.
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Wang, Ying, Hao Wu, Fang Ming Xiao, Ren Heng Tang, and Tai Sun. "Synthesis and Electrochemical Performance of Silicon/Carbon Composite Anodes through Ball Milling and Spray Drying Pyrolysis Process." Materials Science Forum 914 (February 2018): 56–63. http://dx.doi.org/10.4028/www.scientific.net/msf.914.56.
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A facile method was developed to synthesize amorphous carbon coated nano-sized silicon and graphite by using glucose or pitch as organic carbon source, nano-sized silicon particles were uniformly coated onto the artificial graphite by combined ball milling and spray drying pyrolysis, and the effect of binder types, binder amounts on the precursor morphology, feed rate and spray pressure on the electrochemical performance were investigated in detail. The partial size, surface morphology and electrochemical performances of the as-synthesized powders were analyzed by particulate size description analyzer (PSDA), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and constant current charge/discharge tools. It is found that, citric acid and binder are important for improving the free-aggregation of nano-sized silicon and the morphologyof combined silicon and graphite. Therefore, under the optimal experimental conditions, amorphous carbon from pitch coated nano-sized silicon and graphite composite anodes exhibits much higher electrochemical performance. It can deliver the first discharge specific capacity of 796.3mA·h/g at a current density of 100 mA/g, as well as 85% of initial coulombic efficiency. Additionally, the discharge specific capacity retains 724.9mA·h/g, and the discharge capacity retention of a half cell system is 91% after 50 cycles.
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Kubo, Izumi, Nobuyuki Yokota, and Yuko Nakane. "Sensing System for Bisphenol a Utilizing a Molecularly Imprinted Polymer Modified Electrode." Advanced Materials Research 452-453 (January 2012): 922–26. http://dx.doi.org/10.4028/www.scientific.net/amr.452-453.922.
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In order to develop an electrochemical sensing system for bisphenol A, molecularly imprinted polymer (MIP) thin layers for bisphenol A were polymerized on a sputtered gold electrode by UV light irradiation for 2 – 30 min. Their thickness, which was determined by QCM analyzer, was 3.6 ±0.3 nm for 5min of irradiation and increased as the irradiation time increase to 30 min. AFM images of MIP modified surface suggested that the gold electrode was covered with MIP smooth layer. The responses to BPA and ascorbic acid of the gold electrode and MIP modified electrode were examined by cyclic voltammogram, and their anodic peaks were compared. The electrode with MIP polymerized for 5min showed more selective to BPA than that for 2min. This electrode can be served as BPA sensor and the anodic current of BPA depended on its concentration at the range of 5-15 μM.
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Yang, Liang, Ming Xian Liu, Li Hua Gan, Yang Li, Xiao Ping Wang, Zi Jie Xu, and Long Wu Chen. "Synthesis and Electrochemical Performance of Mesoporous Carbon Foams by Microemulsion Method." Advanced Materials Research 347-353 (October 2011): 3416–19. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.3416.
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In this paper, we demonstrated the preparation and electrochemical performance of mesoporous carbon foams as electrode materials for ultracapacitors. By using n-octane as oil phase, cetyltrimethylammonium bromide (CTAB) and butanol as emulsifiers, resorcinol and formaldehyde dissolved in water as the aqueous phase, an O/W microemulsion system was obtained. Mesoporous carbon foams (MCFs) were prepared by the polymerization of the O/W microemulsion, followed by drying and carbonization and subsequently activation at 1273 K by KOH under nitrogen atmosphere. The mesoporous carbon foams were characterized by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analyzer. The results show that MCFs have specific surface area of 666.7 m2/g, total pore volume of 0.36 cm3/g and the most probable pore size of 4 nm. The electrochemical properties of the resultant mesoporous carbon foams have been investigated by cyclic voltammetry (CV) and galvanostatic charge-discharge with a three-electrode system in electrolyte of 6 mol/L KOH solution. The CV curves show quite rectangular shape under the scan rate of 5-20 mV/s, suggesting a typical nonfaradic adsorption/desorption reaction. The mesoporous carbon foams possess linear galvanostatic discharge curves under the current densities of 10-50 mA/cm2 and corresponding specific capacitance values are 132.6-172.1 F/g. Thus the MCFs have good electrochemical performance and they provide an important candidate for electrode materials used in ultracapacitors.
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Fuchiwaki, Yusuke, Naoki Sasaki, and Izumi Kubo. "Electrochemical Sensing System Utilizing Simazine-Imprinted Polymer Receptor for the Detection of Simazine in Tap Water." Journal of Sensors 2009 (2009): 1–6. http://dx.doi.org/10.1155/2009/503464.
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A simazine sensing system, composed of column packed with a molecularly imprinted polymer (Sim-MIP) and an electrochemical analyzer, was scaled down in order to easily determine the concentration of simazine, an environmentally restricted chemical, in tap water. In order to enhance the detection limit, the ratio of the eluent (dilution rate) in the electrolyte was optimized to 10%. A new in-house built column size with∅=1.5 mm was prepared, and 3 mg of Sim-MIP particles was packed in the column. During the sensing process, 90% of the simazine loaded to the column was collected by elution. The reductive current of simazine was determined up to 1–10 μM. Solid phase extraction through the Sim-MIP column enabled simazine to be selectively detected from a mixed aqueous solution containing structural analogues in the range of 10–40 nM. Whether the concentration of simazine in tap water had reached environmentally restricted levels (10–40 nM) was determined within 1 hour using this system.
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Kim, Youngjae, Junsoo Yoo, and Jungshin Kang. "Applicability of the Electrochemical Oxygen Sensor for In-Situ Evaluation of MgO Solubility in the MgF2–LiF Molten Salt Electrolysis System." Metals 10, no. 7 (July 7, 2020): 906. http://dx.doi.org/10.3390/met10070906.
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The measurement and evaluation of MgO solubility in the molten fluoride system is of significant importance in the recently proposed magnesium electrolysis reduction process. In the present study, an in-situ quantitative method of evaluating the concentration of dissolved MgO in molten fluoride is proposed. The MgO solubility in the 32.8MgF2–67.2LiF system was measured at 1083 and 1123 K using a combustion analyzer. MgO saturation was achieved in under 2 h, and higher solubilities were observed as the temperature increased. Thermodynamic assessment was carried out in order to ascertain the applicability of the electrochemical oxygen sensor, which indicated that the logarithm of oxygen concentration in molten fluoride has a linear relationship with the measured electromotive force (EMF) potential. The EMF potential of the controlled MgO concentration was measured, and a straight calibration line was obtained, describing the relationship between the measured EMF and the logarithm of MgO concentration. From the obtained calibration line, MgO concentration in the 0.4 wt% MgO was calculated. The calculated value was 0.44 wt% that was in excellent accordance with the controlled MgO concentration of 0.4 wt%, verifying the practical applicability of electrochemical oxygen for the in-situ monitoring and evaluation of MgO solubility in the electrolysis magnesium reduction process.
