Impedance Method Research Articles

Precise Inner Radius and Inner Surface Shape Estimation in Finite Conductive Tubes Using Eddy Current Technique

Inner radius inspection is critical in the production of tubes, particularly those with small thicknesses, to ensure structural integrity and performance. Traditional ultrasonic methods often fall short in measuring thin-walled tubes, necessitating the use of eddy current method for its non-contact and highly sensitive capabilities. In this paper, we employ the finite element method (FEM) to calculate the output signal of a vertical surface probe in the vicinity of a finite conductive tube. We address the significant impact of edge effects, which can deteriorate the primary signal from material properties. The probe data are then used to determine the inner radius through a regression method, and an evaluation technique is proposed to inspect the ovality of the inner surface. Our results demonstrate the accuracy and efficiency of the FEM to predict coil impedance and regression methods to evaluate both the inner radius and the shape of the inner surface, even in the presence of noise. This research provides significant contributions to the field of tube inspection, particularly in industries where precision is paramount, such as oil and gas industries, automotive, and medical sectors.

Low Serum Beta-2 Microglobulin Level: A Possible Biomarker for Sarcopenia in the Elderly Population.

Background and Objectives: One of the most critical problems regarding sarcopenia is the difficulty of the diagnosis process. This study aimed to determine the prevalence and investigate the role of serum beta-2 microglobulin level as a biomarker for diagnosing sarcopenia. Materials and Methods: This nested case-control study was conducted between 2023 and 2024 on 251 older adults. Muscle strength was measured using a hand dynamometer, and muscle mass was assessed using the bioelectrical impedance method. Individuals with low muscle strength and low muscle mass were accepted as having definitive sarcopenia. Results: The mean age of the 251 older adults included in the study was 72.19 ± 6.11 years. The prevalence of sarcopenia in individuals aged 65 years and over was found to be 5.2%. Serum beta-2 microglobulin levels were statistically significantly lower in sarcopenic participants compared to the control group (p = 0.002). The optimal cut-off value for serum beta-2 microglobulin level was 2.26 mcg/mL, and values lower than this point were found to be diagnostic for sarcopenia. Regarding the cut-off value, the sensitivity was 92.31% and the specificity was 80.77%, the positive predictive value was 70.59%, the negative predictive value was 95.45%, the Youden index was 0.731, and the area under the curve value was 0.901. Individuals who had beta-2 microglobulin levels below 2.26 mcg/mL were found to have a 10.75 times higher risk of sarcopenia. Conclusions: A low serum beta-2 microglobulin level has the potential to be an important candidate biomarker for the diagnosis of sarcopenia.

Validating respiratory rate measurements in patients receiving high flow nasal cannula: a comparative study of Nellcor PM1000N and visual inspection

PurposeRecently, the Nellcor PM1000N was developed for the concurrent assessment of respiratory rate and percutaneous oxygen saturation. However, the validation of respiratory rate measurements in patients receiving a high-flow nasal cannula (HFNC) using the PM1000N remains unestablished. Therefore, this study aimed to assess the validity of respiratory rate measurements obtained using PM1000N in patients receiving HFNC.MethodsA retrospective assessment was conducted on the respiratory rate measurements obtained using the PM1000N and electrocardiogram (ECG) impedance methods in comparison to those visually assessed by nurses. This evaluation included patients admitted to the Intensive Care Unit (ICU) of Sapporo Medical University Hospital who received HFNC between June 2022 and December 2022. Correlation coefficients, intraclass correlation coefficients (ICCs), Bland–Altman plots, and t-tests were employed to assess the concordance between the visually observed respiratory rates by nurses and those recorded by the PM1000N and ECG impedance.ResultsTwenty patients were enrolled in this study. Among them, 119 instances of respiratory rate were recorded. The ICCs for the PM1000N and impedance methods were 0.918 and 0.846, respectively, compared with the rates visually assessed by nurses. The mean differences were p = 0.947 (95% CI −3.186 to 0.2987) and p < .001 (95% CI 16.4609–17.9532), respectively.ConclusionThe PM1000N demonstrated superiority over ECG impedance in measuring respiratory rate in patients with HFNC. Furthermore, PM1000N shows promise for effective application in patients receiving HFNC.

