TUBITAK UME Research Articles

Interlaboratory Comparison of Power Measurements at Millimetre- and Sub-Millimetre-Wave Frequencies

The aim of this paper is to compare the power measurement capabilities in millimetre- and sub-millimetre-wave frequency bands of several national metrology institutes and one research institute. The first comparison, in WR-6.5 waveguide (110 GHz to 170 GHz), involved NPL, TUBITAK UME and PTB. The second comparison, in WR-1.5 waveguide (500 GHz to 750 GHz), involved NPL, METAS, TUBITAK UME, LNE, WAT, GUM and VDI. Two types of travelling standards were used for these comparisons: a thermoelectric power sensor in the WR-6.5 band and a calorimetric power sensor in the WR-6.5 and WR-1.5 bands. The thermoelectric power sensor was characterised by the participants against their own standards and a generalised effective efficiency was calculated. The calorimetric power sensor operating in the WR-6.5 band was measured to observe its behaviour during the comparison and was also measured in the WR-1.5 band after being fitted with a suitable waveguide taper and used in conjunction with a frequency multiplier. The participants measured the output of the calorimetric power sensor and their own power sensor standard. A normalised power ratio method was used as a comparison parameter for the WR-1.5 band measurements. In addition, a pyroelectric power standard was used by METAS to measure absolute power, and a frequency of 650 GHz was used as a link between the absolute power and the power ratios. Finally, all but two of the measurement points compared between the participants achieved agreement in terms of En scores less than 1. For the first time, an interlaboratory comparison of power measurements at sub-millimetre frequencies has been performed and, overall, good agreement was achieved between the different laboratories.

Measuring the enthalpy of combustion of methane gas and establishing the model function to perform comprehensive uncertainty calculations

Natural gas is a plentiful and adaptable energy source among other gases that is used all over the world with an increasing demand nowadays. It is therefore of utmost importance to measure the energy content of the natural gas with high precision for both users and sellers. In this study, methane gas, the main component of natural gas, was combusted using the reference gas calorimeter developed at TUBITAK UME (The Scientific and Technological Research Council of Turkey) - (National Metrology Institute) to determine the enthalpy of combustion. The objective was to measure the enthalpy of combustion of the methane, perform a detailed uncertainty calculation and to compare the enthalpy of combustion of the methane specified in ISO 6976:2016 with the obtained experimental results. The reference gas calorimeter was designed using the temperature, mass, power, flow control, waste water absorption, and waste gas measurement systems with the highest precision and circulating water bath with temperature control insulated so as not to exchange heat from the external environment. All measurements were performed with the instruments having calibration certificates. Experiments were carried out at the temperature of 298.15 K and a constant pressure (101.325 kPa) using the methane with a purity of 99.995 % as a reference gas. The mass of the burnt methane in combustion process was approximately 10-3 kg. As a consequence of the measurements, mean experimental enthalpy of combustion was obtained as −55518.2 kJ kg−1 with the error of 0.2 % (k = 2). The evaluations indicated that the largest source of error in the enthalpy of combustion measurements originated from the temperature and mass measurements.

Material characterization and uncertainty evaluation at millimetre wave frequencies in TUBITAK UME

The frequency response of the materials which are used in communication systems has gained increasing importance nowadays. Frequency response measurements of materials in laboratory environments do not contain sufficient information about real working environment conditions. The free space dielectric measurement method, known as one of the most frequently used material characterization methods at high frequencies, is used to give more accurate results under real operating conditions. In this study, using the TUBITAK UME’s infrastructure, the measurement results in free space at millimetre wave frequency, and the uncertainty calculations of the measurements are given for some materials such as Teflon, Fr4, Komacel, and Air. Measurements were performed at two different frequency bands such as E and D bands by using KMMS software which is known to run up to 50 GHz frequency. Measurement results of materials were compared with the known low-frequency response of the materials in this study. And uncertainty calculation model was discussed in this study either.