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Li, Yang, Ming Xian Liu, Li Hua Gan, Liang Yang, Zi Jie Xu, Xiao Gang Wang, and Long Wu Chen. "Double Templating Synthesis and Electrochemical Properties of Carbon Foams." Advanced Materials Research 347-353 (October 2011): 3400–3403. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.3400.
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In this paper, we demonstrated the synthesis and electrochemical properties of carbon foams for use as supercapacitor electrode materials. Carbon foams were prepared by double templating method in which emulsion and nanosilica were used as soft template and hard template, respectively. By using Span 80 and Tween 80 as emulsifiers, resorcinol/formaldehyde aqueous solution which contained nanosilica as aqueous phase and 1iquid paraffin as oil phase, an O/W emulsion was obtained. Carbon foams were obtained by emulsion polymerization, carbonization and the subsequent removal of the hard template. The as-prepared carbon foams were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analyzer, and electrochemical workstation. The results indicate that the resultant carbon foams have specific surface area of 160 m2/g, total pore volume of 0.15 cm3/g and possess dual pore size distributions with macropore sizes of 0.5-2.0 μm and the most probable pore size of 4.1 nm. The electrochemical properties of the carbon foams have been investigated by cyclic voltammetry (CV) and galvanostatic charge- discharge with a three-electrode system in electrolyte of 6 mol/L KOH solution. The CV curves of the carbon foams show rectangular-like shape without obvious oxidation-reduction evolution peak, which suggests a typical nonfaradic adsorption/desorption reaction. The carbon foams present linear galvanostatic charge-discharge curve under the current densities of 1.0-5.0 A/g and their specific capacitance values are 60-90 F/g. The good electrochemical performances of carbon foams would provide candidate as electrode materials for supercapacitors.
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Bawab, Ali, Stefan Giurgea, Daniel Depernet, and Daniel Hissel. "An Innovative PEMFC Magnetic Field Emulator to Validate the Ability of a Magnetic Field Analyzer to Detect 3D Faults." Hydrogen 4, no. 1 (January 5, 2023): 22–41. http://dx.doi.org/10.3390/hydrogen4010003.
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An original non-invasive methodology of the fuel cell diagnosis is proposed to identify different positions of the faults in Proton Exchange Membrane Fuel Cell (PEMFC) stacks from external magnetic field measurements. The approach is based on computing the external magnetic field difference between normal and faulty PEMFC operating conditions. To evaluate the external magnetic field distribution, in this paper, we propose an improved design of the magnetic field analyzer. This analyzer amplifies the magnetic field around the cell to perform an accurate detection of the fault position. Moreover, the main contribution of this work is represented by conceiving and implementing a 3D multi-physical current distribution emulator of a proton exchange membrane fuel cell. The new concept of a proton exchange membrane fuel cell emulator has been specially designed to emulate the magnetic field of a real fuel cell stack. This emulator concept is also beneficial for a new model of the fuel cell, which implies a multi-physical coupling between electrochemical electric conduction and the generated magnetic field. Finally, finally, the numerical model and the emulator have been involved in the realization of numerical simulations and experimental analysis to prove the ability of the system to detect and localize 3D faults.
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Wang, Dagang, Daozhu Song, and Magd Abdel Wahab. "Effects of Contact Load and Torsion Angle on Crack Propagation Behaviors of Inclined Crossed Steel Wires during Tension–Torsion Fretting Fatigue in Acid Solution." Applied Sciences 11, no. 22 (November 9, 2021): 10529. http://dx.doi.org/10.3390/app112210529.
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The hoisting rope in the kilometer-deep coal mine exhibits the tension–torsion fretting fatigue behaviors of inclined crossed steel wires in acid solution. Distinct contact load and torsion angles of steel wires in the rope cause different crack propagation behaviors, which greatly affect the fatigue lives of steel wires. Therefore, the effects of contact load and torsion angle on the crack propagation behaviors of inclined crossed steel wires during tension–torsion fretting fatigue in acid solution were investigated in the present study. The three-dimensional X-ray tomographic micro-imaging system was used to reveal evolutions of crack profiles and crack propagation depths during the test. The evolution of friction coefficient between steel wires during the test is presented. The three-dimensional white light interference microscope, electrochemical analyzer, and scanning electron microscope were employed to investigate the wear depth profiles, Tafel polarization curves and impedance spectra, and wear scar morphologies, respectively, of steel wires. Effects of contact load and torsion angle on crack propagation behaviors of inclined crossed steel wires during the tests were explored through analyses of friction and wear mechanisms and electrochemical corrosion damage. The results show that as the contact load and torsion angle increase, the crack propagation depth and rate of steel wire both increase and the fatigue life of steel wire decreases. Those are mainly attributed to the increases in the average tangential force between steel wires, wear depth, electrochemical corrosion tendency, and surface damage of steel wire as well as the decrease in corrosion resistance.
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Kim, Hoejin, Mohammad Arif Ishtiaque Shuvo, Hasanul Karim, Juan C. Noveron, Tzu-liang Tseng, and Yirong Lin. "Synthesis and characterization of CeO2 nanoparticles on porous carbon for Li-ion battery." MRS Advances 2, no. 54 (2017): 3299–307. http://dx.doi.org/10.1557/adv.2017.443.
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ABSTRACTCarbon based materials have long been investigated as anodes for lithium ion batteries. Among these materials, porous carbon holds several advantages such as high stability, high specific surface area, and excellent cycling capability. To further enhance the energy storage performance, ceramic nanomaterials have been combined with carbon based materials as hybrid anodes for enhanced specific capacity. The use of metal oxide ceramic nanomaterials could enhance the surface electrochemical reactivity thus leads to the increasing of capacity retention at higher number of cycles. In this research, we synthesized ceria (CeO2) nano-particles on porous carbon to form inorganic-organic hybrid composites as an anode material for Li-ion battery. The high redox potential of ceria is expected to increase the specific capacity and energy density of the system. The electrochemical performance was determined by a battery analyzer. It is observed that the specific capacity could be improved by 77% using hybrid composites anode. The material morphology, crystal structure, and thermal stability were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), and Thermogravimetric Analysis (TGA).
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Xiong, Wei, Ming Xian Liu, Li Hua Gan, Xiao Gang Wang, Zi Jie Xu, Zhi Xian Hao, Hong Lai Liu, and Long Wu Chen. "Synthesis and Electrochemical Properties of Macro-/Microporous Carbon Foams." Advanced Materials Research 239-242 (May 2011): 1396–99. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.1396.