Application of the electrical impedance method to steel/steel EHD point contacts

The authors have previously developed the electrical impedance method which simultaneously measure the thickness and breakdown ratio of oil films in EHD (elastohydrodynamic) contacts. Furthermore, using a ball-on-disc-type apparatus, the authors have also confirmed that the accuracy of oil film measurement by the developed method is comparable to that of optical interferometry (i.e., glass-steel contacts). In this study, we discussed the experimental results obtained by applying the electrical impedance method to steel-steel contacts using a steel disc instead of a glass disc. It was found that under the mixed lubrication regime where wear occurs, the oil film thickness obtained by this method is calculated to be significantly thicker than the theoretical value. This can be attributed to the increase in the apparent dielectric constant of the lubricant due to wear particles in the lubricant.

Structural Damage Detection Using PZT Transmission Line Circuit Model.

Arrangements of piezoelectric transducers, such as PZT (lead zirconate titanate), have been widely used in numerous structural health monitoring (SHM) applications. Usually, when two or more PZT transducers are placed close together, significant interference, namely crosstalk, appears. Such an effect is usually neglected in most SHM applications. However, it can potentially be used as a sensitive parameter to identify structural faults. Accordingly, this work proposes using the crosstalk effect in an arrangement of PZT transducers modeled as a multiconductor transmission line to detect structural damage. This effect is exploited by computing an impedance matrix representing a host structure with PZTs attached to it. The proposed method was assessed in an aluminum beam structure with two PZTs attached to it using finite element modeling in OnScale® software to simulate both healthy and damaged conditions. Similarly, experimental tests were also carried out. The results, when compared to those obtained using a traditional electromechanical impedance (EMI) method, prove that the new approach significantly improved the sensitivity of EMI-based technique in SHM applications.

Impedance measurement of rolling bearings using an unbalanced AC wheatstone bridge

Industry 4.0 drives the demand for cost-efficient and reliable process data and condition monitoring. Therefore, visualizing the state of tribological contacts becomes important, as they are regularly found in the center of many applications. Utilizing rolling element bearings as sensors and monitoring their health by the electrical impedance method are promising approaches as it allows, e.g., load sensing and detection of bearing failures. The impedance cannot be measured directly, but there are various methods available. This paper discusses advantages and disadvantages and suggests the AC Wheatstone bridge as a reliable way of measuring impedances with low phase angles at sampling rates in the kHz range. The corresponding equations are introduced, a simulation built, an uncertainty mode and effects analysis carried out and sample measurement results of real rolling elements shown. It can be demonstrated that the AC Wheatstone bridge meets the proposed requirements for sensory utilization and condition monitoring when the bearing is operated in the hydrodynamic regime.

Clustering classifier of FRP strengthened concrete beams using superpixels and principal component analysis

Nowadays, the application of Fiber Reinforced Polymer (FRP) materials in concrete structures is more and more extended because of their advantages. However, premature and brittle failure caused by debonding of FRP materials from the concrete surface may be critical and needs to be detected at its earliest stages to avoid possible catastrophic events. Digital image correlation (DIC) has been used in the past for the detection of abnormalities from surface digital images. In this work, an efficient computer-aided diagnosis (CAD) system for damage identification for this type of FRP strengthening is developed. It is based on the combination of cells of strain maps built with a DIC system and an automated clustering classifier optimized with the use of superpixels and principal component analysis. Additionally, preprocessing of the images is also done with some filters to enhance the accuracy of the methodology. The procedure has been validated with experimental results on a progressively damaged FRP externally strengthened beam. Results show that the proposed detection scheme achieves an effective automated classification method for the damage detection of this kind of strengthened specimens. Furthermore, the optimal choice of the subset size, number of superpixels and principal components contributed to the success of the method. Simultaneously, an attempt to quantify damage from the proposed method and its validation with electromechanical impedance method has been developed.

