Measurement Configuration Research Articles

Modeling the Impact of Sensitivity Distribution Variations of Tetrapolar Impedance Configurations in Microfluidic Analytical Devices

Goal: The purpose of this work is to investigate the effects of electrode topology and electrode configuration of tetrapole electrical impedance measurement (TEIM) systems used in microfluidic devices. Methods: Two different electrode topologies with fixed dimensions, selected based on reported applications, are investigated. Three dimensional sensitivity maps, generated using finite element modelling (FEM), show fundamental differences in sensitivity distribution between six different injecting and measuring electrode configurations. Transfer impedance values generated for different band sizes and migrating band trains were compared to show the influence of sensitivity distribution on the performance of TEIM used in electrophoresis or cellomics. Results: Fundamental differences of sensitivity distribution between different electrode configurations were detected, with “Inline Dipole” and “Square Across” configurations exhibiting areas of negative sensitivity in the tetrapole centre. This causes baseline impedance differences of up to one order of magnitude and effecting the performance when measuring heterogeneous fluids. Conclusion: The results suggest that certain electrode configurations should be avoided for applications relying on high spatial resolution. Significance: This work demonstrates the significance of impedimetric sensor geometry design in ultimately enabling the miniaturisation of electrophoretic systems towards increasingly portable devices.

High-speed contactless sintering characterization for printed electronics by frequency-domain thermoreflectance

Printed electronics is an alternative manufacturing paradigm for low-cost and large-area microelectronic devices and systems. Metal nanoparticle (MNP) inks are favorable to print conductors due to their high electrical conductivity. As-printed MNP ink requires sintering to become electrically conductive. High-quality MNP conductors require monitoring and optimization of the sintering process. Traditionally, electrical conductivity is measured to monitor the different sintering stages. This requires destructive probing or fabrication of dedicated test structures, which is challenging for in-line monitoring of high-volume manufacturing. Here, we demonstrate that frequency-domain thermoreflectance (FDTR), an optical pump-probe technique, can be used for process monitoring. Conductive features are inkjet printed with a silver nanoparticle ink. Intense pulsed light (IPL) sintering is used rather than traditional thermal sintering due to its capability of millisecond sintering. Thermal conductivity of IPL sintered features is measured using FDTR, where a frequency-modulated heat flux is applied with a pump laser and the obtained thermal phase of the probe laser is fitted to a thermal model. Thermal conductivity measured from FDTR agrees well with thermal conductivity calculated using Wiedemann–Franz Law from electrical conductivity measurements. By appropriately choosing six FDTR pump frequencies with the highest sensitivity and taking all the selected frequency-vs-phase data points at once, we can measure thermal conductivity in 12 s, a fraction of the traditional measurement time. In this way, the measurement time decreases considerably, and thermoreflectance becomes a suitable characterization technique for high-throughput manufacturing. A Monte Carlo-based prediction was performed to observe the effect of shorter measurement time on phase noise, and a much faster measurement configuration is proposed with an acceptable uncertainty in measurement. Our results demonstrate a simple approach for high-speed non-contact characterization of metal nanoparticle conductors with the combination of high-speed printing and high-speed sintering for low-cost electronics manufacturing.

Adaptive State Fidelity Estimation for Higher Dimensional Bipartite Entanglement.

An adaptive method for quantum state fidelity estimation in bipartite higher dimensional systems is established. This method employs state verifier operators which are constructed by local POVM operators and adapted to the measurement statistics in the computational basis. Employing this method, the state verifier operators that stabilize Bell-type entangled states are constructed explicitly. Together with an error operator in the computational basis, one can estimate the lower and upper bounds on the state fidelity for Bell-type entangled states in few measurement configurations. These bounds can be tighter than the fidelity bounds derived in [Bavaresco et al., Nature Physics (2018), 14, 1032–1037], if one constructs more than one local POVM measurements additional to the measurement in the computational basis.

