Impedance Values Research Articles

Impact of a hybrid coating REBCO-CC-Cu to the resistive wall beam impedance of the FCC-hh beam screen

The Future Circular Hadron Collider design studies proposed a novel dual chamber beam screen consisting of copper and stainless steel. However, one concern about the current design is the inherent resistive wall beam impedance of the beam screen, which may not be low enough to guarantee stable beam operation especially critical on the vertical plane. In order to reduce the resistive wall beam impedance as much as possible while keeping the dipole field quality within specifications, a hybrid beam screen consisting of REBCO-CC and Cu is proposed for the inner chamber of the beam screen. We performed a comprehensive position and REBCO-CC content study, leading to an optimum configuration for a REBCO-CC-Cu hybrid design. These studies utilized measured values of REBCO-CC surface impedance obtained under realistic FCC-hh conditions. The calculations were carried out by combining numerical simulations and beam coupling impedance theory for general beam pipe cross sections, where we found a substantial decrease in the vertical resistive wall beam impedance by about an order of magnitude compared to the nominal beam screen design made of copper. Limitations of the proposed design and possible mitigation actions are also discussed.

A simple strategy to significantly improve the anticorrosion and aging resistance of epoxy coatings by adding polyaniline modified multi-walled carbon nanotubes

Epoxy coatings are widely used for corrosion protection of metals, but under extremely harsh environments, the epoxy polymer chains such as the C-O bonds of epoxy ether and aromatic ether, and the -OH in the epoxy chain structure can also undergo aging and degradation, leading to the failure of the coating in service. How to extend the anti-aging capability of epoxy resins while maintaining their other properties unchanged has become a major challenge in the practical application of epoxy coatings. In this study, the polyaniline (PANI) modified multi-walled carbon nanotubes (MWCNT@PANI) were synthesized by polymerization in-situ and added to epoxy resin as an anti-aging filler. The various measurements have been adopted to characterize the composition and structure of MWCNT@PANI, and the anticorrosive performance of the composite coating for carbon steel were evaluated via salt spray, chemical aging and UV light aging. Results showed that the impedance value of the blank epoxy coating decreases by at least two orders of magnitude after the salt spray tests, and the contact angle decreases by about 30° and gradually changes from hydrophobic to hydrophilic, indicating a significant decline in corrosion resistance. In contrast, the composite coating confirmed the excellent anti-aging performance, while the impedance values increased by approximately 2-5 orders of magnitude compared to that in blank epoxy coatings, and remained around 1010 Ω·cm2. Given the dense encapsulation of MWCNT@PANI, the dispersion stability between the filler and EP can be improved, and the effective corrosion resistance performance was also supported by molecular dynamic simulation. Besides that, the ability of free radical quenching along with the labyrinth effect and hydrophobic interaction have also been investigated to explain the anticorrosion and anti-aging mechanism.

Self-healing and mechanical properties of a designed Zn2 + ionic clusters rubber engineered cementitious composites with tight bonding

