Characteristic Calibration Research Articles

Testing for Discontinuities in Metals Using Film Flux Detectors

Results of studying the use of film flux detectors for monitoring artificial continuity defects are presented. Photographs are provided for a film flux detector with images of magnetic fields due to holes 2.0 × 10–3 m in diameter in an iron plate with a thickness of 6 × 10–4 m and a hole 1.0 × 10–2 m in diameter in an aluminum plate with a thickness of 2.0 × 10–3 after exposure to magnetic field pulses with a rise time of approximately 2.0 × 10–5–5.0 × 10–5 s, as well as of fields that passed through gaps 1 × 10–4 and 1 × 10–5 m wide between joined aluminum plates with a thickness of 3.0 × 10–3 m for different applied-field directions. Results of measuring the maximum value of the tangential Hτm (3.9 × 104 A/m) and normal Hτm (3.3 × 104 A/m) components of the strength of the total magnetic field near the surface of the aluminum plate (in the immediate vicinity to the hole in it) using a discrete magnetic-field sensor are presented. Based on the research, magnetic pulsed methods of searching for continuity defects in objects made of diamagnetic, paramagnetic, and ferromagnetic metals have been developed. These methods consist in exposing an object, with a flux detector atatched to it, to a magnetic field pulse and determining the defectiveness of the object based on the analysis of the optical image of magnetic field by studying the shape of the image and the distribution of gray levels (chromaticity) in it, while taking account of anisotropy parameters and the calibration characteristics of the sensor. The amplitude of the field pulse, its rise time, the shape of the leading and trailing edges, the number of pulses, the parameters of magnetic field spikes were preliminarily determined and the uniform illumination of the detector surface was ensured. Before use, the detector was demagnetized or polarized; the type and parameters of the magnetic field inductor were determined. It has been proposed to increase the image contrast by exposing the object–detector assembly to a series of pulses.

Implementation of the Intelligent Metering Systems for Natural Gas in Ukraine

The article proposed and justified the need for on-line calibration, the essence of which is to conduct individual calibration in real time directly at the place of operation of gas meters, taking into account the conditions and influential factors for which they conduct measurements to determine the actual calibration characteristics. This procedure should be one of the primary tools in ensuring widespread adoption of Metrology 4.0. It was noted that the key direction of development of the metrology industry should be the conformity assessment of the gas control and metering system. The given example of calculations (Table 1) carried out in assessing the compliance of such a system. It was found that the greatest weight has the error of the gas meter. In order to carry out the on-line calibration procedure, it is proposed to use the installation with parallel installed reference meters (Fig. 1), which is designed as a mobile stand with the ability to be transported to the work site. The necessity of on-line calibration is justified on the example of the obtained characteristics of gas meters (Fig. 2, Fig. 3). The results of the gas meter calibration on the working environment natural gas (Fig. 4) are presented and the total uncertainty of the gas metering system is calculated (Table 2). The application of the on-line calibration procedure leads to the need to develop the concept of introducing intelligent or smart metering of natural gas using intelligent information-measuring systems. As part of the implementation of smart metering, the possible introduction of two-tariff metering of natural gas. As a tool for statistical processing of the data, it has been proposed to apply control charts that have been tested for reference standards and are recommended in international documents.

Developing A Method for Estimation of Tightness Based on Calibration Characteristics

This article discusses methods of assessing tightness of mass-produced products. In order to reduce errors in the calibration of gas analytical leak detectors, a method is proposed which is based on transferring a certain number of molecules from the measuring chamber. This is done by means of a throttle device called frequency resistance. Based on the tests performed, results of the study are displayed.

Linearization of the Static Characteristics of a Radioisotope Density Meter

The task of linearizing the characteristics of a radioisotope measuring device is considered. The process of nonlinear transformation of a stream of pulses with a Poisson distribution is analyzed. A method for the synthesis of the transformation function of a radioisotope device, taking into account the distribution law of the data signal, is proposed. The general formulas and methods for linearizing the calibration characteristic of radioisotope measuring devices are obtained. The results were used to linearize the characteristic of an albedo radioisotope density meter.