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In this paper, we demonstrated the synthesis and electrochemical properties of macro-/ microporous carbon foams (MMCFs) for application as supercapacitor electrode materials. By using Span 80 and Tween 80 as emulsifiers, resorcinol/formaldehyde solution as aqueous phase, and 1iquid paraffin as oil phase, an O/W emulsion was obtained. Macroporous carbon foams were prepared by the polymerization of the emulsion, followed by drying and carbonization. The macroporous carbon foams then were activated at 1273 K by using KOH as an activated agent to obtain MMCFs. The resultant MMCFs were characterized by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analyzer. The results indicate that the MMCFs have specific surface areas of 529-670 m2/g, total pore volumes of 0.27-0.33 cm3/g and possess dual pore size distributions with macropore sizes of 0.5-5.0 μm and micropore sizes of 1.72-1.86 nm dependent on the specific experiment parameters. The hierarchical pore structure is propitious to decreases the diffusion resistance of electrolyte and accelerate the ion transfer within the pore channel, and thus improve the electrochemical properties of MMCFs. The electrochemical properties of the MMCFs have been investigated by cyclic voltammetry (CV) and galvanostatic charge-discharge with a three-electrode system in electrolyte of 6 mol/L KOH solution. The CV curves of the MMCFs show quite rectangular curve shape without observation of obvious oxidation-reduction evolution peaks, suggesting a typical nonfaradic adsorption/desorption reaction. The MMCFs present linear galvanostatic charge-discharge curve under the current densities of 1.0-4.0 A/g and their specific capacitance values are 89-110 F/g. The MMCFs has good electrochemical performance and they are good candidates as electrode materials for supercapacitors.
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Xu, Kaixuan, Dusty R. Miller, Pragun R. Tuladhar, Patricia A. Ward, M. Diana Neely, and David E. Cliffel. "Electrochemical Analysis Reveals Chlorpyrifos-Induced Dysregulation of Net Astrocytic Glutamate Uptake." ECS Meeting Abstracts MA2022-02, no. 54 (October 9, 2022): 2028. http://dx.doi.org/10.1149/ma2022-02542028mtgabs.
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Chlorpyrifos (CPF), an organophosphate pesticide widely used on food crops and in households, has been a critical public health concern due to its neurotoxic effects. Investigations of CPF-induced neurotoxicity have focused on dysregulation of acetylcholinergic signaling but recent work suggests that alterations in glutamatergic neurotransmission and astrocytic glutamate metabolism may occur. L-glutamate is a major excitatory neurotransmitter that is mostly removed from the synaptic cleft by astrocytic glutamate transporters. Here we assessed the effects of CPF on net glutamate uptake by human-induced pluripotent stem cell derived astrocytes using electrochemical analysis. Our microclinical analyzer (µCA) paired with screen-printed electrodes (SPE) offers an automated sensing system that can be used to monitor cellular metabolism and signaling. In this work, a platinum based SPE combined with the µCA was used to electrochemically quantify glutamate uptake in human astrocytes. Immobilized glutamate oxidase on electrode surfaces provided stable and sensitive glutamate detection. The temperature modification of these electrodes (37°C) led to a nearly four-fold improvement in sensitivity (0.84±0.04 nA/µM), with low limits of detection (2.8±0.1 µM), and quantitation (9.3±0.5 µM). The linear range of the sensor (1-667 µM) is on the same order as typical extracellular glutamate concentrations. These sensors were used to assess the net glutamate uptake efficiency by using escalating concentrations of glutamate (10-200 µM). Glutamate uptake was most efficient when astrocytes were exposed to 50 µM glutamate for 30min (50% net uptake). We are investigating acute and chronic effects of net glutamate uptake using sublethal doses of CPF (0-100 µM). Identifying these cellular mechanisms affected by CPF is critical for the understanding of the impact of organophosphate toxicity.
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Cheng, Yu-Hsuan, Zhenglong Li, Sreerag Kaaliveetil, Ayca Tatli, Charmi Chande, and Sagnik Basuray. "Modular, Portable, Automatically, Rapidly, Sensitive, and Selectively Essence Sensor System." ECS Meeting Abstracts MA2022-02, no. 61 (October 9, 2022): 2238. http://dx.doi.org/10.1149/ma2022-02612238mtgabs.
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The ESSENCE platform is an electrochemical sensor system that utilizes non-planar porous microelectrode microfluidic chips with a fully programmable fluidic/sample system to be a “portable, automatic, rapid, sensitive, and selective” for different emerging contaminants and liquid biopsy. The system is designed with non-planar porous microelectrode interfaces, containing different functional capturing probes for specific sensing tasks. From our previous report, this 3D non-planar structure has advantages such as increased flow’s convective fluxes and disrupts diffusive processes like the electric double layer (EDL). The porous electrode structure utilized the packing material’s higher Zeta potential than the bare glass surface, resulting in the EDL length will be significantly smaller than the clear channel. Due to a smaller EDL length, the relaxation frequency will increase, which shifts the EIS signal to a higher frequency range (1kHz to 100MHz) and results in a fast response with a higher signal-to-noise ratio in Electrochemical Impedance Spectroscopy (EIS) measurements. From the perspective of electric field penetration, the top-down electric direction covers all the packing sensing areas, providing a generally higher electronic signal response than the traditional planar electrode system, leading to a higher signal-to-noise ratio. A second feature from the perspective of microfluidics is the significant fluidic shear force generated due to flow through the porous electrode surface. This higher shear force on the surface can unbind most false-positive signals generated by non-specific binding, such as physical adhesive or biofouling. These unique benefits provide physical enhancements of sensitivity and selectivity without manipulating the chemical material in the system. Earlier we showed that our detection of the biomolecules like DNA (fM sensitivity, which can distinguish against a mismatched DNA), proteins (breast cancer biomarker p53, fM sensitivity, which can distinguish it against another breast cancer biomarker HER2), PFOS (Perfluorooctanesulfonate, 0.5 ng) under the traditional desktop Electrochemical Impedance Spectroscopy (EIS) analyzer in the total process of hourly. In this talk, we have further developed our previous ESSENCE platform to a modular, automatic, and portable, one-stop instrument for clinicians to screen for infectious diseases, liquid biopsy, and toxin detection to detect emerging pathogens while significantly reducing false positives and false negatives, but also decreasing our detecting process to 15 mins in much more hazard background conditions to meet the criteria of POC. Second, A small (15 cm x 17cm) USB programable fluidic/oscilloscope base with a 15 minutes total detecting protocol is applied to our ESSENCE system for a fast Point-of-care (POC) diagnostic. This portable ESSENCE platform can respond to the measurable EIS signals from the oscilloscope with 25 ul samples size (DNA and HER2 proteins in undiluted artificial Urine) with a fully automatic process at the uM to pM regions in 15 minutes. Each ESSENCE chip is also significantly cheaper than the ELISA; the chip costs about $20 (for an academic lab) and can be reused. Figure 1
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Bezerra dos Santos, Vagner, Elson Luiz Fava, Newton Sá de Miranda Curi, Ronaldo Censi Faria, Thiago Brito Guerreiro, and Orlando Fatibello-Filho. "An electrochemical analyzer for in situ flow determination of Pb(ii) and Cd(ii) in lake water with on-line data transmission and a global positioning system." Analytical Methods 7, no. 7 (2015): 3105–12. http://dx.doi.org/10.1039/c5ay00012b.
