Том 61, № 5 (2018)

Algorithms are proposed for determining estimates of the spectral characteristics of the noise of noisy signals, as are techniques for replacing with approximate equivalent values noise readings that are incapable of measurement. The possibility is indicated for applying the specified algorithms and techniques to increase the reliability of spectral analysis results for a noisy signal and of monitoring the beginning of the change of the technical state of units under study.

We present the results of theoretical and experimental investigations of the method for measuring surface tension. The method is based on the deformation of the surface of studied liquid by a gas jet. The criteria for choosing the parameters of aerodynamic action and a given value of the height of a cavity on the liquid surface are formulated. Due to the substantial influence of the density of liquid on the results of measurements, the method is recommended for the evaluation of the surface pressure of surface-active substances.

Modern advances in the area related to the creation of gravimetry instruments are analyzed. Trends in the development and creation of standards of the unit of gravity acceleration, units of vertical and horizontal gravitational gradients, and unit of the plumb line deviation as well as the unit of gravitational potential are considered.

Methods for estimating the parameters of the formula for the optimal discretization of the domain of determining the probability density of a two-dimensional random variable are considered. The properties of the proposed methods are investigated and the conditions for their validity are determined.

A conceptual model of an information-measurement system based on distributed networks of smart geosensors is proposed. Easy scalability of the system performance sufficient for processing streams of spatio-temporal data arriving from a network of geosensors in real time is realized in the development of the model. It is shown that such a model assures a high level of interoperability between allocated logical blocks of the system (compatibility at both the semantic level and at the level of processes), the possibility of implementing its logical blocks as individual components, and the ability to process streams of spatiotemporal data of high intensity.

A reset automatic tool for contactless inspection of an external thread by means of which complex inspection of the fine thread of component parts with soft coating may be achieved is described. The function of the automatic tool is based on optical spatial filtration.

A device for measurements of phase noise with the use of the Mach–Zehnder interferometer is proposed, in which all fi ber components are made based on fiber with polarization state maintenance. This permits not using a basic radiation source in the device, and thereby reducing significantly the installation cost. Two interference signals from orthogonally polarized waves are formed in the device and are then divided by a polarizing demultiplexor that eliminates the effect of external noise on the measurement result. An algorithm for calculating phase noise is described and an estimate of the effect of temperature instability is presented. A comparison of the characteristics of phase noise between calculated and specified in modeling was performed in order to assess the operational capability of the installation and algorithm for signal processing.

A survey of the results of investigations of the frequency instability of output signals of the hydrogen frequency standard is presented. We analyze the causes of development of instability in the measurement range greater than 1000 sec. The influence of the ambient temperature and geomagnetic field is investigated. The methods used to compensate the frequency drift with the help of periodic corrections are described.

We developed a low-pressure interferometric liquid piezometer aimed at the determination of correction to the density of the working liquid of a laser interferometric oil manometer used as a component of the GET 101–2011 State Primary Pressure Standard for the range of absolute pressure 0.1–7·10⁵ Pa. The indicated correction is caused by the compressibility of the working liquid. The comparison of the obtained correction with changes in the density of the working liquid as a result of its deep degassing (measured at the Physical Technical Institute, Germany) shows that, under the working conditions of the laser interferometric oil manometer, these two effects compensate each other almost completely. This confirms the reliability of the results of pressure measurements within the range 0.1–10³ Pa performed by using the GET 101–2011.

We studied the possibility of realizing the International Temperature Scale 1990 tin fixed point using a miniature cell and a portable temperature calibrator to improve the calibration accuracy of small high-precision platinum resistance thermometers so that it is equal to that of a Class 2 resistance thermometer. We show that the melting curves for 99.999% pure tin in a miniature cell cannot be used for this purpose. We determined the amount by which the liquidus temperature for Russian-produced commercial-grade tin is reduced due to impurities. We used the calibration methods developed in this paper to determine the optimum conditions for reproducibility of the freezing curve, and studied the properties of these curves.

The hardware-software complex of an experimental device intended for measuring the electrical resistance of metallic conductors at high temperatures is considered. Designs of individual elements by means of which stable operation and high precision of the results of measurements may be achieved are proposed. The device is tested using ARMCO iron.

Methods and algorithms for control of the operation of a thermocatalytic gas sensor are examined. The use of the data of the methods and algorithms decreases measurement errors and increases the sensor’s service life.