Dynamic Outlier Detection in the Calibration by Comparison Method Applied to Strain Gauge Weight Sensors.

The present work proposes a robust method of analyzing sets of data series shifted in time in respect to each other utilizing the process of dynamic calibration by comparison. Usually the Pearson’s correlation analysis coefficient is applied for this purpose. However, in some cases the method does not bring satisfactory results, as it can be seen in the results of the research conducted for the purpose of this paper. The Dynamic Time Warping method may be the solution to this problem, as it appears to be more efficient while comparing the shapes of calibration characteristics done with the use of the Pearson’s method. The presented method may also be applied to eliminate dynamic outliers collected in the process of recurrence examination or the analysis of strain gauge weight sensors hysteresis. This fact also makes the method a good tool for eliminating improper data series which might appear in the calibration process due to, e.g., malfunctioning devices installed in the calibration stand. The article presents an example of using the proposed method in eliminating improper dynamic characteristics obtained in a simulated calibration stand. Moreover, a comparative analysis performed on the simulation data is also presented in the article, as well as the result of the laboratory experiment.

Design approach for drainage layer in pavement subsurface drainage system considering unsaturated characteristics

Abstract Providing adequate subsurface drainage feature in a pavement system to remove the infiltrated moisture in a minimum time is an important design consideration, which prevents the premature failure of the pavement system, and hence helps in achieving a significantly lower life-cycle cost. Various surface drainage measures are taken to minimize the ingress of moisture into the pavement gradually lose their efficiency with the aging of the pavement. The use of an appropriate open-graded aggregate course as a drainage layer in the pavement is the best way to minimize the time for which the pavement materials are exposed to saturated conditions. The current drainage guidelines have been developed on the basis of moisture flow under saturated condition. A better understanding and estimation of moisture movement in a drainage layer can only be achieved by using seepage analysis that adopts the principles of saturated as well as unsaturated flow conditions. State-of-art of mathematical tools such as finite difference and FEA methods permits a rigorous solution of Richard’s equation for saturated and unsaturated moisture flow in a porous medium, the only major drawback is the need for rigorous modeling and computational tool for the simulations and the design of the drainage layer. This paper focuses on the development of an analytical model for estimating the time to drain considering the unsaturated characteristics of pavement base material and calibration of the developed model based on a mechanistic approach which is relatively inexpensive. The applicability of the approach is explained by using the four-standard aggregate gradations recommended by AASHTO for the drainage layer, as well as a dense graded aggregate layer, and the results are compared with those from the FHWA approach and finite element analysis. The study shows that the developed model performs as good as the finite element analysis, which requires rigorous numerical modeling, predicts drainage times that are significantly different from those obtained from the FHWA analysis, and that it is sensitive to key significant design parameters. Hence, the proposed model is recommended for regular use for the design of the drainage layer and for a parametric study of the complete drainage process.

A Novel Nomogram to Identify Candidates for Extended Pelvic Lymph Node Dissection Among Patients with Clinically Localized Prostate Cancer Diagnosed with Magnetic Resonance Imaging-targeted and Systematic Biopsies

