Specifying the reliability of measurement means

Conclusions The fraction of correction measurements, which is a use indicator for the quality of measurement means and takes their specifications into account, depends on the distributions of failure-free operating time in the presence of sudden and gradual failures and the distribution of the time of an intercheck interval, and also on the relations between these distributions. In the general case the fraction of correct measurements is determined by the integral of the joint distribution of these events. The approach explained here has permitted the consideration of a number of particular cases that are important in metrological practice.Translated from Izmeritel'naya Tekhnika, No. 2, pp. 92–94, February, 1971.     

Interaction between a cylindrical shell in a fluid and a pulsating bubble

The dynamic behavior of a cylindrical fluid-immersed shell in a pressure wave initiated by a pulsating vapor-gas bubble that develops as a result of the action of laser radiation on the absorbing medium (metal) is examined experimentally and theoretically. The results of the experiments suggest that the amplitude of the shock wave that develops as a result of complete or partial vaporization of the absorbing medium is appreciably smaller than the amplitude of the waves due to pulsations of the bubble that is formed. Experimental data on the pattern of structural deformation are confirmed by calculations. The effect of load simulation on the behavior of the shell is established according to computational data.Translated from Problemy Prochnosti, No. 6, pp. 116–120, June, 1990.     

Electrochemical properties of a new electrode material,Ti4O7

Cyclic voltamograms of Ti₄O₇ (Ebonex) together with its overpotentials for the production of H₂ and O₂ in acidic and basic aqueous solutions are reported. Ti₄O₇ electrode properties are compared to other electrodes: TiO₂, Pt, carbon, and vitreous carbon. Strong adsorption of ruthenium and platinum to the surface of Ti₄O₇ reduces the overpotentials for H₂ and O₂ production and modifies its electrode behavior. ESR results indicate small amounts of higher oxide phases (Magneli phases) may be present in the Ebonex material.     

The preparation of high purity Mg2Ni

The intermetallic compound Mg₂Ni has been prepared by the vapour exchange/diffusion reaction of the elements sealed in a stainless steel container. The product has been characterised by powder X-ray diffractometry with Mo-K_α radiation, using step-scanning and profile refinement techniques. The hexagonal unit cell has constants a = 5.2117(4), $\text{c}\text{= 13.2538(9)}\text{A}\text{?}$.     

Polymorphisme du dioxotriplomb (II) tetraoxosulfate (VI) Pb3O2(SO4) a basse temperature. II - Etude structurale de la phase ferroelastique gamma-Pb3O2 (SO4) par diffraction neutronique sur poudres a 2 et 45K

Full-profile neutron powder diffraction structure refinements of dioxotrilead(II)tetraoxosulfate(VI) at 2 and 45K reveal that both the alpha- and the gamma-Pb₃O₂ (SO₄) polymorphs have to be refined simultaneously at these temperatures. Accordingly, the paraelastic alpha phase is trapped in the ferroelastic gamma phase, yielding thus mixtures of both compounds in a nearly 1:1 molar ratio. Both structures are essentially similar. The slight variations of the lead-oxygen distances in the infinite edge-sharing tetrahedral (Pb₃ O₂)n double-chains force the sulfate group to adopt nearly C3v and C2v site symmetries respectively in the alpha and gamma phases. The present work is a good example of the behaviour of the DBW3.2 program (1) when mixtures of very similar structures are refined simultaneously (high correlation between some structural parameters).     

A mechanism of formation of gas-liquid systems

A mathematical model is constructed for the process of formation of a disperse liquid-gas bubble system as a result of evolution of dissolved gas due to changes in the external pressure. The model is implemented numerically for chlorine and air and is used to explain the difference in the rates of bubble growth at small and large excess pressures.