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The giant magneto-impedance (GMI) effect has been, since its discovery, one of the most promising technologies in the development of magnetic sensors. Features such as high sensitivity, stability and low cost are the main reasons for the development of this type of magnetometers. This study reports the design, implementation and experimental characterisation of a high sensitivity GMI gradiometer, aimed at measuring low-intensity magnetic fields. A first-order gradiometer was designed, based on the impedance phase characteristics of two Co 70 Fe 5 Si 15 B 10 amorphous ribbon-shaped sensors connected to an electronic circuit that converts the magnetic field into an output voltage. The developed prototype can operate not only as gradiometer but also as two separate magnetometers, which allows it to incorporate a compensation system against deviations in the biasing field of the GMI sensors. The experimental results for the gradiometer showed a sensitivity of 99 mV/μT, a measuring range of ±30 μT, a magnetic noise of 5 nT Hz -1/2 at 5 Hz and a resolution of 40 nT within a 500 Hz bandwidth. The compensation system has shown a settling time of 1.6 s for perturbations in the range ±10 μT with a steady-state error

The present work aims at demonstrating the applicability of using tubes made of the polymer PVDF as intrinsic flowmeters, considering the peculiar piezoelectric properties of the PVDF-β polymorph and using as flow measurement method the Flow-Induced Vibration (FIV) technique. The work methodology consisted of initially characterizing the material of a commercial PVDF tube spectroscopically, using the Fourier Transform Infrared Spectroscopy (FTIR) technique, to confirm the presence of PVDF-β. Then, the PVDF tube was installed in a hydraulic test circuit and electromechanically tested, to identify the levels of electrical voltages generated by the vibration caused by the passage of water through the tube. To compare the vibration signals, simultaneous measurements were made with commercial accelerometers and with a commercial PVDF film built specifically as a piezoelectric transducer. The results of the FIV tests allowed confirming that the standard deviation of the voltage signal measured by the PVDF tube is related to the flow rate. The uncertainties associated with flow rate measurement by the tube showed a considerable reduction in the higher flow rates. On the other hand, in the lowest flow rate levels, a high instability was observed, possibly due to the process of initial mechanical accommodation of the tube. Despite this, a strong relationship between the signal generated by the PVDF tube and the flow rate that induced this vibration has proven the potential applicability of the PVDF tube as a water flowmeter.

Low-frequency audible noise generated by the magnetostriction effect inherent to the operation of power transformers has become a major drawback, especially in cases where the electrical substation is located in urban areas subject to strict environmental regulations that imposes sound pressure limits, differing for day and night periods. Such regulations apply a +5 dB penalty if a tonal component of noise is present, which is clearly the case of magnetostriction noise, typically concentrated at twice the industrial frequency (50 Hz or 60 Hz, depending on the country). The strategy used to eliminate the tonal characteristics, therefore contributing to establish compliance with the applicable regulation and to alleviate the discomfort it causes to the human ear, consisted in superimposing to the substation noise a masking sound synthesized from “sounds of nature” with suitable intensities, to flatten the noise spectrum while enhancing the soundscape. The masking system (heavy-duty speakers powered by a microprocessor platform) was validated at an already judicialized urban scenario. Measurement results confirmed that the masking solution was capable of flattening the tonal frequencies, whose beneficial effect yielded the cancellation of the public civil action filed by the neighbors. The proposed solution is ready to be replicated to other scenarios.

Three-dimensional (3D) imaging technologies have been increasingly explored in academia and the industrial sector, especially the ones yielding point clouds. However, obtaining these data can still be expensive and time-consuming, reducing the efficiency of procedures dependent on large datasets, such as the generation of data for machine learning training, forest canopy calculation, and subsea survey. A trending solution is developing simulators for imaging systems, performing the virtual scanning of the digital world, and generating synthetic point clouds from the targets. This work presents a guideline for the development of modular Light Detection and Ranging (LiDAR) system simulators based on parallel raycasting algorithms, with its sensor modeled by metrological parameters and error models. A procedure for calibrating the sensor is also presented, based on comparing with the measurements made by a commercial LiDAR sensor. The sensor simulator developed as a case study resulted in a robust generation of synthetic point clouds in different scenarios, enabling the creation of datasets for use in concept tests, combining real and virtual data, among other applications.