Configuration of bioelectrical impedance measurements affects results for phase angle

ObjectivePhase angle (PhA) obtained by bioelectrical impedance analysis is a well-established predictor of malnutrition that reflects the amount and quality of soft tissue. However, PhA results may depend on configurations of the measurement that differ between devices. The aim was to analyze differences between devices for supine and standing measurements. ApproachIn a cross-sectional study, differences in PhA were analyzed comparing supine vs. standing positions, metal vs. adhesive electrodes and the right vs. left side of the body in 302 multi-ethnic adults (18–65y) and 1298 Mexican children and adolescents (4–20y). Main resultsPhA was higher in supine than in standing position (from 0.71°±0.22° in children to 0.97°±0.25° in adults; all p < 0.001) with approximately fifty percent of observed differences explained by electrode placement. PhA differences increased with increasing PhA (r = 0.419) and decreased with age (r = −0.346) in adults, but increased with PhA (r = 0.677), age (r = 0.752) and height (r = 0.737) in children (all p <0.001). In adults, PhA was higher on the right side of the body (standing 0.18°±0.17°; supine 0.36°±0.33°; p <0.001). SignificancePhase angle results are influenced by posture and electrode placement. Measurement configuration must be considered when phase angle values are compared between different devices or with literature values.

Measuring the actual voltage of a triboelectric nanogenerator using the non-grounded method

Abstract Measuring the voltage, including open-circuit voltage (Voc) and output voltage, is of great importance for evaluating the performances of a triboelectric nanogenerator (TENG). However, since one electrode of TENG is connected to the ground in the traditional measurement methods, the charges in this electrode are transferred to the ground, causing the underestimated voltage values. To solve this problem and measure the actual voltage, the non-grounded measurement configuration has been proposed here, in which both electrodes of the TENG are disconnected with the ground. From the measurement results of Voc and output voltage by three non-grounded methods, it is obtained that the voltage ratio of non-grounded methods to traditional grounded methods are about 2.0 and 1.5 for sliding type and vertical type TENGs, respectively. The finite element simulation results for TENGs with three different modes match well with the measurement results. Furthermore, it is simulated that the voltage ratio of non-grounded to grounded methods is dependent on the parameters of the TENGs, such as the size of electrodes and the separation distance between them. Also, the non-grounded method has been applied in the TENG-induced micro-plasma to demonstrate its ability to measure the actual output voltage. The non-grounded measurement methods proposed here can measure the actual voltage of TENGs, which are of great significance to accurately evaluating the performances of TENGs.

Improved micro-impedance spectroscopy to determine cell barrier properties

Abstract The goal of this study was to determine whether the Tethapod system, which was designed to determine the impedance properties of lipid bilayers, could be used for cell culture in order to utilise micro-impedance spectroscopy to examine further biological applications. To that purpose we have used normal epithelial cells from kidney (RPTEC) and a kidney cancer cell model (786-O). We demonstrate that the Tethapod system is compatible with the culture of 10,000 cells seeded to grow on a small area gold measurement electrode for several days without affecting the cell viability. Furthermore, the range of frequencies for EIS measurements were tuned to examine easily the characteristics of the cell monolayer. We demonstrate significant differences in the paracellular resistance pathway between normal and cancer kidney epithelial cells. Thus, we conclude that this device has advantages for the study of cultured cells that include (i) the configuration of measurement and reference electrodes across a microfluidic channel, and (ii) the small surface area of 6 parallel measurement electrodes (2.1 mm2) integrated in a microfluidic system. These characteristics might improve micro-impedance spectroscopy measurement techniques to provide a simple tool for further studies in the field of the patho-physiology of biological barriers.

On different load configurations for mixed-mode load-pull measurements, hybrid imperfections, and tuning ranges

AbstractEach of the various methods for mixed-mode load-pull measurements, which can be found in literature, has its own advantages and disadvantages. In this publication, we analyze two of the most commonly used setups and a third setup of which we provided an initial treatment in a previous publication. We investigated the impact of 180° hybrids on the tuning capabilities of a mixed-mode load-pull system. Furthermore, we provide a rule-of-thumb to easily estimate this impact using only some specifications of hybrids. For all analyzed setups, we use measurement results to show that the tuning range of the newly proposed setup is superior compared to the other setups, though hardware effort and tuning complexity are greater.

