Impedance Technology Research Articles

Piezoelectric Active Sensor Self-Diagnosis for Electromechanical Impedance Monitoring Using K-Means Clustering Analysis and Artificial Neural Network

Piezoelectric sensor is a crucial part of electromechanical impedance technology whose state will directly affect the effectiveness and accuracy of structural health monitoring (SHM). So carrying out sensor self-diagnosis is important and necessary. However, it is still difficult to distinguish sensor faults from structural damage as well as identify the cases and degrees of sensor faults. In the study, three characteristic indexes of admittance which have different indication intervals for damages of structure and sensors were selected from six indexes after comparison. To improve the discrimination effect, three principal components (PC) were extracted by principal component analysis (PCA). And the damage information represented by PCs was clustered by the K-means algorithm to identify the cases of damage. Then, the degrees of sensor damages were classified with the artificial neural network (ANN). The results show that the K-means clustering analysis based on admittance characteristics can accurately distinguish and identify the structural damage and four kinds of sensor damages, namely, pseudosoldering, debonding, wear, and breakage. The trained ANN model has a good recognition effect on the damage degrees and the accuracy of recognition reaches 100%. This study has a certain reference value for piezoelectric sensor self-fault identification.

Effect of Spray Distance on the Microstructure and High Temperature Oxidation Resistance of Plasma Spray-Physical Vapor Deposition 7YSZ Thermal Barrier Coating

In order to study the effect of spray distance on the structure and high temperature oxidation resistance of feather-columnar thermal barrier coatings, the feather-columnar ZrO2-7wt. % Y2O3 (7YSZ) thermal barrier coatings were prepared at spray distances of 650 mm, 950 mm, 1100 mm, 1250 mm, and 1400 mm by plasma spray-physical vapor deposition (PS-PVD) technology. The surface roughness, micro morphology, and porosity of the sprayed 7YSZ coating were analyzed by 3D surface profiler, SEM, XRD, etc., and the impedance spectrum characteristics of the 7YSZ coating were characterized by electrochemical alternating current (AC) impedance technology. In addition, the high temperature oxidation resistance test of 7YSZ coating under different spray distances was carried out at a temperature of 1000 °C to study the influence of spray distance on the high temperature oxidation resistance of 7YSZ coating. The research results show that the surface roughness and porosity of feather-columnar 7YSZ coating increased sequentially with the increase of spray distance. At the same time, The YSZ grain boundary resistance value increased exponentially as the porosity of the coating increases. Where the spray distance was in the range of 650 mm and 1250 mm, the high temperature oxidation rate constant of the coating increased with the spray distance. However, the spray distance was greater than 1250 mm, and the spray distance had no significant effect on the high temperature oxidation resistance of the coating.

The Value of Reflux Monitoring: The Old and the New for the Diagnosis and Assessment of GERD

Reflux monitoring has advanced from inpatient continuous pH recordings on scrolling graph paper introduced 50 years ago to modern catheter-based 24-hour and wireless multiple-day ambulatory recordings, and the capability of detecting reflux episodes irrespective of pH using impedance technology. Testing is performed off antisecretory therapy when there is no prior documentation of reflux disease, and pH-impedance monitoring can be performed on therapy in symptomatic patients with proven reflux. Prolonged wireless pH monitoring evaluates day-to-day variation in reflux exposure. New impedance-based metrics evaluating baseline impedance and post-reflux swallow induced peristaltic wave have potential to augment the diagnostic value of reflux monitoring.

Synergistic Effect of Factors Influencing the External Corrosion of Heavy Oil Pipelines in Reed Pond Soil

At present, the transportation environment of heavy oil pipelines is complex and subject to a specific set of factors. However, external corrosion problems are inevitable. In this work, the corrosion rate, corrosion morphology and corrosion products of 16Mn heavy oil pipeline steel in the reed pond soil of the Liaohe oilfield were studied by immersion experiments and SEM, EDS and XRD analysis methods. Based on the gray correlation analysis method, the effect of five factors influencing the corrosion rate of 16Mn steel in a reed pond soil environment was discussed by utilizing dynamic potential polarization and AC impedance technology. The analysis of potential dynamic polarization and AC impedance technology shows that the corrosion rate gradually increases due to the decrease in pH and the increase in temperature and concentration of the corrosive anions Cl−, SO42− and HCO3− in the environment. The order of the correlation between influencing corrosion factors and the corrosion rate of 16Mn steel is as follows: temperature > Cl− > SO42− > HCO3− > pH value.

