Directorate of Measures and Precious Metals

Belgrade, Serbia

Directorate of Measures and Precious Metals

Belgrade, Serbia
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Skerovic V.,Directorate of Measures and Precious Metals | Zarubica V.,Directorate of Measures and Precious Metals | Aleksic M.,Directorate of Measures and Precious Metals
Journal of Instrumentation | Year: 2010

Realization of the scale of spectral responsivity of the detectors in the Directorate of Measures and Precious Metals (DMDM) is based on silicon detectors traceable to LNE-INM. In order to realize the unit of spectral irradiance in the laboratory for photometry and radiometry of the Bureau of Measures and Precious Metals, the new method based on the calibration of the spectroradiometer by comparison with standard detector has been established. The development of the method included realization of the System of Spectral Comparisons (SSC), together with the detector spectral responsivity calibrations by means of a primary spectrophotometric system. The linearity testing and stray light analysis were preformed to characterize the spectroradiometer. Measurement of aperture diameter and calibration of transimpedance amplifier were part of the overall experiment. In this paper, the developed method is presented and measurement results with the associated measurement uncertainty budget are shown. © 2010 IOP Publishing Ltd and SISSA.

Vucijak N.M.,Directorate of Measures and Precious Metals | Saranovac L.V.,University of Belgrade
IEEE Transactions on Instrumentation and Measurement | Year: 2010

A simple algorithm (SAL) and a modified SAL (MSAL) for the estimation of the phase difference between two sine-wave signals are proposed. The results obtained by SAL and MSAL in simulations and on real samples are given. A comparison between the phase difference results estimated by MSAL, quadrature delay estimator (QDE), unbiased QDE (UQDE), three-parameter sine-fitting algorithm (3PSF), four-parameter sine-fitting algorithm (4PSF), and seven-parameter sine-fitting algorithm (7PSF) is presented. The requirements for the application of SAL and MSAL are analyzed. © 2006 IEEE.

Dimitrijevic S.B.,Mining and Metallurgy Institute Bor | Miric M.B.,Directorate of Measures and Precious Metals | Trujic V.K.,Mining and Metallurgy Institute Bor | Madic B.N.,Mining and Metallurgy Institute Bor | Dimitrijevic S.P.,University of Belgrade
Bulgarian Chemical Communications | Year: 2014

The professional paper is a brief report of an investigation results to be adopted into production. In fact it is a resume of a study on the idea of e-scrap processing and metal production in Mining and Metalurgy Institute Bor, Serbia, based on its expert team investigations of the relevant literature and practice evidences and own research results. The investigations results are presented shortly in the First part of the paper where the chosen technological solution is described including the basic parameters for economic analysis. The second part of the paper is a resume of the economic analysis that approves benefits of the e-scrap processing and profitability of the metals production. Conclusion signifies the investigations and the study importance for realization of a project expected to generate important ecological and economical benefits. © 2014 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria.

Burger M.,University of Belgrade | Pantic D.,Directorate of Measures and Precious Metals | Nikolic Z.,University of Belgrade | Djenize S.,University of Belgrade
Journal of Quantitative Spectroscopy and Radiative Transfer | Year: 2016

Irradiation of samples was performed with 6ns, 1064nm Nd:YAG laser. For an applied irradiance range (108-1010W/cm2), the ablation process exhibits non-linear dependance. Ablated mass of the sample was directly determined using 100ng resolution mass comparator after ablation under various pressures of helium. The ablation rates were dictated by plasma formation mechanisms as well as ambient conditions. However, the surrounding atmosphere did not significantly affect the value of threshold irradiance of about 2 ×109W/cm2 for the onset of ablation mechanism change. This value is additionally verified via spectroscopic information from Cu I lines in the range from 0.4 to 1μs after the laser pulse. Behaviour of spectral lines was monitored with respect to the laser pulse energy. Plasma diagnostics of axial electron density and excitation temperature distributions was performed under He pressure of 200Torr. An influence of the possible shielding mechanisms responsible for the plasma absorption is discussed. © 2015 Elsevier Ltd.