BackgroundAvailable models for predicting lymph node invasion (LNI) in prostate cancer (PCa) patients undergoing radical prostatectomy (RP) might not be applicable to men diagnosed via magnetic resonance imaging (MRI)-targeted biopsies. ObjectiveTo assess the accuracy of available tools to predict LNI and to develop a novel model for men diagnosed via MRI-targeted biopsies. Design, setting, and participantsA total of 497 patients diagnosed via MRI-targeted biopsies and treated with RP and extended pelvic lymph node dissection (ePLND) at five institutions were retrospectively identified. Outcome measurements and statistical analysesThree available models predicting LNI were evaluated using the area under the receiver operating characteristic curve (AUC), calibration plots, and decision curve analyses. A nomogram predicting LNI was developed and internally validated. Results and limitationsOverall, 62 patients (12.5%) had LNI. The median number of nodes removed was 15. The AUC for the Briganti 2012, Briganti 2017, and MSKCC nomograms was 82%, 82%, and 81%, respectively, and their calibration characteristics were suboptimal. A model including PSA, clinical stage and maximum diameter of the index lesion on multiparametric MRI (mpMRI), grade group on targeted biopsy, and the presence of clinically significant PCa on concomitant systematic biopsy had an AUC of 86% and represented the basis for a coefficient-based nomogram. This tool exhibited a higher AUC and higher net benefit compared to available models developed using standard biopsies. Using a cutoff of 7%, 244 ePLNDs (57%) would be spared and a lower number of LNIs would be missed compared to available nomograms (1.6% vs 4.6% vs 4.5% vs 4.2% for the new nomogram vs Briganti 2012 vs Briganti 2017 vs MSKCC). ConclusionsAvailable models predicting LNI are characterized by suboptimal accuracy and clinical net benefit for patients diagnosed via MRI-targeted biopsies. A novel nomogram including mpMRI and MRI-targeted biopsy data should be used to identify candidates for ePLND in this setting. Patient summaryWe developed the first nomogram to predict lymph node invasion (LNI) in prostate cancer patients diagnosed via magnetic resonance imaging-targeted biopsy undergoing radical prostatectomy. Adoption of this model to identify candidates for extended pelvic lymph node dissection could avoid up to 60% of these procedures at the cost of missing only 1.6% patients with LNI.

Anatomical study and clinical application of anterior lateral malleolar venous network graft for repair of superficial palmar arch defects

Objective To explore the anatomic basis of anterior lateral malleolar venous network graft for repair of superficial palmar arch defects and report its clinical efficacy. Methods Microsurgical anatomical study was performed in 6 specimens of fresh Chinese adult lower extremities to observe and measure the branches, distribution, vessel length, caliber and venous valve characteristics of the anterior lateral malleolar venous network. From May 2007 to February 2017, 15 patients with superficial palmar arch defects were treated by anterior lateral malleolar venous network graft. Results Anatomical study results showed that there was a obviously visible venous network in the superficial fascia of the anterior lateral malleolus. The distal end was originated from the fibular side of the arcus venosus dorsalis pedis, and the proximal vessels flowed into the great saphenous vein medially and the small saphenous vein laterally. Between them, there were 4 to 6 fine veins that formed network. The length of the distal dorsal segment of small saphenous vein (BC) was (2.81±0.39) cm. The branch length of the anterior lateral malleolar venous network (CD) was (5.32±0.92) cm. The fibular side vascular diameter of arcus venosus dorsalis pedis was (2.15±0.35) mm. The proximal end of the vascular network had 4.8 branches. The diameter of the vascular branch at the tip of the lateral malleolus E line horizon averaged (1.06±0.43) mm. There are an average of 4.2 valves per anterior lateral malleolar venous network. The valves in branches are toward the proximal direction. Clinically, 15 cases of superficial palmar arch defects were treated by anterior lateral malleolar venous network graft with a total of 54 anastomosis sites of distal area of recipient area and an average of 3.6 anastomosis sites per case. Postoperatively, 1 case suffered partial distal thumb necrosis and the rest of the distal fingers survived uneventfully. The follow-up time ranged from 6 months to 5 years and 3 months in 12 cases. The appearance of the hand was good, and the function of holding and opposition movement was restored. The finger proprioceptive sense was recovered. The two-point discrimination was 5 to 7 mm. According to the upper extremity function evaluation criteria issued by Hand Surgery Society of the Chinese Medical Association, the results were graded as excellent in 6 cases, good in 4 cases, fair in 1 case and poor in 1 case. There was no influence on the function of donor site. Conclusion The anatomy of anterior lateral malleolar venous network is constant. Its shape, diameter and number of branches are similar to the superficial palmar arch. The valve opening is toward the proximal end. It is an ideal method for repairing the defects of superficial palmar arch. Key words: Dissection; Vascular grafting; Venous network; Superficial palmar arch

Liver involvement in hereditary hemorrhagic telangiectasia.