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Chang, Anna, Alice Orth, Bryan Le, Perla Menchavez, and Lupe Miller. "Performance Analysis of the OneTouch® UltraVue™ Blood Glucose Monitoring System." Journal of Diabetes Science and Technology 3, no. 5 (September 2009): 1158–65. http://dx.doi.org/10.1177/193229680900300521.
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Background: OneTouch® UltraVue™ is a new meter for self-monitoring of blood glucose that includes a color display, used-strip ejector, and no-button interface. The system uses an electrochemical biosensor technology based on glucose oxidase chemistry to detect glucose concentrations from 20 to 600 mg/dl (1.1 to 33.3 mmol/liter). Methods: Accuracy and reproducibility were evaluated over a wide range of glucose concentrations according to standard criteria. Clinical accuracy was assessed by health care providers (HCPs) in two studies and by diabetes patients in the second study. Reference glucose levels were determined by a YSI 2300 analyzer. Same-day reproducibility and day-to-day reproducibility were also evaluated. Results: In the accuracy studies, 99.7% and 98.7% of tests by HCPs and 97.0% of tests by patients were within ±15 mg/dl (±0.8 mmol/liter) of the YSI reference for blood glucose <75 mg/dl (<4.2 mmol/liter), and within ±20% for blood glucose ≥75 mg/dl (≥4.2 mmol/liter), respectively. Consensus error grid analysis showed that 99.7% and 95.3% of tests by HCPs and 97.0% of tests by patients fell within zone A (i.e., has no effect on clinical action); all other results were in zone B (i.e., altered clinical action, little or no effect on clinical outcome). In the reproducibility studies, the standard deviation was <1.5 mg/dl (<0.1 mmol/liter) for glucose concentrations <100 mg/dl (<5.6 mmol/liter), and the coefficient of variation was <2% for concentrations ≥100 mg/dl (≥5.6 mmol/liter). Conclusions: OneTouch UltraVue meets standard acceptability criteria for accuracy and reproducibility across a wide range of glucose concentrations. Its simple interface and lack of contact with used strips make it a viable option for older patients and their caregivers.
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Kowalski, Jerzy. "An Experimental Study of Emission and Combustion Characteristics of Marine Diesel Engine with Fuel Injector Malfunctions." Polish Maritime Research 23, no. 1 (January 1, 2016): 77–84. http://dx.doi.org/10.1515/pomr-2016-0011.
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Abstract The presented paper shows the results of the laboratory study on the relation between chosen malfunctions of a fuel injector and composition of exhaust gas from the marine engine. The object of research is a marine 3-cylinder, four-stroke, direct injection diesel engine with an intercooler system. The engine was loaded with a generator and supercharged. The generator was electrically connected to the water resistance. The engine operated with a load between 50 kW and 250 kW at a constant speed. The engine load and speed, parameters of the turbocharger, systems of cooling, fuelling, lubricating and air exchange, were measured. Fuel injection and combustion pressures in all cylinders of the engine were also recorded. Exhaust gas composition was recorded by using a electrochemical gas analyzer. Air pressure, temperature and humidity were also recorded. Emission characteristics of the engine were calculated according to ISO 8178 standard regulations. During the study the engine operated at the technical condition recognized as „working properly” and with simulated fuel injector malfunctions. Simulation of malfunctions consisted in the increasing and decreasing of fuel injector static opening pressure, decalibration of fuel injector holes and clogging 2 neighboring of 9 fuel injector holes on one of 3 engine cylinders.
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Elbayoum,, Maher, Nor Azam Ramli, Noor Faizah Md Yusof, Norrimi Rosaida Awang, Nazatul Syadia Zainordin, Maisarah Sulaiman, Syabiha Shith, and Teh Nur Amalina Zaki. "Evaluation of Indoor Air Quality at Engineering Campus Library at the University Sains Malaysia." Israa University Journal for Applied Science 2 (October 1, 2018): 72–84. http://dx.doi.org/10.52865/nvhy1702.
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The indoor air quality (IAQ) in micro-environments is extremely important due to its impact on health and productivity of students. This study presents the findings of indoor air quality (IAQ) investigations in engineering campus library at the University Sains Malaysia. Four levels of the library were investigated during May 2015. Measurements were carried out by using electrochemical analyzer and hand-held particulate matter (PM) instrument. The results showed that Formaldehyde, carbon monoxide (CO), Ozone, and total volatile organic compounds (TVOC) levels were found below Malaysian guideline values. Temperature ranged between 18.9–28.4 °C and relative humidity (RH) ranged between 49%–73% with an average of 62.2%. The indoor concentration PM2.5 level was 5.73±4.93μg/m3. All the monitoring pollutants’ levels were found below Malaysian guideline values in the ground floor, and the 1st and 2nd floors. However, several exceedances occurred in the 3rd floor. Inadequate introduction and/or distribution of fresh air may be the main problem in the left side of the building and in the 3rd floor. Thus, evaluation of the HVAC (Heating, Ventilation, and Air Conditioning) system should be examined
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Jaworski, Aleksander, Hanna Wikiel, and Kazimierz Wikiel. "Online Monitoring of Copper Damascene Electroplating Bath by Voltammetry: Selection of Variables for Multiblock and Hierarchical Chemometric Analysis of Voltammetric Data." International Journal of Electrochemistry 2017 (2017): 1–13. http://dx.doi.org/10.1155/2017/4289517.
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The Real Time Analyzer (RTA) utilizing DC- and AC-voltammetric techniques is an in situ, online monitoring system that provides a complete chemical analysis of different electrochemical deposition solutions. The RTA employs multivariate calibration when predicting concentration parameters from a multivariate data set. Although the hierarchical and multiblock Principal Component Regression- (PCR-) and Partial Least Squares- (PLS-) based methods can handle data sets even when the number of variables significantly exceeds the number of samples, it can be advantageous to reduce the number of variables to obtain improvement of the model predictions and better interpretation. This presentation focuses on the introduction of a multistep, rigorous method of data-selection-based Least Squares Regression, Simple Modeling of Class Analogy modeling power, and, as a novel application in electroanalysis, Uninformative Variable Elimination by PLS and by PCR, Variable Importance in the Projection coupled with PLS, Interval PLS, Interval PCR, and Moving Window PLS. Selection criteria of the optimum decomposition technique for the specific data are also demonstrated. The chief goal of this paper is to introduce to the community of electroanalytical chemists numerous variable selection methods which are well established in spectroscopy and can be successfully applied to voltammetric data analysis.
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Anghel, Andreea Hortanse, Dorina Nadolu, Elena Ilisiu, and Ana Cismileanu. "Differences on Biochemical Composition of GoatMilk at Carpathian Breed and Half Breed Saanen X Carpathian and French Alpine X Carpathian." Revista de Chimie 71, no. 2 (March 3, 2020): 352–57. http://dx.doi.org/10.37358/rc.20.2.7936.
