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Pure-tone audiometry, using an audiometer, is the fundamental hearing test for diagnosing hearing loss. The requirements of the devices and the detailed process for calibrating the related equipment are described in international standards. However, traceable calibration and uncertainty evaluation processes are not widely accepted or applied to the qualification and maintenance of audiometric equipment. Here, we briefly review standard measurement systems for audiometric devices and introduce their calibration procedures. The uncertainty of each calibration process was investigated, and its impact on hearing test results was considered. Our findings show that the traceability of each procedure can be secured, satisfying the uncertainty requirement and being sufficiently smaller than the permissible deviation from the audiometer requirement. To guarantee the objectivity and reliability of hearing tests and maintain low uncertainty, close cooperation and mutual understanding between the metrology field and the medical community are necessary. [ABSTRACT FROM AUTHOR]

The Lithuanian national standard of voltage is maintained as the basis for calibration and measurement capabilities of Lithuania published in the Key Comparison Database of the International Bureau of Weights and Measures (BIPM). The stability and uncertainty of the voltage value measurements, performed since 2004 using the calibrated values of the Zener solid-state voltage standards (zeners) to predict their future behavior, are discussed. Conclusions regarding short- and long-term predictability of their behavior, which can be used for choosing an appropriate calibration period, are presented. An estimate of merit for approximations is proposed; based upon the estimate, it is concluded that the hyperbolic approximation is the best one in the most of the cases. Also discussed is the behavior of voltage dividers used in the zeners as well as the recovery of the zeners after a failure of their power supply. It is concluded that the voltage standards operated by the Lithuanian National Electrical Standards Laboratory feature stable drift of the voltage reproduced, which is well predictable by means of linear or non-linear regression. [ABSTRACT FROM AUTHOR]

Intimate Partner Violence Against Women (IPVAW) has been defined as a violation of human rights and a serious public health problem rooted in social inequality between women and men. Nevertheless, a significant amount of scientific literature on the topic of IPVAW continues to exclude the gender perspective in both research design and the interpretation of results, despite its conceptual and explanatory relevance. This paper considers certain gender-blind practices in the research on IPVAW. Based on this analysis, we propose explicitly stating the theoretical assumptions inherent in the definition of the construct and clarifying the intended interpretation for measures, so that they can be incorporated into the analysis of validity, and we argue in favor of the need for interdisciplinary studies based on multicausal explanatory models, which incorporate the category gender as a transversal explanatory factor of this type of violence, as well as multi-method approaches, with the aim of overcoming issues of construct underrepresentation and construct-irrelevant variance. [ABSTRACT FROM AUTHOR]

Very Low Frequency (VLF) high voltage measuring system including the resistive high-voltage divider has been designed, developed and implemented from DC to 1 Hz up to 120 kV. The divider consists of three modules stacked on top of each other. The characterization of VLF high voltage measuring system has been performed by the calibration of the scale factor with the precision HVDC measuring system directly to determine the performance of it. The expanded uncertainty value of VLF high voltage measuring system was determined as 0.05% which meets the requirement of IEC 60060-2: 2010. This measuring system has been currently used in TUBİTAK UME (National Metrology Institute of Turkey) as a reference measuring system for the calibration of VLF high voltage test devices in-house and on-site. [ABSTRACT FROM AUTHOR]

The aim of this article is to determine the effect of the biaxial loading of a car seat, in vertical and horizontal directions, on seating comfort. We measured the transfer characteristic in the vertical direction with a free load. The method of laboratory testing of the car seat was chosen due to the simple repetition of the tests, ensuring the same test conditions, with high accuracy of their reproduction. To determine the effect, tests with uniaxial loading were compared with tests with biaxial loading. The resulting characteristic was the transfer characteristic in the vertical direction. The effect of horizontal loading on the transfer characteristic of a car seat was determined. [ABSTRACT FROM AUTHOR]

