Abstract
Currently, the use of algorithms and computer vision systems for metrological purposes has increased in different areas of knowledge to reduce human error and process deviations, ...consequently increasing reliability and reducing measurement uncertainties. This study presents a model for estimating the uncertainty of Feret's diameter (
D
F
) measurements of scanning electron microscopy (SEM) images from regular and irregular gunshot residue (GSR) particles at different magnifications. The data were extracted using the automatic measurement algorithm developed by the Brazilian Institute of Metrology, Quality and Technology (Inmetro). The proposed uncertainty model was based on the recommendations of the guide to the expression of uncertainty in measurement (GUM). The gold standard technique to identify and detect GSR particles is the SEM coupled to energy dispersive X‐ray spectroscopy (SEM/EDS), which was used in the study. The low uncertainty values obtained in this study are justified by the refinement of the measurements performed at each stage of digital image procedures. The proposed uncertainty model contributes in an innovative way to the metrological evaluation of regular and irregular GSR particles at different images magnifications. The correct morphometry definition of these particles allows to study their distinction from other possible sources of GSR and, above all, their correlation with the type of ammunition used when firing the firearm. These measurement uncertainty calculations can be applied to any object images acquired by SEM, which provides more confidence in the results of measurements of the object of interest.
Compatibility of the new environmentally-friendly alternative of diesel engine fuels, biodiesel, with storage and engine part materials, is still an open issue. In this work, the interaction between ...three fuels (petroleum diesel and two types of biodiesel — soybean and sunflower) and two materials (carbon steel and high density polyethylene) used in storage and automotive tanks, is analyzed in detail. A wide set of characterization techniques was used to evaluate the changes in both solid and fluid materials, as weight change measurement, optical, scanning electron and atomic force (AFM) microscopies, Raman and FTIR spectroscopies, and differential scanning calorimetry. The AFM technique allowed detecting surface roughness and morphology changes in the metallic material following the trends in the weight losses. In the case of polymeric material, weight gain by fluid absorption occurred, being detected by the spectroscopic techniques. The biodiesel fuels underwent some ageing however this phenomenon did not affect the interaction between the biodiesel fuels and the substrates. The petrodiesel, which did not age, caused more significant degradation of the substrates.
Nanometrology - challenges for health regulation Damasceno, Jailton Carreteiro; Ribeiro, Ana R.; Balottin, Luciene B. L. ...
Vigilância Sanitária em Debate,
11/2013, Letnik:
1, Številka:
4
Journal Article
Odprti dostop
The relationship between metrology, nanotechnology and nanoscience and sanitary regulation is discussed from the point of view of its importance and the interrelationship between the themes for the ...development of products and services involving nanotech-nology. The discussion involves the main techniques for measuring dimensional, chemical and biological properties of materials, and presents some of the challenges for the future. Issues such as processes of standardization and regulation in Europe, U.S. and Brazil are also addressed, providing an overview of how these processes are related to sanitary regulation.
Nanometrologia – desafios para a regulação sanitária Damasceno, Jailton Carreteiro; Ribeiro, Ana R.; Balottin, Luciene B. L. ...
Vigilância Sanitária em Debate,
11/2013, Letnik:
1, Številka:
4
Journal Article
This chapter presents and explains the most used methodologies for the evaluation of measurement uncertainty in metrology with practical examples. The main topics are basic concepts and importance, ...existing documentation, the harmonized methodology of the Guide to the Expression of Uncertainty in Measurement, types of uncertainty, modeling of measurement systems, use of alternative methods (including the GUM supplement 1 Monte Carlo numerical method), evaluation of uncertainty for calibration curves, correlated uncertainties, uncertainties arising from the calibration of instruments, and the main proposals for the new revised GUM. The chapter also discusses the GUM as a tool for the technical management of measurement processes.
This work addresses the evaluation of the tribo-mechanical performance of DLC and DLC-Si films deposited onto AISI 4340 steel by the use of a combination of tribological and mechanical tests. ...Polished AISI 4340 steel substrates were submitted to a plasma nitriding process prior to the deposition of DLC and DLC-Si thin films in a PECVD system using N(2), CH(4) and CH(4)+5%v. SiH(4) plasmas. Scratch test results showed higher critical load values for the DLC-Si films (8.7 N) when compared with DLC (5.3 N), indicating better adhesion to the substrate when Si is present in the DLC structure. Nanoindentation tests showed typical hardness values for DLC films (16-21 GPa) and lower hardness values for the DLC-Si films (13-15 GPa). Average friction coefficient was 0.13 for DLC films and 0.05 for the DLC-Si films, both much lower than the values found for the uncoated AISI 4340 steel (0.71), as expected. Wear rates obtained for DLC films (0.1 x 10(-6) mm(3)/Nm) were lower than the ones found for DLC-Si films (0.47 x 10(-6) mm(3)/Nm). Obtained data from scratch, wear, friction and nanoindentation tests are set together as a valuable tool for the study of thin films.
This paper presents the preliminary results of a wear simulation test of hip joint prosthesis. The test was performed in a multi-station wear simulator machine with acetabular cups of UHMWPE against ...stainless steel femoral heads, under conditions similar to those described in ISO 14242-1 standard, up to 398, 714 cycles. The results obtained from gravimetry, profilometry and debris microscopy are discussed.
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