Coordinated Control Strategy of Virtual Synchronous Generator Based on Adaptive Moment of Inertia and Virtual Impedance

The application of virtual synchronous generators in the power system eases the pressure on the grid caused by penetration of lots of power electronic devices, but worsens the dynamic frequency stability of the grid. Meanwhile, in order to solve the problem of power coupling in low-voltage micro-grid systems, most measures introduced virtual impedance technology to adjust the equivalent output impedance of the system. Therefore, most studies have adopted the adaptive control strategy of the moment of inertia, to improve the dynamic frequency adjustment of the grid. However, it will cause the frequency response speed reduction problem. In order to deal with the contradiction between the moment of inertia and frequency response speed, the voltage phasor relationship of the micro-source - grid system under signal disturbance in the introduction of virtual impedance is analyzed. Then an adaptive virtual impedance control strategy is proposed to accelerate the active power adjustment process of the virtual synchronous generator system, which helps to complete the first frequency modulation and improve the inertia adjustment ability. Finally, combining these two control strategies, a coordinated adaptive moment of inertia and virtual impedance control strategy is proposed. From the perspective of the moment of inertia and virtual impedance, the proposed method fully exploits the control advantages of the virtual synchronous generator system and achieves the purpose of adjusting the inertia of the virtual synchronous generator system while considering the acceleration of the frequency response speed. The comprehensive simulation results verify the feasibility and effectiveness of the proposed method.

Synthesis and Li-ion diffusion kinetic of Zn2(OH)3VO3 nanosheets with ultra-high electrochemical activity

It has been reported that 2-dimension Zn2(OH)3VO3 possesses the higher electrochemical activity. However, its morphology evolution, formation mechanism and electrochemical kinetics remain elusive. In this study, Zn2(OH)3VO3 nanosheets with a thickness of 20 ~ 50 nm were synthesized by a facile one-pot hydrothermal route without any post heat treatment. We reveal the morphology evolution through the reaction time manipulation and formation mechanism in terms of nucleation, crystallization and growth. Lithium storage performances of the obtained nanosheets were investigated, featuring a discharge capacity retention of 863 mAh g−1 after 100 cycles at 0.1 A g−1 and Coulombic efficiency of 99%. The reversible specific capacity reached 477 mAh g−1 even at 10 A g−1, indicating an analyzed diffusion-controlled mechanism. Furthermore, for the first time, the electrochemical kinetics of Zn2(OH)3VO3 nanosheets electrode during the first cycle were studied in detail by in situ Electrochemical impedance technology, which certified that the solid electrolyte interface (SEI) layer experienced the formation, dissolution and reformation process upon cycling. The present work might greatly promote the application of Zn2(OH)3VO3 in Li-ion batteries and other fields.

生物电阻抗技术在维持性血液透析患者营养状况评估中的研究进展

生物电阻抗技术在维持性血液透析患者营养状况评估中的研究进展

Analysis of the influence of virtual impedance on the stability of Parallel Voltage Inverters with Different Voltage Levels

Using virtual impedance technology to optimize the double closed-loop control structure can improve the equivalent output impedance of the inverter to be inductive, improve the power distribution accuracy of traditional sensibility droop control strategy in low-voltage microgrid, and effectively restrain the circulation. But rarely consider the impact of virtual impedance on system stability. Therefore, Derive the transfer function of the three loop control structure including virtual impedance, line impedance and common point voltage, establish a parallel models of inverters with different voltage levels considering virtual complex impedance and simplify the model using Thevenin’s equivalent. According to the Nyquist stability criterion Analyze the effect of virtual impedance on system stability under various operating conditions. The analysis results show that the multi-inverter parallel system can maintain stable operation after adding the virtual impedance.

Determination of Bioelectrical Impedance Thresholds for Early Detection of Breast Cancer-related Lymphedema.