This paper investigates the direct application of standardized designs on the robot for conducting robot hand–eye calibration by employing 3D scanners with collaborative robots. The well-established geometric features of the robot flange are exploited by directly capturing its point cloud data. In particular, an iterative method is proposed to facilitate point cloud processing towards a refined calibration outcome. Several extensive experiments are conducted over a range of collaborative robots, including Universal Robots UR5 & UR10 e-series, Franka Emika, and AUBO i5 using an industrial-grade 3D scanner Photoneo Phoxi S & M and a commercial-grade 3D scanner Microsoft Azure Kinect DK. Experimental results show that translational and rotational errors converge efficiently to less than 0.28 mm and 0.25 degrees, respectively, achieving a hand–eye calibration accuracy as high as the camera's resolution, probing the hardware limit. A welding seam tracking system is presented, combining the flange-based calibration method with soft tactile sensing. The experiment results show that the system enables the robot to adjust its motion in real-time, ensuring consistent weld quality and paving the way for more efficient and adaptable manufacturing processes. [Display omitted] • A novel hand–eye calibration method with intrinsic design features of robot. • An iterative algorithm for effective optimization of hand–eye calibration. • Quantitative evaluation of the calibration method on various cobots and 3D scanners. • A safe and adaptable weld seam tracking system with the calibration method. [ABSTRACT FROM AUTHOR]

The Lithuanian national standard of electric resistance is maintained as the basis for calibration and measurement capabilities published in the key comparison database of the International Bureau of Weights and Measures (BIPM). The stability and uncertainty of the resistance value measurements, performed since 2004 using the calibrated values of the standard resistors to predict their future behaviour as well as influence of environmental conditions, are discussed. Also discussed is the recovery of a standard resistor which had undergone a mechanical disturbance. It is concluded that the standard resistors operated by the Lithuanian National Electrical Standards Laboratory feature stable drift of resistance, which is well predicted by means of linear regression.

This paper describes new realization of a sampling-based four-terminal-pair digital impedance bridge and test measurements performed with it. The bridge is based on a new two-channel high-stability digitally synthesized source and a commercial PXI synchronous sampling system. The bridge is capable of comparing any two impedances, regardless of type (R–C, R-L, or L-C), over a large frequency range (from 20 Hz to 20 kHz). Comparisons at 1 kHz and 1592 Hz in the impedance range from several hundred Ω to several kΩ give ratio errors at the level 10−6 for any kind of impedances, with potential for further improvements.

The article describes an approach to establishing the metrological traceability of reference materials adopted by TC 1.12 Reference Materials of the Euro-Asian Cooperation of National Metrological Institutions (COOMET). Specific examples of the production of COOMET reference materials are given. Approaches to demonstrating metrological traceability of reference materials depending on the method of their characterization are considered, i.e., the application of state measurement standards, interlaboratory experiments, as well as primary reference measurement procedures for characterizing reference materials when no state standards for measurement units are available. [ABSTRACT FROM AUTHOR]

Many countries are currently focused on expanding the range of national means for measurement unit transfer characterized by established metrological traceability within international organizations. As well as demonstrating the high level of measurement capabilities provided by organizations and countries, such activities facilitate a solution to the global problem of ensuring the comparability of measurement results obtained for different objects at various times in diverse parts of the world. The present article highlights issues involved in establishing the metrological traceability of physicochemical measurement results. Curent international practice in establishing traceability of reference material certified values is described. In addition, the authors provide a brief overview of internationally recognized concepts related to the metrological traceability of reference materials. [ABSTRACT FROM AUTHOR]

Advances in power electronics, increasing share of renewables in the energy system and e-mobility cause an increase of disturbances in the frequency range 2-150 kHz, also known as supraharmonics. A rigorous, credible and agreed measurement framework is essential to evaluate electromagnetic compatibility (EMC) in this frequency range. While a normative method exists for measuring equipment emission in the laboratory, no normative method exists yet for the measurement of supraharmonic disturbance levels in the grid. The aim of this research is a detailed comparison of potential measurement methods derived from existing standards IEC 61000-4-7, IEC 61000-4-30, CISPR 16-1-1 and a critical assessment of their suitability for disturbance measurements in grid applications. Based on a comprehensive set of synthetic signals and real measurements from laboratory and field, this article studies the ability of the methods to assess the typical characteristics of supraharmonic emission with relevance to EMC coordination. It presents the benefits and drawbacks of the existing measurement methods and discusses the suitability of possible modifications for grid compliance assessment. The results and recommendations intend to be an input for the present activities of IEC SC 77A WG 9 to define a normative method for the measurement of supraharmonic disturbance levels to be included in the next edition of IEC 61000-4-30.

