Mass transfer in gas-liquid layer on vortex contact stages

The results of studying mass transfer in a gas-liquid layer on vortex contact stages with tangential swirlers are presented. Relationships for calculating the mass transfer coefficients and Murphree efficiency are derived.     

Schnelle optische Tomographie zum Nachweis von OH*‐Verteilungen in Flammen

A recently developed and patented fast tomographic reconstruction system has been applied to detect two‐dimensional distributions of the OH* chemiluminescence in laminar and turbulent flames. This could be achieved by the arrangement at exposure times down to 100 – 200 μs at a spatial resolution of < 1 – 2 mm, even though the concentration of OH* in flames is in the order of some ppb and, therefore, extremely small. Among other things the results provide important information regarding the determination of the heat release rate in flames to predict unstable operating points of gas turbines.     

Influence of mutual alignment of mine shafts on thermal drop of ventilation pressure between the shafts

The paper presents a number of mine ventilation schemes for variously located shaft collars and a main fan diffuser. The calculations of thermal drop of ventilation pressure in the inter-shaft area in each of the discussed variants involve the assessment of their effect on the mine pressure drop.     

Efficient Output Mode Converter for 30 GHz Gyroklystron at IAP

An output mode converter for Ka-band multi-MW gyroklystron in the Institute of Applied Physics (IAP) operating in the TE₅₃ mode is suggested. Two variants of the converter, aimed for different applications, are presented: the TE₅₃ to TE₀₁ mode converter with power output along the device axis and the TE₅₃ mode to Gaussian wavebeam quasi-optical converter with a visor. The suggested designs include the built-in electron beam collector. The converters were designed using a new synthesis algorithm, which implies iterative improvement of the waveguide wall shape in order to achieve high efficiency. The calculation results were proven by HFSS simulation and low-power tests of one version of the converter.     

Grain-Boundary Segregation of Phosphorus in Low-Alloy Steel

Grain-boundary segregation of impurity elements, such as phosphorus, arsenic, antimony, and others, decreases the grain-boundary cohesion, which can substantially increase the temperature of the ductile-brittle transition in low-alloy structural steel. The most dangerous surface-active impurity for low-alloy steel employed for nuclear reactor vessels is phosphorus. A change of the cohesive strength of grain boundaries as a result of radiation-stimulated phosphorus segregation is considered to be one of the main mechanisms determining the radiation embrittlement of reactor-vessel materials. Since the mechanisms of embrittlement during development of reversible temper brittleness and radiation-stimulated grain-boundary segregation of phosphorus are the same, the main characteristics of the influence of the latter on the mechanical properties of steel can be determined by investigating steel treated in the range 400–600°C. The present investigation made it possible to develop a relation for determining the change in the temperature of the ductile-brittle transition in low-alloy steel as a result of the development of temper brittleness.     

Methods of calculating massive reinforced-concrete members and hydraulic structures

Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 5, pp. 21–24, May, 1990.     

A Method of Testing the Pour Point of Petroleum Products on a Refrigerated Sloping Surface

The method of testing pour points of pure substances and multicomponent hydrocarbon mixtures basing on the analyses of the path lengths of passing of equal volumes of substances along the tracking grooves on the refrigerated sloping metallic panel has been presented. Repeatability of the method makes up ±0.3°C, which surpasses the repeatability of testing pour points by the known international standards (ASTM D5853-95, ASTM D97-09, ISO 3016, GOST 20287-91) 5–7 times. Operability of the method has been shown on the example of testing pour points of hexadecane, octadecane, and paraffinic oil. It has been established that experimental curve plotted in coordinates (length of sample passing path ? temperature), can be presented by the sum of two terms, the first of which is described by hyperbola with asymptote at temperature, equal to the pour point of the sample, which actually corresponds to the flow regime, and the second term is described by the parabola of variable exponent and the contribution to drop rolling regime. Drop rolling has a greater contribution into the experimental curve with the increase of the panel slope angle, and with the greater difference between the temperature of the panel and the pour point of the sample.     

Use of overdriven detonation in coating application

Overdriven detonation waves allow one to produce coatings of high-melting powder materials and improve the quality of coatings sprayed from lower-melting-point materials. The kinetic and thermal energies of detonation products behind the front of overdriven detonation waves are much higher than those behind the front of self-sustained Chapman-Jouguet detonation waves traditionally used in spray processes. This paves the way toward the design of small-size spraying guns including those for applying coatings on the inner surfaces of parts.     

Linear electron accelerators for industry and medicine

Linear accelerators are described together with accelerator systems based on them, which have been designed and produced in the linear-accelerator and cyclotron division at the D. V. Efremov Fundamental Electron Applications Research Institute. Brief information is given on future developments in resonant linear accelerators and systems based on them. D. V. Efremov Fundamental Electron Applications Research Institute. Translated from Atomnaya énergiya, Vol. 87, No. 2, pp. 145–151, August, 1999.