Detecting False Data Injection Attacks Using Canonical Variate Analysis in Power Grid

With the knowledge of the measurement configuration and the topology structure of a power system, attackers can launch false data injection attacks (FDIAs) without detection by existing bad data detection methods in state estimation. The attacks can also introduce errors to estimated state variables, which are critical to grid reliability and operation stability. Existing protection methods cannot handle dynamic and variable network configurations. In this paper, to effectively defend against FDIAs, we propose a canonical variate analysis based detection method which monitors the variation of statistical detection indicators $\boldsymbol{T}^2$ and $\boldsymbol{Q}$ about projected canonical variables before and after attacks. Unlike most statistic models that only consider cross-correlation of discrete measurements constrained by Kirchhoff's Law at each independent sampling time, we also consider the auto-correlation of measurements caused by time series characteristics of varying loads. Experiment results on IEEE-14 bus system demonstrate the effectiveness and accuracy of our proposed method based on both synthetically generated data and real-world electricity data from the New York independent system operator.

Proximity‐Effect‐Induced Superconductivity in Nb/Sb2Te3‐Nanoribbon/Nb Junctions

AbstractNanohybrid superconducting junctions using antimony telluride (Sb2Te3) topological insulator nanoribbons and Nb superconducting electrodes are fabricated using electron beam lithography and magnetron sputtering. The effects of bias current, temperature, and magnetic field on the transport properties of the junctions in a four‐terminal measurement configuration are investigated. Two features are observed. First, the formation of a Josephson weak‐link junction. The junction is formed by proximity‐induced areas in the nanoribbon right underneath the inner Nb electrodes which are connected by the few tens of nanometers short Sb2Te3 bridge. At 0.5 K a critical current of 0.15 µA is observed. The decrease of the supercurrent with temperature is explained in the framework of a diffusive junction. Furthermore, the Josephson supercurrent is found to decrease monotonously with the magnetic field indicating that the structure is in the small‐junction limit. As a second feature, a transition is also observed in the differential resistance at larger bias currents and larger magnetic fields, which is attributed to the suppression of the proximity‐induced superconductive state in the nanoribbon area underneath the Nb electrodes.

Non-enzymatic and highly sensitive lactose detection utilizing graphene field-effect transistors

Field-effect transistor (FET) biosensors based on low-dimensional materials are capable of highly sensitive and specific label-free detection of various analytes. In this work, a FET biosensor based on graphene decorated with gold nanoparticles (Au NPs) was fabricated for lactose detection in a liquid-gate measurement configuration. This graphene device is functionalized with a carbohydrate recognition domain (CRD) of the human galectin-3 (hGal-3) protein to detect the presence of lactose from the donor effect of lectin – glycan affinity binding on the graphene. Although the detection of lactose is important because of its ubiquitous presence in food and for disease related applications (lactose intolerance condition), in this work we exploit the lectin/carbohydrate interaction to develop a device that in principle could specifically detect very low concentrations of any carbohydrate. The biosensor achieved an effective response to lactose concentrations over a dynamic range from 1 fM to 1 pM (10−15 to 10−12 mol L−1) with a detection limit of 200 aM, a significant enhancement over previous electrochemical graphene devices. The FET sensor response is also specific to lactose at aM concentrations, indicating the potential of a combined lectin and graphene FET (G-FET) sensor to detect carbohydrates at high sensitivity and specificity for disease diagnosis.

Reverse-time migration for evaluating the internal structure of tree-trunks using ground-penetrating radar

Modern socioeconomic factors such as global timber trade and international travelling have contributed to the rapid increase of Emerging Infectious Diseases (EIDs) of trees with devastating effects to the European forests and woodlands. To that extent, numerous non-destructive methodologies have been suggested as diagnostic tools in order to effectively monitor and maintain potential outbreaks. Ground-penetrating radar (GPR) is an appealing method for tree monitoring as it provides with a trivially deployable and efficient detection tool, suitable for large-scale forestry applications. Nonetheless, traditional GPR approaches are tuned for surface measurements and they are not compatible with the unique measurement configurations associated with forestry applications. Within that context, we present a novel-processing framework, which is capable of addressing features with irregular measurements on closed surfaces. A positioning method is described that exploits a wheel-measuring device in order to accurately associate each A-Scan with its corresponding coordinates. In addition, a processing pipeline is presented that aims at eliminating the ringing noise due to the layered nature of the trees. Lastly, a reverse-time migration is applied to the processed B-Scan in order to effectively map the reflectors present within the trunk. The suggested scheme is successfully tested in both numerical and real-field experiments, indicating the validity of the current approach.