A sampling current ratio measurement system has been developed to calibrate the voltage dependence of ratio error and phase displacement of current transformers (CTs) used for medium-voltage (MV) and high-voltage (HV) applications. The influence of voltage-induced leakage current on the apparent ratio error and phase displacement of the reference circuit was unambiguously demonstrated using a novel measurement method. Measurement results for voltages up to 24 kV show that the observed leakage current is purely capacitive and caused by the shielded cable capacitance of the HV cable used to feed the current. The maximum ratio error and phase displacement were found to be about 100 parts in 106 and $100~\mu $ rad for the smallest current of 100 A used for these investigations. Since these values scale linearly with the applied voltage and inversely proportional with current, the assumption of negligible voltage dependence used in other reference systems presented in literature is questionable. Using the corrected reference circuit, a commercial class 0.2S MV CT with 2500-A nominal current was calibrated at voltage levels up to 24 kV. The voltage dependence of ratio error and phase displacement for primary currents up to 500 A was demonstrated to be capacitive as well, with a maximum impact on the current ratio of almost 0.9% for a primary current of 100 A (corresponding to 3.6% at 1% of nominal current). This value is beyond the limits of in-force standards, which emphasizes the necessity of implementing voltage dependence testing in those standards. [ABSTRACT FROM AUTHOR]

This article presents a standard field generation system with an antenna for the calibration of a Ka-band electric-field probe. We constructed a measurement system having capability of not only rotating the azimuth angle of the probe but also changing the separation distance between the antenna and the probe. As a result, the orientation and separation distance of the probe can be suggested for minimal variation of the measurand, which reduces the overall uncertainty. For traceable electric-field strength measurements, we measured the associated quantities of the power, antenna gain, and impedance of the individual components constituting the field generation system. An evaluation of the uncertainty of the components providing traceability to the system was also conducted. The system is expected to generate a standard field higher than 10 V/m in the frequency range of 26.5–40 GHz. Uncertainty in the correction factors is quantified to determine the factors that affect the calibration, and the expanded uncertainty of the standard field generation system is found to be 5.1% at 26.5 GHz and 5.3% at both 33 and 40 GHz. [ABSTRACT FROM AUTHOR]

To establish the RF power traceability up to 50 GHz in Mexico by means of a primary standard for microwave power and millimeter-wave power, a new coaxial microcalorimeter system in 2.4-mm line size along with thermoelectric-type transfer standards (TSs) were developed and their metrological characterization was performed. Coaxial microcalorimeters allow both broadband operation and power substitution through its feeding line; however, characterization and fabrication of millimeter-wave coaxial lines are technologically difficult. Thus, the design of the microcalorimeter is described, as well as the RF performance of its adiabatic lines. To overcome the lack of coaxial TSs up to 50 GHz, commercially available 2.4-mm thermoelectric power sensors are investigated to use them as low-frequency (LF) power substitution detectors. The effective efficiency is measured in the microcalorimeter by means of calorimetric measurements and the substitution of LF power; the developed measurement procedure is presented as well as the measurement results and the uncertainty analysis. The theoretical basis for the procedure employed to determine the microcalorimeter correction factor, based on the use of specially constructed open and short standards, is described with the measurement results and uncertainties are shown as well. To avoid the drift of the millimeter-wave power during the calorimetric measurements, a novel software leveling loop method for thermoelectric power sensors was devised. This method allows to keep the RF power level variations less than 100 ppm and being a straightforward solution to recent complex hardware realizations. [ABSTRACT FROM AUTHOR]

This article presents results of a comparison of a traveling ac voltage standard, which was a fused-silica planar multijunction thin-film thermal converter (PMJTC) developed at the National Institute of Standards and Technology (NIST). The ac–dc voltage-transfer difference of the standard was measured at 2 V and selected frequencies from 1–30 MHz against primary thermal ac voltage standards at the Silesian University of Technology, Istituto Nazionale di Ricerca Metrologica, RISE Research Institutes of Sweden, and Trescal A/S Silkeborg. [ABSTRACT FROM AUTHOR]