Several three-dimensional scanning methods have been developed and improved over the past 40 years. The peculiarities of each technique, associated with the computational advances of the period, allowed the increasing application and diffusion of the technology in several sectors, among them those related to metrology in ballistics and the testing of protective materials. The specific goal of such ballistic tests is to estimate the depth of indentation caused by projectiles. In particular, this study presents a comparative analysis between two three-dimensional optical scanning methods, taking into account the same object of interest. The comparative analysis was based on reference planes detected by Random Sample Consensus methodology in each cloud. By comparing the results of the different techniques, it was found for this case that three-dimensional reconstruction by stereo images estimated values closer to the real ones in comparison to those estimated by the structured light scanner, mainly due to the fact that, for three-dimensional reconstruction, the image acquisition was conducted statically.

This paper presents an algorithm based on Convolutional Neural Networks (CNN) to find the depth and angles of inclination and rotation of a foreign object inside the human body based on images of the magnetic field generated by it. The key challenge is to provide information with enough accuracy to be used in surgical procedures. We tested three distinct CNN architectures for values prediction, and our best model achieved a mean - average F1-score of 66 %, 100 %, and 98 % in the test dataset for depth and angles of inclination and rotation, respectively. We also propose an approach for converting classification values to real values and we calculate the type A uncertainty for all models, with our best model showing an uncertainty of 10.8 mm for depth, 2.0° for inclination and 7.5° for rotation values.

This manuscript studies the sound pressure levels resulting from the operation of electrical substations in areas of considerable urban density. Although it is not possible to completely eliminate the acoustic noise generated by high voltage transformers, since it results from the natural phenomenon of magnetostriction, which is intrinsic to the operation of any transformer, the work shows that it is possible to adjust the sound pressure level to the limits imposed by the environmental legislation. As part of the strategy, the work recommends, as a first action, to eliminate the tonal component of the noise, since its presence in the frequency spectrum causes discomfort to the human ear and penalizes the measured levels by + 5 dB. The work also shows that it is not trivial to discuss the impact of the acoustic noise generated by substations in urban communities that generate their own noises, even with a higher intensity.

The bend sensor is a resistive sensor that, due to its material properties, changes its electrical resistance as it is bent. In general, one of its most notable characteristics is its ample versatility. In this sense, this work characterizes, experimentally and by simulation, a sensor of this type to study the feasibility of its use for measuring the volume of water drained through a pipe. Therefore, some basic principles are shown to establish the correlation between the sensor resistance and flow velocity, and a methodology to characterize the bend sensor is described. Also, a comparison between the results obtained from this experimental characterization with a computer simulation is presented. The results indicate that the bend sensor can be a viable option to integrate a water volume meter. Finally, future work is proposed to implement the bend sensor in a hydraulic testing section to confirm its potential through experiments.

The widespread use of point clouds in many applications is prompting many researchers to find new ways to generate such datasets, as the technology is still costly and slow depending on the experiment’s parameters. Virtual scanning, a computer simulation of scanning a real target, is one of these solutions. This paper is a short presentation of the current development of a light detection and ranging (LiDAR) system simulator based on metrological parameters, sensor error model and light scattering treatment.

In the last decade, there has been an increasing interest in measuring and evaluating intangible assets, not only by private firms but also by knowledge organizations such as universities, research centers, and testing laboratories. This paper aims to present a model for measuring and evaluating intangible assets developed for electrical equipment diagnosis and testing laboratories. For the proposal and selection of indicators and metrics that integrate the model, multicriteria decision support methods were embedded into the model, combined with fuzzy logic. The applicability of the model has been demonstrated through an empirical study in one electrical equipment diagnosis and testing laboratory that integrates the Laboratory Network of Eletrobras Enterprises (Relase) in Brazil. The results of this research can be replicated within Relase, which covers today a total of 98 laboratories, of which 16 are accredited for calibration services.

