Vol 62, No 3 (2019)

The design, principle of operation, and budget of errors of a laser interference oil manometer developed at the Mendeleev All-Russia Research Institute of Metrology (VNIIM) and subsequently incorporated into the State Primary Standard of the unit of pressure GET 101–2011 are described. The results of studies of precision instruments for measurements of pressure with the use of the laser interference oil manometer are presented. Summaries of key comparisons and international cooperation in the field of liquid manometry are presented.

The use of terms that relate to processes of assessment and confirmation of conformity of instruments and techniques of implementing measurements to metrological requirements is considered. The terms are found in regulatory documents in force in the Russian Federation. Signs of generality, subordination, equivalence, and affinity of terms related to technical regulation, quality assurance, assessment of conformity, and management of measurements are discussed. Existing differences in the definitions of terms in regulatory documents are noted. Proposals to achieve a more orderly and unambiguous definition and understanding of the terms that are discussed here are formulated.

A method of solving systems of nonlinear equations for use in metrological applications based on the generalized method of bisection is presented. It is shown that through the use of the proposed approach it is possible to satisfy requirements imposed on the solution as regards the set of results of indirect measurements and to take into account data on the inaccuracy of the coefficients of the equations to be solved, which are the results of direct measurements. The resulting solution is automatically tracked by a reliable estimate of the limiting error of its components.

The concept of invariant images which do not change form as a result of a double-sided matrix transformation is introduced. Invariant images of double-sided strip transformations are investigated. The problem of selecting transformation matrices is considered. An example of a strip transformation of an individual image is presented. Three methods of solving the problem of synthesis of strip transformation matrices from given invariant images are proposed.

An optico-electronic dust meter that functions on the basis of the method of fluctuations is proposed. The error of continuous variation of the concentration of dust can be substantially reduced because of the design of the device, and the average size of the dust particles in the particular medium determined. The occurrence of occupational diseases may be predicted on the basis of the obtained results.

We developed a new method for measuring the pitch frequency of speech signals with elevated noise immunity. The problem of protection against intense background noise is solved in this method by the frequency selection of vocalized segments of speech signals according to a scheme with comb filter of interperiodic accumulation. The efficiency of the method is analyzed both theoretically and experimentally with the help of a multichannel frequency meter intended for the acoustic speech analysis. It is shown that, for a signal-to-noise ratio of 10 dB and higher, the error of the method does not exceed 2%.

We solve the problem of dynamic nonlinear stochastic estimation of moving object orientation parameters from measurements of spatially separated satellite receivers. It is shown that the use of the Euler–Krylov angles as the current parameters of object orientation provides for a sharp reduction in the dimension of the proposed estimation algorithm as compared with the existing algorithms. An example is given illustrating the effectiveness of the developed stochastic estimation algorithm.

We consider aspects of using the method of anemometry on particle images to measure the velocity fields of nonstationary air vortices. To prevent the loss of a cross-pair when a particle passes through a light curtain, a method is proposed for determining the time delay between frames. Methods for measuring the velocity fields of nonstationary air vortices are described taking into account the vertical velocity of particles when the actual velocity is reproduced from the measured horizontal projection in the case of using a two-dimensional (single-chamber) type of anemometry method.

Some versions of construction of the linear digital systems of automatic frequency adjustment are analyzed from the viewpoint of their fast response and accuracy. The engineering realization of a system of this kind in a commercial GLONASS/GPS receiver-comparator is demonstrated.

We consider a version of the differential pressure method with various Venturi nozzles and tubes used as standard narrowing devices. By using the formula for the expansion coefficient applied in this version of the method as a correction for the compressibility of the medium, we estimate the measurement error of the expansion coefficient under of conditions of gas-metering stations. We also perform the comparative analysis of the actual parameters of accuracy and the parameters regulated by standards in measuring the expansion coefficients for various narrowing units.

We perform experimental investigation of the method of horizontal hydroacoustic sounding intended for measuring the flow of water in rivers with ice cover. The serviceability of the method is confirmed. We study two versions of the method: impulsive sounding by broad-band signals with linear-frequency modulation and difference-phase sounding by narrow-band sinusoidal signals. The characteristics of sounding signals and the order of values of measurement errors are determined.

This article is devoted to analyzing the noise immunity of pulse waveform contour analysis. Different approaches to the implementation of the pulse waveform contour analysis were considered. It was demonstrated that a classical approach for the morphological analysis of the pulse wave based on using the stiffness index and the reflection index do not provide sufficient diagnostic accuracy due to the instability of detection of the reflected wave peak. The technique of contour analysis based on spectral transformation of replicated fragments of the pulse wave is proposed. As a diagnostic index the ratio of the amplitudes of the first two harmonics of the spectrum was used. The influence of measurement uncertainty of the pulse wave amplitude on determining the accuracy of the morphological analysis of the pulse wave realized by different methods was researched.

A method for measuring the concentration of chemicals in gases and liquids using sensors based on piezoelectric resonators with sensitive films of elastic polymers is considered. It is shown that the metrological characteristics of sensors with elastic films, the thickness of which is greater than the depth of penetration of oscillations of the resonator into the film, are determined by the vibrorheological properties of the film. Parameters of the acetone vapor sensor based on butyl acetate film are given.