In this study, a hydrophilic Carboxylated styrene butadiene rubber/ Zinc dimethacrylate (XSBR/ZDMA) rubber with a surface rich in ionic clusters was developed and introduced into engineered cementitious composites (ECC), focusing on the effect of the interfacial bonding between aggregate-matrix on the mechanical properties of ECC. As part of this study, the hydrophilicity of rubber was evaluated by scanning electron microscopy (SEM) and DSA100E tests. And the effects of matrix-aggregate bonding on the mechanical properties of ECC were assessed by uniaxial tensile tests, compared to normal rubber-ECC with the same 40 % replacement of silica sand, XSBR/ZDMA-ECC has 32.73 % higher tensile strength and 27.11 % higher ductility. In addition, electrochemical impedance spectroscopy (EIS) tests were conducted on the self-healing properties of ECC at different pre-loading levels. The test results indicate a high consistency between the electrochemical impedance spectroscopy (EIS) and the conclusions drawn from the second tensile experiment following self-healing, along with the digital microscope measurement of crack number and width. The results showed that the XSBR/ZDMA rubber established more chemical bonding connections with the cement matrix, resulting in finer cracks in the ECC, with a 20 % increase in the number of crack bars and a 36.8 % decrease in crack width compared to the same level of normal rubber-ECC. Moreover, under the conditions of dry and wet cycles, the fine cracks in the ECC exhibit a more effective self-healing effect. At 2 % preload, XSBR/ZDMA-ECC maintains strain hardening and high strength, exceeding normal rubber-ECC's ultimate load by 67.7 %. Characterization of ECC self-healing using electrochemical impedance spectroscopy showed a 66 % increase in real impedance values for XSBR/ZDMA-ECC and a 93.2 % increase in real impedance values for normal rubber-ECC over a 28-day self-healing age period at a 2 % preloading level, and the real impedance of XSBR/ZDMA-ECC was 56 % lower than that of normal rubber-ECC at 0 days of self-healing curing age, and the impedance value reached a flat state earlier. It is recognized in the field of ECC that aggregate-matrix interfaces are a gap in the literature, and the results of this study can contribute in some way to exploring this direction.

Impedance Value Prediction of Carbon Nanotube/Polystyrene Nanocomposites Using Tree-Based Machine Learning Models and the Taguchi Technique

The impedance characteristics of multi-walled carbon nanotube (MWCNT)/polystyrene nanocomposites synthesized via microwave-assisted in-situ polymerization were systematically investigated to determine the effects of microwave power, exposure time, and frequency on impedance properties. The Taguchi method and analysis of variance (ANOVA) identified microwave power as the most significant factor, followed by exposure duration and frequency. A predictive model was developed, demonstrating high accuracy with a coefficient of determination (R²) of 0.96 between model predictions and experimental results. Additionally, response surface methodology (RSM) and contour plots were applied to explore optimal parameter combinations, offering valuable insights for achieving tailored impedance values. Machine learning model including Decision Tree, Random Forest, Extreme Gradient Boosting (XGBoost), Categorical Boost (CatBoost), and Light Gradient-Boosting Machine (LightGBM) were employed to enhance predictive capabilities. Among these, Random Forest and CatBoost demonstrated superior accuracy, achieving R² values of 0.9880 and 0.9811 on testing data, respectively, while Decision Tree and LightGBM exhibited lower performance. This study highlights the potential of machine learning methods to precisely adjust and tailor impedance properties of PS/CNT nanocomposites, supporting the engineering of materials for diverse applications across materials science and engineering.

NIR-driven self-healing PANI/Ag/ basalt scales coatings with robust anticorrosion and microwave absorption properties

Addressing electromagnetic interference and corrosion of electronic devices and communications facilities in the marine environments with high humidity and high salt spray remains a challenge. In this study, polyaniline/silver/basalt scales (PANI/Ag/BS) fillers were prepared to obtain dual functions of microwave absorption (MA) and corrosion resistance, whereas the introduce of PANI not only enabled the fillers to possess the photo-thermal effect, but also improved their compatibility with epoxy resin. The MA performance test proves that the PANI/Ag/BS has a minimum reflection loss (RL) of -30.55 dB at a thickness of 2.08 mm and achieves an effective absorption bandwidth (EAB) value of 5.28 GHz at a thickness of 2.40 mm. Meanwhile, the EIS measurement demonstrates that the coating has exceptional performance during the 240 h immersion, and the low-frequency impedance value (|Z|0.01Hz) is about 2.5 × 108 Ω·cm2. In addition, the photothermal effect of PANI/Ag/BS endows the coating with remarkable photothermal repair capability, which enabled self-healing within 30 s. This work opens another avenue for the development of bifunctional coating with enhanced anti-corrosion and microwave absorption.