Development- and Validation-Improved Metrological Methods for the Determination of Inorganic Impurities and Ash Content from Biofuels

In this study, five laboratories, namely, BRML (Romania), TUBITAK UME (Turkey), IMBIH (Bosnia and Herzegovina), BAM (Germany), and DTI (Denmark), developed and validated analytical procedures by ICP-MS, ICP-OES, MWP-AES, WD-XRF, and ID-MS for the determination of inorganic impurities in solid and liquid biofuels, established the budget of uncertainties, and developed the method for determining the amount of ash in the measurement range 0–1.2% with absolute repeatability less than 0.1% and absolute reproducibility of 0.2% (according to EN ISO 18122). In order to create homogeneous certified reference materials, improved methodologies for the measurement and characterization of solid and liquid biofuels were developed. Thus, information regarding the precision, accuracy, and bias of the method, and identifying the factors that intervened in the measurement of uncertainty were experimentally determined, supplementing the information from the existing standards in the field.

High polarity analyte(s) in aqueous media: Determination of L-PFOA and L-PFOS in ground water

Main textTrack C key comparison on determination of L-PFOA and L-PFOS in ground water (CCQM-K156) coordinated by TUBITAK UME was completed in 2022. A subsequent comparison (CCQM-K156.1) was offered to those NMIs or DIs who did not get the chance to participate in the previous comparison or who would like to repeat this measurement challenge.This study provides the means for assessing measurement capabilities for determination of high polarity measurands in a procedure that requires extraction, clean-up, analytical separation and detection. Successful participation in CCQM-K156.1 demonstrates measurement capabilities in determining mass fraction of organic compounds, with molecular mass of 200 g/mol to 700 g/mol, having high polarity pKow > -2, in mass fraction range from 0.5 ng/kg to 500 ng/kg in aqueous media.Five NMIs and DIs participated in CCQM-K156.1 key comparison. SPE was applied in the sample pre-treatment and LC-MS was applied for detection. All participating laboratories applied isotope dilution mass spectrometry (IDMS) techniques for quantification. Participants established the metrological traceability of their results using certified reference materials (CRMs) from NMIs with stated traceability.The CCQM-K156.1 results for L-PFOA and L-PFOS range from 4.71 ng/kg to 9.36 ng/kg with a % RSD of 23.5 % for L-PFOA and from 4.62 ng/kg to 7.67 ng/kg with a % RSD of 18.6 % for L-PFOS. The KCRV and u(KCRV) for this comparison were the results of TUBITAK UME, since TUBITAK UME was a participant in the previous CCQM-K156 and its results agreed well with the CCQM-K156 KCRV. The KCRV was 9.36 ng/kg ± 0.98 ng/kg for L-PFOA and 7.01 ng/kg ± 0.94 ng/kg for L-PFOS. For L-PFOA, the result of SYKE agreed with KCRV, while the results of VNIIM, BAM and NMISA were biased low. As for L-PFOS, BAM, SYKE and NMISA results agreed with the KCRV, whereas VNIIM result was biased low.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

New apparatus for the determination of liquid density at primary level in TUBITAK UME

This work aimed to describe the new apparatus of TUBITAK UME for determining the density of liquids at the primary level by means of a hydrostatic weighing (HW) using a solid density standard. This new apparatus provides TUBITAK UME with the necessary infrastructure to certify reference liquids of density with adequate uncertainty to be used at a secondary level, such as for calibration of oscillation type density meters. The HWS produces reference values for liquids with different physical properties such as viscosity, surface tension and viscoelasticity in the case of non-Newtonian liquids. In this HWS, the automation of all mechanical parts such as loading/unloading of the reference weights and sinker, movement of bath, working of pump etc. took place. In this way, the primary level liquid density measurements were realized with uncertainities smaller than 0,01 kg/m3. The automation also effected the robustness of the system by providing the lower repeatability value and stabilization of temperature.