High and ultra high voltage tests are commonly carried out to determine external and internal dielectric performances of electric power equipment. The standardization of these tests in different laboratories is obtained by following the standards with the requirements necessary to perform the tests. Among such requirements, the test voltage parameters must be measured within acceptable uncertainties. For a correct analysis of the test and presentation of the results it is necessary that the measuring system and the instrument used be able to estimate all parameters according to standard IEC 60060-1:2010, depending on each type of voltage and test, AC, DC or impulse. However, simpler conventional instruments, such as multimeters, are not capable of measuring and indicating all parameters required by current standards. Thus, dedicated instruments and software are needed, capable of performing the analysis of these parameters within the acceptable uncertainty limits. The use of software or measurement algorithms for voltage impulse testing is already described in IEC 61083-1 and -2 standards. Specifically, part 2 presents the reference waveforms used for the validation of the software used in the tests. Similarly, IEC 61083-4 is being developed for high voltage AC and DC tests, with standard waveforms for validation of the measurement software. The objective of this work is presenting the HVAT AC-DC virtual instrument developed in LabVIEW environment, capable of estimating the required AC and DC test parameters of the ABNT NBR IEC 60060-1:2013 standard and analyzing the robustness of such a virtual instrument through low and high voltage tests.

The development of systems capable of characterizing the positioning and inclination of metallic objects inside the human body is seen with great interest by health professionals who are responsible for their extraction. A surgical procedure can be shortened from a few hours to minutes with a system that provides accurate positioning data. Thus, the present work aims at the construction of a measurement system of magnetic fields originated by ferromagnetic objects, based on magnetoimpedance (GMI) sensors. The developed system is capable of positioning a ferromagnetic object to be measured with 5 degrees of freedom, being 3 linear (X, Y, Z) and 2 angular (θ, Φ), and measure the magnetic flux density of this source in an automated way. Three tests were performed with a steel needle, varying the angles of inclination to the measurement plane (θ) and rotation angles in the same plane (Φ). The obtained results yieded records of the magnetic patterns formed by the needle, which can be later processed in order to create a localization software.

A computational model of the dynamic behaviour of a go-kart has been implemented as the first step in the development of an electrical vehicle advanced control system and the lateral dynamics model needed its yaw moment of inertia as input value. Therefore, this study presents experimental measurements of the yaw moment of inertia of a recreational go-kart using two similar methodologies: the ‘three cables’ (trifilar) swinging torsion pendulum and the ‘four cables’ (quadrifilar) swinging torsion pendulum. Parallel to the experimental tests carried out, yaw moment of inertia calculation was done by the traditional methodology of mechanical engineering. Also, the measurement uncertainty was calculated for each method. The trifilar method presented, in this test, the lowest measurement uncertainty.

The transducer most widely used for vibration measurement is the piezoelectric accelerometer. This application has been explored for flow rate measurement, since some studies have verified the narrow correlation between ratio of flow and vibration. The technique consists of measure the vibration induced by the flow in the pipeline, has been considered as promising, in the sense of enabling the development of a sensor that presents advantageous characteristics such as non-intrusiveness, non-invasiveness and reduced cost. This paper shows the method of measurement of flow in pipe based on vibration caused by transit of water, without the need of flow interruption or opening of pipe for installation of water meters. Further are present experimental measurements and metrological validation in laboratory accredited for calibration of flow meters.

This paper presents a method for measuring flow rates in pipelines based on the flow induced vibration principle using water as fluid, eliminating the need for interrupting the flow and opening of the pipeline for installation of traditional water flow meters. Experimental measurements are carried out in an accredited laboratory for calibration of rate flow meters and a metrological validation, followed by an uncertainty evaluation, are presented. Data analysis is accompanied by a method of optimization that minimizes adjustment errors of measurement using regression by parts and by the selection of the optimum period to estimate more accurately the flow rate. The results meet the specifications of Brazilian Metrology Institute.