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The aim of our study was to evaluate the gradient of milk yield, of milk biochemical composition and fatty acids profile according to breed, for primipara goats from Carpathian breed and Saanen x Carpathian and French Alpine x Carpathian half breed that were grown in semi-intensive system (Dobrogea, South Romania). The studies were performed on goats raised at ANCC CAPRIROM farm, located in Constanta, Romania. The biochemical parameters (fat, proteins, lactose) were studied by electrochemical method with a Lactostar analyzer Funke Gerber type specialized for goat milk. Milk fatty acids profile, as fatty acids methyl esters (FAME), was determined by chromatographically gas method. The considerable high protein content found in half breeds, might be explained by the fact that bucks from specialized breeds such us Saanen and French Alpine which were used for half breeding, come from imported animals from France, which were locus genotyped for alpha S1 casein gene and were selected dominant genotypes that lead to a higher protein concentration in milk.The statistical analysis shows that the milk coming from Carpathian does and their half breeds is not significantly different regarding the levels of various fatty acids, saving omega 3 acids, which are considerable higher at Carpathian does, proving that food has the decisive role regarding composition.
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Sankhala, Devangsingh, Sriram Muthukumar, and Shalini Prasad. "A Four-Channel Electrical Impedance Spectroscopy Module for Cortisol Biosensing in Sweat-Based Wearable Applications." SLAS TECHNOLOGY: Translating Life Sciences Innovation 23, no. 6 (February 15, 2018): 529–39. http://dx.doi.org/10.1177/2472630318759257.
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A four-channel electrochemical impedance spectroscopy (EIS) analyzer module has been demonstrated on flexible chemi-impedance sensors fabricated with gold electrodes for wearable applications. The module can perform time division multiplexed (TDM) impedance measurements on four sensors at 1 kHz. In this work, we characterize the system for the detection of cortisol in an ultralow volume (1–3 µL) of perspired human sweat, sensor performance, and effects during continuous cortisol dosing and with pH and temperature variations expected on the surface of the skin that would be representative of use conditions as seen by a wearable device. Detection of cortisol was shown for concentrations of 1 pg/mL to 200 ng/mL in both synthetic and perspired human sweat, and output response reported as a change in impedance with varying cortisol concentrations. Continuous dose testing was performed to demonstrate the stability of the sensors over prolonged periods of operation for cortisol concentrations within the physiologically relevant range of 10–200 ng/mL reported in human sweat. Temperature and pH effects testing was performed for pH range 4–8 and in a temperature chamber for the clinical range reported on the surface of human skin: 25–40 °C. The cortisol sensor demonstrated stability of operation with 7.58% variability under these conditions.
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Kolkovskyi, P. I., B. K. Ostafiychuk, M. I. Kolkovskyi, N. Ya Ivanichok, S.-V. S. Sklepova, and B. I. Rachiy. "Mechanisms of charge accumulation in electrochemical systems formed based on of nanoporous carbon and manganese oxide." Physics and Chemistry of Solid State 21, no. 4 (December 30, 2020): 621–27. http://dx.doi.org/10.15330/pcss.21.4.621-627.
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In this work, the processes occurring in electrochemical systems based on nanoporous carbon material and manganese oxide in an aqueous solution of lithium sulfate are analyzed. Furthermore, it is shows the feasibility of these materials combination cycling as electrodes of a hybrid electrochemical capacitor. The combination of electrode materials with different mechanisms of charge accumulation was determined. Consequently, an increase in the accumulated energy by more than 25% by the formation of an electric double layer and the occurrence of redox reactions based on carbon and manganese oxide respectively. The laboratory sample of an aqueous electrolyte hybrid electrochemical capacitor was formed. Moreover, the laboratory sample is electrochemically stable at an operating voltage of 2 V.
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Schulpis, Kleopatra H., Ioannis Papassotiriou, Maria Vounatsou, George A. Karikas, Stylianos Tsakiris, and George P. Chrousos. "Morning Preprandial Plasma Ghrelin and Catecholamine Concentrations in Patients with Phenylketonuria and Normal Controls: Evidence for Catecholamine-Mediated Ghrelin Regulation." Journal of Clinical Endocrinology & Metabolism 89, no. 8 (August 1, 2004): 3983–87. http://dx.doi.org/10.1210/jc.2004-0311.
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Patients with phenylketonuria (PKU) have a diet-controlled deficiency in the conversion of phenylalanine (Phe) to tyrosine (Tyr), leading to decreased production of noradrenaline, adrenaline, and dopamine. Poor diet control results in high plasma Phe and low plasma Tyr and catecholamine concentrations. Ghrelin, a recently described gastrointestinal hormone that is elevated in the fasting state and low in the fed state, is considered a major appetite-stimulating hormone, possibly involved in the generation of obesity and insulin resistance. We evaluated morning preprandial plasma ghrelin levels in 14 diet-controlled and 15 poorly controlled PKU patients and 20 age- and body mass index (BMI)-matched healthy children (controls) and correlated its concentrations with those of Phe and catecholamines as well as with their BMI and 24-h nutrient intake. Plasma ghrelin levels were measured by RIA, plasma catecholamine concentrations were determined by HPLC with electrochemical detection, and Phe and Tyr levels were measured in an amino acid analyzer. The ghrelin concentration (744 ± 25 ng/liter) in diet-controlled patients did not differ from that in controls (802 ± 26 ng/liter; P > 0.05). On the contrary, the ghrelin concentration was significantly reduced in poorly controlled patients (353 ± 23 ng/liter; P < 0.0001). Ghrelin correlated negatively with Phe in all three groups, whereas it correlated positively with catecholamine levels and energy intake and negatively with BMI only in diet-controlled patients and controls. We conclude that ghrelin secretion may receive positive direct or indirect input from catecholamines. The absence of a correlation between ghrelin and catecholamines, energy intake, or BMI in PKU patients on an inadequate diet may be due to dysregulation of their neuroendocrine system and might be affected by high Phe levels in the stomach and/or central nervous system.
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Yoon, Subin, Alexander Kotsakis, Sergio L. Alvarez, Mark G. Spychala, Elizabeth Klovenski, Paul Walter, Gary Morris, et al. "Development and testing of a novel sulfur dioxide sonde." Atmospheric Measurement Techniques 15, no. 14 (July 29, 2022): 4373–84. http://dx.doi.org/10.5194/amt-15-4373-2022.