Final report "Key comparison CCM.FF-K1.2015 - water flow: 30 m3/h ... 200 m3/h"

Main textThe objective of the Key Comparison CCM.FF-K1.2015 for water flow measurement was to support and prove the Calibration and Measurement Capabilities (CMC) of the participating NMIs of Japan (AIST), Mexico (CENAM), Chinese Taipei (ITRI), Korea (KRISS), P.R. China (NIM), Germany (PTB), USA (NIST), Sweden (RISE), UK (NEL), Turkey (TUBITAK UME) and Netherlands (VSL). The comparison was organized as a round robin, started in December 2015 at PTB and finished in April 2018, also at PTB. As pilot laboratory, the national metrology institute of Germany (PTB) organised the comparison. A combined setup of a turbine meter and Coriolis meter was used as a transfer standard (TS), which was provided by the pilot laboratory. The nominal calibration conditions of the KC were defined within the flow range between 30 m3/h and 200 m3/h, 20 °C fluid temperature and 3 bar line pressure.A special focus of the comparison was to estimate the uncertainties of the transfer standard (u TS). Both transfer meters were subjected to extensive characterization measurements at pilot laboratory, with the following investigated parameters: fluid temperature, line pressure, repeatability, flow stability, meter sensitivity to varying inflow conditions and hysteresis effects.For turbine meter, all labs passed the E N criteria of ≤ 1.20. The calibrations of the turbine meter were strongly affected by the presence of the large values for u TS with > 0.12 % k =1) which were mainly caused by the meter sensitivity to disturbed inflow conditions. This effect led to inconclusive calibration results for all laboratories. The evaluation criteria u comp/u base exceeded the critical value of 2.00. Finally, the turbine meter was not suitable for a confirmation of all submitted CMC values.For Coriolis meter, all labs passed the E N criteria of ≤ 1.20. In contrast to turbine meter, the evaluation criteria u comp/u base exceeded the critical value of 2.00 for one laboratory, only. The maximum uncertainty u TS of Coriolis meter was estimated with 0.022 % (k =1).In summary, the comparison was successfully finished for a confirmation of the submitted CMC values, related to mass calibrations. For volume related CMCs this comparison was not suitable.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

High polarity analyte(s) in aqueous media: determination of L-PFOA and L-PFOS in ground water

Main textThe CCQM-K156 comparison was coordinated by TUBITAK UME on behalf of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) for National Measurement Institutes (NMIs) and Designated Institutes (DIs) which provide measurement services in organic analysis under the 'Comité International des Poids et Mesures' Mutual Recognition Arrangement (CIPM MRA).Perfluoro alkyl substances (PFAS) such as PFOS and PFOA have been used in numerous industrial applications and products. Because of their high stability and resistance to biodegradation, atmospheric photooxidation, direct photolysis and hydrolysis, they are extremely persistent in the environment. The European Union (EU) Water Framework Directive lists PFOS as a priority hazardous substance that poses a significant risk to the aquatic environment. The use of PFOS-containing Aqueous Film-Forming Foams (AFFFs) has been banned since June 2011 in the EU. As relatively water-soluble, effectively non-degradable compounds, PFOS and PFOA migrate to ground water. They are not removed in the conventional drinking water treatment, and therefore cause health risks in polluted areas. The EU Drinking Water Directive and the European Commission has proposed a limit value of 100 ng/L for the sum of 20 PFAS, including PFOS and PFOA.This study provides the means for assessing measurement capabilities for determination of high polarity measurands in a procedure that requires extraction, clean-up, analytical separation and detection. Successful participation in CCQM-K156 demonstrates measurement capabilities in determining mass fraction of organic compounds, with a molecular mass of 200 g/mol to 700 g/mol, having high polarity pKow > -2, in a mass fraction range from 0.5 ng/kg to 500 ng/kg in aqueous media.Nine NMIs and DIs participated in the CCQM-K156 key comparison. Seven institutes reported their results. SPE was applied in the sample pre-treatment and LC-MS was applied for detection. All participating laboratories applied isotope dilution mass spectrometry (IDMS) techniques for quantification. Participants established the metrological traceability of their results using certified reference materials (CRMs) from NMIs with stated traceability; where commercially available high purity materials were used the purity was determined in-house. The CCQM-K156 results for L-PFOA and L-PFOS range from 2.75 ng/kg to 5.50 ng/kg with a % RSD of 19.5 % for L-PFOA and from 2.04 ng/kg to 4.45 ng/kg with a % RSD of 21.3 % for L-PFOS. The KCRV was assigned using a Hierarchical Bayesian Random Effects Model (HB REM) estimator from the values reported by six of the participants. One participant result of L-PFOS and one result of L-PFOA were excluded from the KCRV for technical reasons. The KCRV was 4.9 ng/kg ± 0.4 ng/kg for L-PFOA and 3.8 ng/kg ± 0.4 ng/kg for L-PFOS. The six institutes that were included in the assignment of consensus KCRV all agreed within their standard uncertainties.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main Results of the 27th International Conference on Vacuum Technique and Technology (VTT2020)

