Metrological Problems Research Articles

The quality of nanomaterials and nanotechnologies is largely determined by the stability of the applied technologies, which, to a large extent, depend on the constancy of particle sizes. In this regard, metrological problems arise that are associated both with measuring the dimensions of the microstructure of aerosols, suspensions and powders, and with ensuring the uniformity of measurements when transferring a unit of a physical quantity from a standard to working measuring instruments. The purpose of this work was to determine and calculate the error in transferring the size of a unit of length when measuring the diameter of nanoparticles.An analyzer of differential electric mobility of particles was determined as a reference measuring instrument for which the calculation was made. It allows the separation of aerosol particles based on the dependence of their electrical mobility on the particle size. In combination with a condensation particle counter, it allows you to scan an aerosol and build a particle size distribution function. This measurement method is the most accurate in the field of measuring the diameters of particles in aerosols, therefore, the error in the transmission of particle size must be set as for a standard.The paper describes the physical principles of measurement by this method and presents an equation for determining the diameter of nanoparticles. Based on this equation, the sources of non-excluded systematic error were identified. Also, an experimental method was used to determine the random component of the measurement error of nanoparticles and to calculate the error in transferring the size of a unit of length when measuring the diameter of nanoparticles.The obtained results will be used for metrological support of standard samples of particle size, ensuring traceability of measurements of aerosol particle counters and for aerosol research.

The history of Euro-Asian Cooperation of State Metrological Institutions (COOMET) began three decades ago, on June 12, 1991, when the COOMET Memorandum of Understanding was signed. COOMET is an officially recognized regional organization on metrology, as well as a regional organization on legal metrology. Cooperation in COOMET allows its member countries to successfully solve urgent metrological problems facing the national economies in the context of market globalization, as well as to integrate into the international metrological system. This article briefly reviews the history of COOMET and its major achievements. An assessment of the COOMET effectiveness is given, and promising directions of COOMET development are outlined.

The metrological problems of measuring the physic and mechanical characteristics of materials by dynamic indentation are considered. It is shown that the estimation of measurement error demanding the creation of the reference blocks is ineffective due to the wide variety of controlled materials and a wide range of changes in their properties. A technique has been developed for evaluating the accuracy of measurements based on the errors of individual parameters included in the calculation equation, i.e. by determining the error of indirect measurements. The technique is based on the estimation of the boundaries of the random error of the measured characteristics of the material and the non-excluded systematic errors of the parameters that are used for the calculations of needed characteristics. The results of experimental studies are presented, indicating that due to the different character of the dependencies of hardness and elastic modulus, the error in measuring the elastic modulus exceeds the error in measuring hardness. In addition, it was found that the error in measuring the characteristics of materials by the dynamic indentation method exceeds the measurement error by the static indentation method and can be reduced by increasing the accuracy of the equipment used for the registration of impact process. The obtained values of the physic and mechanical characteristics of the materials and the values of the measurement error show that the dynamic indentation method can effectively solve the problem of non-destructive testing of hardness, elastic modulus, and strain hardening exponent of metals and products with an appropriate error.

In occupational exposure to vibration, the risk assessment process is defined through a regulatory framework that presents some relevant metrological problems. This framework considers methods based on estimation and on measurements. Estimation methods could employ existing information that is provided for each manufacturer to each individual tool or application to carry out such estimation. The use of estimation methods has some problems, such as substantial uncertainty. When using measurement methods, some metrological aspects are not fully defined. Therefore, a new and emerging risk appears due to certain methodologic limitations. Consequently, the variation between the estimated and the actual values could overestimate the level of occupational exposure to vibrations. Thus, with this paper, a critical analysis of this emerging metrological problem is provided. For this, a critical analysis of the metrological requirements regarding European standards is developed. To this end, the estimation method and measure method are investigated, considering, in both cases, the main factors related to uncertainty, reliability, and traceability. With this structure, a set of metrological limitations have been identified, thus pointing towards future lines of research that allow the improvement of the process of assessing the level of occupational exposure to vibrations.

In the present paper, current possibilities for further research into the structure of Mendeleev’s Periodic System are considered. The four-valued logic of quantum measurements is demonstrated to be applicable for the classification of chemical elements. Quantum scales containing data on the position of a chemical element with a given ordinal number are used in the definition of new metrological research problems leading to the development of new approaches to quantum metrology.

Humanity has been measuring distances, weights, time, etc. for a long time. Currently, the value of measurement results is constantly increasing due to the fast growth in the scale of industrial and information technologies. Producers and consumers every day have to make a huge number of decisions based on the measurement results with a direct impact on the functioning of business entities, level of well-being of the population and ability to evaluate the effectiveness of actions of state authorities in implementing national projects.

