Showing papers in "Measurement Techniques in 2020"
TL;DR: In this paper, a new method for the determination of the composition of liquid mixtures of substances that do not participate in chemical reactions with each other is proposed, which enables one to determine the contributions of absorption and dispersed signals to the recorded NMR signals of condensed media.
Abstract: We describe some devices used for the express analysis of the state of environment based on the phenomenon of nuclear magnetic resonance. We propose a new method for the determination of the composition of liquid mixtures of substances that do not participate in chemical reactions with each other. The application of this method enables us to determine the relative concentrations of components of the analyzed mixture. We present the results of investigations of the mixtures of hydrocarbons. The comparison of the numerical and experimental data on the compositions and concentrations of components of the media is performed. The proposed method enables one to determine the contributions of absorption and dispersed signals to the recorded NMR signals of condensed media, which can be either in the stationary state or in the flowing state.
19 citations
TL;DR: In this article, the use of a Raman lidar for remote measurement of the concentration of molecules of various pollutants at level of tens and hundred of units of the maximum permissible concentration is considered.
Abstract: Issues of atmospheric pollution by hydrofluoride molecules are brought to light. The use of a Raman lidar for remote measurement of the concentration of molecules of various pollutants at level of tens and hundred of units of the maximum permissible concentration is considered. The measurement error is estimated for the concentration on the order of 1014 cm–3 and greater by hydrofluoride molecules in synchronous photon counting mode by lidar of the Raman scattering of light in the atmospheric boundary layer of altitude up to 1.5 km. Results are presented of the numerical solution of the lidar equation for Raman scattering of light by hydrofluoride molecules: the possible measured concentration of hydrofluoride molecules is approximately 1.5·1014 cm–3 with relative measurement error less than 25% at the wavelength of 405 nm for investigatory altitude no greater than 500 m.
7 citations
TL;DR: It is shown that the most universal recommendations for the selection of methods of determining or adjusting the intervals between inspections (calibrations) and a comprehensive critical analysis of these recommendations are presented in the document, OIML D10–2007, Guidelines for the Determination of the Calibration Intervals of Measuring Instruments.
Abstract: The problem of determining and adjusting the inter-inspection and inter-calibration intervals of measuring instruments is analyzed. Well-known recommendations for describing the drift of the error of a measuring instrument in the course of use are analyzed. It is shown that the most universal recommendations for the selection of methods of determining or adjusting the intervals between inspections (calibrations) and a comprehensive critical analysis of these recommendations are presented in the document, OIML D10–2007, Guidelines for the Determination of the Calibration Intervals of Measuring Instruments. D10–2007 sets forth the most general approach to the description of these methods in different fields of application of measuring instruments of the greatest diversity and recommends five methods of reviewing the inter-calibration intervals. The selection of the most acceptable method is performed by the party involved in thes study, i.e., the designer, manufacturer, or user of the measuring instrument, or the calibration or testing laboratory. The development of procedures for determining and adjusting the inter-calibration intervals that take into account specific features characterizing the organization that executes these studies and the field of application of the measuring instruments and their operating regimes, the form and method of measurements and the extension of the procedure by type, group, or concrete copy of the measuring instrument must follow the selection of the method. The procedure may be created in the form, for example, of a standard of the organization.
6 citations
TL;DR: In this paper, a method is proposed for measuring the longitudinal relaxation time of a flowing liquid over the entire range within which its flow rate is measured, compared with measurements of steady state longitudinal relaxation times of liquid media in a commercial nuclear-magnetic relaxometer; these measurements coincide to within the measurement error.
Abstract: The problems of monitoring the state of flowing liquids used in various branches of industry, power production, and agriculture are examined. Means of monitoring the state of flowing liquids based on the phenomenon of nuclear magnetic resonance are discussed. These devices are free of the shortcomings and limitations inherent in the use of optical analyzers and flow-through refractometers. When monitors based on nuclear magnetic resonance are used, the monitored parameters are the relaxation times of the flowing liquid; in particular, the greatest difficulties arise when measuring the longitudinal relaxation time. A method is proposed for monitoring the longitudinal relaxation time of a flowing liquid over the entire range within which its flow rate is measured. A design for a nuclear-magnetic flowmeter-relaxometer is developed for implementation of the new method. The obtained data are compared with measurements of steady-state longitudinal relaxation times of liquid media in a commercial nuclear-magnetic relaxometer; these measurements coincide to within the measurement error.