Electrical insulation of high voltage (HV) power equipment/apparatus plays very important roles in the sound functioning of power systems. Examining the insulation condition through partial discharge (PD) measurements has considerable importance as the presence of PDs in any HV systems stands for a sign of defects and degradations in electrical insulation. Generally, the PD measurements are performed with a supply voltage of normal power frequency (PF‐50/60 Hz). As an attractive alternative, the PD measurement with a very low frequency (VLF–1 Hz or lower) applied voltage has emerged as a powerful diagnostic tool. A PD event is a random physical process, it depends mostly on the availability of free electrons that triggers the PD and the presence of space charge usually originated after a discharge. As the discharge characteristics vary with the supply voltage frequency; thus, the existing interpretation knowledge at 50 Hz may or may not be directly applicable to other test frequencies, particularly in the VLF range. Therefore, to provide a general insight, this paper presents various diagnostic aspects of PD measurements, and at the end, various discharge sources (e.g., void, surface, and corona) and their behaviours under varying the test voltage frequencies are discussed in detail. [ABSTRACT FROM AUTHOR]

The Lithuanian national standard of electric resistance is maintained as the basis for calibration and measurement capabilities published in the key comparison database of the International Bureau of Weights and Measures (BIPM). The stability and uncertainty of the resistance value measurements, performed since 2004 using the calibrated values of the standard resistors to predict their future behaviour as well as influence of environmental conditions, are discussed. Also discussed is the recovery of a standard resistor which had undergone a mechanical disturbance. It is concluded that the standard resistors operated by the Lithuanian National Electrical Standards Laboratory feature stable drift of resistance, which is well predicted by means of linear regression. [ABSTRACT FROM AUTHOR]

The article presents the application of the "one hundred minus sum of impurities" approach in the development of a reference material of ascorbic acid composition using state primary and secondary measurement standards. High-performance liquid chromatography (HPLC) with a diode-array detector is used for the quantitative determination of impurities of similar structure and with the highest content compared to other impurities. Traceability of certified values was provided using the calibration method of the State Primary Standard of units of mass (molar) fraction and mass (molar) concentration of organic components in liquid and solid substances and materials based on liquid and gas chromatography-mass spectrometry with isotope dilution and gravimetry GET 208-2019. The paper presents the use of the reference material of ascorbic acid composition to test the qualifications of laboratories. Satisfactory results of the participants confirmed the applicability of the reference material for various measurement methods. [ABSTRACT FROM AUTHOR]

The article raises the problem of ensuring metrological traceability of quality and nutritional value measurement results for food products and food raw materials: water (moisture), nitrogen (protein, crude protein), fat, ash and carbohydrate content. The problem under consideration can be solved by applying reference materials of food composition, traceable to state primary measurement standards GET 173-2017 and GET 176-2019 and primary reference measurement procedures (PRMP), for attestation of measurement procedures and accuracy verification of measurement results. The article discusses the results of PRMP development for measuring mass fraction of fat, ash and carbohydrates in food products and food raw materials, and mass fraction of crude fat (oil content) in oilseeds and products based on them. The paper also presents metrological characteristics of reference materials of the composition of dried dairy products, dried grain and dairy-grain cereals for babies, egg powder, freeze-dried meat products, animal feed. The results of the work allow for building a chain of metrological traceability from GET 173-2017, GET 176-2019 and PRMP to routine measurement procedures, thereby ensuring the uniformity of measurements of nutritional value of food products. [ABSTRACT FROM AUTHOR]

The article is devoted to the development of the state secondary measurement standard of mass fraction units and mass (molar) concentration of organic components in liquid and solid substances and materials based on gas and liquid chromatography. The composition of the state secondary measurement standard, as well as the results of evaluating metrological characteristics have been considered. The problem of ensuring the traceability of measurement results to SI units is given in the article. Two approaches are proposed for obtaining a unit from the state primary standard of mass (molar) fraction units and mass (molar) concentration of organic components in liquid and solid substances and materials based on liquid and gas chromatography-mass spectrometry with isotopic dilution and gravimetry GET 208-2014: by comparing and using transfer standards. Examples of implementing the indicated approaches used during the development of reference materials of toxic substances, namely a certified reference material for composition of p,p-DDT (p,p-DDT, CRM of UNIIM) and a certified reference material for composition of benz(a)pyrene solution in acetonitrile (C20H12, CRM of UNIIM) are given. Results of determining metrological characteristics of reference materials including standard uncertainty due to characterization and standard uncertainties due to inhomogeneity, short and long-term instabilities are described.

