Virtual Training Laboratory for Primary Impedance Metrology

This article presents the concept and some aspects of the physical implementation of a virtual training laboratory (VTL) in the field of primary impedance metrology. The creation of a VTL provides a novel method of disseminating metrological knowledge and expertise in a practical way and at a low cost. It will expose new users to the live experience of operating a digital impedance bridge thus helping to encourage the uptake of this novel and useful impedance measurement technology. The VTL was developed as part of the EMPIR projects VersICal 17RPT04, A versatile electrical impedance calibration laboratory based on digital impedance bridges, and GIQS 18SIB07, Graphene impedance quantum standard

A Comprehensive Analysis of Error Sources in Electronic Fully Digital Impedance Bridges

open12sìFully digital impedance bridges are emerging as measuring instruments for primary electrical impedance metrology and the realization of impedance units and scales. This article presents a comprehensive analysis of electronic fully digital impedance bridges for both generating (based on digital-to-analog converters) and digitizing (based on analog-to-digital converters) bridges. The sources of measurement error are analyzed in detail and expressed by explicit mathematical formulas ready to be applied to the specific bridge and measurement case of interest. The same can be employed also as a basis to optimize the design and the operating parameters of digital bridges and evaluate the measurement uncertainty. A practical application of the analysis to the digital bridges developed and measurements performed in the framework of an international research project is presented.openOrtolano, Massimo; Marzano, Martina; D'Elia, Vincenzo; Mai Tran, Ngoc Thanh; Rybski, Ryszard; Kaczmarek, Janusz; Koziol, Miroslaw; Musiol, Krzysztof; Christensen, Andreas Elmholdt; Callegaro, Luca; Kucera, Jan; Power, OliverOrtolano, Massimo; Marzano, Martina; D'Elia, Vincenzo; Mai Tran, Ngoc Thanh; Rybski, Ryszard; Kaczmarek, Janusz; Koziol, Miroslaw; Musiol, Krzysztof; Christensen, Andreas Elmholdt; Callegaro, Luca; Kucera, Jan; Power, Olive

Practical Precision Electrical Impedance Measurement for the 21st Century – EMPIR Project 17RPT04 VersICal

The core objective of EMPIR project 17RPT04 VersICaL is to improve the European measurement infrastructure for electrical impedance, with particular emphasis on the capabilities of developing NMIs and calibration centres. The project will seek to exploit the results of existing research on digital impedance bridges (DIBs) by designing, constructing and validating simple, affordable versions suitable to realise the impedance scale in the range 1 nF to 10 μF and 1 mH to 10 H with relative uncertainties in the range 10-5 to 10-6. The first results of the research project, including the bridge designs and details of a polyphase digitally synthesized multichannel source capable of providing voltage outputs of precise ratio and phase are presented

Measurements of signal delays in software defined radio with use of GNSS modules

In the work a method of latency measurement in software defined radio (SDR) is proposed and validated. The test setup uses customer grade GNSS modules as reference time sources and enables relative delay calculation between signals received directly and those bypassed through SDR platform. The method is hardware agnostic in a sense, that it does not involve any custom software or hardware modifications. Tests that compare reported carrier-to-noise ratio and positioning errors were performed to prove functionality of such system. Additionally, authors measured several gnuradio blocks with respect to their impact on total latency introduced into signal path. All tests were performed on a bladeRF low-cost RF front-end. Minimum observed latency for the signal was below 10 ms

Improving the Accuracy of Digital Unbalanced Impedance Bridges

This article presents an automatic digital unbalanced impedance bridge for comparing two-port impedances: R-R, R-C and C-C. The bridge consists of a two-channel digital source of voltage sinusoidal waveforms supplying the bridge arms and a three-channel precise digitizer, by means of which the complex ratio of the source output voltages and the relative bridge unbalanced voltage are determined. The hardware implementation of the bridge is based on a relatively inexpensive universal data acquisition (DAQ) card by National Instruments, USB-6281, which contains, among others, a multi-channel 18-bit analog-to-digital converter (ADC) and two 16-bit digital-to-analog converters (DAC). Thanks to the new approach to the bridge operation algorithm, consisting in the use of the interpolation method in the comparison process, the influence of the accuracy of the measurement of the bridge unbalanced voltage and some bridge parasitic admittances on the uncertainty of the impedance comparison were minimized. This simplifies the measurement procedure and shortens its execution time. The obtained results confirmed that a relatively simple digital unbalanced bridge can compare impedance standards with an uncertainty of less than 10−5. By reducing the requirements regarding the uncertainty of the measurement, and thus its execution time, the presented bridge supplemented with impedance sensors can be used in many areas of industry