6 citations
TL;DR: In this paper, a method for estimating functionals of derivatives of the probability densities that assumes fulfillment of the following steps is developed on the basis of these results, and the results are confirmed by analyzing data from a numerical simulation.
Abstract: In justifying a method for rapid choice of the spread coefficient of kernel probability density estimates, a constant has been found which is a functional of the second derivative of the density. This result is generalized to the derivatives of symmetric probability densities of different orders in this paper. Functional dependences of these constants on the coefficient of antikurtosis of a random variable are found. The features of these constants are studied. A method for estimating functionals of derivatives of the probability densities that assumes fulfillment of the following steps is developed on the basis of these results. The mean square deviation of the one-dimensional random variables and the antikurtosis coefficient are estimated from the original sample. The recovered functional dependences of the antikurtosis are used to estimate the values of constants which are functionals of the derivatives of the probability density. For the known estimates of the mean square deviation of random variable being studied and the constant examined here, the values of the functional of the derivative of the probability distribution of the chosen order are calculated. The results are confirmed by analyzing data from a numerical simulation. It is found that with increasing order of the derivative, the estimates of these functionals increase. This fact is explained by the increasing complexity of the integrand in these functionals. The proposed method provides objective results for the first three derivatives of the probability density of the random variable. The results of this study are confirmed by a confidence estimate for the functionals studied here.
6 citations
TL;DR: In this article, a model of a new high-precision apparatus for measurement of the cut-off wavelength of an optical fiber is proposed, which is performed on the basis of the reference bending method described in GOST R MEK 60793-1-44-2013.
Abstract: Problems that arise in the course of attempting to determine and monitor an optical fiber, the medium of transmission of fiber-optic communication systems, are considered. One of the controllable parameters is the cut-off wavelength of a single-mode optical fiber. The cut-off wavelength defines the minimal wavelength of optical radiation at which an optical fiber supports only a single propagated mode, i.e., it functions in a single-mode regime. The problem of determining the cut-off wavelength of an optical fiber used in fiber-optic communication systems is critical, since in a multi-mode regime of operation of an optical fiber its throughput decreases as a consequence of inter-mode dispersion. Methods of measuring the cut-off wavelength of an optical fiber are considered. A model of a new high-precision apparatus for measurement of the cut-off wavelength of an optical fiber is proposed. The measurements are performed on the basis of the reference bending method described in GOST R MEK 60793-1-44-2013. The precision characteristics of the newly developed apparatus are analyzed and a quantitative assessment of the measurement error is obtained.
5 citations
TL;DR: In this paper, the problems of measuring viscosity using Brookfield viscometers directly in vessels with controlled liquids without transferring into a special measuring tank are considered, and equations for approximating the dependences of the viscometer readings on the diameter of the vessel and the distance from its bottom to the end of the spindle are derived.
Abstract: The problems of measuring viscosity using Brookfield viscometers directly in vessels with controlled liquids without transferring into a special measuring tank are considered. To increase the accuracy of viscosity measurements in vessels of arbitrary shape and size, experimental and theoretical studies of the LVF Brookfield viscometer sensitivity to the influencing values were carried out, which are the diameter of the vessel with a liquid, the distance from the spindle to the bottom of the vessel, and the immersion level of the spindle. A general characteristic of the factors influencing the accuracy of viscosity measurements is given. Based on the known formulas for rotational viscometers, equations for approximating the dependences of the viscometer readings on the diameter of the vessel and the distance from its bottom to the end of the spindle are derived. Formulas that allow making corrections to the measurement results when the mentioned influencing values change are obtained. The correction factors necessary for measuring viscosity in vessels, the sizes of which differ from the recommended ones, are determined. It was found that the distance from the spindle to the bottom of the vessel with the liquid affects the measurement results only when using the LV1 spindle and the immersion level affects only when using the LV4 spindle. The results of the viscometer calibration using viscosity standard samples REV-100, REV-300, REV-1000, Brookfield 12500, Brookfield 100000 are presented. A correction factor for the case of using the LV3 spindle without a guard leg was obtained. The research results presented in the article allow measuring viscosity with a Brookfield viscometer in vessels with diameters up to 40, 30, 23, 10 mm for spindles LV1, LV2, LV3, LV4, respectively.
