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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.

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.

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.

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 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.

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.

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.