The article presents information about one of the largest in RF manufacturer of the approved types reference materials (GSO), intended for the metrological assurance of safety and quality parameters control for water, aqueous medium and different types ofproduction. It's shown measurement capabilities of the Center. It's also shown traceability schemes to primary standards and SI units for characterization results for all types of prodused CRM.

Falling weight deflectometer (FWD) is widely used in traffic transport industry. In order to solve the traceability of FWD, the definition of deflection was studied, the use and measurement of FWD was thoroughly analysed, and the measurement parameters were determined. Calibration device, standard foundation, and experimental environmental conditions of FWD was set up. The measurement uncertainty of the calibration equipment has been analysed. Through the test of the typical FWD, the performance of the calibration equipment is tested. Through the establishment of the traceability chain of ‘ Absolute normal low frequency vibration standard device-FWD calibration equipment-FWD’, it can meet the calibration/verification requirements of FWD.

The rapid progress of modern science and technology promotes the continuous development of precision measurement technology and improves the accuracy and efficiency of measuring instruments. In optical precision measurement technology, grating measurement technology has the advantage of high precision and large range. This study introduces the principle, structure and data handling of grating tester for dial indicator gauges. As the grating tester for dial indicator gauges is a kind of high precision measuring standard instrument, the verification basis, verification method and uncertainty analysis are also discussed in depth in this study.

Vibration sensor calibration is performed using the absolute calibration method and the comparison calibration method. The comparative calibration method is used to take a carefully calibrated benchmark to the measured sensor and the vibration sensor for a contrast test, the use of standard sensors requires regular inspection to traceability to national standards to ensure the reliability and accuracy of dissemination. From the measurement perspective, using the absolute calibration method to calibrate a laser interference vibration acceleration sensor can achieve high precision, wide field, high reliability calibration to ensure the sensor of high accuracy, vibration signal high reliability is of great significance. The vibration method of absolute calibration is based on laser interference technology research, put forward in the development of the laser absolute method based on the technology of vibration calibration device, a further optimised method of the absolute calibration device, the mathematical model is used to improve the technical indicators and to provide reliable technical guarantee for vibration transducer calibration.

A shock tube-based calibration installation for dynamic pressure transducers was designed and manufactured. The hardware of the calibration installation contained a shock tube, two pressure transmitters, three transducers for velocity measurement, a temperature transmitter, two data sampling cards and a industrial personal computer, etc. The software of the calibration installation was a data sampling and data processing system. The functions of the software included test conditions monitoring, performance parameters computation, and calibration reports generation, etc. The performance of the calibration installation was tested. The test result showed that the range of the step pressure was 9.60 kPa–1.101 MPa, the maximum rise time of the step pressure was no more than 1μs, the minimum duration of the step pressure plateau was longer than 4 ms, the fluctuation of the step pressure plateau was better than ± 2%, and the maximum 2nd order expand uncertainty of the step pressure was less than 4%. Thus the calibration installation was qualified to be a shock tube-based dynamic pressure standard because that the performance of the calibration installation was verified to meet the requirements of ‘Verification Regulation of Dynamic Pressure transducers’ and ‘Verification Regulation of Dynamic Pressure standards’.