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Abstract. A novel technique has been developed to measure sulfur dioxide (SO2) using a modification of the existing electrochemical concentration cell (ECC) ozonesonde technology. The current sonde-based method to measure SO2 (i.e., the dual-sonde approach) involves launching two ozonesondes together, with one of the sondes having a filter to remove SO2 at the inlet. The SO2 profile is determined by taking the difference between the measurements from the two instruments. The dual-sonde method works well in typical tropospheric conditions when [O3]>[SO2] but saturates when [SO2]>[O3] and has large uncertainties in the upper troposphere and lower stratosphere that would limit its effectiveness in measuring SO2 from an explosive volcanic eruption. Due to these limitations, several modifications were made to create a single-sonde system that would directly measure SO2 (i.e., the SO2 sonde). These modifications included (1) a positively biased ECC current, (2) the addition of an O3 removal filter, and (3) the addition of a sample dryer. The SO2 sonde measures SO2 as a reduction in the cell current. There was a strong correlation (r2>0.94) between the SO2 sonde and a Thermo 43c analyzer during controlled laboratory tests and pre-flight tests. Varying humidity levels affected the SO2 sonde's sensitivity (avg =84.6±31.7 ppbv µA−1, 1σ RSD =37 %) during initial field tests, which was resolved by adding a sample dryer upstream of the O3 removal filter and pump inlet. This modification significantly reduced the variability and increased the sensitivity of the SO2 measurements (avg =47±5.8 ppbv µA−1, 1σ RSD =12 %). Field tests included measurements near Kīlauea volcano (before and during the 2018 eruption of the Lower East Rift Zone), Costa Rica's Turrialba volcano, and anthropogenic plumes from the Athabasca oil sands region of Alberta, Canada. This single-SO2-sonde system is an effective, inexpensive instrument for measuring both ground-based and vertical profiles of SO2 from anthropogenic and natural sources (i.e., volcanic eruptions) over a wide range of concentrations.
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Przondziono, Joanna, and Witold Walke. "Influence of the Type of Medical Sterilisation on Electrochemical Properties of Passive Layer Created on X10CrNi 18-8 Steel." Solid State Phenomena 212 (December 2013): 141–44. http://dx.doi.org/10.4028/www.scientific.net/ssp.212.141.
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The study presents results of impedance tests performed for wires made of X10CrNi 18-8 steel after electrochemical polishing and chemical passivation, subject to medical sterilisation with pressurised water steam or ethylene oxide. In order to determine the impact of sterilising agent on electrochemical characteristics of the passive layer, impedance measurements were made. Measurements were made with application of measurement system Auto Lab PGSTAT 302N equipped with FRA2 (Frequency Response Analyser) module. Impedance spectra of the system were determined in the tests and data obtained in the measurement was matched to the equivalent system. It made the ground for determination of numerical values of resistance and capacitance of the analysed systems. Impedance spectra of the tested system are presented in the form of Nyquist diagrams for various values of frequency, and as Bode diagrams. On the ground of performed test it was explicitly proved that application of steam sterilisation and sterilisation with ethylene oxide of wires made of X10CrNi 18-8 steel after chemical passivation used for urological guide wires has a favourable impact on their electrochemical characteristics.
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Zhang, Hong Bo, Yong Sheng Li, Ting Ting Ning, and Ying Ying Zhu. "Analysis of Electrochemical Mechanism of Electrolyte and Coal." Advanced Materials Research 962-965 (June 2014): 837–42. http://dx.doi.org/10.4028/www.scientific.net/amr.962-965.837.
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In order to study the electrochemical performance of coal in the HCL electrolyte system, researchers prepared the chemically modified carbon paste electrode, measured the volt-ampere curves and Tafel curves of the samples and analyzed the mechanism of the electrochemically catalysis of oxidation of coal. The studies indicate that what occurs to the coal sample in the process of electrolytic sulfur removing is a quasi-reversible diffusion controlled process. In the beginning of the sulfur removing, the rate of electrolytic corrosion is fast, in which oxidation on the anode denominates, and the cathode plays a role of reduction in the late period.
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Jin, Kai, Qi Huang, Chenxuan Hu, Siyi Hu, and Jinhua Li. "A digital microfluidic system with integrated electrochemical impedance detection arrays." Journal of Physics: Conference Series 2196, no. 1 (February 1, 2022): 012005. http://dx.doi.org/10.1088/1742-6596/2196/1/012005.
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Abstract Electrochemical sensing provides a new way for miniaturization and low cost of equipment. Meanwhile, digital microfluidic (DMF) technology is making lab-on-chip a reality. The two technologies are essential in the point-of-care area. Electrochemical detection on electrodes and DMF-based droplet driving electrode realize their respective functions by means of electrical signals. In terms of working mode, it seems to have certain similarity, and electrochemical sensing seems to be more suitable for integrating digital microfluidic systems. We thus integrated electrochemical sensing on an active matrix (AM) DMF system. As a common transparent conductive glass, indium tin oxide (ITO) has been widely used as the top plate of the digital microfluidic chip. In this work, we used ITO glass with patterned interdigital electrodes as the top plate of the AM-DMF chip. We achieved on-chip droplet volume detection by electrochemical impedance spectroscopy (EIS). We also proposed a novel sample dilution method on the DMF chip. It takes only 30 seconds to dilute solutions into 4 different concentrations. We then analyzed droplet samples of different concentrations with EIS method. And the correlation coefficient of the fitted curve is as high as 0.9964. In conclusion, EIS is a powerful detection technology for fast, high-integration and low-cost detection on DMF system. The integration of EIS and DMF can be used in various biochemical analyses in the future.
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Sanchez-Amaya, M., M. Bárcena-Soto, R. Antaño-López, A. Rodríguez-López, A. Gutierrez-Becerra, and E. R. Larios-Durán. "Frequency Responses of Molar Electrochemical Peltier Heat and Entropy Changes Analyzed as Thermometric Transfer Functions." Journal of The Electrochemical Society 168, no. 12 (December 1, 2021): 126501. http://dx.doi.org/10.1149/1945-7111/ac38f3.
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In honor of Prof. Dr. Fritz Scholz in his recent retirement. This work proposes a theoretical framework to obtain the frequency response of molar electrochemical Peltier heat and entropy changes induced by a modulated electrical signal. This is based on an internal energy balance developed for a working electrode thermistor in ac regime. Then, from an analysis that correlates the electrochemical impedance and the interfacial temperature variation, two new transfer functions that depend on the frequency ω , named as entropy changes Δ S ω , and molar electrochemical Peltier heat, Π ω are obtained. This strategy is tested in two electrochemical systems: the ferrocyanide/ferricyanide couple and the copper ions in an acid sulphate-chloride medium. Both systems are analyzed by dc thermometric measurements, electrochemical impedance spectroscopy and ac-thermometric experiments namely variation of interfacial temperature. As a result, Δ S ω and Π ω , are obtained and their values are correlated to the relaxation processes involved in the electrochemical reaction. Additionally, a brief discussion is included concerning the differences between the classical dc thermoelectrochemical methodology and the proposed approach here.
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Domalanta, Marcel Roy, and Julie Anne del Rosario. "(Digital Presentation) An Electrochemical-Thermal Coupled Thermal Runaway Multiphysics Model for Lithium Polymer Battery." ECS Meeting Abstracts MA2022-01, no. 2 (July 7, 2022): 439. http://dx.doi.org/10.1149/ma2022-012439mtgabs.