Liver vascular malformations (VMs) in hereditary hemorrhagic telangiectasia (HHT) are typically diffuse and can evolve from small telangiectasias to large arteriovenous malformations, with various stages of severity. Doppler US is the ideal first-line investigation for the assessment of liver VMs in HHT due to its safety, tolerability, low costs, and accuracy for the detection of liver VMs. The caliber, course, and flow characteristics in the hepatic artery, portal vein, and hepatic vein as determined by Doppler US, together with parenchymal abnormalities, support the diagnosis of liver VMs in HHT and their severity staging. When Doppler US expertise is lacking or an assessment of HHT patients with symptoms/signs suggestive of complicated liver VMs is required, particularly if OLT is considered, multiphase CT or MRI is suitable to investigate symptomatic liver VMs. Liver biopsy is neither necessary for the diagnosis of hepatic VMs related to HHT nor should be considered in HHT patients with liver mass/es suggestive of focal nodular hyperplasia.

Evaluating the predictive accuracy and the clinical benefit of a nomogram aimed to predict survival in node‐positive prostate cancer patients: External validation on a multi‐institutional database

To assess the predictive accuracy and the clinical value of a recent nomogram predicting cancer-specific mortality-free survival after surgery in pN1 prostate cancer patients through an external validation. We evaluated 518 prostate cancer patients treated with radical prostatectomy and pelvic lymph node dissection with evidence of nodal metastases at final pathology, at 10 tertiary centers. External validation was carried out using regression coefficients of the previously published nomogram. The performance characteristics of the model were assessed by quantifying predictive accuracy, according to the area under the curve in the receiver operating characteristic curve and model calibration. Furthermore, we systematically analyzed the specificity, sensitivity, positive predictive value and negative predictive value for each nomogram-derived probability cut-off. Finally, we implemented decision curve analysis, in order to quantify the nomogram's clinical value in routine practice. External validation showed inferior predictive accuracy as referred to in the internal validation (65.8% vs 83.3%, respectively). The discrimination (area under the curve) of the multivariable model was 66.7% (95% CI 60.1-73.0%) by testing with receiver operating characteristic curve analysis. The calibration plot showed an overestimation throughout the range of predicted cancer-specific mortality-free survival rates probabilities. However, in decision curve analysis, the nomogram's use showed a net benefit when compared with the scenarios of treating all patients or none. In an external setting, the nomogram showed inferior predictive accuracy and suboptimal calibration characteristics as compared to that reported in the original population. However, decision curve analysis showed a clinical net benefit, suggesting a clinical implication to correctly manage pN1 prostate cancer patients after surgery.

Calibration of the Pressure Gage via GA and LSM Based Combined Calibration Method

Abstract Low cost accurate measurement apparatus are one of the main goal of metrology engineers. One way for decreasing the sensor uncertainties is the calibration process. This study deals with the calibration of a low cost sensor using the corresponding values obtained by reference standards. From the practical point of view, the calibration characteristics should be in a polynomial form. In this study a Genetic Algorithm (GA) is used for the measurement apparatus calibration purpose. As an example, GA based calibration of a differential pressure gauge using standard pressure setting devices is examined. The calibration results, founded using proposed GA, are compared with the results obtained via the classical Least Square Method (LSM). As a result, the recommendations on how to get the better calibration characteristics for the differential pressure gauge are given.

Experimental Identification of Condition of Position Sensor

Paper deals with experimental identification of condition of potentiometer position sensor. Calibration characteristic is obtained. Uncertainty of measurement also has been evaluated.