This study proposes an analytical method for calibrating and orienting online photogrammetric systems using a scale bar. The primary idea is building control lengths in the measurement volume by moving and rotating the scale bar and then conducting a self-calibration bundle adjustment using images of the control lengths. In this study, the five-point relative orientation method is used to provide estimations of the exterior camera parameters. Additionally, this study elaborates the model of the lengths constrained self-calibration bundle adjustment, the block computation algorithm and the accuracy assessment. This method obtains both the interior and the exterior orientation parameters of the two cameras, and provides spatial bar length reconstruction precision as the performance evaluation. Simulations are conducted to analyze the calibration accuracy and the results show that the method achieves comparable accuracy and precision against the state-of-the-art method. However, the method does not need steady and well distributed 3D points and is easy to operate. Real data experimental results show that the maximum length measurement error of this method in a volume of 5 m × 4 m × 2 m is

Based on laser power meter calibration requirements, through the purchase of standard equipment and field monitoring equipment developed, standard laser detector, optical path related equipment, such as construction of laser radiation power meter calibration test system, implementation of laser power meter of laboratory test and vehicle, large equipment form a complete set of laser power meter field test and field test of the radiated power of the laser equipment. Calibration system is introduced in detail the composition and working principle of the uncertainty of the system are analysed in detail, and through the system stability test, laser power, beam monitoring and correction device performance test, ate test for power meter calibration experiment data analysis, proved in this study, the laser power meter calibration method provided will enable calibration system, the expanded uncertainty of relative reached 2% (k = 2), which can realise wavelength of 532 and 1064 nm, power measuring the range of 0.1 mW–20 W laser power meter calibration.

This paper discusses a method of the current derivative measurement using a standard closed-loop Hall-effect current sensor. The proposed method can operate with PWM-driven inverters and provides the estimation of motor-phase inductances required for an encoderless or self-sensing control. The method is based on the current transformation feature of the closed-loop sensor where a sensing inductor is connected in series with the measuring resistor. The voltage drop across the inductor is proportional to the current derivative. The experimental results are demonstrated that the measurement of the current derivative can be performed under a good accuracy, though the measurement should be executed while inverter is in the steady-state condition.

This study proposes an analytical method for calibrating and orienting online photogrammetric systems using a scale bar. The primary idea is building control lengths in the measurement volume by moving and rotating the scale bar and then conducting a self-calibration bundle adjustment using images of the control lengths. In this study, the five-point relative orientation method is used to provide estimations of the exterior camera parameters. Additionally, this study elaborates the model of the lengths constrained self-calibration bundle adjustment, the block computation algorithm and the accuracy assessment. This method obtains both the interior and the exterior orientation parameters of the two cameras, and provides spatial bar length reconstruction precision as the performance evaluation. Simulations are conducted to analyze the calibration accuracy and the results show that the method achieves comparable accuracy and precision against the state-of-the-art method. However, the method does not need steady and well distributed 3D points and is easy to operate. Real data experimental results show that the maximum length measurement error of this method in a volume of 5 m × 4 m × 2 m is <0.4 mm. [ABSTRACT FROM AUTHOR]

The rapid progress of modern science and technology promotes the continuous development of precision measurement technology and improves the accuracy and efficiency of measuring instruments. In optical precision measurement technology, grating measurement technology has the advantage of high precision and large range. This study introduces the principle, structure and data handling of grating tester for dial indicator gauges. As the grating tester for dial indicator gauges is a kind of high precision measuring standard instrument, the verification basis, verification method and uncertainty analysis are also discussed in depth in this study. [ABSTRACT FROM AUTHOR]

Based on laser power meter calibration requirements, through the purchase of standard equipment and field monitoring equipment developed, standard laser detector, optical path related equipment, such as construction of laser radiation power meter calibration test system, implementation of laser power meter of laboratory test and vehicle, large equipment form a complete set of laser power meter field test and field test of the radiated power of the laser equipment. Calibration system is introduced in detail the composition and working principle of the uncertainty of the system are analysed in detail, and through the system stability test, laser power, beam monitoring and correction device performance test, ate test for power meter calibration experiment data analysis, proved in this study, the laser power meter calibration method provided will enable calibration system, the expanded uncertainty of relative reached 2% (k = 2), which can realise wavelength of 532 and 1064 nm, power measuring the range of 0.1 mW–20 W laser power meter calibration. [ABSTRACT FROM AUTHOR]