Changes in ultrasonic elastometry parameters of the liver parenchyma during its radiofrequency ablation (experimental study)

Objective. To determine in the experiment the changes in the elasticity of the liver parenchyma during its radiofrequency ablation at different distances from the electrode and their correspondence to the zones of irreversible thermal damage of the tissue. Materials and methods. The elasticity of the parenchyma of six samples of isolated porcine liver during radiofrequency ablation in automatic mode for 12 min with an initial applicator power of 50 W and its subsequent automatic increase by 10 W/min until critical impedance values were reached was evaluated by ultrasonic elastometry with the determination of the Young's modulus. The elasticity of the liver in kilopascals was determined before the start of radiofrequency ablation, during its implementation every minute for 12 minutes and 15, 30 and 60 minutes after the procedure in three zones located at a distance of 1.0, 1.8 and 3.0 cm from the applicator. Results. Before radiofrequency ablation, the elasticity of the liver parenchyma ranged from 4.1 to 9.3 kPa and averaged (6.64 ± 1.55) kPa. At the maximum power of the applicator – (109.67 ± 4.97) W – the transverse size of the hyperechogenic “cloud” at the 12th minute of the procedure was (18.0 ± 1.41) mm. The value of Young's modulus in the first zone of elastometry statistically significantly increased from the 1st minute of radiofrequency ablation and by the 11th minute reached the level of (46.38 ± 5.43) kPa and did not change significantly thereafter. In the second zone, a statistically significant increase in the value of Young's modulus to (44.22 ± 6.55) kPa was observed throughout the procedure, and after its termination it changed statistically insignificantly. In the third zone, changes in the value of Young's modulus occurred 3 minutes after the start of the procedure and continued until its completion, but its maximum value – (15.63 ± 1.57) kPa – exceeded the baseline level only about 2 times, and an hour after the completion of radiofrequency ablation, the value of Young's modulus decreased statistically significantly. Conclusions. The stiffness of the parenchyma of isolated porcine liver increases significantly during radiofrequency ablation under conditions of its sufficient duration, and depending on the distance to the electrode, these changes have different phase character. In loci corresponding to the zone of irreversible tissue necrosis, the initial slow approximately twofold increase in Young's modulus during the first 3 to 4 minutes is followed by a rapid exponential increase in the next 5 to 6 minutes and the formation of a plateau with 6 to 8 times the initial level, after which the index does not change significantly. To determine the edge of liver parenchyma ablation by elastometry, in addition to the absolute value of Young's modulus at the end of radiofrequency ablation and the multiplicity of its increase relative to the baseline value, such criteria as the three–phase nature of the increase in this indicator and the absence of its decrease within an hour after the procedure are equally important.

A highly sensitive microfluidic biosensor for rapid and accurate detection of Salmonella in raw chicken products

This paper presents an investigation of a fluidic-based impedance biosensor for rapid and accurate detection of Salmonella Typhimurium in raw chicken carcass rinsate. The biosensor is engineered with multiple distinct regions that concentrates Salmonella antigens to a detectable level, subsequently trapping the concentrated Salmonella samples on top of the detection interdigitated electrode array coated with a specific Salmonella antibody, maximizing the number of captured antigens. Detection is achieved through the antibody-antigen binding process, where binding events changes impedance values, providing a reliable method for identifying and quantifying Salmonella. The biosensor demonstrated a low limit of detection (LOD) of 1–2 cells/ml within 40–50 min. The findings demonstrated that the biosensor distinguishes low concentrations of live Salmonella cells, even in the presence of high concentrations of dead Salmonella cells, and non-specific binding pathogens viz., Listeria monocytogenes and E. coli O157:H7.