Transcranial magnetic stimulation (TMS) is a noninvasive technique that promotes the neuromodulation effect aiming at treating diseases of neuro-psychiatric origin. TMS electromagnetic coils provide an alternating magnetic field that induces bioelectric currents in a targeted region of the brain tissue. The guarantee of treatment effectiveness and safety of both patients and device operators depends on the distribution of the magnetic flux density emitted in the vicinity of the TMS equipment, according to the design of the induction coil employed. This work presents the development of a multichannel measuring system to evaluate the configuration of magnetic flux density generated in the proximities of TMS devices. By using the developed measuring system, it is performed the magnetic mapping along a plane under the figure-of-eight TMS coils, including the study of its response to different intensities and distances from the device. The results allow characterizing the decay of field magnitude towards the region closer to the operator’s hand position and its spatial distribution in areas intended to receive the therapeutic effect.

The goal of this manuscript is the use of the statistical methods to analyze differences caused by the application of the correction methods defined on different standards for the measurement of the volume of liquid petroleum derivatives. This correction is necessary because pressure and temperature variations can cause differences between measurements made by the customer and supplier due to operational condition variations. To standardize this measurement, it was established that all volumes used on transactions in Brazil should be corrected to a base condition (20 °C and 101.325 kPa). To study these possible differences, the applied methodology uses statistical distributions that model the density of the products during the production process and, i.e., uses data collected during certain periods. Corrected density values are then obtained for each method. With these values in hand, a hypothesis test based on measurement uncertainty shows that numerical differences don’t always have statistical significance.

This work describes an approach for digital processing of voltage impulse signals in puncture tests of insulators on high voltage laboratories, using wavelet transform based multi-resolution analysis. Quantifying the amplitude of such impulses is not a trivial task because they have typical magnitudes of hundreds of kilovolts and rise times of 100 ns to 200 ns. The processing is mainly necessary due to high frequency electromagnetic interferences caused by the impulse generation system, which may strongly affect the measurement accuracy and, consequently, the test result. This manuscript presents qualitative and quantitative results for different types of wavelets studied, as well as the best performance obtained by the filter. Software for signal processing and analysis was also developed for this application. Results are also presented using the wavelet filter for a pioneering inter-laboratory comparison between high voltage measuring systems used in impulse puncture tests of insulators.

The results of a computer simulation examining the compliance of a given transcranial magnetic stimulation device to the 2010 International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines are presented. The objective was to update the safe distance estimates with the most current safety guidelines, as well as comparing these to values reported in previous publications. The 3D data generated was compared against results available in the literature, regarding the MCB-70 coil by Medtronic. Regarding occupational exposure, safe distances of 1.46 m and 0.96 m are derived from the simulation according to the 2003 and 2010 ICNIRP guidelines, respectively. These values are then compared to safe distances previously reported in other studies.

The objective was to analyze a recently developed flow measurement technique based on the vibration captured by an accelerometer attached to the pipeline surface for use in the oil industry. The applied methodology consists of performing an experimental study to obtain data in an accredited laboratory for calibration of flowmeters, estimating a flow rate for each vibration measured, followed by an uncertainty analysis. The results of water flow rates showed a measurement uncertainty between 2.5% and 5.0% of reading (95% confidence). While these results do not meet to Brazilian regulations for the measurement of crude oil of 0.3% of reading, they are acceptable under the regulations for produced, injected, captured, or discarded water, which occur the processing of oil.

The International Electrotechnical Commission (IEC) issued in 2010 a revision of the family of standards IEC 60060, describing, among other requirements, how to calculate the various amplitude and time parameters used to evaluate high-voltage impulse waveforms. However, the standards are not clear in some aspects, especially when describing tail-chopped lightning impulses. This paper aims at describing in detail how to properly estimate the time parameters of such impulses.

This paper describes IMPREAL 2.0, a system developed in LabVIEW that automates the acquisition of voltage impulse waveforms from digital oscilloscopes and implements the mathematical procedures described in the new standards from the International Electrotechnical Commission IEC 60060:2010. The system controls commercial digital oscilloscopes and is able to automatically calculate the time and amplitude parameters of lightning impulses (LI), switching impulses, chopped LI, and oscillating impulses (lightning and switching) waveforms, generating test reports tailored for the needs of the calibration and tests labs. The estimated uncertainty due to the software processing is also presented here, following the guidelines defined by standard IEC 61083-2:2013.