5 citations
TL;DR: In this paper, a simple method for recording and quantifying the structural changes occurring in highly dispersed ceramic samples under the influence of a microwave field is proposed, and the effect of reducing the size of structural elements (particles) of the surface of such ceramic samples influenced by microwave radiation by an average of 20%.
Abstract: The problem of the possibility of visualizing multiscale phenomena developing on the surface of a ceramic material, which is characterized by a high dispersion of structural elements, is important for modern materials science. The relevance of using wavelet analysis to visualize and measure the structural elements of the surface of ceramic samples is shown. The experimental results of processing images of the surface of samples using wavelet analysis are presented. Examples of applying the wavelet transform to the study of model “chessboard” images with simple geometry and precisely known sizes of structural elements are observed. A relation that relates the particle size to the scale parameter of the wavelet spectrum is derived. A simple method for recording and quantifying the structural changes occurring in highly dispersed ceramic samples under the influence of a microwave field is proposed. The effect of reducing the size of structural elements (particles) of the surface of such ceramic samples influenced by microwave radiation by an average of 20% is discovered. The surface of such samples becomes more uniform, which is extremely promising for the development of technology for producing finely dispersed ceramic materials.
5 citations
TL;DR: In this paper, a spectrometric system for measuring temperature in conditions of a magnetic resonance imaging room is proposed, which can be used to assess the magnetic resonance compatibility of implantable medical devices, to develop scanning protocols for patients with metal structures, and to confirm or refi ne mathematical models of heat transfer.
Abstract: To determine the compliance of an implantable medical device with the safety requirements in magnetic resonance imaging, an experimental assessment of the heating of this device during a study is necessary. The use of traditional methods, such as thermocouple measurements or radiation thermometry, is difficult in the conditions of a magnetic resonance imaging room. A spectrometric system for measuring temperature in conditions of a magnetic resonance imaging room is proposed. The developed system has a sensitivity of 0.01°C and an error of 0.1% in the range of 10–50°C. The temperature sensors used in the system are Fabry–Perot interferometers. The design of the sensors and the method of calibration are described. The system was tested in determining the heating of two passive implants during the study in a magnetic resonance imager with a magnetic field induction of 1.5 T. The compliance of the developed system with the recommendations adopted in magnetic resonance imaging for evaluating the heating of implantable medical devices is demonstrated. The temperature value obtained is comparable with the value found during testing of this implant according to ASTM F 2182. The presented measuring system can be used to assess the magnetic resonance compatibility of implantable medical devices, to develop scanning protocols for patients with metal structures, as well as to confirm or refi ne mathematical models of heat transfer.
5 citations
TL;DR: In this paper, a contactless aero-hydrodynamic device with a laser triangulation detector was developed to measure the range to the surface of the liquid; this viscosity measurement device supports full automation, while providing a significant increase in measurement accuracy.
Abstract: We review a variety of contactless techniques for fluid viscosity measurement. We discuss contactless aero-hydrodynamic techniques capable of providing high-accuracy viscosity measurements for non-homogeneous and non-transparent fluids over the range 2–100 Pa·s. We describe a very promising approach in need of additional work–a contactless aero-hydrodynamic technique that involves using a pulsed gas jet to distort the surface of the fluid being measured and determining the viscosity based on the time required to reach a specified deformation level after the gas jet comes on. We have developed a contactless aero-hydrodynamic device with a laser triangulation detector to measure the range to the surface of the liquid; this viscosity measurement device supports full automation, while providing a significant increase in measurement accuracy. We studied four possible options for implementation of the device, and selected the best option to improve the measurement accuracy and reduce the sensitivity of the device to external effects. We describe the design and operating principle for the device, and describe how device design parameters affect systematic and random measurement error. The relative measurement error in fluid viscosity was 2% or less over the entire range from 2 to 100 Pa·s. This contactless aero-hydrodynamic device will be useful for measurement of viscous fluids in a wide variety of industrial fields.
4 citations
TL;DR: In this paper, the magnetic moments of water protons and 7Li ions were calculated using the known data on the magnetic moment of the proton and the electronic shielding of these nuclei.