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With the rising energy demand, safe and efficient energy storage technologies have been increasing in importance. Lithium-ion batteries (LIBs) have been dynamically prevalent as energy storage and power sources for various electrical systems, from communication purposes to transportation applications. Lithium Polymer (LiPo) batteries are a subcategory of LIBs that use a solid or semisolid (gel) polymer to act as both a separator and electrolyte for the system. Compared to a conventional liquid electrolyte, gel polymer electrolyte is more thermally and electrochemically stable and relatively safer. Various companies produce a vast number of different LiPo batteries; however, a limited number of studies have been conducted concerning modeling and simulation. Besides exploring new materials for performance enhancement, engineering a reliable model is equally vital to exploit and optimize existing LiPo batteries' potential. In this study, a multiphysics model for a mobile Lithium Cobalt Oxide (LCO)-graphite- Poly(vinylidene fluoride - hexafluoropropylene) (PVdF-HFP) pouch LiPo battery was established to characterize the battery's behavior. The pseudo-2-dimensional electrochemical model and 3D thermal-thermal runaway model were coupled with temperature and heat generation variables. Working voltage and temperature during galvanostatic discharge were examined for the electrochemical-thermal model. In contrast, temperature as a function of time during an oven test was analyzed for thermal runaway models. The electrochemical-thermal and thermal runaway behavior was investigated using the simulation model, and validations were compared with experimental data. Overall, the models can be employed as a design tool to evaluate the component design and estimate the system performance of LiPo batteries for commercial applications. KEYWORDS: Multiphysics model, Lithium-polymer battery, Thermal runaway
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Bagdžiūnas, Gintautas, and Delianas Palinauskas. "Poly(9H-carbazole) as a Organic Semiconductor for Enzymatic and Non-Enzymatic Glucose Sensors." Biosensors 10, no. 9 (August 23, 2020): 104. http://dx.doi.org/10.3390/bios10090104.
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Organic semiconductors and conducting polymers are the most promising next-generation conducting materials for electrochemical biosensors as the greener and cheaper alternative for electrodes based on transition metals or their oxides. Therefore, polycarbazole as the organic semiconducting polymer was electrochemically synthesized and deposited on working electrode. Structure and semiconducting properties of polycarbazole have theoretically and experimentally been analyzed and proved. For these electrochemical systems, a maximal sensitivity of 14 μA·cm−2·mM−1, a wide linear range of detection up to 5 mM, and a minimal limit of detection of around 0.2 mM were achieved. Moreover, Michaelis’s constant of these sensors depends not only on the enzyme but on the material of electrode and applied potential. The electrocatalytic mechanism and performance of the non- and enzymatic sensors based on this material as a conducting layer have been discussed by estimating pseudocapacitive and faradaic currents and by adding glucose as an analyte at the different applied potentials. In this work, the attention was focused on the electrochemical origin and mechanism involved in the non- and enzymatic oxidation and reduction of glucose.
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Drazic, Dragutin, Jovan Popic, B. Jegdic, and D. Vasiljevic-Radovic. "Electrochemistry of active chromium, part IV: Dissolution of chromium in deaerated sulfuric acid." Journal of the Serbian Chemical Society 69, no. 12 (2004): 1099–110. http://dx.doi.org/10.2298/jsc0412099d.
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Chromium dissolution in aqueous sulfuric acid solutions in the pH range 0.5 ?3 was studied electrochemically by the potentiostatic or very slow potentiodynamic method, and by the analyses of the Cr ion concentrations in the electrolyte formed during the experiments. It was shown that the electrochemical anodic dissolution follows a common Tafel line with a slope of ca. 120 mVdec-1, independent of the solution pH and the hydrodynamics while the passivation potentials and passivation currents were independent on hydrodynamics but strongly dependent on the pH. In parallel with the electrochemical dissolution, a considerable "anomalous" or chemical Cr dissolution process occurs, as evidenced by the spectrophotometric analyses of the electrolytes for Cr ions after prolonged potentiostating of the electrodes at different potentials, as well as by measuring the electrode weight losses. All these results indicate the existence of a potential independent reaction of Cr dissolution occurring in parallel to the anodic dissolution process. Mechanisms for both the electrochemical and the chemical process are proposed. The consequences of these phenomena on the behavior of some practical systems where chromium or a chromium alloy (e.g., stainless steels) are used are discussed.
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Kosnan, Muhammad Akmal, Mohd Asyadi Azam, Nur Ezyanie Safie, Rose Farahiyan Munawar, and Akito Takasaki. "Recent Progress of Electrode Architecture for MXene/MoS2 Supercapacitor: Preparation Methods and Characterizations." Micromachines 13, no. 11 (October 27, 2022): 1837. http://dx.doi.org/10.3390/mi13111837.
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Since their discovery, MXenes have conferred various intriguing features because of their distinctive structures. Focus has been placed on using MXenes in electrochemical energy storage including a supercapacitor showing significant and promising development. However, like other 2D materials, MXene layers unavoidably experience stacking agglomeration because of its great van der Waals forces, which causes a significant loss of electrochemically active sites. With the help of MoS2, a better MXene-based electrodecan is planned to fabricate supercapacitors with the remarkable electrochemical performance. The synthesis of MXene/MoS2 and the ground effects of supercapacitors are currently being analysed by many researchers internationally. The performance of commercial supercapacitors might be improved via electrode architecture. This analysis will support the design of MXene and MoS2 hybrid electrodes for highly effective supercapacitors. Improved electrode capacitance, voltage window and energy density are discussed in this literature study. With a focus on the most recent electrochemical performance of both MXene and MoS2-based electrodes and devices, this review summarises recent developments in materials synthesis and its characterisation. It also helps to identify the difficulties and fresh possibilities MXenes MoS2 and its hybrid heterostructure in this developing field of energy storage. Future choices for constructing supercapacitors will benefit from this review. This review examines the newest developments in MXene/MoS2 supercapacitors, primarily focusing on compiling literature from 2017 through 2022. This review also presents an overview of the design (structures), recent developments, and challenges of the emerging electrode materials, with thoughts on how well such materials function electrochemically in supercapacitors.
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Kapitonov, Oleksandr. "Cyber-physical Systems in electrochemical measurements." System technologies 4, no. 129 (April 6, 2020): 3–7. http://dx.doi.org/10.34185/1562-9945-4-129-2020-01.
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Effectiveness of cyber-physical systems in electrochemical measurements was analyzed. It was shown that measurements connected tightly environment, computation and communication; the whole system is multi-dynamic, with feedback interaction between 'cyber' and 'physical' parts; volume of data to be processed is unlimited in many cases. These features of the process are typical for cyber-physical systems' application domain.
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Santoso, Agus Dwi, Ferry Budi Cahyono, Widyo Tri Laksana, and Yosi Nurfalah. "Analysed power quality of electrical system ahts vessel." Research, Society and Development 9, no. 8 (July 31, 2020): e836986151. http://dx.doi.org/10.33448/rsd-v9i8.6151.