Background: Bioelectrical impedance technology is a common technique used for the early detection of breast cancer-related lymphedema (BCRL). However, studies on the threshold value established by Inbody 720 device (Biospace, Korea) have been extremely limited. We aimed to determine its reference range and cutoff values.Methods: All patients were recruited from October 2017 to October 2019 at the Peking University People's Hospital Breast Center. In total, 82 patients with unilateral BCRL and 1305 healthy subjects were recruited in this study. We measured the extracellular fluid (ECF) ratio, extracellular water (ECW) ratio, as well as the single-frequency bioimpedance analysis (SFBIA) ratios at 1 and 5 kHz with the Inbody 720 device. The Youden index-based cutoff points, mean + 2SD and mean + 3SD values of these four indicators for both dominant and nondominant arms were also calculated.Results: Data were collected from 1387 women, including healthy subjects and patients with lymphedema. All statistical analyses were performed with SPSS. Significant differences were found between the two groups in the ECW, ECF, and SFBIA ratios. For the dominant affected arms, the Youden index-based cutoff points for the ECF, ECW, as well as SFBIA ratios at 1 and 5 kHz were 1.009, 1.008, 1.068, and 1.068, respectively. For the nondominant affected arms, the Youden index-based cutoff points were 1.014, 1.013, 1.047, and 1.048, respectively. The mean + 2 standard deviations (SD) and mean + 3SD values were also calculated.Conclusions: We determined the Youden index-based cutoff points, mean + 2SD and mean + 3SD values of the ECF, ECW, as well as SFBIA ratios at 1 and 5 kHz for both dominant and nondominant arms with data from 1305 healthy subjects. Next, the Youden index-based cutoff points, the mean + 2SD and mean + 3SD values were used to recognize patients with lymphedema. We found that the Youden index-based cutoff points and the mean + 2SD showed similar identification capacity on lymphedema, and they seemed to distinguish more patients with lymphedema than mean + 3SD values.

Application of a real-time cell analysis system in the process development and quantification of Rift Valley fever virus clone 13.

Conventional cell-culture viral quantification methods, namely viral plaque and 50 % tissue culture infective dose assays, are time-consuming, subjective and are not suitable for routine testing. The viral plaque formation assay is the main method utilized for Rift Valley fever virus (RVFV) clone 13 quantification. The RVFV is a mosquito-borne RNA Phlebovirus belonging to the family Bunyaviridae. The virus comprises a single serotype and causes the zoonotic Rift Valley fever disease. The real-time cell analysis (RTCA) system has been developed for the monitoring of cell growth, cell adhesion, cell viability and mortality using electronic impedance technology. In this study, Vero cell growth kinetics and RVFV clone 13 replication kinetics were investigated in a roller bottle and RTCA systems. In roller bottles, Vero cell growth was measured by cell counts through trypan blue staining, whilst impedance expressed as the cell index (CI) was used for Vero growth measurement in the RTCA system. Similar growth patterns were observed in both roller bottle and RTCA systems. Exponential growth phase was observed between 48 and 100 h, followed by a stationary phase from 100 to 120 h, before cell death was observed. Viral plaque assay quantification of RVFV clone 13 in the roller bottle system and the time required for the CI to decrease 50 % after virus infection (CIT50) in the RTCA system were comparable. The highest RVFV clone 13 titre was obtained at 120 h in both roller bottle and RTCA systems. An increase in time for cytopathic effect (CPE) formation was observed with a decrease in the concentration of the virus used to infect the RTCA plates. A positive correlation was observed between the viral concentration and the time for a CPE and was used to calculate CIT50. A similar correlation was observed between the viral concentration and the time for a CPE in the roller bottle system. This study shows that the RTCA system can be used as an alternative method for conducting cell culture kinetics and viral quantification.