In this preface the main results of the 27th International Conference on Vacuum Technique and Technology (VTT2020) that was held on 27–29 October 2020 in Saint Petersburg, Russia are discussed.From 27 to 29 October 2020, the 27th International Conference on Vacuum Technique and Technology was held in the virtual form at the Saint Petersburg Electrotechnical University “LETI”. The Conference was organized by the Ministry of Science and Higher Education of the Russian Federation, Saint Petersburg Electrotechnical University “LETI” named after V I Ulyanov (Lenin), All-Russian Research Institute of Metrology named after D I Mendeleev, Institute of Problems of Mechanical Engineering of the Russian Academy of Sciences, Russian Scientific and Technical Vacuum Society named after Academician S A Vekshinskiy, Peter the Great Saint Petersburg Polytechnic University, Euro-Asian Cooperation of National Metrology Institutes (COOMET), National Metrology Institute (TUBITAK UME, Turkey).List of Images, Organizing Committee, Program Committee, Members, are available in this pdf.

CCM PILOT STUDY OVERVIEW: GEOMETRICAL MEASUREMENT OF THE ROCKWELL DIAMOND INDENTER.

This paper describes an overview of the capability of the NMIs that participated on the CCM Pilot Study measurement systems, conducted by the CIPM/CCM/Working Group on Hardness, to characterize the Rockwell hardness diamond indenter geometry, by measuring the included cone angle, the straightness of the generatrix, the spherical tip radius, the deviation of the local radius and the tilt angle. Nine NMIs took part in this study: INMETRO (Brazil); INRiM (Italy); KRISS (South Korea); NIM/PR (China); NIMT (Thailand); NIST (USA); PTB (Germany); TUBITAK UME (Turkey); VNIIFTRI (Russia), where INMETRO (Brazil) served as pilot laboratory.

Primary level electrolytic conductivity measurements at National Metrology Institute of Turkey (TUBITAK UME)

Primary level electrolytic conductivity measurements at National Metrology Institute of Turkey (TUBITAK UME)

Türkiye Ulusal Metroloji Enstitüsü’nde Sertifikalı pH Tampon Çözeltilerinin Üretimi

pH, a thermodynamic function, is the negative logarithm of the activity of hydronium ions. It is well-known concept used in many different areas from science to industry. The widespread use of pH measurements has increased the need for certified reference solutions in this field. The primary pH measurement system that was established in Turkey as the first and only was used for production and certification of reference pH buffer solutions. The system consists of measurement cell named as Harned cell, Ag/AgCl electrodes, Pt/Ptblack or Pt/Pdblack electrodes, thermostatic bath, PT-100 probe and display unit, data acquisition unit and barometer. The software of primary system was developed and validated in TUBITAK UME. Moreover, high precision coulometry system has been used to determine the acid molality utilized at first step of primary level pH measurement system. Homogeneity, short and long term stability, characterization, certification and post-production studies were performed according to ISO Guide 34: 2009, ISO Guide 35: 2006 and ERM Application Note 1: 2010 for the production and evaluation of the results of certified pH buffer solutions. Thanks to this situation, traceability will be disseminated through TUBITAK UME directly. Moreover the foreign currency spent for these solutions, that are generally used for calibration of pH meters and used in many other areas, will be retained in the country.