Abstract: The ratio of NMR frequencies of lithium isotopes f(7Li)/f(6Li) = 2.6409061846(13) was determined with an error of 4.9·10–10. The use of a nuclear magnetic resonance spectrometer operating in the mode of simultaneous registration of signals from two nuclei to obtain data allowed the random and systematic errors in the measurement results to be reduced by an order of magnitude. The ratio of the resonant frequencies of water protons and 7Li ions was determined: f(H2O)/f(7Li) = 2.557100473(9) with an error of 3.5·10–9 for solutions with an extremely low concentration of LiOH*H2O salt in water and at a temperature of 25°C. Based on the obtained data, the magnetic moments of lithium nuclei were calculated: μ(6Li) = 0.8220454(25)μN, μ(7Li) = 3.2564171(98)μN. The known data on the magnetic moment of the proton and data on the electronic shielding of these nuclei were used. A comparison of the experimental data for μ(6Li) and μ(7Li) and the corresponding theoretical calculation data was performed.
TL;DR: In this paper, the results of an analysis of the asymptotic properties of a multidimensional nonparametric estimate of the probability density of the Rosenblatt-Parzen type and its modifications are investigated.
Abstract: The dependencies between the sampling intervals of the domain of values of a multidimensional random variable and the blur coefficients of the kernel probability density estimate are determined. The results of an analysis of the asymptotic properties of a multidimensional nonparametric estimate of the probability density of the Rosenblatt–Parzen type and its modifications are investigated. Modification of the kernel probability density estimate is a smoothed multi-dimensional histogram. The formulas for calculating the optimal parameters of the kernel function blur coefficients and the lengths of the sampling intervals of the values of the components of a multidimensional random variable are analyzed. Blur coefficients are presented as the products of an indefinite parameter and the mean square deviations of random components. An indefinite parameter and the number of sampling intervals of multidimensional random variables are found from the condition of minimum mean square deviations of the considered probability density estimates. Based on the results obtained, the relationships between the blur coefficient parameters and the discretization procedure of the range of values of a multidimensional random variable are established. The discovered patterns are characterized by a set of constants. The constants under consideration are represented by the ratio of nonlinear functionals of the probability density and their second derivatives with respect to each random component. The values of the constants are characterized by the type of probability density and are independent of their parameters. From computational experimental data, we establish the relationships between the constants and the product of the counterexcess coefficients with the components of a multidimensional random variable. The results obtained make it possible to quickly determine the lengths of sampling intervals of the values of the components of a multidimensional random variable from the kernel function blur coefficients of a nonparametric probability density estimate.
TL;DR: In this paper, an overview of the results obtained at the All-Russia Research Institute of Physicotechnical and Radio Measurements when creating a fountain type clock is presented, and the technical solutions required for the creation of an atomic gravimeter with given values of the sensitivity for measuring the acceleration of gravity are proposed.
Abstract: An overview of the research results obtained at the All-Russia Research Institute of Physicotechnical and Radio Measurements when creating a fountain type clock is presented. The possibility of using the results obtained for the development of a sensitive atomic interferometer (gravimeter) based on cold rubidium atoms is analyzed. The relevance of the study lies in assessing the prospects for creating an interferometer (gravimeter) based on cold rubidium atoms for absolute measurements of the local value of the gravitational acceleration. The physical principles of operation of an atomic gravimeter are described. A comparison is made between an atomic gravimeter and a fountain-type frequency standard based on cold atoms. The technical solutions required for the creation of an atomic gravimeter with given values of the sensitivity for measuring the acceleration of gravity are proposed. To achieve a gravimeter sensitivity of the order of 1 μGal/Hz1/2, the phase noise of laser radiation, the pressure of residual gases in the vacuum system, and the parameters of the magnetic shield system are estimated.
TL;DR: To evaluate the biological properties of water and highlight the corresponding informative features of the gas-discharge radiation images, a one-dimensional wavelet transform of the brightness profile is proposed and helps reveal the measurement uncertainty of the quantitative characteristics of the images.
Abstract: This study analyzed the relevance of using measurement methods based on visual data and identified the main problems that arise when calculating the measurement uncertainty of the estimates of quantitative characteristics of images in automated image analysis systems due to the lack of general recommendations for this type of calculation. Moreover, the study highlights the challenges in developing a method for calculating the measurement uncertainty of the detailing coefficients of the wavelet transform applied to the automated analysis of gas-discharge radiation images of water. To evaluate the biological properties of water and highlight the corresponding informative features of the gas-discharge radiation images, a one-dimensional wavelet transform of the brightness profile is proposed. This method of calculating the uncertainty is based on the results of repeated cases and helps reveal the measurement uncertainty of the quantitative characteristics of the images.