Ultra-thin low-frequency broadband absorber based on layered coiled channel structure

To improve and broaden the performance in absorbing sound waves of metamaterials at the lower and mid-frequency ranges, a layered coiled channel composite structure (LCCS) with deep subwavelengths is proposed in this paper, which extends the acoustic wave propagation paths longitudinally by connecting the Helmholtz resonator channels in each layer and achieves the multistep resonance of the coupling cavities, which results in the cancellation of acoustic energies, reduces the acoustic reflections and scattering, and enhances the absorption performance. A model to simulate theoretical sound absorption and finite elements simulation of the metamaterial were evolved to reveal its potential mechanismfor absorbing sound. Using the single-variable method to study the impact of altering structural parameters on the effectiveness of sound absorption, it shows good tunability in the target frequency range and obtains four fundamental unit LCCSs having distinct frequency absorption peaks, and designs a multi-unit coupling construction having low frequencies wideband sound absorption performance by connecting them in parallel to realize a large-broadband continuous and high-efficiency sound absorption within the scope of 370–1400 Hz, using a mean peak sound absorption value higher than 0.7. The structure was put together by 3D printing, and the impedance tube method test verified the precision of the simulation’s findings. This study offers a practical means to create lightweight, low-frequency broadband acoustic absorbing metamaterials.

Definition of Significant Platelet Clumping: Should We Review All Samples With a Platelet Clumping Flag From Automated Hematology Analyzer?

This study aimed to determine a definition for significant platelet clumping (PC) and evaluate the performance of the Sysmex XN instrument for detecting platelet clumps. For part 1, 372 specimens with a 'PLT_clump?' flag in XN-9000 were classified into five groups according to the average number of PCs. We compared the initial platelet count (measured by XN-9000 using impedance method) and corrected platelet count (counted optically or re-analyzed by XN-9000 using vortexed or re-collected sample) of each group. For part 2, 1000 specimens with a PC flag divided into three subgroups {group N (PC = 0), Y (PC ≥ 1), and Z (microscopic fibrin clot)} and additional two groups {group S (PC(+) specimens without any flag and with flags of other categories) and group NC (negative control)} were collected. Positive predictive value (PPV), negative predictive value (NPV), sensitivity and specificity of PC detection of XN-9000 were obtained and the platelet counts and four indices (PDW, MPV, P_LCR, and PCT) of groups NC, N, Y, Z, and S were compared to detect PC more precisely. In part 1, all groups showed significant difference between the initial and corrected platelet counts. In part 2, PPV, NPV, prevalence, sensitivity, and specificity were 41.5%, 56.5%, 43.4%, 2.18%, and 98.3%, respectively. The platelet counts and four indices showed statistical differences for detecting PCs, and especially PDW and P_LCR were significantly smaller in group Z than group N or Y. We suggest the definition of significant PC by the presence of at least three platelets. In addition, utilizing platelet-related indices should be developed to improve the efficiency of the PC detection.

6731 Initial therapeutic effects of weekly growth hormone replacement therapy: somapacitan

Abstract Disclosure: S. Fujio: None. R. Makino: None. J. Sugata: None. T. Hanada: None. R. Hanaya: None. Introduction: In Japan, the restriction on the administration of somapacitan, a long-acting growth hormone (GH) analogue, was lifted in December 2022, allowing the drug to be administered to many patients with severe growth hormone deficiency (sGHD). [Patients and methods] We have 10 patients for whom somapacitan was started as a new drug regime and 26 patients who switched from their daily GH replacement therapy. Among these 36 patients, 21 patients (5 new cases and 16 switched cases) who were followed for more than 6 months after the start of treatment were included in the present study. We compared lipid metabolism, glucose tolerance, liver function, and quality-of-life before and after treatment with somapacitan. [Result] The study population included 12 men and 9 women with a median age of 65 years. Cases included 15 NF-PitNET, 2 Lactotroph PitNET, 2 germ cell tumor, 1 craniopharyngioma, and 1 granuloma. Starting doses of somapacitan were 1.5 mg/week for adults to 60 years of age and 1.0 mg/week for patients aged &amp;gt;60 years. In the switched cases, the median levels of T-chol dropped from 214.5 to 198.5 mg (p&amp;lt;0.05). The median levels of HbA1c dropped from 5.9 to 5.8% (p&amp;lt;0.05). In the newly prescribed cases, the median levels of γ-GTP dramatically improved from 53 to 34I U/L, but this was not statistically significant. In the newly prescribed cases, quality-of-life assessment by Adult Hypopituitarism Questionnaire; AHQ showed improvement in both psychological/social aspects and physical function, but the number of cases was small and no significant difference was obtained. Body fat percentage measured by the impedance method showed no significant change in either the switched or newly prescribed groups. There were no adverse events, but some participants commented that it was easier to forget weekly injections of somapacitan than the daily GH. [Discussion] We were able to introduce somapacitan without any major problems. In newly prescribed cases, somapacitan resulted in a significant improvement in liver function. Improvements in lipid metabolism and glucose tolerance were observed in the switched patients. Compared to the daily GH replacement therapy, somapacitan may have a higher GH replacement effect. Presentation: 6/3/2024

