This work investigates the statistical methods used in the calibration of piezoelectric transducers, which are critical for measuring transient pressure in ammunition testing. These transducers play a vital role in determining internal pressure during the combustion of ammunition propellant, a key factor in assessing ammunition safety and performance. The study focuses on evaluating the significance of the intercept in the linear regression model used for calibration and compares the uncertainty of the fit with the linearity error, a parameter employed by NATO to classify the usability of transducers. Additionally, the study delves into the theoretical background of piezoelectric transducers, the calibration process, and the associated statistical methods. It underscores that NATO mandates the use of a linear regression model with a zero intercept for calibration. However, the study suggests that examining the significance of the intercept could reveal systematic errors or issues with the transducer. The research also explores whether the uncertainty of the fit could serve as an alternative to the linearity error in evaluating transducer usability. In summary, the article investigates the calibration process of piezoelectric transducers, with a focus on the significance of the intercept in linear regression and the potential of using fit uncertainty as a metric for transducer usability. The findings could lead to enhanced calibration standards and better assessments of transducer performance in ammunition tests.

In ballistics, the measurement of the internal pressure developed with the firing of ammunition propellant has extreme relevance for the design of weapons and ammunition. Pressure measurement, as a rule, can be performed by means of a copper crusher (copper cylinders), or by a piezoelectric transducer. Both methodologies are presently accepted in ammunition tests by standardization organizations (SAAMI and CIP), which motivates the comparison between them. The main objective of this study is to determine the relationship between the maximum pressures determined by copper crushers and piezoelectric transducers, aiming to verify the feasibility of using the copper crusher as a method of checking the calibration of piezoelectric transducers. For this, three series of shots were fired with 7.62 mm × 51 mm ammunition, where the maximum pressure was measured simultaneously with a copper crusher and three different piezoelectric transducers for each series.

Notoriously, measurement proves to be essential to encourage water conservation. Thus, this work characterizes two thin-film resistive sensors (bend sensors) with different coatings aiming at their application to measure water consumption. For this, the individual water measurement system is presented and discussed briefly. Then, resistive sensor parameters and operating principles are detailed, as well as the mathematical formulation of the correlation of the sensor resistance with the flow velocity. Methodologically, the system developed for the electromechanical and thermal characterization of the sensor is presented. The results allowed obtaining a quadratic relationship between the sensor deflection angle and the resistance. Furthermore, it was observed that the polyester-coated sensor presented a low hysteresis value when subjected to temperature variation, obtaining a negative linear relationship between the sensor resistance and temperature. In turn, the polyimide-coated sensor did not show low hysteresis when exposed to temperature change and flexed at 50° and 70° angles. Finally, it is proposed for future work computer simulations and experimental tests to confirm the applicability of the sensor for water measurement.

The use of piezoelectric transducers for internal dynamic pressure measurements in ammunition testing provides a significant advantage in the development and performance analysis of weapons and ammunition. Knowledge of the electrical characteristics of the dynamic pressure measurement chain, which includes the piezoelectric transducer and the charge amplifier, is a relevant condition for the design of interior ballistics pressure measurement systems. Thus, this study aims to characterize and model a piezoelectric transducer and its associated charge amplifier. First, the piezoelectric transducer was characterized using impedance analysis and modeled using a least squares curve-fitting tool, according to the Butterworth–Van Dyke model. Next, the charge amplifier was characterized through response analysis based on known inputs and modeled using LTSpice simulation techniques and the least squares curve-fit tool. Consequently, a measurement chain model is presented and simulated for two cases with different impulse signals. The first impulse signal was obtained from an interior ballistics computer simulation, and in the second case, it was considered the negative step signal characteristic of the calibration of piezoelectric transducers by means of dead weight. From the simulations, it was possible to verify the effectiveness of the model, which provided results with a low error in relation to the original pressure curve, and its applicability is demonstrated by the result of the simulation of the pressure variation in the calibration, where the attenuation of the signal can be visualized as the characteristic of the input curve changes.