TL;DR: Analytic and computer models of false failure and undetected failure in tolerance control of the parameters of the components of a measuring technique are developed and a geometric interpretation of error functions in the form of two-dimensional surfaces that depend on the tolerance of a controllable parameter and the measurement error is presented.
Abstract: Questions related to control of the performance of a measuring techniques are considered. Analytic and computer models of false failure and undetected failure (error functions) in tolerance control of the parameters of the components of a measuring technique are developed. A geometric interpretation of error functions in the form of two-dimensional surfaces that depend on the tolerance of a controllable parameter and the measurement error is presented. The newly developed models may be used both for theoretical as well as statistical laws of distribution of a measurable quantity and a measurement error. The results obtained will be useful in the development of metrological support of a measuring technique, performance of verifications of measurement instruments, metrological examination of technical documentation, and certification of measurement methods.
TL;DR: In this paper, the effect of background noise on the external calibration of a microwave radiometric system using an external "deterministic" noise signal source is explored. And the conditions for performing calibration in a system with compensation for the influence of background noises are analyzed.
Abstract: It is shown that for microwave radiometric systems for remote sensing of natural environments, the issue of unambiguous determination of the correspondence of the output signal to the value of the radio brightness temperature of the probed region, from which the physical parameters are estimated, is important. Microwave radiometric systems operate under external noise and background noise. This article explores the effect of background noise on the external calibration of a microwave radiometric system using an external “deterministic” noise signal source. The conditions for performing calibration in a system with compensation for the influence of background noise are analyzed. The analysis of the output signal of the microwave radiometric system showed a significant effect of background noise on the parameter that determines the reference origin of the receiver scale. The possibility of reducing the interference effect of background noise on the measurement results in a microwave radiometric system with a two-channel antenna operating on two modes of a circular waveguide is considered. It is shown that an additional compensation signal is formed at the antenna output. An analytical assessment of the degree of compensation of the influence of background noise on the output difference signal of the system is carried out. We perform a numerical analysis of the error of external calibration of a three-band microwave radiometric system with compensation of background noise when receiving thermal radiation to a common aperture of the antenna.
TL;DR: It is demonstrated that the automated antenna positioner developed for ground-penetrating radar inspection of structural elements can be used for automated radar scanning and identification of high- and low-density zones in wood structures and to measure the electrophysical parameters of the host environment.
Abstract: When ground-penetrating radar inspection is used to determine the parameters of wood and concrete structural elements employed in commercial construction, both the radar scanning process and subsequent reduction of the data obtained should be automated. An automated antenna positioner was developed for ground-penetrating radar inspection of structural elements. A laboratory mockup of this automated antenna positioner was developed and examined to determine its performance. We demonstrate that such a positioner can be used for automated radar scanning and identification of high- and low-density zones in wood structures. We also show that the automated antenna positioner can be used to measure the electrophysical parameters of the host environment. An algorithm was developed to process the images of reinforced-concrete slabs, improve radar contrast, and detect metallic inclusions. Wiener filtration is found to be effective for noise suppression for reconstruction of rebar from radar images of reinforced-concrete slabs. Ground-penetrating-radar techniques can be used to verify component integrity and identify high-and low-density zones in structural elements.
TL;DR: In this article, the authors proposed a method for the evaluation of the flow rate of two-phase flows in flowmeters without separation based on the Venturi tube, which takes into account the changes in density, mass vapor quality, and temperature of cryogenic two-phase flows depending on the level of pressure in the venturi tube.
Abstract: We propose a method for the evaluation of the flow rate of cryogenic two-phase flows in flowmeters without separation based on the Venturi tube. The proposed procedure takes into account the equations of state of two-phase medium, i.e., the changes in density, mass vapor quality, and temperature of cryogenic twophase flows depending on the level of pressure in the Venturi tube. It is shown that if we do not take into account the evolution of the parameters of flow, then we get an additional error in the evaluation of the flow rate. Hence, it is impossible to correctly determine the sensitivity and measurement range of the flowmeter. We determine the optimal range of measurements of the pressure drop and propose a procedure of measurement of the flow rate of two-phase cryogenic flows according to the temperature drop in the Venturi tube. The problem of measurement of the flow rates of two-phase cryogenic flows is urgent for accelerators, as well as for the aerospace and gas-transportation equipment.
