National Institute of Metrology of Brazil

Duque de Caxias, Brazil

National Institute of Metrology of Brazil

Duque de Caxias, Brazil
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Grant
Agency: European Commission | Branch: FP7 | Program: CP-IP | Phase: NMP-2010-1.3-1 | Award Amount: 13.15M | Year: 2011

The growing development, production and use of engineered nanomaterials and associated products will increase exposure of both humans and ecosystems to these new materials. However, current knowledge is still incomplete and established test methods are as yet inappropriate to reliably assess the extent of exposure and risk of materials at the nano-scale. There is an urgent need to develop methods to overcome the current limitations of existing hazard and risk assessment schemes and to generate the body of reference data needed as the basis for regulative requirements and for measures to safeguard production, application and the disposal of nanomaterials. The proposed project will mobilize the critical mass of international scientific knowledge and technical expertise required to address these questions. Current analytical and toxicity test methods and models will be put to test and subjected to rigorous intercalibration and validation. Where necessary, methods and test materials will be modified, adapted and validated, and new reliable reference methods developed, in cooperation with international standardisation bodies and the concerned industry, to support both pre and co-normative activities and to make the applicability of existing RA and LCA schemes to ENPs more reliable. The feasibility of validated measurement, characterization and test methods will be assessed by selected case studies to help the significant improvement of the performance of existing exposure monitoring systems as well as the development of new risk management and reduction strategies.


Menezes M.G.,Federal University of Rio de Janeiro | Capaz R.B.,Federal University of Rio de Janeiro | Capaz R.B.,National Institute of Metrology of Brazil
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

We study the electronic structure and magnetic properties of h-BN triangular clusters embedded in graphene supercells. We find that, depending on the sizes of the clusters and the graphene separation region between them, spin polarization can be induced through charge doping or can be observed even in the neutral state. For these cases, half-metallicity is observed for certain charged states, which are otherwise metallic. In these half-metallic states, the spin density is concentrated near the edges of the clusters, in analogy to the more common predictions for half-metals in zigzag graphene nanoribbons and h-BN/graphene intercalated nanoribbons. Since experimental realizations of h-BN domains in graphene have already been reported, these heterostructures can be suitable candidates for nanoelectronics and spintronics applications. © 2012 American Physical Society.


Mikhailov M.D.,National Institute of Metrology of Brazil | Freire A.P.S.,Mechanical Engineering Program
Powder Technology | Year: 2013

An accurate model for the drag coefficient (CD) of a falling sphere is presented in terms of a non-linear rational fractional transform of the series of Goldstein (Proc. Roy. Soc. London A, 123, 225-235, 1929) to Oseen's equation. The coefficients of the six polynomial terms are improved through a direct fit to the experimental data of Roos and Willmarth (AIAA J., 9:285-290, 1971). The model predicts CD up to Reynolds number 100,000 with a standard deviation of 0.04. Results are compared with eight different formulations of other authors. © 2012 Elsevier B.V.


Grant
Agency: European Commission | Branch: FP7 | Program: CSA-SA | Phase: ENERGY-2007-3.7-03 | Award Amount: 626.88K | Year: 2008

With the increased addition of biological products to petrol and diesel, e.g. ethanol and FAME, the quality of these products becomes more important. There is, however, up to now no international consensus on the technical specifications of biofuel. Nor is it clear what measurement standards, reference materials and measurement techniques are needed. The proposed project will deal with the subject of measurement standards (= reference materials). Reference materials with well-characterized reference values are essential for pre-normative research and standardization, i.e., in the development and validation of measurement methods. In the project it will be investigated which reference materials are already available and how the reference values for these materials were established. From this investigation it will become clear for which parameters and for which type of bio-ethanol and FAME reference materials are missing. The next step will be to investigate the feasibility of developing these reference materials for the identified parameters. Finally the project will establish the current quality of measurement practice by means of interlaboratory comparisons using these materials. The information supplied on the applied methodology and the performance characteristics can be used for the development of harmonized standard methods. An additional aim is to provide guidance and material for producing reference materials for the different test methods required by the ultimate global biofuel blend specifications.