An applicability discussion of the in-situ measurement method using the ensemble averaging technique for sound absorption characteristics

In our former papers, the authors have proposed a measurement method for sound absorption characteristics, surface impedance and sound absorption coefficient, of materials using the ensemble averaging technique. We named it EA-method, for short. So far, we have shown the robustness as well as the reproducibility of the results obtained by the method at various environments. The method consists of two kinds according to sensor types employed: i.e. two-microphone and PU-sensor. In this paper, the applicability of the EA-method is discussed onto three types of absorption: porous, panel, and resonator. At first, the outline of the EA-method is summarized and measurement mechanism is explained. Then, the robustness as well as the reproducibility of the method are discussed based on accumulated results of measurements conducted in various environments including reverberation rooms and in-situ conditions.

Offshore wind turbine noise propagation and the "ground effect" of the sea: a comparison of Effective Flow Resistivity (EFR) of still and moving water surfaces

With the proliferation of Offshore Wind Turbine (OWT) development, the potential annoyance problems caused onshore from long range propagation of noise over the sea surface generated by the turbines must be investigated thoroughly. Measurement of the Ground Effect in relation to the sea surface is onerous and under-researched. In this suite of experiments, a method similar to that described in ANSI S1.18-1999 "Template method for Ground Impedance" is used to compare the differences in effective flow resistivity (EFR) between water surfaces that have 1) a surface that is still, 2) gravity waves that move in the direction of the noise propagation 3) gravity waves that flow opposite the direction of noise propagation. These results are further compared to standard surfaces such as soil and concrete. The frequency response of the surface under these different scaled-down surface gravity wave conditions may provide some insight into the behaviour of lower frequencies over the large scale surface wave conditions at sea.

Start-Up and Fault-Ride-Through Strategy for Offshore Wind Power via DRU-HVDC Transmission System

The diode-rectifier unit (DRU)-based high-voltage direct current (HVDC) transmission system offers an economical solution for offshore wind power transmission. However, this approach requires offshore wind farms to establish a strong grid voltage. To meet this requirement while fulfilling the dynamic characteristics of the DRU, this paper proposes an advanced grid-forming (GFM) control strategy for offshore wind turbines connected to DRU-HVDC. The strategy incorporates a P-U controller and a Q-ω controller based on reactive power synchronization. Furthermore, a novel virtual power-based pre-synchronization method and an adaptive virtual impedance technique are integrated into the proposed GFM control to improve system performance during wind turbine (WT) integration and low-voltage ride-through (LVRT) scenarios. The virtual power-based pre-synchronization method reduces voltage spikes during the integration of new wind turbines, while the adaptive virtual impedance technique effectively suppresses fault currents during low-voltage faults, enabling faster recovery. Simulation results validate the effectiveness of the proposed GFM control strategy, demonstrating improved start-up and LVRT performance through the pre-synchronization and adaptive virtual impedance methods.