TL;DR: In this article, a new information indicator of speech signal distortions is proposed, along with a method for its measurement under conditions of small observation samples, which facilitates the transformation of an initially distorted speech signal into compliance with a registered voice template using an acceptable algorithmic information discrimination criterion.
Abstract: The present paper discusses the problem of distortions in speech signals transmitted over a communication channel to a biometric system during voice-based remote identification. A possible rectification approach involves a preliminary correction of the frequency spectrum of the received signal based on the pre-distortion principle. Taking into account a priori uncertainty, a new information indicator of speech signal distortions is proposed, along with a method for its measurement under conditions of small observation samples. An example of fast practical implementation of the method based on a parametric spectral analysis algorithm is considered. Results of an experimental test of the proposed approach are provided for three different communication channel instantiations. It is shown that the proposed method facilitates the transformation of an initially distorted speech signal into compliance with a registered voice template using an acceptable algorithmic information discrimination criterion. The described approach may be used in existing biometric systems and speaker identification technologies.
TL;DR: In this paper, the potential informativeness of a multifrequency radio-wave method for slow surface electromagnetic waves for reconstruction of the electrical and geometric parameters of multilayer dielectric coatings is investigated.
Abstract: One of the most important problems in the diagnostics of multilayer dielectric materials and coatings is the development of methods for quantitative interpretation of the results of monitoring the electrical and geometric parameters of these materials. Results are presented from a study of the potential informativeness of a multifrequency radio-wave method for slow surface electromagnetic waves for reconstruction of the electrical and geometric parameters of multilayer dielectric coatings. A simulation model is shown for evaluating the accuracy of reconstructing the electrical and geometric parameters of multilayer dielectric coatings. The model takes into account the electrical and geometric parameters of the coating, the level of noise in the measurement data, and the measurement bandwidth. Simulation modeling and experimental test data for the reconstruction of the relative dielectric constants and thicknesses of one- and two-layer equal-thickness dielectric coatings based on polymethyl methacrylate, ftoroplast (teflon) F-4D, and RO3010 for different values of the mean square deviation of the noise level in the measured attenuation coefficients for the field of a slow surface electromagnetic wave. The accuracy of the reconstruction of the geometric and electrical parameters of the layers is found to decrease as the number of estimated parameters and the noise level increase, as well as when the dielectric constant and thickness of the layers are reduced. Experimental data confirm the adequacy of the simulation model developed here. This model can be used for a specific measurement complex employing a multifrequency radio-wave technique for slow surface electromagnetic waves to estimate quantitatively the potential possible accuracy of reconstructing the geometric and electrical parameters of multilayer dielectric materials and coatings. A simulation model and experimental study of a multilayer dielectric coating show that for a measurement bandwidth of 1 GHz the errors in estimating the dielectric constants and thicknesses of the layers do not exceed 10% with a confidence coefficient of 0.95 for a mean square deviation of 0.003–0.004 in the noise level.
TL;DR: The presented results can be used in the development of multisensory converters of binary displacements of control systems and the control and monitoring of energy-saturated objects, for which high noise immunity, electrical neutrality, low chemical activity, and information security are crucial.
Abstract: In this study, the design and operation principle of a multisensory converter of binary mechanical signals to electrical signals are considered; the device is based on a fiber-optic digital-to-analog converter consisting of a kit of optical attenuators and a fiber-optic adder unit. A generalized mathematical model of the multisensory converter operation is developed. The model combines particular mathematical models of operation of a fiber-optic digital-to-analog converter, photo amplifier, and double-integration voltage-to-digit converter. The model is presented in the form of analytical equations for defining the output electric code based on the bit digits of the input mechanical code, considering a complex of constructive, sheet-oriented, and power-related parameters of the converter. The conversion of the frequency signals into codes is analyzed. The algorithm is developed for the numerical analysis of the mathematical model of operation of the investigated device, providing values of the maximum permissible instrumental errors in the manufacture of converter elements, while ensuring the full reliability of the device operation. The presented results can be used in the development of multisensory converters of binary displacements of control systems and the control and monitoring of energy-saturated objects, for which high noise immunity, electrical neutrality, low chemical activity, and information security are crucial.
TL;DR: In this paper, the authors studied the long-term instability of new-generation hydrogen frequency and time standards from the State Primary Standard of time and frequency units and national time scale, GET 1-2018, based on the results of processing the frequency difference with respect to TAI.