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A number of power quality issues including electrical harmonics, poor power factor, and voltage instability and imbalance impact on the efficiency of electrical equipment. To support that equipment operates optimally, electrical power is generated must be have good quality. This study has a purpose to examine the power quality of electrical system AHTS (Anchor Handling Tug Supply) vessel. This research was done by quantitative method. Computational techniques used by the software of Total Harmonic Distortion (THD), which shares characteristics and Electrochemical Impedance Spectroscopy (EIS). The result of this analysis indicated that Electrical system in VM INPOSH REGENT have quality power very good of utility systems during full way condition, however during maneuver, there was a particularly high harmonic from non-linier devices used as motor control, which functional a role propulsion. Based on the result above, it can be concluded that after filtering so that harmonic can correct until perimeter secure ABS standard, system is very good during maneuver long site and maneuver on DP system.
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Hoi, T. K. N. "CORROSION CHARACTERIZATIONS OF CARBON STEEL IN CAI TAU RIVER WATER SYSTEM - VIET NAM." Vietnam Journal of Science and Technology 55, no. 5B (March 24, 2018): 66. http://dx.doi.org/10.15625/2525-2518/55/5b/12211.
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Corrosion problem happens in Cai Tau river water system; however, the mechanism is still questionable, resulting in unsolved ways. Therefore, this study focuses on the corrosion characterizations of carbon steel in Cai Tau river water system to analyze the corrosion mechanism using advanced electrochemical techniques and surface analysis. Electrochemical results indicated that Cl‾ and SO42- ions shows a significant effect on corrosion of carbon steel, resulting in pitting corrosion. Whereas, carbon steel showed passive behavior when it immersed in solution containing CO32- ion. Furthermore, pH strongly affects the corrosion properties of carbon steel. It indicated that corrosion of carbon steel increased with a decrease of pH. Surface analysis was done to identify the surface area of the pitting corrosion of carbon steel. Corrosion rates, pitting and corrosion products were clearly observed and analyzed by optical microscopy and X-ray diffraction.
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Villamañán, Rosa M., and Fernando Mata-Pérez. "Kinetic and electrochemical analysis of Ni(II) reduction at the dropping mercury electrode in the presence of thiourea." Canadian Journal of Chemistry 69, no. 4 (April 1, 1991): 599–605. http://dx.doi.org/10.1139/v91-090.
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A study of the two polarographic prewaves of the Ni(II)–thiourea system has been made. The results were analysed by determining Koutecky's parameter from the ratio of the limiting current of the prewaves and the main wave. This parameter is considered an experimental rate constant and the influence of different variables on its value was analyzed. An electrochemical study of the prewaves was also made. Two formal mechanisms to explain both prewaves are proposed. Key words: polarographic prewaves, electrochemical kinetics, reaction mechanisms.
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Bielecki, Zbigniew, Jacek Janucki, Adam Kawalec, Janusz Mikołajczyk, Norbert Pałka, Mateusz Pasternak, Tadeusz Pustelny, Tadeusz Stacewicz, and Jacek Wojtas. "Sensors and Systems for the Detection of Explosive Devices - An Overview." Metrology and Measurement Systems 19, no. 1 (January 1, 2012): 3–28. http://dx.doi.org/10.2478/v10178-012-0001-3.
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Sensors and Systems for the Detection of Explosive Devices - An Overview The paper presents analyses of current research projects connected with explosive material sensors. Sensors are described assigned to X and γ radiation, optical radiation sensors, as well as detectors applied in gas chromatography, electrochemical and chemical sensors. Furthermore, neutron techniques and magnetic resonance devices were analyzed. Special attention was drawn to optoelectronic sensors of explosive devices.
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Paolini, Nicolas Augusto, Alexandre Gonçalves Cordeiro Neto, Alana Cristine Pellanda, Agne Roani de Carvalho Jorge, Bryan de Barros Soares, João Batista Floriano, Marcos Antonio Coelho Berton, Poornima Vijayan P, and Sabu Thomas. "Evaluation of Corrosion Protection of Self-Healing Coatings Containing Tung and Copaiba Oil Microcapsules." International Journal of Polymer Science 2021 (March 3, 2021): 1–13. http://dx.doi.org/10.1155/2021/6650499.
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The objective of the current research is to evaluate and compare the corrosion protection efficiency of the microcapsules containing tung oil and copaiba oil using stereoscopic images, electrochemical tests, open circuit potential (OCP), and polarization curves (Tafel analysis). Carbon steel plates were painted with three different coating systems: (a) a coating system with an automotive primer which served as the control, (b) a coating system with microcapsules containing 3% tung oil, and (c) a coating system with microcapsules containing 3% copaiba oil. A crosscut was performed using a scalpel on the coating surfaces to promote the release of the oils, and after drying, electrochemical cells were assembled using electrolyte 3% NaCl. From OCP analyses, it was verified that the coating system containing tung oil loaded microcapsules obtained more positive final values than the control system and the coating system containing copaiba oil loaded microcapsules. The stereoscope images corroborate the OCP results, and the polarization curve analyses also indicated that the microcapsules containing tung oil offer better corrosion protection than the other systems studied.
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Giacobassi, Cassie A., Daniela A. Oliveira, Cicero C. Pola, Dong Xiang, Yifan Tang, Shoumen Palit Austin Datta, Eric S. McLamore, and Carmen L. Gomes. "Sense–Analyze–Respond–Actuate (SARA) Paradigm: Proof of Concept System Spanning Nanoscale and Macroscale Actuation for Detection of Escherichia coli in Aqueous Media." Actuators 10, no. 1 (December 23, 2020): 2. http://dx.doi.org/10.3390/act10010002.
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Foodborne pathogens are a major concern for public health. We demonstrate for the first time a partially automated sensing system for rapid (~17 min), label-free impedimetric detection of Escherichia coli spp. in food samples (vegetable broth) and hydroponic media (aeroponic lettuce system) based on temperature-responsive poly(N-isopropylacrylamide) (PNIPAAm) nanobrushes. This proof of concept (PoC) for the Sense-Analyze-Respond-Actuate (SARA) paradigm uses a biomimetic nanostructure that is analyzed and actuated with a smartphone. The bio-inspired soft material and sensing mechanism is inspired by binary symbiotic systems found in nature, where low concentrations of bacteria are captured from complex matrices by brush actuation driven by concentration gradients at the tissue surface. To mimic this natural actuation system, carbon-metal nanohybrid sensors were fabricated as the transducer layer, and coated with PNIPAAm nanobrushes. The most effective coating and actuation protocol for E. coli detection at various temperatures above/below the critical solution temperature of PNIPAAm was determined using a series of electrochemical experiments. After analyzing nanobrush actuation in stagnant media, we developed a flow through system using a series of pumps that are triggered by electrochemical events at the surface of the biosensor. SARA PoC may be viewed as a cyber-physical system that actuates nanomaterials using smartphone-based electroanalytical testing of samples. This study demonstrates thermal actuation of polymer nanobrushes to detect (sense) bacteria using a cyber-physical systems (CPS) approach. This PoC may catalyze the development of smart sensors capable of actuation at the nanoscale (stimulus-response polymer) and macroscale (non-microfluidic pumping).