Development and Internal Validation of a Novel Model to Identify the Candidates for Extended Pelvic Lymph Node Dissection in Prostate Cancer

BackgroundPreoperative assessment of the risk of lymph node invasion (LNI) is mandatory to identify prostate cancer (PCa) patients who should receive an extended pelvic lymph node dissection (ePLND). ObjectiveTo update a nomogram predicting LNI in contemporary PCa patients with detailed biopsy reports. Design, setting, and participantsOverall, 681 patients with detailed biopsy information, evaluated by a high-volume uropathologist, treated with radical prostatectomy and ePLND between 2011 and 2016 were identified. Outcome measurements and statistical analysisA multivariable logistic regression model predicting LNI was fitted and represented the basis for a coefficient-based nomogram. The model was evaluated using the receiver operating characteristic-derived area under the curve (AUC), calibration plot, and decision-curve analyses (DCAs). Results and limitationsThe median number of nodes removed was 16. Overall, 79 (12%) patients had LNI. A multivariable model that included prostate-specific antigen, clinical stage, biopsy Gleason grade group, percentage of cores with highest-grade PCa, and percentage of cores with lower-grade disease represented the basis for the nomogram. After cross validation, the predictive accuracy of these predictors in our cohort was 90.8% and the DCA demonstrated improved risk prediction against threshold probabilities of LNI ≤20%. Using a cutoff of 7%, 471 (69%) ePLNDs would be spared and LNI would be missed in seven (1.5%) patients. As compared with the Briganti and Memorial Sloan Kettering Cancer Center nomograms, the novel model showed higher AUC (90.8% vs 89.5% vs 89.5%), better calibration characteristics, and a higher net benefit at DCA. ConclusionsAn ePLND should be avoided in patients with detailed biopsy information and a risk of nodal involvement below 7%, in order to spare approximately 70% ePLNDs at the cost of missing only 1.5% LNIs. Patient summaryWe developed a novel nomogram to predict lymph node invasion (LNI) in patients with clinically localized prostate cancer based on detailed biopsy reports. A lymph node dissection exclusively in men with a risk of LNI >7% according to this model would significantly reduce the number of unnecessary pelvic nodal dissections with a risk of missing only 1.5% of patients with LNI.

The algorithm of measuring parameters of separate oil streams components

This paper describes a development in the area of non-contact measurement of moving flows, including mass flow, the number of components and their mass ratios in a multicomponent flow, as well as measurement of flows based on algorithms and functional developed for various industries and production processes. The paper demonstrates that at the core of the proposed systems, there is the physical information field created in the cross section of the moving flow by hard electromagnetic radiation. The substantiation and measurement of the information parameters are performed by the hardware and the software of the automatic measuring system. A new way of statistical pulsation measurements by the radioisotope technique is described, being alternative to the existing stream control methods and allowing improving accuracy of measurements. The basic formula fundamental for the method of calibration characteristics correction is shown.

System for measurement of interaction forces between wheel and rail for railway vehicles

Determination of the interaction forces between wheel and rail of railway vehicles is essential for assessment of the vehicle dynamic characteristics from point of view of running safety and rail loading as well as for approval the vehicle and alignment them to the Technical Specification for Interoperability. The direct measurement of transverse and vertical interaction forces using the existing full-disk wheel is practical impossible due to the impossibility of separating the two types of forces. To avoid this impediment it was realized a measuring wheelset fitted with 12 spokes achieved as force transducers for measurement of the vertical forces and 12 spokes achieved as force transducers for measurement of the transverse forces. The measuring wheelset was calibrated as a force transducer and was used to determine the wheel and rail interaction forces for LE-MA 6000kW electric locomotive made by Softronic Craiova. The article presents the measuring wheelset, the calibration principle and the calibration characteristics as well as some time history of the main parameters which characterize the running safety and rail loading, determined in the on-track tests.

