Slovak Institute of Metrology

Slovak, Slovakia

Slovak Institute of Metrology

Slovak, Slovakia
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Hernandez-Gomez R.,University of Valladolid | Fernandez-Vicente T.,Centro Espanol Of Metrologia Cem | del Campo D.,Centro Espanol Of Metrologia Cem | Valkova M.,Slovak Institute of Metrology | And 2 more authors.
Fuel | Year: 2017

In this work the thermodynamic behavior of a synthetic four-component biomethane-like mixture, composed mainly of methane (96.48%), with small amounts of carbon dioxide (2.00%), nitrogen (1.50%), and traces of oxygen (0.02%), is studied using accurate (p,ρ,T) experimental data. Two mixtures of identical nominal compositions were prepared by the gravimetric method at the Spanish National Metrology Institute (Centro Español de Metrología, CEM) and at the Slovak National Metrology Institute (Slovenský Metrologický Ústav, SMÚ). The composition was double checked by Gas Chromatography, at both NMI and at the beginning and end of the measurements. An additional test of the consistency of the given compositions was performed by measuring the density of both mixtures at selected points, with two different techniques, in two different laboratories. Accurate density measurements have been taken over a wide temperature range, from (240 to 350) K, and pressures up to 14 MPa, using a single-sinker densimeter with magnetic suspension coupling. Experimental data are compared with the densities calculated with the GERG-2008 and AGA8-DC92 equations of state. Deviations between experimental and GERG-2008-estimated densities are within a ±0.03% band at all temperatures, which shows the outstanding performance of the current reference equation for natural gases when describing a biomethane-like mixture. Deviations between experimental and AGA-8-estimated densities are higher than 0.04% at 250 K for pressures greater than 10 MPa and also at 240 K for pressures higher than 9 MPa. This work is part of the research project ‘Metrology for Biogas’ supported by the European Metrology Research Program. © 2017 Elsevier Ltd


Benkova M.,Czech Metrology Institute | Mikulecky I.,Slovak Institute of Metrology
16th International Flow Measurement Conference 2013, FLOMEKO 2013 | Year: 2013

To enlarge calibration capacity of existing liquid flow test bench in CMI - Czech Republic to lower flows a new primary test bench using gravimetric method at atmospheric conditions is being established. The range of flow is (0,001 - 100) mL/min. With accuracy increasing of offered flow meters, of course, requirements to reduce the uncertainty of the primary or secondary standard has been rising. Detailed design of the CMI primary standard equipment and experience with used measuring methods are subject of the article. The main focus of the paper are gap analysis for different dynamic testing methods (weighing, volumetric with piston) as well as detailed uncertainty analysis. Also a traceability chain to the end userś flow meters is presented. Copyright© (2013) by the International Measurement Federation (IMEKO).


Javornik A.,Slovak Institute of Metrology | Svec A.,Slovak Institute of Metrology
Applied Radiation and Isotopes | Year: 2014

The presented advanced method of activity determination of large area beta emitting sources is based on a version of efficiency tracing method using a test foil placed between the source and a conventional large area detector. It is shown that the total efficiency of the measuring system may depend on a dimensionless parameter derived from the difference in count rates caused by inserting the test foil while other disturbing effects are mostly reduced or compensated. © 2013 Elsevier Ltd.


Yahya A.E.M.,Slovak University of Technology in Bratislava | Halaj M.,Slovak Institute of Metrology
Applied Mechanics and Materials | Year: 2013

Capability indexes of several types belong to the most common tools used for evaluation of the measuring instruments performance over a certain period of time. The indices differ by calculation method, properties as well as by intended use. But their design principle is approximately the same. The ratio of prescribed (required) accuracy and really achieved process accuracy is always observed. However, this evaluation represents only a part of the overall measurements management system. The suitability of capability indexes for the evaluation of CMMs accuracy over a time. After analyzing the results we had found machine capability indexes good method for evaluation of Coordinate Measuring Machines (CMM) accuracy over a certain time interval. CMM are high accuracy and capable to perform the measurement of lengths, machine capability indexes helps to determine the ability for coordinate measuring machine between tolerance limits and engineering specifications, but the use of x-control charts to get and keep processes under control. © (2013) Trans Tech Publications, Switzerland.


Svec A.,Slovak Institute of Metrology
Applied Radiation and Isotopes | Year: 2016

Photon energy conversion efficiency coefficient is presented as the ratio of total energy registered in the collected spectrum to the emitted photon energy. This parameter is calculated from the conventional gamma-ray histogram and in principle is not affected by coincidence phenomena. This feature makes it particularly useful for calibration and measurement of radionuclide samples at close geometries. It complements the number of efficiency parameters used in gamma-ray spectrometry and can partly change the view as to how the gamma-ray spectra are displayed and processed. © 2015 Elsevier Ltd.


