Flowrates of condensate through the annular gaps in the partitions used in steam-water heaters

We present the results obtained from experiments on determining condensate flowrate through the annular gaps at locations in which heat-transfer tubes pass through the holes in the horizontal spacer partitions used in vertical steam-water heaters. Expressions for calculating the coefficient of pressure drop due to friction λ_fr = f(Re) in real gaps are proposed on the basis of the obtained data.     

Multiregime character of the nonlinear precession of the second-order magnetization under the conditions for the orientational transition

The forced nonlinear precession of the magnetization vector in the normally magnetized magnetic plate is considered under the conditions for the orientational transition. The time dependences and precession patterns of the oscillations of magnetization are presented. Five regimes of precession are revealed: small-amplitude circular precession, precession of the equilibrium position without encircling of center, undamped precession of equilibrium position with encircling of center, damped precession of equilibrium position with encircling of center, and full-scale circular precession. The transitions between the regimes are studied using the 3D model of potential. The domains of the regimes of precession are determined on the plane decay parameter-ac field amplitude. It is demonstrated that a variation in the amplitude of the ac field leads to the stepwise dynamic orientational transition from the fourth regime to the fifth regime. The recommendations for the practical applications are worked out using the results.     

Propagation of magnetostatic surface waves in a ferrite plate magnetized by a spatially periodic transverse field

Propagation of magnetostatic surface waves (MSSWs) in a ferrite plate magnetized by a spatially periodic transverse field has been considered. The parameters of MSSW propagation have been calculated by the Hamilton-Auld method. It is shown that only noncollinear MSSWs, whose wave-beam trajectories as well as wave numbers and angles, which determine the directions of the vectors of the phase and group velocities, are described by functions that are periodic in the direction of the wave propagation, can exist in this field. The period of these functions is determined by the period of the spatially periodic field. The frequency range of existence of the collinear waves is narrower than that of the waves in a uniformly magnetized plate. The characteristics of wave propagation in a nonuniform spatially periodic field are compared to the characteristics of wave propagation in nonuniform fields of known types.     

Dispersion characteristics of magnetostatic surface waves in a two-layer ferromagnetic film

The dispersion characteristics (dispersion and isofrequency curves and dispersion surfaces) of magnetostatic surface waves propagating in an arbitrary direction in a two-layer ferromagnetic film are investigated. The shapes of these curves and surfaces are studied at different ratios between the saturation magnetizations of the ferromagnetic layers, and the conditions for existence of external waves (always forward) and internal waves (forward and backward or only forward) are determined.     

Comparison of the results of calculations and post-reactor investigations of VVÉR-1000 fuel elements with burnup 49 MW·days/kg

The results of calculations performed with the PINw99, TRANSURANUS (V1M1V03), and TOPRA-2 computer programs are compared with data obtained from post-reactor investigations of fuel elements which operated for four years in the No. 1 unit of the Zaparozh’e nuclear power plant with a VVéR-1000 reactor to burnup ≈ 49 MW·days/kg. The initial data are analyzed, and a comparison is made of the computed and experimental elongation of the fuel elements (49 fuel elements), the yield of gaseous fission products and the subcladding pressure (35 fuel elements), and the decrease of cladding diameter and fuel-cladding gap width. It is shown that these computer programs can be used to calculate VVéR fuel elements. __________ Translated from Atomnaya énergiya, Vol. 101, No. 6, pp. 413–420, December, 2006.     

Electron-microscopic investigation of a SiC/Si(111) structure obtained by solid phase epitaxy

First results of the electron-microscopic investigation of thin silicon carbide (SiC) layers grown on silicon using a new method of solid phase epitaxy are presented. It is shown that, at the initial stage of epitaxial growth, a transition layer is formed which consists of various SiC polytypes. This layer occurs at the interface between the substrate and a single-crystalline SiC layer possessing predominantly a 3C polytype structure. It is established that pores with dimensions ranging from a fraction of micron to several dozen nanometers are formed in a near-surface layer of the silicon substrate, which favor the growth of epitaxial, weakly strained single-crystalline SiC layers.