Mobile brain imaging in butoh dancers: from rehearsals to public performance

BackgroundDissecting the neurobiology of dance would shed light on a complex, yet ubiquitous, form of human communication. In this experiment, we sought to study, via mobile electroencephalography (EEG), the brain activity of five experienced dancers while dancing butoh, a postmodern dance that originated in Japan.ResultsWe report the experimental design, methods, and practical execution of a highly interdisciplinary project that required the collaboration of dancers, engineers, neuroscientists, musicians, and multimedia artists, among others. We explain in detail how we technically validated all our EEG procedures (e.g., via impedance value monitoring) and minimized potential artifacts in our recordings (e.g., via electrooculography and inertial measurement units). We also describe the engineering details and hardware that enabled us to achieve synchronization between signals recorded at different sampling frequencies, along with a signal preprocessing and denoising pipeline that we used for data re-sampling and power line noise removal. As our experiment culminated in a live performance, where we generated a real-time visualization of the dancers’ interbrain synchrony on a screen via an artistic brain-computer interface, we outline all the methodology (e.g., filtering, time-windows, equation) we used for online bispectrum estimations. Additionally, we provide access to all the raw EEG data and codes we used in our recordings. We, lastly, discuss how we envision that the data could be used to address several hypotheses, such as that of interbrain synchrony or the motor theory of vocal learning.ConclusionsBeing, to our knowledge, the first study to report synchronous and simultaneous recording from five dancers, we expect that our findings will inform future art-science collaborations, as well as dance-movement therapies.

New method for graphing impedance values as an analytical tool suitable for electrochemical impedance spectroscopy

A new method for graphing electrical impedance values named a “differentiation-based Bode plot” is proposed. This method facilitates the analysis procedure and reduces the arbitrariness of the interpretation of electrochemical impedance spectroscopy (EIS) data. Among the various methods for graphing impedance values, Nyquist plots are commonly adopted (primarily in the field of EIS) because of the apparent correlation between their shape and the corresponding equivalent circuit. However, because Nyquist plots do not contain frequency information, Bode phase and magnitude plots are frequently utilized. Although such plots are suitable for determining the absolute magnitude and phase of the impedance, they are not always useful for selecting the structure of an equivalent circuit, which is a hypothetical model for electrochemical cells. In the proposed method, instead of the real (Z’) and imaginary (Z’’) parts, two functions of the impedance derivatives with respect to frequency, i.e., dZ’/d(log f) and dZ’’/d(log f), are plotted. As substitutions for the Bode phase and magnitude plots, arctan{dZ’’/d(log f) ÷ dZ’/d(log f)} and log[sqrt{(dZ’/d(log f))2 + (dZ’’/d(log f))2}] are plotted against log f. Unlike the classical Bode plot, the differentiation-based Bode plot is independent of the lateral shift in the Nyquist plot, which is advantageous for determining an equivalent circuit. To demonstrate this advantage, the impedance values of typical equivalent circuits used in electrochemistry are calculated and plotted to compare differentiation-based Bode plots with Nyquist and classical Bode plots.

Ti3C2Tx MXene/MoS2 hybrid nanocomposites for synergistic smart corrosion protection of epoxy coatings

MXene nanosheets have recently become a focus of research for corrosion protection due to their two-dimensional, sheet-like structure and distinct physicochemical characteristics. Nevertheless, their susceptibility to restacking and oxidation restricts their practical applications. To address this, the study proposes a custom hybrid structure by growing molybdenum disulfide (MoS2) nanoparticles on the Ti3C2 MXene nanosheets (MX/MS) to prevent oxidation and restacking. This innovative structural design is essential for corrosion-protective coatings, as the sheet-like configuration enhances the barrier properties. The manufacturing of the MX/MS nanoparticles was verified by their characterization employing field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The barrier properties and self-healing functions of the nanoparticle-filled epoxy coatings were evaluated using electrochemical impedance spectroscopy (EIS) and salt spray tests. The epoxy resin including 0.5 wt% MX/MS nanoparticles exhibited outstanding corrosion resistance, with an impedance value (|Z|0.01Hz) of 23.77 GΩ.cm2 after 70 days of immersion. After 48 h of immersion, the coatings also showed a high impedance value (log|Z|0.01Hz = 4.24) and excellent self-healing capabilities in the scratched areas. Additionally, after 42 days, the filled nanohybrid coatings showed the least amount of rust and corrosion product according to salt spray analysis. The results of cathodic delamination and pull-off tests indicated that in comparison to the neat epoxy (11 mm and 70 %), the filled coatings containing the synthesized nanofiller had the lowest cathodic delamination radius (1.7 mm) and lowest adhesion loss (46 %). This study highlights the effectiveness of Ti3C2/MoS2 hybrid in enhancing the anticorrosive performance of organic coatings, offering a novel approach for designing high-performance additives with promising applications in various fields requiring corrosion protection.