Comparison on calibration factor measurement of power sensor

This comparison covers the measurement of calibration factors (CF) of power sensors and was carried out where SASO NMCC and TUBITAK UME participated, on the frame of GULFMET.Calibration factors are used for characterization of RF power sensors. RF power sensors are used to measure RF power, and is an important mean to achieve traceability of RF power measurements. This bilateral comparison was performed by measuring a power sensor at frequencies of 10 MHz, 50 MHz, 1 GHz, 4 GHz, 8 GHz, 12 GHz, 15 GHz, and 18 GHz, at a power level of 0 dBm.TÜBİTAK UME was acting as the pilot laboratory. The travelling standard was provided by SASO NMCC. TUBITAK UME was responsible for monitoring standard performance during the circulation and the evaluation and reporting of the comparison results.The comparison was carried out in accordance with the CCEM Guidelines for Planning, Organizing, Conducting and Reporting Key, Supplementary and Pilot Comparisons.Main textTo reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Bilateral comparison of luminous flux (EURAMET.PR-K4.3)

This report gives the result of a bilateral comparison of luminous flux between the Instituto de Óptica, IO-CSIC (Spain) and the Ulusal Metroloji Enstitüsü, TUBITAK UME (Turkey). This bilateral comparison is intended to link the TUBITAK UME realized lumen to the CCPR K4 reference value. The measurement artefacts were specially developed transfer standard lamps for luminous flux of the Polaron LF200W type.The comparison and its protocol were approved by the CCPR and registered with KCDB with the comparison number: EURAMET.PR-K4.3.KEY WORDS FOR SEARCHLuminous flux, PR K4, Bilateral ComparisonMain textTo reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCPR, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

High precision calibration of polygons for emerging demands

The polygons are basic angle standards that are still considered as one of the most precise-robust references for establishment of traceability in angle measurements. Investigations for high precision calibration of polygons to answer new demands (expanded uncertainties less than 0.1”) were carried out. Three high precision 36 sided polygons were calibrated using the primary angle measuring system of TUBITAK UME. Agreement of TUBITAK UME’s and polygon manufacturer Möller-Wedel Optical (MWO)’s results was better than 0.1”. Reproducibility of 0.043” as peak-to-valley (pv) and 0.013” as root mean square (rms) value was achieved for successive calibration of polygons. The results are reported with descriptions of our high precision calibration system and the process.

A New Generation of Open Zinc Freezing Point Cells at TUBITAK UME

The Temperature Laboratory at TUBITAK UME initiated a study which focused on the construction of freezing point cells of ITS-90 as primary temperature standards. The first cell constructed within the scope of this study was an open tin freezing point cell and the results were in good agreement with the reference tin fixed point cell of UME. The second set of cells constructed was two open zinc freezing point cells. The design of these cells is similar to the tin freezing point cell. After construction, all the home-made cells were evaluated by analyzing their melting and freezing curves. Finally comparison measurements were performed between the current laboratory reference zinc cell and all newly constructed cells.

TÜBİTAK UME vacuum laboratory capabilities and activities

TÜBİTAK National Metrology Institute (TÜBİTAK UME) is a research and development institute that operates under the Scientific and Technological Research Council of Turkey (TÜBİTAK). TÜBİTAK UME Vacuum laboratory takes part in under the mechanics group among the groups of physics, mechanics and chemistry group laboratories. TUBITAK UME Vacuum Laboratory aims to develop and maintain national measurement standards, to establish vacuum pressure traceability to SI units and to disseminate this to industry, science and research in Turkey. The laboratory was founded in 1996 and started to provide secondary level calibration services with Vacuum Gauge Calibration System (VGCS-200). Primary vacuum standard called Multi-Stage Static Expansion System (MSSE1) was established in 2000. Commercially available secondary vacuum gauge calibration system was improved with the addition of automation under the name Vacuum Gauge Metrology System (VGMS) in 2010. The main activities of the Vacuum Laboratory are conducted in the following working fields: Primary and secondary vacuum measurements and calibrations, secondary calibrations of leak standards, primary constant pressure flowmeter (CPFM) standard establishment works, renewal works of existing primary static expansion system, European Metrology Research and Innovation Projects, Quadrupole Mass Spectrometer (QMS) characterization measurements on Dynamic Vacuum System (DVS), training and consultancy services in the field of vacuum metrology. In this paper, the Vacuum Laboratory capabilities and activities will be briefly introduced.