Abstract: The latest changes in the algorithms for the formation of the International Atomic Time (TAI) scale are reported in terms of estimating the weights of the clocks involved in the formation of TAI. The characteristics of the long-term instability of new-generation hydrogen frequency and time standards from the State Primary Standard of time and frequency units and national time scale, GET 1-2018, were studied. The study was based on the results of processing the frequency difference with respect to TAI. It is confirmed that presently, new-generation hydrogen standards of frequency and time show significantly less long-term instability compared with similar and other quantum frequency standards.
TL;DR: In this paper, a prototype device for characterizing biphoton light sources using quantum tomography based on spontaneous parametric down-conversion is presented, which enables determination of the statistical characteristics of the measured quantum state, calculation of the tomographic and most probable estimates of the density matrix, and evaluation of the quality of the quantum state of the biphotons.
Abstract: The development of methods and devices for measuring the quantum states of photon fluxes is a matter of current interest. In this paper, we propose a prototype device for characterizing biphoton light sources using quantum tomography based on spontaneous parametric down-conversion. This prototype device is an experimental implementation of a specialized quantum tomograph designed to measure the quantum polarization states of radiation generated by biphoton sources. In this article, we present the operational principle of the device for characterizing biphoton light sources and describe our specially developed software that enables determination of the statistical characteristics of the measured quantum state, calculation of the tomographic and most probable estimates of the density matrix, and the measurement errors of the density matrix elements, as well as evaluation of the quality of the quantum state of the biphotons.
TL;DR: In this paper, a method of studying the error of a laser dynamic goniometer by a cross-calibration method with the use of a created calculation algorithm is proposed.
Abstract: A method of studying the error of a laser dynamic goniometer by a cross-calibration method with the use of a created calculation algorithm is proposed. The algorithm is based on the method of sequential rotations of a polygon relative to a ring laser from the goniometer structure. The results of the application of the specified calculated algorithm to estimate the error of a laser dynamic goniometer are presented. The dominant source of error of this goniometer is defined: the nonuniformity of the angle scale of the ring laser, which is caused by the slope of the scale to the angle of rotation of the spindle of the goniometer. Adjustment corrections are computed and introduced into the calculation algorithm, which made it possible to reduce the systematic error of the goniometer to 0.03″.
TL;DR: In this article, a mathematical model of the relative humidity measurement process is proposed under the assumption that they correspond to first-order aperiodic factors, and analytical dependencies are obtained to identify the parameters of the transient response of the capacitive relative humidity sensor.
Abstract: This paper presents the results of identifying the transient response of a relative air humidity sensor. It is shown that the capacitive relative humidity sensor is an integrated microprocessor system that performs joint processing of the readings of the absolute humidity sensor and the temperature sensor. A mathematical model of the relative humidity measurement process is proposed. The transient responses of the absolute humidity sensing element and the temperature sensor are specified under the assumption that they correspond to first-order aperiodic factors. Based on the relationships of thermodynamics, Arden Buck equation, and given transient functions, analytical dependencies are obtained to identify the parameters of the transient response of the capacitive relative humidity sensor. The results of several field experiments are processed and analyzed in accordance with the proposed mathematical model. The effect of anomalous sensor readings is revealed and consists in the fact that with simultaneous stepwise changes in humidity and temperature, the sensor records a change in relative humidity with the opposite sign. It has been established that the cause of the anomalous results of relative humidity measurements is the presence of a large difference between the response time constant of the absolute humidity sensing element and that of the temperature sensor. Measures are proposed to prevent anomalous results of relative humidity measurements.
TL;DR: In this article, an interpretation of definitional uncertainty as a scattering parameter (standard deviation) of the contour estimate of the error of inadequacy is given for the equations of the method of indirect measurement.
Abstract: An interpretation of definitional uncertainty as a scattering parameter (standard deviation) of the contour estimate of the error of inadequacy is given for the equations of the method of indirect measurement. The problem of calibration of a thermometer from the Guide to the Expression of Uncertainty in Measurement is considered. In solving the calibration problem, an estimate of the definitional uncertainty obtained this way amounts to 74.1% of the standard uncertainty of the corrections.
TL;DR: In this article, it was shown that the errors in the Friedman-Robertson-Walker model as an equation for indirect measurement of distance are multiplicative and that the hypothesis of a Gaussian form for these errors corresponds to a shift of -2.8% and a mean square deviation of 16.3% for a 1.8%.