Sometimes, analytical chemicals forget that the measurement process begins with the selection of the sample; thus, it must be understood that the measurement uncertainty is constituted by the association of the uncertainty arising from the sampling and the uncertainty arising from the traditional analytical process, that which is carried out in the laboratory. The analytical process is well-controlled, so its uncertainty is well defined; however, the uncertainty arising from sampling, for not having this controlled environment, is often not evident, so that there is still no culture to consider it for the calculation of measurement uncertainty. This study discusses the importance of the sampling uncertainty concerning the analytical uncertainty and details the current approaches available in the literature, such as the classical analysis of variance, the robust analysis of variance, and the range statistics. Moreover, this work highlights the recent manuscripts that are using these mentioned approaches, correlating them to the matrices, chemical and physical-chemical analytes, and analytical techniques. Finally, some case studies using the uncertainty information in compliance assessment show that the measurement uncertainty arising from sampling in chemical and physicochemical analyses cannot always be neglected.

Sulfur-containing compounds are naturally found in crude oil, and they can be partially removed during the refining process. The wide use of fossil fuels has a significant contribution to sulfur emissions into the atmosphere, and Governments are striving to reduce the amount of the fuels by environmental regulations. The reduction of sulfur levels in diesel and other transportation fuels is beneficial from economic and environmental points, but meeting this standard represents a major operational and economic challenge for the oil and gas industry. Quantitative measurement of the sulfur amount must be taken along the oil refining chains guided by standards of measurement and recommended analytical methods such as various American Society for Testing and Materials methods (ASTM D2622, ASTM D5453, ASTM D7039, and ASTM D7220). Advancement in the refining processes and environmental regulations also require reliable measurements and well-defined criteria for compliance assessment. This work presented a brief review of the ASTM Standards used in the laboratories of the Brazilian oil and gas industry to determine the total sulfur content in fuels. We also presented an approach based on the reproducibility of the measurement methods and the guard band concept to evaluate the conformity statement.

Considering the recent use of three-dimensional digitalization equipment in ballistic vest tests to characterize trauma caused by projectiles, this study carried out a performance analysis of a 3D structured light scanner to measure trauma depths. Artifacts were manufactured and digitized by a 3D scanner and by an articulated arm coordinate measuring machine, which provided the reference values. A process was developed for estimating the depth from the point clouds, one of the main contributions of this work. Filtering and segmentation of the point clouds allowed the extraction of the trauma depths for later comparison. The systematic errors reported in the literature for structured light scanning equipment were confirmed, and it was statistically verified that the critical trauma measurement values are correctly measured, with a bias of 0.11 mm and standard measurement uncertainty of 0.12 mm. Finally, a real ballistic vest test shows the applicability in a practical scenario.

Historically, owing to the increase in processing capacity over the years, validation and adjustment of measurements have become imperative. In particular, concerning discussions related to data and results in analytical chemistry, there is always a need to improve their reliability. The data reconciliation technique has the objective of using measurement redundancies to obtain the best estimate of the true value and, consequently to minimize its uncertainty. Unfortunately, this powerful tool is less known and used by analytical chemists compared to other areas. This approach can be satisfactorily performed in decision-making procedures that focus on chemical analysis, chemometrics, biochemistry analysis, forensics, and environmental sciences, such as in a characterization study, regarding conformance or nonconformance with the specification, doubts related to the malfunctioning of meters and about the compatibility of test methods. This work discusses and sheds light on the importance of data reconciliation, including data reconciliation statistics and application of the technique, traditional data reconciliation in analytical chemistry, principal component analysis based on data reconciliation in analytical chemistry, and fuzzy data reconciliation in analytical chemistry.

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.

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-beta 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-beta. 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. (C) 2019 Elsevier Ltd. All rights reserved.

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 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. (C) 2016 Elsevier Ltd. All rights reserved.