Kyriazis G.A.,National Institute of Metrology of Brazil
CPEM Digest (Conference on Precision Electromagnetic Measurements) | Year: 2012

Two algorithms for estimating signal harmonics were compared in waveform metrology applications: Swerlein's and least squares. It is confirmed that the estimates provided by them agree well within the measurement uncertainties and that the least squares algorithm is the fastest one. © 2012 IEEE.


Kyriazis G.A.,National Institute of Metrology of Brazil
IEEE Transactions on Instrumentation and Measurement | Year: 2013

A simple method for estimating the parameters of complex modulated signals from digital sampling data is proposed. It can be employed with advantage to analyze the modulation functions of commercial arbitrary waveform (AW) generators. Although this problem of inference has many applications in communication technology, it has also become a concern to the power industry in issues related to mains flicker measurements. Prior information available to metrologists about AW carriers or modulating signals allows the reduction of the dimensionality of the search algorithm with consequent time savings. © 1963-2012 IEEE.


Barbieri Gonzaga F.,National Institute of Metrology of Brazil | Pereira Sobral S.,National Institute of Metrology of Brazil
Talanta | Year: 2012

A new method is proposed for determining the acid number (AN) of biodiesel using coulometric titration with potentiometric detection, basically employing a potentiostat/galvanostat and an electrochemical cell containing a platinum electrode, a silver electrode, and a combination pH electrode. The method involves a sequential application of a constant current between the platinum (cathode) and silver (anode) electrodes, followed by measuring the potential of the combination pH electrode, using an isopropanol/water mixture as solvent and LiCl as the supporting electrolyte. A preliminary evaluation of the new method, using acetic acid for doping a biodiesel sample, showed an average recovery of 100.1%. Compared to a volumetric titration-based method for determining the AN of several biodiesel samples (ranging from about 0.18 to 0.95 mg g -1), the new method produced statistically similar results with better repeatability. Compared to other works reported in the literature, the new method presented an average repeatability up to 3.2 times better and employed a sample size up to 20 times smaller. © 2012 Elsevier B.V. All rights reserved.


Kyriazis G.A.,National Institute of Metrology of Brazil
IEEE Transactions on Instrumentation and Measurement | Year: 2011

A Bayesian approach to spectrum analysis using approximations based on the posterior mode is applied here to waveform metrology. A simple algorithm for obtaining accurate estimates of signal parameters and their associated uncertainties is presented. It is assumed that the data can be modeled with trigonometric equations. The algorithm can be easily implemented with those commercial laboratory software packages routinely used by metrologists for controlling instrumentation and reporting measurement results. Its performance has been confirmed through several experimental setups. © 2006 IEEE.


Kyriazis G.A.,National Institute of Metrology of Brazil
CPEM Digest (Conference on Precision Electromagnetic Measurements) | Year: 2010

Two methods for the harmonic analysis of periodic arbitrary signals based on digital sampling data were compared: an extension of Swerleińs algorithm to nonsinusoidal signals and a Bayesian spectrum analysis using approximations based on the normal distribution and the posterior mode. © 2010 IEEE.


Olinto A.C.,National Institute of Metrology of Brazil
Clean Technologies and Environmental Policy | Year: 2014

In this work, a sustainability analysis based on concepts of normed linear vector space is presented. The processes of production are vectors whose components are the manufacturing factors. The sustainability assessments are measured by the magnitude of the vectors, that is, by their norms. The properties of the space are simple, and the applications are straightforward. The formalism applies equally well whether the indicators are positive or negative, without the recourse of shifting variables. Whenever available, values of the sustainability threshold limits can be handled by the formalism. © 2014 Springer-Verlag Berlin Heidelberg.

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