Enhanced Grain Boundary Resistance Resulting in High Permittivity and Low Dielectric Loss in CaCu3Ti4O12/LaNiO3

(1-X) CaCu3Ti4O12 + (X) LaNiO3 composite ceramics were fabricated using pre-reacted calcium copper titanate CaCu3Ti4O12 (CCTO) and lanthanum nickelate LaNiO3 (LNO) and their crystallographic structure and morphology were studied to measure dielectric, impedance, and conductivity values. X-ray diffraction peaks show that CCTO/LNO composites are in a cubic structure. Scanning electron microscopy images show denser and more uniform grains with thin grain boundaries and a smaller average grain size. The permittivity of CCTO is stable in the range 102–106 Hz, but the composites show huge progress in permittivity by space charge polarization and relaxation in the range 103–104 Hz, demonstrating improved dielectric properties. The 0.98(CaCu3Ti4O12)+0.02(LaNiO3) sample showed a dielectric constant of 2.58 × 104 at 1 kHz, which is superior to pure CCTO (2.28 × 104 at 1 kHz). The electrical behaviour of the metallic filler on the composites was investigated using impedance spectroscopy analysis. The resistance of grain boundary increases with LNO. Activation energies were found to be 0.92, 0.95, and 0.90 eV for x = 0.1, 0.2, and 0.3, respectively, and these values are better than that of pristine CCTO (0.85 eV) sample. These results indicate that the prepared CCTO/LNO samples could be useul for high energy applications.

Esophageal chest pain resembles heartburn in reflux metrics and response to proton pump inhibitor therapy.

Gastro-esophageal reflux disease (GERD) is the most common cause for noncardiac chest pain (NCCP), with an estimated prevalence rate ranging between 30% and 60%. Heartburn and NCCP may share common mechanisms. To assess whether particular patterns of impedance-pH variables characterize patients with dominant heartburn, regurgitation, or NCCP and their ability to predict proton pump inhibitor (PPI) response for each symptom, GERD patients, evaluated with high-resolution manometry (HRM) and impedance-pH, were included. In total, 109 NCCP, 68 heartburn, and 64 regurgitation patients were included. Pathological reflux episodes were observed in 28%, 19%, and 56% (p < 0.001). Pathological mean nocturnal baseline impedance (MNBI) values were observed in 55%, 53%, and 34% (p < 0.05). Hypomotility was more frequent in NCCP compared to heartburn patients (p < 0.05). When comparing NCCP with heartburn, hypomotility was associated with NCCP perception (OR: 2.34, 95% CI: 1.23-4.43; p < 0.01). When comparing NCCP with regurgitation, >80 refluxes and type 2/3 esophagogastric junction (EGJ) were associated with regurgitation perception (OR: 0.31, 95% CI: 0.16-0.59; p < 0.001, and OR: 0.5, 95% CI: 0.27-0.93; p < 0.05), while pathological MNBI was associated with NCCP perception (OR: 2.34, 95% CI: 1.23-4.43; p < 0.01). 45.5% NCCP patients, 45.6% with heartburn, and 36% with regurgitation responded to PPIs (p < 0.05). At multivariate analysis, pathological MNBI or PSPW index were associated with PPI responsiveness in patients with NCCP or heartburn, while in patients with regurgitation, pathological MNBI was associated with PPI responsiveness and a reflux number >80 to PPI refractoriness. We highlight the usefulness of an accurate clinical and functional evaluation of GERD patients, allowing to discriminate particular characteristics in patients with dominant heartburn, NCCP, or regurgitation, which may benefit of distinct therapeutic strategies.