Silvana D.,Mining and Metallurgy Institute Bor | Vlastimir T.,Mining and Metallurgy Institute Bor | Aleksandra I.,Mining and Metallurgy Institute Bor | Stevan D.,University of Belgrade | Mladen M.,Directorate of Measures and Precious Metals
Iranian Journal of Chemistry and Chemical Engineering | Year: 2013

Recovery of gold and other valuable metals from electronic scrap involves a complex metallurgical flow sheet and requires state-of-the-art recovery technologies that are available in large-scale, integrated smelter and refinery operations. At the end of their use, electronic and other electrical product scrap offer an important recycling potential for the secondary supply of gold and silver into the market. With gold concentrations reaching 200-250 g/t for computer circuit boards, this scrap is an 'urban mine' that is significantly richer in gold than the sources of the primary ores today. This paper gives methods of gold and silver recovery from printed circular board. The methods of purification are given and they separate gold from the impurities (tin, copper and nickel). The obtained gold and silver have 99.99% quality.

Kolendic P.I.,University of Belgrade | Genic S.B.,University of Belgrade | Jacimovic B.M.,University of Belgrade | Cupric N.L.,University of Belgrade | And 2 more authors.
Thermal Science | Year: 2015

This paper presents an analysis of working parameters of the pressure-powered pump. Mathematical models for determining the pump filling and discharge periods were developed and statistically compared to experimental results. The statistical parameters of the final correlation between here presented mathematical model and experimental results are in the acceptable range. Pump characteristics are presented in the common manner: in the form of the pump head vs. capacity diagram.

Zivkovic V.,Directorate of Measures and Precious Metals | Zelenika S.,Directorate of Measures and Precious Metals | Stefanovic G.,Directorate of Measures and Precious Metals
International Journal of Metrology and Quality Engineering | Year: 2012

This paper presents the evaluation of the uncertainty for the length measurement of gauge blocks by optical interferometry. In order to improve the gauge block calibration method and to decrease measurement uncertainty the old Zeiss-Kösters gauge block interferometer has been modified and improved by DMDM (Directorate of Measures and Precious Metals of Serbia). The main modification of the interferometer covers introduction of two laser sources, as new wavelength standards, as well as new hardware system and interferometer software, developed to completely automate the calibration process. The validation of the new measurement procedure details the uncertainty budget. The measurement method and model equation, which serves as the basis for the uncertainty evaluation is described. The uncertainty evaluation is performed in accordance with the document JCGM 100:2008-Evaluation of measurement data - Guide to the expression of uncertainty in measurement (GUM). © EDP Sciences 2012.

Bercea S.,Horia Hulubei National Institute of Physics and Nuclear Engineering | Nikolic A.,Directorate of Measures and Precious Metals | Cenusa C.,Horia Hulubei National Institute of Physics and Nuclear Engineering | Celarel A.,Horia Hulubei National Institute of Physics and Nuclear Engineering
Journal of Physics: Conference Series | Year: 2010

Ionizing radiations are radiations of atomic origin (X) or nuclear origin (α, β, γ). They are composed of either subatomic particles (α, β) or electromagnetic waves (X, γ) which possess enough energy to remove electrons from the atoms and molecules of the medium with which particles interact. They thus generate ionizing processes. The effects that are produced by the interaction of the ionizing radiations with a particular medium (which could be human tissue) have different intensities depending on the nature of the incident radiations, on the rate in which these radiations release energy to the medium and on the total amount of energy released to the medium. For this reason, the energy released by a particular type of ionizing radiations to a particular type of medium has become of great interest both for researchers and for specialists who deal with using ionizing radiations in different fields, such as the biomedical one. The aim of the present paper is to briefly present some of the aspects connected to the way certain quantities are defined, quantities which are specific to the interaction of ionizing particles with the medium they pass through and which are also connected to the energy released in the medium. The paper also describes methods of measuring these quantities. © 2010 IOP Publishing Ltd.

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