Vibration sensor calibration is performed using the absolute calibration method and the comparison calibration method. The comparative calibration method is used to take a carefully calibrated benchmark to the measured sensor and the vibration sensor for a contrast test, the use of standard sensors requires regular inspection to traceability to national standards to ensure the reliability and accuracy of dissemination. From the measurement perspective, using the absolute calibration method to calibrate a laser interference vibration acceleration sensor can achieve high precision, wide field, high reliability calibration to ensure the sensor of high accuracy, vibration signal high reliability is of great significance. The vibration method of absolute calibration is based on laser interference technology research, put forward in the development of the laser absolute method based on the technology of vibration calibration device, a further optimised method of the absolute calibration device, the mathematical model is used to improve the technical indicators and to provide reliable technical guarantee for vibration transducer calibration. [ABSTRACT FROM AUTHOR]

A shock tube-based calibration installation for dynamic pressure transducers was designed and manufactured. The hardware of the calibration installation contained a shock tube, two pressure transmitters, three transducers for velocity measurement, a temperature transmitter, two data sampling cards and a industrial personal computer, etc. The software of the calibration installation was a data sampling and data processing system. The functions of the software included test conditions monitoring, performance parameters computation, and calibration reports generation, etc. The performance of the calibration installation was tested. The test result showed that the range of the step pressure was 9.60 kPa–1.101 MPa, the maximum rise time of the step pressure was no more than 1μs, the minimum duration of the step pressure plateau was longer than 4 ms, the fluctuation of the step pressure plateau was better than ± 2%, and the maximum 2nd order expand uncertainty of the step pressure was less than 4%. Thus the calibration installation was qualified to be a shock tube-based dynamic pressure standard because that the performance of the calibration installation was verified to meet the requirements of 'Verification Regulation of Dynamic Pressure transducers' and 'Verification Regulation of Dynamic Pressure standards'. [ABSTRACT FROM AUTHOR]

Falling weight deflectometer (FWD) is widely used in traffic transport industry. In order to solve the traceability of FWD, the definition of deflection was studied, the use and measurement of FWD was thoroughly analysed, and the measurement parameters were determined. Calibration device, standard foundation, and experimental environmental conditions of FWD was set up. The measurement uncertainty of the calibration equipment has been analysed. Through the test of the typical FWD, the performance of the calibration equipment is tested. Through the establishment of the traceability chain of ' Absolute normal low frequency vibration standard device-FWD calibration equipment-FWD', it can meet the calibration/verification requirements of FWD. [ABSTRACT FROM AUTHOR]

This paper discusses a method of the current derivative measurement using a standard closed-loop Hall-effect current sensor. The proposed method can operate with PWM-driven inverters and provides the estimation of motor-phase inductances required for an encoderless or self-sensing control. The method is based on the current transformation feature of the closed-loop sensor where a sensing inductor is connected in series with the measuring resistor. The voltage drop across the inductor is proportional to the current derivative. The experimental results are demonstrated that the measurement of the current derivative can be performed under a good accuracy, though the measurement should be executed while inverter is in the steady-state condition. [ABSTRACT FROM AUTHOR]

The calibration process is one of the methods for decreasing the measurement apparatus uncertainties. In this study, the sensor calibration is performed using the values reproduced by stan-dard setting devices. Generally, the calibration characteristics of measurement apparatus are taken in a polynomial form. In this study, a genetic algorithm (GA) is used for the measurement apparatus calibration purpose. As an example, GA‐based calibration of a differential pressure gauge using standard pressure setting devices is examined. The calibration results, founded using the proposed GA, are compared with the results obtained via the classical least square method. As a result, the recommendations on how to get better calibration characteristics for the differential pressure gauge are given. [ABSTRACT FROM AUTHOR]

Microcalorimeters are used by National Metrology Institutes (NMIs) for the realization of the radio frequency and microwaves (RF&MW) primary power standard. Since they are not available on the market, NMIs have to design their own systems. It involves the design of complex mechanical structures and of low-noise data acquisition systems. Resulting setups allow precision measurements of RF&MW power by applying difficult and time-consuming measurement techniques. Weaknesses to be addressed in order to improve the performance, whether in the mechanical structure or in the data acquisition electronics, are not easy to identify. Anyway, they can be found by analyzing the microcalorimeter measurement uncertainty. In recent years, several improvements have been made on the [Istituto Nazionale di Ricerca Metrologica (INRIM), Italy] coaxial microcalorimeter with the aim of making its operation more stable and to reduce the measurement uncertainty. Its weak points are here analyzed by means of a comprehensive uncertainty budget. Details are also given on how uncertainty contributions have been determined. The method here applied is general and can be conveniently used in many other fields or applications, provided that the analytical model is known. It is useful while designing an experiment and/or a posteriori to identify the parts of the apparatus and of the measurement setup that needs to be optimized. [ABSTRACT FROM AUTHOR]