Structure and properties of aluminum alloy composite conversion coating

The intrinsic corrosion resistance of aluminum alloy is relatively poor and needs to be enhanced through anodic oxidation treatment. Traditional anodic oxide films predominantly consist of aluminum oxide and are characterized by low toughness and poor impact resistance, making them unsuitable for environments with high temperatures, large temperature variations, and stringent corrosion resistance requirements. This study employs oxalic acid and trace amounts of ammonium fluoride as the electrolyte for anodic oxidation treatment of 6061 aluminum alloy. Through electrochemical oxidation and chemical co-deposition, a composite oxide film is prepared. The composition of the oxide film includes Al2C6O12, AlF3, AlOOH, and amorphous Al2O3, exhibiting a micro-porous structure with an average pore diameter of 10–20 nm. The surface of the micropores is covered by a relatively dense chemical conversion film, which seals the micropores and enhances the corrosion resistance of the oxide film. When the concentration of oxalic acid is 10 g/L and the concentration of ammonium fluoride is 0.5 g/L, the composite oxide film does not crack when bent at 90° at room temperature. Furthermore, no cracks are observed after heating to 100°C and holding for 30 min or even after maintaining at 300°C for 6 h. The electrochemical impedance reaches 5.891 × 106 Ω cm2, while the sulfuric acid anodic oxide film develops cracks when bent at 30° at room temperature or heated to 58°C, with a low-frequency impedance value of 3.649 × 105 Ω cm2.

Assessing Pain Levels Using Bioelectrical Impedance in Low Back Pain Patients: Clinical Performance Evaluation.

Musculoskeletal pain is one of the leading causes of years lived with disability worldwide and has a negative impact on daily life and quality of life. The purpose of this study was to analyze the electrical characteristics of back pain by measuring and calculating bioelectrical impedance variables (R, Z, PA) in 85 subjects (45 in the Healthy group and 40 in the LBP group). Additionally, impedance measurements were conducted on 20 subjects (10 in the Young group and 10 in the Older group) to assess the impact of aging. Bioelectrical impedance parameter values were higher in cases of back pain, and correlation analysis showed that there was a statistically significant difference between the Healthy and LBP groups (p < 0.05). A positive correlation was found between impedance parameters and pain related indices (ODI, RMDQ, VAS) (mean R, Z, PA: 0.68, 0.54, 0.75), with BMI positively correlating only with PA (0.493). Diagnostic accuracy for detecting back pain exceeded 95% (R, Z, PA: 0.984, 0.984, 0.963). Results indicated that aging did not significantly affect impedance values. The bioelectrical impedance measurement device used in this study, with its simultaneous diagnostic and therapeutic capabilities, proved useful for real-time pain diagnosis and treatment monitoring, highlighting its potential clinical utility.

Effect of Gd doping on the microstructure and electrical characteristics of Maghemite (γ-Fe₂O₃) ceramics

AbstractThis paper presents a novel study on the microstructure and electrical properties of gadolinium (Gd) doped maghemite (γ-Fe₂O₃) nanoparticles, emphasizing their significance for advanced applications in efficient materials. X-ray diffraction analysis confirmed that both pure and doped samples crystallized in a cubic structure (P4332 space group) with high purity. Gd doping significantly increased crystallite size and altered particle morphology, as shown by transmission electron microscopy (TEM), which revealed larger nanoparticles with cubic shapes. Thermal analysis (TGA and DTG) indicated that higher Gd concentrations enhanced thermal instability, affecting structural integrity. FTIR spectra showed shifts in Fe-O bond vibrations, suggesting lattice distortions and increased disorder. BET measurements indicated that higher Gd doping led to greater mesoporosity and surface area, countering expectations of densification. Electrical conductivity and impedance studies revealed two distinct regions: a constant conductivity at low frequencies and an exponential increase at high frequencies, attributed to small polaron hopping. Activation energy values below 200 meV support this mechanism. Gd doping decreased overall conductivity due to disrupted atomic arrangements, increased electron scattering, and modifications in the electronic band structure. Complex impedance spectroscopy illustrated higher real impedance values for doped samples, with increased Gd concentration leading to enhanced impedance. These findings elucidate the impact of Gd on the electrical properties of maghemite nanoparticles and highlight their importance in meeting the growing demands for highly efficient technologies in energy storage and electronic devices. Graphical Abstract