Generalizations of the General Lotto and Colonel Blotto games

In this paper, we generalize the General Lotto game (budget constraints satisfied in expectation) and the Colonel Blotto game (budget constraints hold with probability one) to allow for battlefield valuations that are heterogeneous across battlefields and asymmetric across players and for the players to have asymmetric resource constraints. We completely characterize Nash equilibrium in the generalized version of the General Lotto game and find that there exist sets of nonpathological parameter configurations of positive Lebesgue measure with multiple payoff nonequivalent equilibria. Across equilibria each player achieves a higher payoff when he more aggressively attacks battlefields in which he has lower relative valuations. Hence, the best defense is a good offense. We, then, show how this characterization can be applied to identify equilibria in the Colonel Blotto version of the game.

Compensated Load Flow Solutions for Distribution System State Estimation

State estimation of distribution systems typically relies on measurement sets with very low redundancy levels. In this paper, this fact is exploited by first solving a conventional load flow, using exclusively a critical set of measurements, and then compensating the solution to account for the few redundant measurements available. This leads to a suboptimal but sufficiently accurate estimate. It is shown how the sparse triangular factorization of the load flow Jacobian matrix can be fully exploited throughout the compensation-based procedure, preventing in this way the ill-conditioning associated with the gain matrix arising in the conventional least-squares formulation. Simulation results are provided for measurement configurations customarily found in distribution systems, showing the potential advantages of the proposed methodology.

A parallel-wire microwave resonant sensor for measurement of water holdup in high water-cut oil-in-water flows

In the present study, we propose a parallel-wire microwave resonant sensor (PMRS) with transmission-through configuration for water holdup measurement in high water-cut oil-in-water flows. Through the finite element method (FEM) analysis using HFSS software, the variations of sensor responses for changing water holdup and salinity are investigated. In this manner, the optimum working frequency of microwave resonant sensor is tuned to 1.8 GHz. With the designed PMRS measurement system, an experimental test of vertical high water-cut oil-in-water flows is conducted in a 20 mm inner diameter pipe, through which the relationship among dimensionless normalized phase output of PMRS which reflects the water holdup information, water-cut and total flow rate are investigated. The results show that PMRS presents a high resolution in measurement of water holdup. By establishing statistics models, water-cut can be accurately predicted. Besides, PMRS can still retain high resolution under the circumstance of high salinity. To conclude, PMRS can possess high resolution in measurement of water holdup with both high water-cut and salinity variation in oil-in-water flows, and satisfactory water-cut measurement results can be achieved.

Nondestructive pressure measurement of pressurized vessels via local magnetization and magnetic sensing

Abstract This paper presents a nondestructive method for measuring the pressure of pressurized vessels through local magnetization (LM) and magnetic sensing. Firstly, tensile experiments of steel plates are carried out to character the magnetic sensitivity to plate stress with LM; It is demonstrated that the sensitivity to stress is higher when the magnet and magnetometer are fixed on different sides of the plate than that on the same side, and demagnetizing the steel plate can enhance the sensitivity. Then, pressure measurement comparison experiments on a pressurized vessel with and without optimized LM and magnetic measurement configurations are carried out to test the sensitivity and anti-interference ability of this method. It is demonstrated that LM can improve the magnetic sensitivity to vessel pressure by 2-3 times; LM can reduce the radial, circumferential and axial magnetic sensitivity fluctuations due to moving/rotating by 90.4%/94.4%, 96.5%/77% and 82.4%/87.4%.

A multilevel index optimization method for fast kinematic calibration configuration of serial manipulators based on Compute Unified Device Architecture parallel computing

The kinematic calibration accuracy of serial manipulators is affected by the error expression ability of the selected measurement configurations and non-geometric errors such as joint disturbance, measurement noise, etc. Based on the observability of configurations, deviation of identifiable parameters, and calibration robustness, this paper proposes a multilevel evaluation criterion for measurement configuration optimization. In addition, based on the Compute Unified Device Architecture (CUDA) parallel computing technique, the most time-consuming Jacobian matrix calculation program in the algorithm is modified, and an efficient optimization algorithm for measurement configurations is established, to guarantee the feasibility of the evaluation criterion. Combined with CUDA algorithm, fast calibration is implemented with fewer measurement points and relatively higher accuracy, by means of multilevel optimization. The results illustrate the effectiveness and the universality of the proposed multilevel evaluation criterion. The criterion can be applied in calibration experiments of multi-degree of freedom (DOF) serial manipulators with complex structures.