Influence of high dose γ irradiation on the calibration characteristics of type K mineral-insulated metal-sheathed thermocouples

In this paper, the influence of high dose γ irradiation on the thermoelectric drift of the mineral-insulated metal-sheathed (MIMS) thermocouples has been investigated by calibrations from 100 °C to 400 °C and Electron Probe Micro-Analysis (EPMA) composition analysis. The results show that the thermal electromotive force (EMF) of the thermocouples increases dramatically and the highest drift reaches to about +173 μV at 400 °C after γ irradiation. Moreover, the total EMF drift is consisted of reversible and irreversible changes. The reversible drift is positive and has been recovered by annealing at 1070 °C. This is because of the short order arrangement of the positive thermoelement (KP). For the irreversible drift, the EMF decreases −24 μV at 200 °C and increases about +32 μV at 300 °C and +55 μV at 400 °C, respectively. The irreversible changes are attributed to a small amount of oxidation of the KP thermoelement and the aging of the two thermoelements. The deep understanding of the EMF drift mechanism is of crucial importance in terms of the manufacture of thermocouple sensor and the safety operation system in the nuclear reactors.

Study of the dynamic and calibration characteristics of semiconductor sensors of Ammonia

Study of the dynamic and calibration characteristics of semiconductor sensors of Ammonia

Estimation of power losses in a high-frequency planar transformer using a thermal camera

Abstract This paper presents the implementation of a thermal camera for the quantitative estimation of power losses in a high frequency planar transformer (100 kHz/ 5600 VA). The methodology is based on the observation of the transient temperature rise and determination of the power losses by means of curves representing the derivative of temperature as a function of power losses dissipated in the transformer. First, the thermal calibration characteristics had to be obtained from a simple experiment, where power losses are generated by DC current in the ferrite core and windings. Next, experimental investigations focused on the determination of the transformer power losses for a short circuit and no load, with a resistive load and with the rectifier as a load were carried out. Finally, to verify the obtained results, analytical calculations based on Dowell’s and modified Steinmetz’s equations were additionally made, which showed a good convergence. The proposed method is easy to implement and can be used as an alternative to the calorimetric method which is time-consuming and requires a complicated measurement setup.

Fast Search Algorithms for the Best Approximation Polynomials for Reproduction of Functional Dependences in Data-Measurement Systems

Fast algorithms are proposed to search for the best polynomial approximations for the functional dependences and calibration characteristics of measurement systems. The number of iteration cycles in searches for optimal values of the physical standards for calibration of measurement channels is reduced.

Spatial and temporal scales of variability in Tropical Atlantic sea surface salinity from the SMOS and Aquarius satellite missions

Taking advantage of the spatially dense, multi-year time series of global Sea Surface Salinity (SSS) from two concurrent satellite missions, the spatial and temporal decorrelation scales of SSS in the Tropical Atlantic 30°N–30°S are quantified for the first time from SMOS and Aquarius observations. Given the dominance of the seasonal cycle in SSS variability in the region, the length scales are calculated both for the mean and anomaly (i.e. seasonal cycle removed) SSS fields. Different 7–10 days composite SSS products from the two missions are examined to explore the possible effects of varying resolution, bias corrections and averaging characteristics. With the seasonal cycle retained, the SSS field is characterized by strongly anisotropic spatial variability. Homogeneous SSS variations in the Tropics have the longest zonal scales of over ~ 2000 km and long temporal scales of up to ~ 70–80 days, as shown by both SMOS and Aquarius. The longest meridional scales, reaching over ~ 1000 km, are seen in the South Atlantic between ~ 10°–25°S, most discernible in Aquarius data. The longest temporal scales of SSS variability are reported by both satellites to occur in the North-West Atlantic region 15°–30°N, at the Southern end of the Sargasso Sea, with SSS persisting for up to 150–200 days. The removal of the seasonal cycle results in a noticeable decrease in the spatio-temporal decorrelation scales over most of the basin. Overall, with the exception of the differences in the South Atlantic, there is general agreement between the spatial and temporal scales of SSS from the two satellites and different products, despite differences in individual product calibration and resolution characteristics. These new estimates of spatio-temporal decorrelation scales of SSS improve our knowledge of the processes and mechanisms controlling the Tropical Atlantic SSS variability, and provide valuable information for a wide range of oceanographic and modelling applications.