Svec A.,Slovak Institute of Metrology
Applied Radiation and Isotopes | Year: 2015

The paper deals with an alternative model of beta radiation transmissions through attenuation layers and brings another analytical description of this phenomenon. The model is validated with a reliable data set and brings a possibility to calculate characteristic material parameters with low uncertainties. Using no correction factors, these calculations can be considered fundamental and inspiring for further research in the field. © 2015.


Sorokina S.,Slovak Academy of Sciences | Sorokina S.,Russian Academy of Sciences | Markova E.,Slovak Academy of Sciences | Gursky J.,Slovak Academy of Sciences | And 3 more authors.
International Journal of Radiation Biology | Year: 2013

Purpose: In order to evaluate DNA damage induced by protons at low and radiotherapeutic doses at the therapeutic proton complex at Ružomberok, Slovak Republic, lymphocytes from umbilical cord blood (UCB) of the same four probands were irradiated in the dose range of 1-200 cGy with γ-rays and protons (200 MeV, irradiation in the Bragg peak). Materials and methods: DNA repair γH2AX/53BP1 foci were analyzed by fluorescent microscopy and flow cytometry. Results: Statistically significant effects of radiations were detected by fluorescent microscopy at all doses higher 1 cGy. Almost all distributions of foci in irradiated cells fitted to the Poisson distribution. In general, there was no difference in the levels of γH2AX and 53BP1 foci in irradiated cells. Flow cytometry was less sensitive and detected radiation induced effects at doses of 50 cGy and higher. Factorial analysis of variance in the whole studied dose range has shown no significant effect of radiation quality on number of γH2AX and 53BP1 foci. The ratio of proton-induced foci to γ-ray-induced foci was 0.86 ± 0.16 (53BP1) and 0.99 ± 0.34 (γH2AX) as measured by fluorescent microscopy and 0.99 ± 0.16 (γH2AX) as measured by flow cytometry at the radiotherapeutic dose of 2 Gy. Conclusions: Both flow cytometry and fluorescent microscopy indicated that the average value of relative biological efficiency (RBE) at radiation doses ≥ 20 cGy was about 1.0. Our data that RBE increased at low doses ≤ 20 cGy are relevant both to the development of treatment modalities and exposures that take place during space exploration and should be verified by further studies. © 2013 Informa UK, Ltd.


Sabol D.,University College Dublin | Sabol D.,Slovak Institute of Metrology | Gleeson M.R.,University College Dublin | Sheridan J.T.,University College Dublin
Optik | Year: 2013

Despite the practical significance of slanted volume holographic gratings, most research presented in the photopolymer literature involves the use of unslanted reflection or transmission geometry gratings. A physically accurate electromagnetic model of the slanted holographic non-uniform gratings recorded in photopolymers is necessary in order to extract key volume grating parameters. In this paper we present a model, based on a set of two coupled differential equations, which include the effects of: (i) an exponential decay of refractive index modulation in the direction of the beam propagation due for example to the effects of dye absorption with depth; (ii) Gaussian profile of refractive index modulation due to recording by finite Gaussian beams, and (iii) a quadratic variation in the spatial period of the grating (chirp) arising due to non-uniform average index and thickness changes, i.e., shrinkage and swelling. Analytic results and numerical simulation are presented. In Part II the model developed in Part I is applied to fit experimental data, i.e., angular scans, of slanted gratings recorded in a polyvinylalcohol/acrylamide based material for different slant angles in order to extract key volume grating parameters. © 2012 Elsevier GmbH.


Sabol D.,University College Dublin | Sabol D.,Slovak Institute of Metrology | Gleeson M.R.,University College Dublin | Sheridan J.T.,University College Dublin
Optik | Year: 2013

In Part I of this paper the modelling of diffraction by non-uniform volume grating was examined. In Part II slanted volume gratings are recorded in PVA/AA based photopolymer material layers and both the grating growth curves and off-Bragg angular scans are measured. Best fits to the resulting experimental data, using the non-uniform diffraction model previously described, are performed and the grating parameters which give the best fits to these data curves are identified. The quality of these fits is quantified using the root mean square error. © 2012 Elsevier GmbH.


Palencar R.,Slovak Institute of Metrology | Duris S.,Slovak Institute of Metrology | Ranostaj J.,Slovak Institute of Metrology
Measurement Techniques | Year: 2011

The effect of covariances between the resistances of a standard platinum resistance thermometer when measuring temperature and its resistances at fixed points in a calibration on the uncertainty of temperature measurement is shown. A procedure for calculating the uncertainties, which enables any covariances that occur to be taken into account, is considered. © 2011 Springer Science+Business Media, Inc.

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