Online Diagnostic System to Monitor Temperature of In-Flight Particles in Suspension Plasma Spray

Suspension plasma spray (SPS) is going through a transition phase from research and development to daily use on production lines. Improving repeatability and reproducibility of coating elements and parameters makes SPS a replacement of former well-developed processes. This transition can be achieved by using in-flight particles diagnostic systems to monitor and control key parameters that influence the coating microstructure. Temperature and velocity of the in-flight particles are among the most critical parameters that should be monitored. However, accurately characterizing the in-flight particles in SPS is particularly challenging due to the small particle size of coating materials, harsh spray conditions, considerably shorter spray distances compared to APS, possible interference from the solvent, and limitations of previous measurement systems. In this study, different strategies were investigated to improve the accuracy of temperature measurements of in-flight particles in SPS. For this purpose, two light collection configurations (double-point and single-point measurement) were investigated along with the influence of plasma radiation. The results were evaluated by collecting and studying splats. The size and shape of splats were correlated with the temperature of in-flight particles in order to confirm the accuracy of the sensor’s temperature measurements. In addition, the sensitivity of temperature measurements to the optical filter used for two-color pyrometry, reflection of plasma radiation from surrounding objects, and direct radiation from plasma were investigated. The results showed that the single-point measurement configuration was well adapted for SPS.

Physical Insight Unveils New Imaging Capabilities of Orthogonality Sampling Method

The orthogonality sampling method (OSM) is a recently introduced qualitative inverse scattering approach for the estimation of the morphological properties of unknown targets. Both the simplicity of implementation and the applicability to various measurement configurations make this method very effective. In this article, a general physical understanding of this otherwise “pure mathematical” method is given for the first time. Such an interpretation is derived from the relationship between the currents induced in the investigated scenario and the so-called reduced scattered field, which is the core of the orthogonality sampling indicator function. Interestingly, the nature of such a relationship implies that the reduced scattered field can be related to the radiating component of the induced currents. A direct consequence of such a result is that the OSM is capable of imaging discontinuities within the unknown targets and hence identify regions with different electromagnetic properties. This possibility represents a unique feature among qualitative inverse scattering methods, as these latter have been introduced as tools to image just the external shape of the unknown targets. The new interpretation as well as the above distinctive capability of the OSM are proved with examples on both simulated and experimental data.

Handclap for Acoustic Measurements: Optimal Application and Limitations

Handclap is a convenient and useful acoustic source. This study aimed to explore its optimal application and limitations for acoustic measurements as well for other possible utilizations. For this purpose, the following steps were performed: investigation of the optimal hand configuration for acoustic measurements and measurements at different microphone source distances and at different spaces and positions. All measurements were performed with a handclap and a dodecahedron speaker for comparison. The results indicate that the optimal hand configuration (among 11) is with the hands cupped and held at an angle due to the superior low frequency spectrum. This configuration produced usable acoustic parameter measurements in the low frequency range in common room background levels unlike other configurations. The reverberation time was measured across different spaces and positions with a deviation less than three and just a noticeable difference of the signal-to-noise ratio within or near the ISO 3382-1 limits for each corresponding octave band. Other acoustic parameters (i.e., early decay time, clarity) were measured with greater deviations for reasons discussed in the text. Finally, practical steps for measurements with a handclap as an acoustic source are suggested.

Prediction and diagnosis of vertebral tumors on the Internet of Medical Things Platform using geometric rough propagation neural network

Vertebral tumors have a percentage of back pain that causes other vertebral region-born symptoms. Cancers that affect the vertebral column are visceral organ cancer metastases that are mostly seen in older patients. Vertebral dysfunction and neurological failure vertebral column cancers are the most important occurred cancers for patients. In the past, only few methods have been used to combat main and metastatic vertebral tumors. These methods are accessible for short-term monitoring and possess standardized classification consistency for vertebral diagnosis. In this paper, geometric rough propagation neural network has been used for the identification of genetic factors in the examination of a clinical sample with vertebral columns. The proposed neural network has C-statistics of 79.1%, a parameter pitch of 96.1%, and configuration for measurement in the study range with the Brier’s score of 95.6%. The algorithm shows great net gain on the decision curve study, with promising performance results of 98.5% on internal testing for preoperative non-routine estimation of discharges with 0.5% error rate and 96% accuracy range. Also, these models have been externally validated by the online healthcare careers cloud-based open access web application on Internet of Medical Things Platform with 97.9% specificity ratio.