An Impedance Based Electrochemical Immunosensor for Aflatoxin B1 Monitoring in Pistachio Matrices

Aflatoxins are highly toxic fungal secondary metabolites that often contaminate food and feed commodities. An electrochemical immunosensor for the determination of aflatoxin B1 (AFB1) was fabricated by immobilizing monoclonal AFB1 antibodies onto a screen-printed gold electrode that was modified with carbo-methyldextran by N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide cross-linking. An electrochemical interfacial modelling of biomolecular recognition was suggested and reasonably interpreted. Impedance technology was employed for the quantitative determination of AFB1. The limit of detection concentration of AFB1 for standard solutions and spiked pistachio samples was 0.5 ng/mL and 1 ng/mL, respectively. The immunosensor was able to successfully determine AFB1 concentrations in the range of 4.56–50.86 ng/mL in unknown pistachio samples. Comparative chromatographic analysis revealed that AFB1 concentrations that were higher than 345 ng/mL were not within the immunosensor’s upper limits of detection. Selectivity studies against Ochratoxin A and Aflatoxin M1 demonstrated that the proposed AFB1 immunosensor was able to differentiate between these other fungal mycotoxins. The novel electrochemical immunosensor approach has the potential for rapid sample screening in a portable, disposable format, thus contributing to the requirement for effective prevention and the control of aflatoxin B1 in pistachios.

Stability of Routine Hematology Sample Using The Medonic M-Series Analyzer

Routine hematology tests (Hb, Hct, RBC, WBC, PLT) generally done by automation methods using a hematology analyzer. Ideally, the examinations should be done as soon as possible, although, in some circumstances, it can be delayed. Based on the literature, the sample for routine hematology testing should be processed within 4 – 8 hours of venesection. Some studies revealed that the sample could be stored for up to 48 hours, and it can be influenced by the technology applied to the hematology analyzer. Studies conducted to see the stability of the samples using a hematology analyzer with impedance technology. Tests performed on whole blood samples collected from 12 ostensibly healthy individuals, immediately after collection (fresh sample, <1hour) and 2h, 4h, 6h, 8h, 24h, 48h afterward. The samples stored at room temperature (20-240C) and 2-60C. There are no significant differences after 48 h under different storage conditions for Hb, Hct, RBC, PLT count, except for WBC count that has a significant difference at temperature 2-60C. CV for Hb, Hct, RBC, PLT, WBC count is less than 5% at room temperature. WBC and PLT count have a CV of more than 5% at 2-60 C. Sample for Hb, Hct, RBC was found to be stable up to 48 h at room temperature and 2-60C. PLT and WBC count were stable for 48 h if stored at room temperature.

Stability of Routine Hematology Sample Using The Medonic M-Series Analyzer

Routine hematology tests (Hb, Hct, RBC, WBC, PLT) generally done by automation methods using a hematology analyzer. Ideally, the examinations should be done as soon as possible, although, in some circumstances, it can be delayed. Based on the literature, the sample for routine hematology testing should be processed within 4 – 8 hours of venesection. Some studies revealed that the sample could be stored for up to 48 hours, and it can be influenced by the technology applied to the hematology analyzer. Studies conducted to see the stability of the samples using a hematology analyzer with impedance technology. Tests performed on whole blood samples collected from 12 ostensibly healthy individuals, immediately after collection (fresh sample, <1hour) and 2h, 4h, 6h, 8h, 24h, 48h afterward. The samples stored at room temperature (20-240C) and 2-60C. There are no significant differences after 48 h under different storage conditions for Hb, Hct, RBC, PLT count, except for WBC count that has a significant difference at temperature 2-60C. CV for Hb, Hct, RBC, PLT, WBC count is less than 5% at room temperature. WBC and PLT count have a CV of more than 5% at 2-60 C. Sample for Hb, Hct, RBC was found to be stable up to 48 h at room temperature and 2-60C. PLT and WBC count were stable for 48 h if stored at room temperature.

Efeito do tempo e da temperatura de armazenamento nos parâmetros hematológicos de cães hígidos

The aim of this study was to evaluate the stability of hematological parameters at different storage times and temperatures. Whole blood from 7 healthy dogs (Canis lupus familiaris) was used. The samples were divided into 2 aliquots of 2 mL stored in EDTA-K3 tubes, kept at room temperature at 22º C and refrigerated at 4º C, in the following time intervals T0h, T6h, T12h, T24h, T48h. The exams were performed in SDH-3 VET® hematology analyzer. The hematological variables were stable over time with the exception of red blood cells that underwent variation at T12h at room temperature and platelets that at T6h at room temperature and under refrigeration remained below the reference range. It is concluded that the samples of dogs analyzed by the impedance technology, more specifically by the labtest SDH-3 VET® equipment, were stable for 48 hours for red blood cell count, hemoglobin concentration, hematocrit and total leukocytes; however, the platelets should be performed with samples taken within 6 hours.