Abstract: The so-called “unexpected” results of statistical processing of data from increasingly more accurate astrophysical and gravitational measurements are examined. The reasons for the breakdown of the logic of statistical inference, which several leading experts have interpreted as a “metrological and scientific impasse” in cosmology, are pointed out. The data on type SN Ia supernovae used to detect the “accelerating expansion of the universe” are analyzed. It is shown that the errors in the Friedman–Robertson–Walker model as an equation for indirect measurement of distance are multiplicative. Here the hypothesis of a Gaussian form for these errors corresponds to a shift of –2.8% and a mean square deviation of 16.3% for a mean square deviation of the arithmetic mean of 1.8%. It is noted that using the mean square deviation of the arithmetic mean as an indicator of the accuracy of the scale is a crude mistake.
TL;DR: In this paper, a complex of high-precision measurement instruments that form the new State Primary Standard of the heat capacity of solids (GET 60-2019) at the head of which is the KA-S4 high precision calorimeter was created.
Abstract: The results of studies designed to improve the State Primary Standard of the unit of specific heat capacity (GET 60-74) carried out from 2017 to 2019 are described. A complex of high-precision measurement instruments that form the new State Primary Standard of the heat capacity of solids (GET 60-2019) at the head of which is the KA-S4 high-precision calorimeter was created. A set of standard measures of specific heat capacity was created to reproduce and transmit the unit from GET 60-2019 to lower-echelon measurement instruments. The measurement chain for transmission of the unit of specific heat capacity from GET 60-2019 to lower-echelon measurement instruments was developed. The expanded uncertainty of measurements performed on the basic KA-S4 adiabatic calorimeter of the standard complex in the working temperature range of GET 60-2019 does not exceed 0.27–0.36% with conformance factor k = 2.
TL;DR: Estimates of mutually correlated functions between the useful signal and noise have been found and these can be used to correct errors of the results of analysis of test data in information-measurement complexes and systems, which enhances significantly their metrological characteristics.
Abstract: The factors that have an effect on estimation errors of the correlation functions of noisy signals in using traditional algorithms to evaluate them are analyzed. It is shown that the sum noise of a noisy signal is caused by the influence of external factors and by noise which originates due to various imperfections in the operation of objects under test. In order to eliminate the error of the results of correlation analysis of noisy signals, algorithms and techniques for determining estimates of the variance of noise and the mutually correlated functions between the useful signal and a noise have been created. Techniques for determining approximate equivalent readings of the noise of noisy signals are proposed. It is shown that in using equivalent samples of noises, it is possible to obtain results identical to the results of actual samples of noises in the correlation analysis of noisy signals. In selecting equivalent samples of noise from a noisy signal, equivalent samples of the useful signal are defined. These samples make it possible to determine estimates that are equivalent to the estimates of correlation functions of the useful signal. Estimates of mutually correlated functions between the useful signal and noise have been found. Studies have shown that despite existing errors of equivalent samples, over a sufficiently long observation period it is possible to reduce significantly the errors of traditional techniques of correlation analysis of noisy signals with equivalent samples. The application of these techniques can be used to correct errors of the results of analysis of test data in information-measurement complexes and systems, which enhances significantly their metrological characteristics.
TL;DR: In this paper, the authors studied the problem of computing the density of entropy production, i.e., to find this density according to the experimental thermograms (variations of temperature with time) of heating or cooling.
Abstract: We study the linear mode of thermodynamics, which is now extensively investigated. One of the main concepts of the linear mode is the density of entropy production. We increase the class of problems for which it is necessary to compute the density of entropy production, i.e., to find this density according to the experimental thermograms (variations of temperature with time) of heating or cooling. The thermograms of heating or cooling are widely used in the nonstationary thermophysical experiments aimed at the investigation of the properties of substances and materials: the phase transformations of the first and second kind, heat capacity, and thermal diffusivity. We give quantitative substantiation of the formula for the density of entropy production. This formula is based on the data of thermograms obtained by the method of impulsive electric heating. The input time dependences of the electric power and brightness temperature of niobium specimens are simultaneously measured within a microsecond range. We reveal the agreement of the obtained two time dependences of the density of entropy production: one dependence takes into account the input of electric power, whereas the second dependence is based on the thermogram.