A sample of polyvinylidene fluoride removed from a riser component was tested in laboratory to evaluate its electromechanical behavior. For this, an experimental setup was developed, after Fourier Transform Infrared Spectroscopy (FTIR) results have shown through the absorption bands, that this sample had a spectrum of the piezoelectric phase β. In order to identify if such sample would be able to respond electrically to the application of external mechanical excitation applied by a shaker, measurements were made of the induced voltages by piezoelectric effect, with varying accelerations and frequencies. The results indicated that the material, although it has not been processed for this purpose, responds electrically to the applied mechanical stimulus, demonstrating a good correlation between the measured signals and the accelerations.

This work aims to evaluate the influences of the water content dissolved in crude oil and of the meter factor on the uncertainty of the fiscal oil measuring system using ultrasonic flow meters, considering that the overall uncertainty of the measuring system shall not exceed 0.3%. The development of this work was motivated by the fact that the Brazilian Technical Regulation for the Measurement of Oil and Natural Gas (RTM) limits which methodologies can be used for water analysis and defines the maximum permissible uncertainty for the oil flow meter in which this analysis is inserted. However, the RTM does not define the uncertainty required for the water analysis. There is a risk of adopting one of the permitted methods of analysis and, even so, the measurement uncertainty of the flow meter exceeding the values defined by the legislation. In addition, the RTM adopts a repeatability criterion when validating the calibration of ultrasonic meters, thus the influence of this aspect on the oil uncertainty is also evaluated. The methodology used is the design of experiments and response surfaces. The results demonstrate that it is possible to simulate the influence of the water content and of the meter factor uncertainties on the overall uncertainty of the oil flow measuring system. Finally, the conclusions show that the average uncertainties currently observed for the water content are adequate to keep the oil measuring system uncertainty within the range allowed by the RTM, but small variations may cause this limit to be exceeded. The influence of the meter factor uncertainty was less than or similar to the influence of the water content. Finally, adoption of an acceptance criterion for the ultrasonic meters based on the uncertainty instead of repeatability is suggested.

This paper proposes a new technique based on the employment of genetic algorithms to solve the inverse biomagnetic problem. The biomagnetic measurements analyzed in this paper were performed on isolated rabbit hearts and acquired by a 16-Channel SQUID system. The developed method focused on defining the single equivalent current dipole that best fits the experimental data. The genetic algorithm is used to determine the position, angle and magnitude of the current dipole, attempting to minimize the error between the experimental magnetic field map and the one obtained by using the estimated current dipole.

This work presents an experimental study aiming the sensitivity optimization of Giant Magnetoimpedance (GMI) sensors, by means of properly choosing the values of their conditioning parameters. The optimized GMI sensors, together with the development of improved transduction electronic circuits, can lead to the sensitivity enhancement of GMI biomedical, pressure and magnetic transducer prototypes, previously developed by the research group at LaBioMet, PUC-Rio. Those prototypes are, respectively, aimed at the measurement of arterial pulse waves and the localization of magnetic foreign bodies inserted in the human body. Thus, the experimental characterization of GMI ribbon-shaped samples (Co 70 Fe 5 Si 15 B 10 ) was performed, as a function of the external magnetic field, including the experimental evaluation of the asymmetric GMI effect (AGMI). The parameters that affect the behavior of the GMI samples were experimentally analyzed, such as the DC level (0 mA to 100 mA) and frequency (100 kHz to 10 MHz) of the excitation current, as well as the samples length (1 cm, 3 cm, 5 cm and 15 cm). The conditioning parameters, experimentally identified, that optimize the GMI samples sensitivity lead to a maximum specific sensitivity of 0.84 W·Oe -1 ·cm -1 (8400 Ω ·T -1 ·cm -1 ). A new electronic circuit was developed for conditioning and reading of the GMI samples, which directly contributed to the performance enhancement of both transducers. The electronic circuits developed were evaluated supposing the operation of the GMI samples in their most sensitive region. Comparing to previously developed prototypes, the optimum sensitivity achieved for the new configuration of the GMI magnetic transducer increased about 9 times (from 0.12 mV/nT to 1.08 mV/nT), and the sensitivity of the modified pressure transducer increased approximately 7 times (from 1 mV/Pa to 7 mV/Pa).