Optically-pumped magnetometers (OPM) based on parametric resonance allow real-time tri-axial measurement of very small magnetic fields with a single optical access to the gas cell. Most of these magnetometers rely on circularly polarized pumping light. We focus here on the ones relying on linearly polarized light, yielding atomic alignment. For these magnetometers we investigate three second order effects which appear in the usual regimes of operation, so to clarify if they translate to metrological problems like systematic errors or increased noise. The first of these effects is the breakdown of the three-step approach when the optical beam has a large intensity. The second one is the breakdown of the rotating wave approximation when the frequencies of the RF fields are not much larger than the rates of other atomic processes. The third one is the tensor light-shift which appears when the light is slightly detuned from resonance. This work should help to clarify the accuracy reachable with OPM, which is an important question notably for medical imaging applications.

This is a tutorial aimed at illustrating some recent developments in quantum parameter estimation beyond the Cramèr–Rao bound, as well as their applications in quantum metrology. Our starting point is the observation that there are situations in classical and quantum metrology where the unknown parameter of interest, besides determining the state of the probe, is also influencing the operation of the measuring devices, e.g. the range of possible outcomes. In those cases, nonregular statistical models may appear, for which the Cramèr–Rao theorem does not hold. In turn, the achievable precision may exceed the Cramèr–Rao bound, opening new avenues for enhanced metrology. We focus on quantum estimation of Hamiltonian parameters and show that an achievable bound to precision (beyond the Cramèr–Rao) may be obtained in a closed form for the class of so-called controlled energy measurements. Examples of applications of the new bound to various estimation problems in quantum metrology are worked out in some details.

On-line testing of high power electromagnetic devices is one of the most important problems of modern industrial metrology. In the paper, the results of experimental investigations of the electric field optical fiber sensor based on the electroluminescent phenomena are presented. The electro¬luminescent effect is observed in some composite semicon¬ductors, among others in zinc sulfide ZnS crystals. In our investigations, the used ZnS crystal was doped with copper Cu atoms as activators. The concentration of activator in the ZnS crystal was about 5.10-4 [g/g]. According to plans of investi¬gations of the elaborated electroluminescent sensor, the spectral properties as well as the intensity of light emission in sinusoidal alternating electric field were tested.Full Text: PDF

In measurements of fast-changing flows, one of the key issues is knowledge of the anemometer frequency bandwidth. In such measurements, the measurement technique often used is hot-wire anemometry. The determination and optimization of the measurement bandwidth of the hot-wire system is very important for the quality of the measurements carried out. One of the methods used is square-wave or sine-wave electrical testing. The article proposes modification of this method, which involves applying an electrical test signal wirelessly directly to the sensor, using transformer inductive coupling. This modification may in some cases be beneficial and find application in selected metrological problems. The article describes the modified method and its example application.

Identification of the optimal quantum metrological protocols in realistic many particle quantum models is in general a challenge that cannot be efficiently addressed by the state-of-the-art numerical and analytical methods. Here we provide a comprehensive framework exploiting matrix product operators (MPO) type tensor networks for quantum metrological problems. The maximal achievable estimation precision as well as the optimal probe states in previously inaccessible regimes can be identified including models with short-range noise correlations. Moreover, the application of infinite MPO (iMPO) techniques allows for a direct and efficient determination of the asymptotic precision in the limit of infinite particle numbers. We illustrate the potential of our framework in terms of an atomic clock stabilization (temporal noise correlation) example as well as magnetic field sensing (spatial noise correlations). As a byproduct, the developed methods may be used to calculate the fidelity susceptibility—a parameter widely used to study phase transitions.

The problems of the metrological certification of beams of high-energy heavy charged particles (HCPs) and protons that will be used in the study—as well as testing for radiation resistance—of promising products of semiconductor micro- and nanoelectronics, solid-state microwave electronics, and micromechanical systems are considered. One of the main requirements for such beams is ensuring the desired range of linear energy transfer (LET). Two methods for changing the LET are considered, one of which is based on using the ions of various types (16O, 22Ne, 40Ar, 56Fe, 84Kr, 136Xe, 209Bi), and the other is based on using ion of the same type (197Au), but with different energies. The advantages of using both methods are considered and the problems arising when using the second method are analyzed.

We study metrological problems encountered in measuring the volume-average temperature of heated tungsten filaments. The process of heating is realized by electric currents within the temperature range 300–3000 K. The measurements were carried with the use of an improved method of thermal resistance characterized by a weaker influence of the heat losses and contact potential drops in current-supplying wires, a lower error of measurements of the resistance of filament at the initial temperature, and the possibility of taking into account the nonlinearity of temperature dependences of the analyzed resistance near or below the Debye temperature. The relative error of measurements is estimated.