Concept and Implementation of Measurement Systems for Stationary and Remote Testing of Sensors for Electrical and Non-Electrical Quantities

In intelligent transportation, various types of sensors are used both in traffic control systems as well as in the control, safety, and entertainment systems of the vehicles themselves. In the process of educating future designers and developers of such systems, it is necessary to familiarize them with the operation and parameters of sensors. The recent years of the COVID-19 pandemic have disturbed this process due to the need to conduct classes remotely. This article presents the general concept of a laboratory stand for testing sensors of electrical and non-electrical quantities, which can be used both in stationary and remote learning. Additionally, the practical implementation of two laboratory stands for testing current and linear displacement sensors was also presented. Both stands have been tested in the remote access mode. The tests showed some shortcomings in the management software but also confirmed the correctness of the adopted concept of their implementation

Concept and Implementation of Measurement Systems for Stationary and Remote Testing of Sensors for Electrical and Non-Electrical Quantities

In intelligent transportation, various types of sensors are used both in traffic control systems as well as in the control, safety, and entertainment systems of the vehicles themselves. In the process of educating future designers and developers of such systems, it is necessary to familiarize them with the operation and parameters of sensors. The recent years of the COVID-19 pandemic have disturbed this process due to the need to conduct classes remotely. This article presents the general concept of a laboratory stand for testing sensors of electrical and non-electrical quantities, which can be used both in stationary and remote learning. Additionally, the practical implementation of two laboratory stands for testing current and linear displacement sensors was also presented. Both stands have been tested in the remote access mode. The tests showed some shortcomings in the management software but also confirmed the correctness of the adopted concept of their implementation

Impedance spectroscopy method used for the unpasteurized beer microbiological contamination degree assessment

The main aim of the below presented work was to investigate the possibility of using impedance spectroscopy in the unpasteurized beer microbial contamination degree assessment. Advantages of the impedance spectroscopy method, a negligible number of similar published results as well as their practical aspect make the research important. Four different types of beers were investigated which were unfit for consumption due to improper storage and were heavily microbiologically contaminated. Their impedance was measured in the frequency range from 0.1 Hz to 1 kHz before and after centrifugation. Based on the measured values, an innovative electrical equivalent circuit was proposed and the parameters of the circuit elements were fitted. The obtained results show significant differences (23 up to 35%) in the values of resistance modelling the diffusion phenomenon. Such large changes, resulting from the removal of biomass from the samples, prove the validity of impedance spectroscopy in the study of the properties of unpasteurized beer. According to the authors, it would be possible to use the proposed methodology during the production of beer. With some limitations, it should aid in the early detection of microbial contamination

Influence of surgery treatment quality on longtime results gastric cancer combination therapy

Introduction.The aim of this study was to analyze the influence of surgical center experience on long-term survival of patients with locoregionally advanced gastric adenocarcinoma undergoing primary surgery followed by complementary chemoradiotherapy according to MacDonald's regimen. Material and methods. 154 patients treated surgically, including 75 (48.7%) at the Maria Sklodowska-Curie National Researche Institute of Oncology (NIO-PIB) in Warsaw, and 79 (51.3%) outside this center, were retrospectively analyzed. The compared groups were statistically homogeneous. The following parameters were analyzed: age, gender, tumor differentiation, TNM VII (2010) staging, nodal index, radicality of surgical treatment, tumor type according to Lauren classification, clinical stage, presence of prognostic factors, overall survival time. Results. Among the patients operated at NIO-PIB, 71 (94.7%) patients underwent radical resection, 4 (5.3%) cases were microscopically non-radical resection. There were no macroscopically non-radical resections (0%). For patients operated outside NIO-PIB, 60 (75.9%) R0 resections, 15 (19%) R1 resections and 4 (5.1%) R2 resections were performed. The percentage of radical resections was significantly higher at NIO-PIB (p = 0.001). In 77% of patients operated on at NIO-PIB, disease progression in terms of feature n could be established. This percentage for patients operated on outside the NIO-PIB was 54% and was significantly lower (p = 0.001). The probability of 5-year survival was 41.6% in total, with 45.3% for the group of patients operated on in the NIO-PIB and 38.0 % for the group of patients operated on outside the CO-I, respectively (p = 0.628) Conclusions. The quality of surgical treatment was significantly higher in NIO-PIB. The difference in 5-year overall survival (OS) between the compared groups is not statistically significant. Complementary treatment with chemoradiotheraphy (CRT) according to MacDonald's regimen reduces the shortcomings in the quality of surgical treatment in locoregionally advanced gastric adenocarcinoma