A-147 Comparative Precision of Platelet Counting by Optical, Fluorescent, and Impedance Techniques in Thrombocytopenia and Microcytosis Patients

Abstract Background In today's era of automation driven by Artificial Intelligence, even the most efficient automated hematology analyzer may struggle to accurately determine platelet count in patients with low platelet count and microcytosis. The Sysmex XN-series analyzer (Sysmex, Kobe, Japan) uses optical density, fluorescence, and electronic impedance methods for platelet counting. This study aimed to evaluate the accuracy of optical, fluorescence, and electrical impedance methods in estimating precise platelet counts in thrombocytopenic and microcytic patient samples. Methods A cross-sectional study was conducted in the Department of Laboratory Medicine at AIIMS, New Delhi, for 30 days consecutively. A total of 200 blood samples collected, of which 100 samples were of thrombocytopenia (&amp;lt;100x10^9/L) and 100 samples were of microcytosis (Mean corpuscular volume &amp;lt;76 femtoliters). MCV&amp;lt;76 fl was further categorized into 2 groups- MCV 60-70 fl and MCV 71-76 fl accordingly. Males and females were categorized and analyzed distinctly for thrombocytopenia and microcytosis. Statistical analysis was performed using SPSS 16.0 for Windows (SPSS Inc., Chicago, IL, USA) and the Bland Altman plot was analyzed. Results Of the 100 patients with thrombocytopenia (platelet&amp;lt;1 lakh/L) females were predominantly 54% while males were 46% and the median age was 29 years (0.02-70). Of the 100 patients with low MCV (&amp;lt;76 fl) females were 53%, while males were 47% and the median age was 29 years (0.3-69). The findings were compared against the standard manual platelet count method in peripheral smears verified by two expert pathologists. The Bland Altman plot for Platelet &amp;lt;1 lakh/L and MCV &amp;lt;76 fl were compared with standard manual platelet count method and the following findings were obtained i) In female with PLT- &amp;lt;1 lakh/L, PLT-O showed least bias (9.8) followed by PLT-F (10.4) and PLT-I (12.1) ii) In males with PLT-&amp;lt;1 lakh/L, PLT-O showed least bias(14.1) followed by PLT-F(16.5) and PLT-I(17.0) iii) For MCV 61-70fl, PLT-O showed the least bias (4.4) followed by PLT-F (6.7) and PLT-I (28.5) iv)For MCV 71-76fl, PLT-F showed least bias (-0.2) followed by PLT-O (1.5) and PLT-I(31.2). Conclusions Platelet count by optical method (PLT-O) detects platelet count more accurately with minimum bias when compared with PLT-F and PLT-I in patients with thrombocytopenia. In patients with microcytosis, PLT-I is less reliable in comparison to PLT-O and PLT-F. A limitation of the automated hematology analyzer is the inability to detect platelet clumps which is appreciated in peripheral smears.

Stability Analysis of Cascaded LCC-MMC Hybrid HVDC System Based on Impedance Method

Stability Analysis of Cascaded LCC-MMC Hybrid HVDC System Based on Impedance Method

Review of methods for detecting electrode-tissue contact status during atrial fibrillation ablation

Atrial fibrillation is a common cardiac arrhythmia with an annually increasing global prevalence. Ablation of atrial fibrillation is a minimally invasive procedure that treats atrial fibrillation by using a catheter to deliver radiofrequency energy to heart tissues generating abnormal electrical potentials. The success of this procedure relies significantly on the adhesion between the catheter and the heart tissue, presenting a challenge in accurately assessing the contact force (CF) during surgery. To improve the safety and success rate of surgery, researchers are committed to developing various methods to evaluate or detect catheter-tissue CF. Among these, some studies integrated optical fibers or magnetic elements into the catheter tip to create CF sensing catheters that monitor CF in real time; other studies used impedance measurement, electrical coupling index, local impedance and other methods to evaluate the CF between the catheter and the tissue by measuring changes in electrical signals. These methods have achieved certain success in clinical practice, offering new ways to improve the effectiveness and safety of cardiac radiofrequency ablation surgery.