Green Film Forming Technology Based on Polydopamine Galvanized

At present, the mainstream passivation agent is chromate passivation agent, but it has the disadvantages of high toxicity and high price, so this project seeks to find a safer, cheap and green chromium-free passivation agent. Because dopamine and chitosan derivatives have certain corrosion inhibition properties on metals in acidic media, these polymer corrosion inhibitors can achieve high corrosion inhibition rates at high concentrations. Therefore, in this experiment, dopamine was added on the basis of sodium silicate, and the sample was passivated to explore the potential enhancement effect of dopamine on the passivated film performance. After the sample was treated, the impedance value could be fitted by electrochemical impedance spectroscopy and Zsimpwin software, and then the Tafel polarization curve was drawn. It was found that the addition of dopamine significantly improved the corrosion resistance of the passivated film. By promoting the positive shift of self-corrosion potential and greatly reducing the self-corrosion current density, the protective barrier effect of passivation film on metal matrix is effectively enhanced. Finally, the experiment successfully proved that the corrosion resistance of the passivation film after adding dopamine was better

Standardization of transthoracic impedance values for estimating heart failure and its utility

Abstract Background The use of intrathoracic impedance for examining pleural effusion in heart failure patients has been explored previously. However, due to concerns about its accuracy and complexity, transthoracic impedance values have had limitations in quantifying extravascular lung water. Our dual objectives were to clarify the relationship between intrathoracic conditions and percutaneous transthoracic impedance values, and to establish a basic model for a new machine learning-based estimation system for assessing intrathoracic conditions in patients with heart failure. Methods First, we developed a live porcine congested lung model that induced pleural effusion by substantial fluid loading, and then longitudinally evaluated its correlation with percutaneous transthoracic impedance values. Second, we conducted multi-frequency bioelectrical impedance analysis to simultaneously collect electrical, physical, and hematological data from 63 hospitalized heart failure patients and 82 healthy volunteers Results In the porcine model, pleural effusion correlated with a concurrent decrease in SpO2 and a gradual decrease in impedance. We indexed and generated features from the measured values and developed an intrathoracic estimation model based on electrical measurements and clinical findings using a decision tree-based machine learning approach. Among the 286 features collected per individual, the model used 16 features. Notably, the model demonstrated high accuracy in discriminating patients with pleural effusion, achieving an AUC of 0.905 (95% CI: 0.870-0.940) in cross-validation, significantly outperforming the conventional frequency-based method. Conclusions Transthoracic impedance values, when indexed, reflect intrathoracic conditions and improve estimation. Our results highlighted the potential of machine learning and thoracic impedance measurement for accurate estimation of pleural effusion. This approach provides an effective means of assessing intrathoracic conditions. Figure: The upper figure shows the relationship between impedance values and pleural effusion in the congested lung model. On these results, human data were collected to construct the estimation model. The lower illustrates the accuracy of the model and provides a comprehensive view of the system.