A tribute to Antonio Piccoli, a father and a pioneer in body composition assessment using bioelectrical impedance technology.

Antonio Piccoli, MD, MSc, the pioneer and international leader in the development and application of bioelectrical impedance vector analysis (BIVA) for identification of fluid imbalance, sadly passed away on August 4, 2020.

Flip Technology for Assessing Esophageal Structural and Motor Disorders: a Skeptic's View.

Functional lumen impedance (FLIP) technology has become commercially available to assess structural and motor abnormalities of the esophagus. Increasing numbers of papers have described novel findings with this technology. This review examines the validity of the FLIP technique, how it compares with existing diagnostic modalities, and evidence to date on diagnostic accuracy. FLIP studies require deep sedation at the time of endoscopy to complete. They assess a simulated state of esophageal obstruction in only a distal part of the esophagus rather than deglutitive motor function of the entire esophagus. The available normative dataset is small and not matched to the older age of patients typically being evaluated. The test-retest agreement in health and disease is unknown, as is the operator dependence on performing and interpreting findings. Studies to date have largely excluded patients with structural disorders, which FLIP cannot reliably distinguish from motor disorders. FLIP is an expensive technology that has been made clinically available without its true utility being established. For FLIP to be deemed a device ready for widespread clinical use, additional studies on validity, diagnostic accuracy, and outcomes need to be performed. Prospective clinical studies need to include all patients and assess the incremental cost-effectiveness of FLIP over more innovative use of existing technology, such as high-resolution manometry with provocative challenges.

Impedance in the evaluation of the esophagus.

The aim of this paper is to review esophageal electrical impedance technologies and to discuss the use of these technologies for physiological measurements, diagnostics, and therapy of esophageal disease. In order to develop a better understanding of the pathophysiology of and improve the diagnosis of esophageal disorders, such as gastroesophageal reflux disease (GERD) and achalasia, several new diagnostic tests, including intraluminal impedance, esophageal mucosal impedance, and the functional luminal imaging probe, have been developed. These technologies have proven valuable for assessment of the esophagus in recent years. They provide information on esophageal flow properties, mucosal integrity, lumen shape, and distensibility in esophageal disorders, in particular for GERD and achalasia. Despite their promise and novel clinical studies, the potential of these technologies has been far from realized. New multidisciplinary approaches will contribute to our understanding and interpretation of esophageal impedance data and disease mechanisms.

Increased Mean Platelet Volume is Associated with Decreased Survival in Patients Supported with Impella

Increased mean platelet volume (MPV) has been associated with elevated risk of stroke and myocardial infarction in the general population and stroke/pump thrombosis in Heartmate II recipients. It has been proposed that contact with foreign surfaces and centrifugation promote prothrombotic states with platelet activation and increased MPV. An association between MPV and outcomes of patients treated with percutaneous short-term circulatory devices has not been investigated. This was a retrospective study of 67 patients who received percutaneously inserted ventricular assist device (pVAD) support for high risk percutaneous coronary interventions. Mean platelet volume (MPV) was measured by impedance technology with Sysmex XN-10 hematological analyzer and expressed in femtoliters (fL). Average MPV (aMPV) and percentage change from admission (∆MPV%) were calculated. All patients experienced rise in MPV during the hospital stay (10.7+/-0.9 pre-pVAD, 10.8+/-0.8 in 24hrs post pVAD, and 11.1+/-1 fL at 7d, p<0.0001). However, MPV increase was more pronounced in the 24 patients (34.5%) who expired in the hospital (Figure A) and the ∆MPV% was significantly higher in expired patients (7.7+/-7.8 vs. 4.6+/-4.9% in survivors, p=0.026). When adjusted for clinical variables (age, gender, and histories of atrial fibrillation, hypertension, coronary artery disease, and congestive heart failure), every 1% increase in ∆MPV% was associated with 11% increased odds of dying in patients undergoing high risk PCI with pVAD support (OR 1.111, 95%CI 1.015-1.216, p=0.022). This pilot study indicates that rise in MPV is associated with increased mortality in PCI patients treated with pVAD. Simple and widely available MPV measurements may be useful in identifying high risk patients and estimating prognosis, which may aid in proper resource allocation. More studies on this subject are necessary.