Experimental void fraction measurement approach of small channel two-phase flow

This investigation presents a novel experimental approach for assessing void fraction parameters in two-phase flows within microchannels. The study critiques the conventional impedance methods that utilize alternating current (AC) for void fraction measurements, highlighting the inherent drawbacks such as ground capacitance interference and non-uniform current distribution. To circumvent these issues, the research introduces the use of direct current (DC), which ensures a homogeneous distribution across the conductor's cross-section, as a more reliable alternative. Termed the "Direct Impedance Method," this technique employs DC to enhance the accuracy of void fraction measurements. The study explores various geometric configurations of full-ring and half-ring electrodes, both vertical and horizontal, within a microchannel of 500 μm diameter. An empirical formula is derived to calculate the void fraction from the electrical data obtained. High-speed imaging at 4000 frames per second supplements the method by providing visual confirmation of the flow patterns. The comparative analysis of the direct impedance method and image processing using the homogeneous theoretical model reveals a deviation of approximately 2 %–10 % for the slug and annular flow pattern. In contrast, the deviation is more for the bubble pattern. The results affirm that the Direct Impedance Method is a cost-effective and reasonably precise technique for small-channel applications. Its accuracy is inversely proportional to the channel diameter, rendering it unsuitable for channels larger than 2 mm. The method's low construction cost further enhances its practical appeal.

Robotic grinding and polishing of complex aeroengine blades based on new device design and variable impedance control

Owing to the advantages of good flexibility and low cost, robots are gradually replacing manual labor as an effective carrier for the grinding and polishing of aeroengine blades. However, the geometric features of blades are complex and diverse, and the contour accuracy and surface quality requirements are high, making the robotic grinding and polishing of blades still a challenging task. For this reason, this article first designs a new device by integrating different tools, which can achieve full-feature grinding and polishing of blades. Then, in order to improve the accuracy and stability of force tracking during the robotic grinding and polishing processes, a variable impedance control approach with simultaneous changes in stiffness and damping and parameter boundaries is proposed. Finally, the superiority of the proposed variable impedance control method is verified by comparative experiments on surface tracking. In addition, by combining the device with the variable impedance control method in the robotic grinding and polishing experiments of an aeroengine blade, their effectiveness in practical situations is confirmed.

Er3+ doped BZBO single crystal: Growth and electro-elastic property characterization

Large-sized and high-quality Er: Bi2ZnB2O7 (Er: BZBO) single crystal has been grown using the Kyropoulos method. The crystal structure is refined by the Rietveld method, Er: BZBO belongs to the orthorhombic system and space group Pba2, lattice parameters: a = 10.811(1) Å, b = 11.006(1) Å, c = 4.8817(4) Å, which are slightly reduced after doping with Er3+. The thermal expansion anisotropy is studied and shows a decrease with coefficients of α11 = 7.69(1) × 10−6 K−1, α22 = 9.90(9) × 10−6 K−1, and α33 = 1.98(8) × 10−6 K−1, respectively. The relative dielectric constants are found to be εT11/ε0 = 32.8(1), εT22/ε0 = 17.2(1), and εT33/ε0 = 17.0(9), respectively. The dielectric, elastic, and piezoelectric constants for the Er: BZBO crystal are determined by the impedance method, with the piezoelectric coefficients d15, d24, d31, d32 and d33 are measured as 1.1(9), −5.4(2), 1.8(7), −5.9(1) and 1.1(5) pC/N, respectively. Furthermore, the temperature dependence of the piezoelectric coefficients from room temperature to 500 °C is evaluated, showing good temperature stability for d24 and d32 with variations were −7 % and 13 %, respectively.

Research on single-phase grounding fault location technology in distribution networks based on impedance method

This article mainly introduces the impedance based single-phase grounding fault location method for distribution networks, including its theoretical basis, algorithm steps, and simulation verification. First, starting from the impedance analysis of the transmission line model, the method of accurately measuring the location of the fault point through phase domain analysis is explained. Next, the process of impedance analysis for single-phase grounding faults was described in detail, that is, how to solve the impedance of the grounding fault points by calculating the voltage and current signals. Then, the specific process of the impedance based grounding fault location algorithm was introduced, including the calculation of equivalent load impedance, the calculation of starting voltage and current, the calculation of grounding current, and the solution of fault point location. Finally, simulation verification was conducted using an IEEE 34 node distribution system example in a MATLAB/Simulink environment, and the results showed that the algorithm has high positioning accuracy, with a maximum error of within 3%.