Modeling and Simulation of Wide-Frequency Characteristics of Electromagnetic Standard Voltage Transformer

To achieve the broadband applicability of standard voltage transformers in “dual high” power systems, an equivalent circuit model of the standard voltage transformer is first established. Using the complex magnetic permeability method and utilizing existing core parameters, the excitation impedance values are obtained. Next, based on the equivalent circuit model, the no-load error function of the standard voltage transformer is analyzed, and through simulation, the no-load error response curve of the standard voltage transformer in the frequency range of 20 Hz to 3000 Hz is derived. The simulation results indicate that within the 20 Hz to 700 Hz range, both the no-load ratio error and the no-load angular error meet the accuracy requirements, with the ratio error within ±0.05% and the angular error within 2′. Additionally, the derivation of the error transfer function demonstrates the correlation between the no-load error values and the number of turns and cross-sectional area of the standard voltage transformer. Simulation results, obtained by increasing and decreasing the number of turns and cross-sectional area by 10%, provide valuable insights for the error compensation and structural design of standard voltage transformers.

Constructing ZSM-5 loaded with 2-mercaptobenzimidazole on glass fiber for enhancing the anti-corrosion and erosion resistance properties of epoxy coating

Glass fiber reinforced polymer coatings (GFRPC) are used to protect steel structures in harsh marine environments due to high mechanical strength and chemical stability. The composite coating not only suffers from impact damage by seawater and sediment but also experiences corrosion damage in the splash zone. However, the GF has weak interfacial adhesion with polymer resins due to the chemical inertia and smooth surface, which limits the service lifespan of GFPRC. Hence, ZSM-5 zeolite were in situ prepared on the surface of glass fibers by hydrothermal synthesis, and 2-mercaptobenzimidazole (MBI) was further adsorbed to obtain difunctional hybrid glass fibers (ZGFM) to enhance the interfacial adhesion strength of glass fiber/resin and also the erosion resistance and anti-corrosion ability of composite coatings. Compared to GF/EP, the interfacial shear strength of ZGFM/EP was increased by 104.39 %. After immersion under an alternating hydrostatic pressure of 20 MPa for 12 days, the impedance value of the ZGFM/EP composite coating remained at 6.40 × 109 Ω•cm2, demonstrating outstanding deep-sea anti-corrosion performance. Following the erosion test, the ZGFM/EP exhibited a reduction in mass loss and volume loss by 10.65 % and 12.55 %, respectively, in comparison to the pure EP coating. The excellent interfacial strength between ZGFM and EP ensured effective stress transfer, which prevented crack propagation, thus enhancing the mechanical properties and erosion resistance of the composite coating. Meanwhile, electrochemical experiment proves glass fiber with MBI loaded obviously inhibits the corrosion reaction.

Corrosion mapping of intermetallic in a dissimilar weldment using in-situ alternating current scanning electrochemical microscopy

In the present work, in-situ corrosion activity mapping across explosively welded 304 L SS-Zr-4 dissimilar joint interfaces was performed using intermittent contact alternating current-scanning electrochemical microscopy (IC-AC-SECM). Two weld joint samples, one with a regular interface and another with an irregular interface, were examined for their local surface activities at an open circuit potential in tap water without using a redox mediator. The SEM micrographs showed the formation of intermetallics at localized regions of the irregular interface weld sample but not in the regular interface sample. The 304 L SS regions of the welds were relatively anodic, with current and impedance magnitude values of 270 ± 20 nA and 380 ± 20 kΩ respectively, when compared to the Zr-4 regions with the corresponding values of 160 ± 20 nA and 630 ± 20 kΩ, due to galvanic coupling effect. The IC-AC-SECM technique enabled the in-situ determination of corrosion activity of localized intermetallic region within the weldment. The current and impedance magnitude values of the intermetallic region were ∼ 240 nA and ∼ 450 kΩ, respectively, showing only a slightly lesser anodic activity as compared to the 304 L SS base metal. The results obtained from the IC-AC-SECM mapping showed a good correlation with the EDS elemental mapping of the dissimilar weldment with intermetallic. The findings indicate the effectiveness of the IC-AC-SECM technique for the in-situ localized corrosion mapping of dissimilar weld joints, showcasing its potential for various applications in assessing weld integrity.