We performed calibrations of four different commercial picoammeters using the ultrastable low-noise current amplifier (ULCA) as a calibrator current source operated in the range between 1 fA and $1~\mu \text{A}$. The results allow the comprehensive characterization of the devices under test regarding noise, settling, and burden voltage behavior as well as stability of the gain factor, and confirm the performance of the ULCA for use as small-current calibrator standard. Also, we present a further advanced setup for the calibration of transimpedance amplifiers. Accuracy limits for the best electrometer calibrations in the current range between 1 fA and $1~\mu \text{A}$ and possible implications on corresponding calibration and measurement capabilities are discussed. [ABSTRACT FROM AUTHOR]

To assess the reliability of dc energy measurement equipment on-board trains, a setup was developed to characterize current transducers under realistic operating conditions. The operating principle is based on a current ratio measurement technique. The reference sensor is a high-precision zero-flux current transducer in combination with a broadband high-precision current shunt. The influence of ac distortion on this reference sensor was found to be within a few parts in 106 using an initial version of the setup, in which ac distortion was applied through a separate winding. A revised version of the setup employs a programmable electronic load to apply dynamic currents up to 600 A. The setup was used to characterize a 100 $\mu \Omega $ high-current shunt resistor. The effect of dissipative heating on the dc transresistance error was around 0.03 %, with a settling time of about half an hour. The short-term intrinsic current dependence was also around 0.03 %. The effect of ac distortion was within a few parts in 106. The intrinsic current dependence and the onset of the heating effect were also observed when exposing the sensor to a dynamic current profile that was recorded during a trip between two successive underground train stations on Metro de Madrid. These results demonstrate that the setup described in this paper is very effective for characterizing dc current sensors for practical railway applications. Future work will concentrate on even more demanding current signals, such as chopped signals, and on other types of sensors and measurement systems. [ABSTRACT FROM AUTHOR]

We have developed a system to extend, by a factor of up to 1000, the voltage range over which Josephson arbitrary waveform synthesizers (JAWS) can be used in ac voltage metrology. The system is based on a precision inductive voltage divider, with a lock-in amplifier as the detector. Using a JAWS with a maximum output voltage of 250 mV (root mean square), we have made accurate voltage measurements up to 120 V at 60 Hz with expanded uncertainties ($k = 2$) of no more than 1.5 $\mu \text{V}$ /V and demonstrate that the system can operate up to 1 kHz. We anticipate that our JAWS-based system will improve uncertainties in ac voltage metrology by one order of magnitude compared to techniques based on thermal voltage converters. [ABSTRACT FROM AUTHOR]

This paper presents a simplified method for realizing absolute phase and ac resistance for current shunts using only impedance ratio measurements. The method is based on three geometrically identical current shunts with different resistances, but with the same inductance, capacitance, and ac–dc resistance change. We demonstrate how the inductance, capacitance, and ac resistance can be calculated from the complex impedance ratio measurements, therefore realizing absolute current shunt impedance. The method gives competitive uncertainties of around $200~ \mu \Omega / \Omega $ for amplitude and $400~ \mu $ rad for phase at 1 MHz in the 1- $\Omega $ range. [ABSTRACT FROM AUTHOR]

Measuring the field strength of an electromagnetic wave based on atomic quantum mechanics is expected to be an innovative method to realize stable and reliable measurements. However, the major issue of atomic measurements is that the measurable frequency is limited to the resonant frequency of atoms. Therefore, in this paper, we demonstrate the measurement at arbitrary frequencies using the Zeeman effect in a static magnetic field. A cesium vapor cell is placed in a static magnetic field of approximately 40 mT, which causes the resonant frequency of the cesium atom to shift from 9.2 to 8.2 GHz. In addition, the Rabi frequency due to the interaction between cesium atoms and microwaves is measured at the frequency of 8.2 GHz in this experiment. [ABSTRACT FROM AUTHOR]