Dimensionless units and numbers

The theory of measurement, scales is used to show that there is no foundation for attempting to extend the SI system to measurements of quantities and properties which are described by ordering and naming scales or by absolute scales. It is proposed that the units of planar and solid angles should be considered to be outside the system. Dimensionless quantities are conditionally classified. An analysis is made of specified order scales in which the concept of a “unit of measurement” is not applicable and for which it makes no sense to attribute dimensionality to the numbers and scale points used in them. Translated from Izmeritel'naya Tekhnika, No. 9, pp. 3–10, September, 1999.     

Dynamics of a contrast agent microbubble attached to an elastic wall

A modified Rayleigh-Plesset equation is derived to model the oscillation of a contrast agent microbubble attached to an elastic wall. The obtained equation shows that contact with the wall affects the bubble oscillation as if the bubble oscillated in a liquid with a changed (effective) density. Depending on the wall properties, the effective density can be either higher or lower than the real liquid density and hence the natural frequency of the attached bubble can be either lower or higher than the natural frequency of the same bubble in an unbounded liquid. Numerical simulations are made for a contrast bubble with shell properties similar to those used in the Marmottant shell model. The cases of a rigid wall and a plastic wall are compared. The properties of the plastic wall are set to correspond to walls of OptiCell chambers commonly used in experiments. It is shown that contact with the rigid wall decreases the natural frequency of the bubble as compared to its natural frequency in an unbounded liquid, whereas contact with the OptiCell wall increases the natural frequency of the bubble. Bubble resonance curves for three cases are compared: the bubble in an unbounded liquid; the bubble at a distance from an OptiCell wall; the bubble in contact with an OptiCell wall. Results obtained for a 2- μm -radius bubble insonified with a 10-cycle, 40 kPa, 2.1 MHz Gaussian pulse show that contact with the OptiCell wall leads to the following effects. The amplitude of the radial oscillation of the attached bubble is decreased by about 70% as compared to that of the same bubble in an unbounded liquid. The fundamental component in the spectrum of the scattered pressure of the attached bubble is decreased by 12 dB. A strong second harmonic appears in the spectrum of the scattered pressure of the attached bubble; its magnitude is about 11.5 dB higher than the level corresponding to the case of an unbounded liquid.     

Optimization of the National Standards Base: A Discussion

The problem is considered of optimizing the standards base of Russia. The interrelationship of the standards is considered. Factors which are external to the system of standards are taken into account.     

Measurable Properties

A variety of properties may be divided into four classes: qualitative (discrete, continuous, similarity-ordered, and multidimensional), quantitative ones (non-Archimedean, scalar, and multidimensional quantities), space-time ones (quantitative and qualitative), and combined ones. Examples are used to show that there are measurable properties in all these classes, not only quantitative ones but also qualitative ones.     

The Results of the CCQM-K9 Key International Comparisons of National Standards of pH Measurements

A summary of the first CCQM-K9 key international comparisons of pH measurements to assess the level of the national standards of ten countries is presented. It is shown that there is good agreement between the results obtained within the limits of the measurement uncertainty declared by the participants.     

Application of deconvolution methods to gamma-radiation spectra of thermonuclear plasma

The possibility of application of deconvolution methods to solving the problem of reconstruction of gamma-radiation spectra of thermonuclear plasma is demonstrated. The DEGAS code is created, which implements the modified algorithms of deconvolution. The results of the code application to the test spectra, the discrete spectra of radiation sources, and the gamma spectra measured during the experiments at the JET tokamak using methods for additional plasma heating are presented. The possibility of reconstruction of spectra with low statistics is shown.     

Myuller''s Structural Models in Statistical Thermodynamics of Glasses1

The impact of Myuller's chemical–structural method on the development of the modern concepts concerning the structure and physicochemical properties of glasses is considered. Making allowance for the switching of homo- and heterobonds, it is demonstrated that this method permits one to investigate the ranges of variations in glass parameters (adaptivity) and to estimate the energy accumulated during structural transformations. The partition function and the main thermodynamic functions of glasses are calculated by choosing a set of structural states that can be realized in glasses. It is proved that the adaptivity leads to multivaluedness of thermodynamic functions even for a particular glass composition.     

Transmission of the measure of units and scales of measurements

Translated from Izmeritel'naya Tekhnika, No. 11, pp. 8–9, November, 1992.