COMPARISON OF PLATELET COUNTS SHOWN BY AUTOMATIC HAEMATOLOGY ANALYSERS AND COUNTS MEASURED MANUALLY IN POPULATION OF MOUNTAINOUS HILLY REGION OF CHENAB VALLEY ATTENDING OPD ON ROUTINE BASIS IN GMC DODA. ASSOCIATED HOSPITAL

In clinical practice it is very important to perform the platelet counts. The estimation of platelet counts from peripheral blood smears is an accurate method and provides adequate quality assurance in traditional methods as the automated cell counters are not available at all hospital setups especially in rural areas. In modern era use of automated analyzers based on impedance technology has resulted in improvement of accuracy and helps in measurement of platelet indices such as Mean Platelet Volume (MPV) Plateletcrit (PCT) and Platelet Distribution Width (PDW). However, both the methods have certain limitations. Platelet counts were estimated on a 5-part Differential Automated Hematology Analyzer and manually on Leishman stained peripheral blood SMEAR.&#x0D; Aims &amp; Objective: 1. This study was conducted to compare platelet counts by peripheral blood smear method and automated method in patients attending OPD on routine basis in a mountainous hilly region of J&amp;k .&#x0D; &#x0D; It also aims to study the relation, if any, between the platelet count (automated) and platelet indices like Mean Platelet Volume (MPV) and Platelet Distribution Width (PDW) and to assess the possible role of these parameters in certain defined situations.&#x0D; &#x0D; Materials and methods: A prospective study was conducted in a tertiary care hospital on 200 Ethylene Diamine Tetra Acetic acid (EDTA) anticoagulated blood samples. Samples were evaluated by 5-Part differential automated hematology analyser using impedance counting method and by examination of peripheral blood smear method (PBF).&#x0D; Results: In thrombocytopenic patients, the platelet count assessed by automated analyzer revealed an inverse relation with Mean Platelet Volume (MPV) and Platelet Distribution Width (PDW) and showed large granular and giant platelets on PBS.&#x0D; Conclusion: Automated hematology analyzer is essential for immediate and accurate complete blood count evaluation but blood samples showing erroneous results or low platelet counts on analyzer should be confirmed on peripheral blood smear. The platelet indices like Mean Platelet Volume (MPV) and Platelet Distribution Width (PDW) can point to the underlying pathology especially in cases of thrombocytopenia.&#x0D; Keywords: Automated analyser, Peripheral blood smear, MPV, PDW, large granular platelets.

Evaluation of Characterization Indexes and Minor Looseness Identification of Flange Bolt Under Noise Influence

Based on electromechanical impedance (EMI) technology, we studied the indication effect of each characterization index on flange bolt looseness under different noise levels. A new evaluation index T is constructed to solve the problem that the minor looseness and noise under the actual monitoring environment cannot be distinguished with existing indexes. The results show that among the five characterization indexes, the root mean square deviation (RMSD) and the correlation coefficient deviation (CCD) can reflect the minor looseness sensitively and are positively correlated with the degree of looseness. They also have good performance of looseness identification under the noise of 30 dBW. However, the indexes' indication range of the case under 1 dBW-6 dBW noise overlaps with the case under 36 N·m-39.5 N·m torque. So it is impossible to judge the structure state with mere characterization indexes. Evaluation index T can extract the correlation difference of the conductance spectrum under the noise conditions and looseness conditions with the benchmark respectively. And there are different indication ranges of T on the noise and minor looseness. By determining a threshold and comparing T with it, whether bolt looseness occurs in an unknown condition can be effectively judged. Finally, T is applied to other flange structure with 8 bolts to verify the effectiveness and general applicability of the method. The evaluation index plays an important role in avoiding misjudgment of flange bolt caused by noise influence on minor looseness and improving the ability of identification when the bolt is at the critical state.