Constrained least-squares fitting has gained considerable popularity among national and international standards committees as the default method for establishing datums on manufactured parts. This has resulted in the emergence of several interesting and urgent problems in computational coordinate metrology. Among them is the problem of fitting inscribing and circumscribing circles (in two dimensions) and spheres (in three dimensions) using constrained least-squares criterion to a set of points that are usually described as a “point-cloud.” This paper builds on earlier theoretical work, and provides practical algorithms and heuristics to compute such circles and spheres. Representative codes that implement these algorithms and heuristics are also given to encourage industrial use and rapid adoption of the emerging standards.

In this work we have considered metrological problems and measurement of magnetic parameters and presented methods of measuring effective magnetic anisotropy field HAeff and ferromagnetic resonance bandwidth ∆H in magnetically uniaxial hexagonal ferrites in the electromagnetic microwave working frequency range. The methods allow measuring HAeff in the 10–23 and 28–40 kE ranges and ∆H in the 0.5–5.0 range. One method (suitable for wavelength measurements in free space in the 3-mm wavelength range) has been implemented for the 78.33–118.1 GHz range. The other method (based on the use of microstrip transmission lines) has been implemented for the 25–67 GHz range. The methods have been tested for polycrystalline specimens of hexagonal barium and strontium ferrites with nominal composition or complex substituted and having high magnetic texture. The measurement results have been compared with those obtained using conventional measurement methods and spherical specimens. Our methods prove to be highly accurate and reliable.

An essential part of modern quality management system in cement production is state-of-the-art radiation measurement technologies based on methods of neutron activation, X-ray fluorescence and X-ray diffraction chemical analysis of substance. The high speed and accuracy of measuring the characteristics of raw materials and finished products can be achieved by their complex application, thereby ensuring an improving in the level of automation of cement production and the quality of cement in general. The main stages of the portlandcement production process by dry method are considered, including the keypoints of quality control of their implementation by applying mentioned radiation methods of chemical analysis of raw materials and completed product. The metrological problems of their practical implementation in continuous cement production are analyzed, in particular problems of uncertainty assessment, static and dynamic calibration and increase of accuracy of measuring systems that implement neutron activation analysis methods. Shown the directions of their improvement by the use of alternative neutron sources, methods of Monte Carlo N-Particle Transport Code for neutron activation analysis physical processes simulation and machine learning for the efficient processing of spectral characteristics of investigated substances.

Metrological problems that arise in the measurement of the temperature of physical objects performed by means of pyrometers, where the emissivity of the particular object differs from unity and may vary as a function of wavelength, are considered. Methods of correction of spectral (CT) ratio pyrometers are analyzed. A disturbance in the traceability of pyrometers provided with components for correction to the primary standard of the unit of temperature is identified. Recommendations for establishing traceability are given.

Many calibration problems in metrology involve fitting a model to measurement data representing the response of a system. The standard assumption about the measurement system is that the random effects associated with the measurements are drawn from the same distribution. In practice however, the uncertainty associated with the measurements may depend on the magnitude of the response being measured. For example, the measurement of displacement using laser interferometry follows such a model in which the uncertainty has a dependence on length due to the uncertainty associated with the refractive index of the air. For such systems, the model is inherently nonlinear for which standard approaches such linear least-squares estimation provide only approximate solutions.This paper describes a Bayesian approach for analysing such data. The data is modelled as a linear or non-linear response subject to additive and multiplicative noise components. We assume that prior, possibly vague, information about the variances associated with additive and multiplicative noise components is given in terms of Gamma distributions. The Bayesian posterior distribution for such models cannot be expressed analytically in closed form and a Metropolis-Hastings Markov chain Monte Carlo algorithm is used to sample from the posterior distribution. This method is illustrated on data relating to the radioactive decay of Pb211.

Many problems in time-dependent metrology can be phrased mathematically as a deconvolution problem. In such a problem, measured data is modeled as the convolution of a known system response function with an unknown source signal. The goal of deconvolution is to estimate the unknown source signal given knowledge about the system response function. A well-studied method for calculating this estimate is Tikhonov regularized deconvolution which attempts to balance the average difference between the estimated solution and true source signal with the variance in the estimated solution. In this article we study this so-called bias-variance tradeoff in the context of estimating a source measured by a high speed oscilloscope. By assuming we have bounds on the true source’s Fourier coefficients and a structural model for the uncertainties in the system response function, we derive pointwise-in-time confidence intervals on the true signal based on the estimated signal. We demonstrate the new technique with simulations relevant to the high speed measurement context.

Main problems of metrology in connection with tendencies of engineering development are discussed. Incorporation measuring elements into most of technical systems is treated as fundamental factor having an influence on applied metrology development. Nearly the same effect is caused by introduction logic information elements into measuring instruments and systems. The problem consists in that it is impossible to determine traditional measuring channels in the system and represent through metrological characteristics of the channel comprising both measuring and logic elements. Another problems or more correct - opportunities - arise because of transfer to new definitions of units. Metrology development perspectives in connection with above-mentioned factors and context are considered. Two possible alternative ways - widening or narrowing metrology object and sphere - are discussed.