CMOS technology miniaturization limits have promoted research on new alternatives which can keep the technologically advanced level of the last decades. Quantum-dot cellular automata (QCA) is a new technology in the nanometer scale that has been considered as one of these alternatives. QCA have a large potential in the development of circuits with high space density and low heat dissipation and allow the development of faster computers with lower power consumption. Differently from conventional technologies, QCA do not codify information by means of electric current flow, but rather by the configuration of electrical charges in the interior of the cells. The Coulomb interaction between cells is responsible for the flow of information. This paper proposes the use of computational intelligence techniques in the simulation and in the automatic synthesis of QCA circuits. The first results show that these techniques may play an important role in this research area since they are capable of simulating efficiently and fast, synthesizing optimized circuits with a reduced number of cells. Such optimization reduces the possibility of failures and guarantees higher speed

The International Electrotechnical Commission (IEC) issued in 2010 a revision of the family of standards IEC 60060, describing, among other requirements, how to calculate the various amplitude and time parameters used to evaluate high voltage impulse waveforms. However, the standards are not clear in some aspects, especially when describing tail chopped lightning impulses. This paper aims at describe in detail how to properly estimate the time parameters of such impulses.

A technique was previously developed, based on magnetic field measurements, to localize hypodermic and sewing needles lost in the human body, with the purpose of surgical extraction. The measurements are performed using a SQUID magnetometer, which detects the magnetic field associated with the remanent magnetization of the needle. The technique allowed easy surgical localization of the needles with good precision in all six clinical cases studied so far. The procedure greatly decreases the surgery time for foreign body extraction, and also reduces the generally high odds of failure. This paper presents an improvement of the original algorithm, which is now independent of any constant magnetic field component, thus overcoming the main experimental difficulty usually found, namely that a SQUID system does not measure absolute fields.

It is often challenging to supply high alternating currents at high frequency to inductive loads, because it demands very high voltages at the load terminals. Usually, in such a scenario, the use of large, heavy and expensive high-voltage/power active devices is mandatory. However, the set of requirements of an ongoing project, demanding portability, low cost and electrical efficiency, led to the necessity of working on that issue. An original method that enables the use of low-voltage active devices and a low-voltage source to supply high currents to inductive loads is described. The basic principle used was the reduction of the equivalent impedance seen by the active devices at the desired frequency, leading to lower terminal voltages. Further adaptations were made, including measures to improve power dissipation and protection from transients. The respective developed electronic circuit is shown and experimentally analysed.

The concept of Quality by Design (QbD) has been widely used by the pharmaceutical industry since 2004, changing the focus on inspections to embrace greater control in the manufacturing process. This new approach contributed to lower production costs and higher quality of medicines. This work discusses the first steps towards the implementation of a QbD approach aimed at ensuring the quality of a biomedical device under development. This device will be applied as a non-magnetic metallic foreign body localization system for surgical removal guidance. It should be highlighted that a new approach was used to define the Design Space, based on fuzzy logic rather than the typical statistical techniques.

Image processing techniques were used to enhance magnetic data generated by SQUID nondestructive evaluation of conducting plates. The process consists of low-pass filtering the acquired data with a FIR filter with order depending on the standoff distance and background noise. In addition a high-pass FIR filter is used to enhance the magnetic field disturbance due to the flaw. The technique was tested on magnetic field data generated through a dc current applied to flawed aluminum test samples, and detected by using an RF-SQUID system. It was observed that when the standoff distance exceeds 5 times the size of the flaw, image inspection is difficult. Applying the enhancement algorithm, magnetic field disturbances could be visualized at distances 10 times the size of the flaw. >

The construction of new Ultra High Voltage laboratories requires more studies about standards for equipment as well as for testing and measurement techniques. Currently, the analysis of tail chopped lightning impulse waveforms is possible only by prior application of a full reference lightning impulse, creating difficulties for testing and processing of waveforms. A new method for evaluating the relevant parameters of tail chopped waveforms has been previously developed and this paper studies the effect of the overshoot in this alternative method.