A New Primary Dew-Point Generator at TUBITAK UME

An implementation of a new low-range primary humidity generator as a part of an international collaboration between TUBITAK UME and VTT MIKES was initiated as a EURAMET Project Number 1259. The dew-point generator was designed and constructed within the scope of the cooperation between TUBITAK UME and VTT MIKES in order to extend the dew-point temperature measurement capability of Humidity Laboratory of TUBITAK UME down to − 80 °C. The system was thoroughly characterized and validated at TUBITAK UME to support the evidence for dew-point temperature uncertainties. The new generator has a capability of operating in the range of − 80 °C to +10 °C, but at the moment, it was characterized down to − 60 °C. The core of the generator system is a saturator which is fully immersed in a liquid bath. Dry air is supplied to the saturator through a temperature-controlled pre-saturator. The operation of the system is based on the single-pressure generation method with a single pass, i.e., the dew-point temperature is only controlled by the saturator temperature, and the humidity-controlled air is not returned to the system after leaving of the saturator. The metrological performance of the saturator was investigated thoroughly at both National Metrology Institutes. The pre-saturator was also tested using a thermostatic bath at VTT MIKES prior to sending them to TUBITAK UME. This paper describes the principle and design of the generator in detail. The dew-point measurement system and the corresponding uncertainty analysis of the dew-point temperature scale realized with the generator in the range from − 60 °C to 10 °C is also presented.

Comparison tests for the determination of the viscosity values of reference liquids by capillary viscometers and stabinger viscometer SVM 3001

The present study was realized for measuring viscosities of reference liquids using capillary viscometers and Stabinger viscometer SVM 3001 with viscosity interval between 1 mm2/s and 5000 mm2/s with temperatures from 20 °C to 80 °C. Based on our measurement with various liquids, we determine the viscosity values and compare both of the results. The aim of this study to evaluate the results of the primary level viscosity measurement system and stabinger viscometer and to compare the measurement results due to the providing traceability of Stabinger viscometer by TUBITAK UME. An increasing number of national metrology institutes and accredited laboratories provide viscometer calibration with reference liquids in a wide viscosity range. It is a common practice to use the viscosity of water as the metrological basic of viscometry. The national standard of viscosity provided by TUBITAK UME consists of a set of ubbelohde viscometers covering the measuring range of kinematic viscosities from about 0.5 mm2/s to 100 000 mm2/s. At the low viscosity, long − capillary viscometers are used as primary standards which are directly calibrated water.

A differential spectral responsivity measurement system constructed for determining of the spectral responsivity of a single- and triple-junction photovoltaic cells

A differential spectral responsivity (DSR) measurement system has been designed and constructed at National Metrology Institute of Turkey (TUBITAK UME) to determine the spectral responsivity (SR) of a single- or a multi-junction photovoltaic device (solar cell). The DSR setup contains a broad band light bias source composed of a constructed Solar Simulator based on a 1000 W Xe-arc lamp owning a AM-1.5 filter and 250 W quartz-tungsten-halogen lamp, a designed and constructed LED-based Bias Light Sources, a DC voltage bias circuit, and a probe beam optical power tracking and correction circuit controlled with an ADuC847 microcontroller card together with an embedded C based software, designed and constructed in TUBITAK UME under this project. By using the constructed DSR measurement system, the SR calibration of solar cells, the monolitic triple-junction solar cell GaInP/GaInAs/Ge and its corresponding component cells have been performed within the EURAMET Joint Research Project SolCell.