Classification-driven watershed segmentation.

This paper presents a novel approach for creation of topographical function and object markers used within watershed segmentation. Typically, marker-driven watershed segmentation extracts seeds indicating the presence of objects or background at specific image locations. The marker locations are then set to be regional minima within the topological surface (typically, the gradient of the original input image), and the watershed algorithm is applied. In contrast, our approach uses two classifiers, one trained to produce markers, the other trained to produce object boundaries. As a result of using machine-learned pixel classification, the proposed algorithm is directly applicable to both single channel and multichannel image data. Additionally, rather than flooding the gradient image, we use the inverted probability map produced by the second aforementioned classifier as input to the watershed algorithm. Experimental results demonstrate the superior performance of the classification-driven watershed segmentation algorithm for the tasks of 1) image-based granulometry and 2) remote sensing.     

Long-wave Marangoni Convection in Two-layer Films Under the Action of Gravity Modulation

The influence of the gravity on the long-wave Marangoni patterns in two-layer films is considered. The numerical analysis is carried out in the lubrication approximation. Periodic boundary conditions have been applied on the boundaries of the computational region. The development of instabilities is investigated by means of nonlinear simulations. The cases of a constant gravity and a time-periodic gravity modulation are considered. In the case of a constant gravity, non-stationary three-dimensional and two-dimensional structures have been found. It is shown that the periodic modulations of the gravity force lead to the development of new three-dimensional spatially-periodic patterns. Outside the region of parameters, corresponding to three-dimensional structures, dynamical regime of two-dimensional traveling waves have been observed.     

Comparison of the Griffith and Irwin Criteria for a Crack Asymmetrically Propagating in the Plane

On the basis of asymptotic formulas for the stress intensity factors and strain energy and the variational formulations of the Griffith and Irwin criteria, we propose asymptotic models of quasistatic crack growth. Under certain conditions, the transition to asymptotic models violates the equivalence of these criteria typical of the complete variational formulations. This phenomenon is analyzed and explained for a specific problem of asymmetric growth of a rectilinear crack in the elastic plane used as an example.     

The first ribbed functionalized tris-dioximate clathrochelates with inherent hydroxyl substituents: Synthesis, spectra and X-ray structure

The controlled hydrolysis of the dichlorine-containing iron(II) clathrochelate FeBd₂(Cl₂Gm)(BF)₂ precursor (where Bd²⁻ and Cl₂Gm²⁻ are α-benzyldioxime and dichloroglyoxime dianions, respectively) afforded the hydroxy-containing clathrochelate derivatives with the hydroxyl substituent inherently bound to the ribbed chelate fragment of the macrobicyclic ligand. The triethylammonium and tetra-n-butylammonium salts of the clathrochelate [FeBd₂(OClGm)(BF)₂]⁻ anion have been characterized using elemental analysis, MALDI-TOF mass spectrometry, IR, UV–Vis, ⁵⁷Fe Mössbauer and ¹H, ¹³C{¹H}, ¹¹B and ¹⁹F NMR spectroscopies, and X-ray crystallography. The X-ray structural data for this deprotonated anion showed strong delocalization of its negative charge into the clathrochelate framework.     

Tests of a P-67 boiler for an 800 MW unit

The rebuilding of the P-67 boiler for an 800 MW unit at the Berezovskaya GRéS, as well as changes in the thermal engineering characteristics of the coal from the Berezovskii-1 seam and its slagging properties, are described. The results of balance tests of the boiler and changes in the thermal efficiency of heating surfaces during 2006 – 2008, including after mechanical cleaning and modernization of the combined cleaning system, as well as with coal dust coarsening and loading of the lower burner layers and downward blast, are discussed.     

The dislocation origin and model of excess tunnel current in GaP p-n structures

An excess tunnel current in GaP epitaxial nondegenerate p-n junctions on GaP and Si substrates was studied. An important experimental result is that the slope of exponential current-voltage (I–V) characteristic (in lnI–V coordinates) is independent of the width of the space-charge region, i.e., on n-and p-region doping levels. This fact is unexplained by existing models. A dislocation shunt model based on multihop tunneling through a dislocation line, which may be considered as a chain of parabolic potential barriers, is proposed. The density of dislocations predicted by this model is in agreement with the transmission electron microscopy (TEM) observations.     

Neutron-Physical Calculation of a Fresh Zone in the Natural Nuclear Reactor at Oklo

A full-scale computer model of zone 2 of the Oklo reactor with a realistic materials composition is constructed. Modern Monte Carlo programs are used to calculate the multiplication factor, the excess reactivity, and the neutron flux for the fresh reactor zone 2. The calculations are performed in a wide range of variation of the zone parameters: the uranium content in the contemporary Oklo zone is varied from 35 to 55 mass% and the water content from 0.355 to 455 g/cm³. The power effect is determined. The temperature of the fresh zone is found to be 725 ± 55 K, at which the reactor is critical and can operate in a stable manner for a long time. The power of the reactor is maintained by negative feedback. The neutron spectrum, over which the cross section of strong absorbers must be averaged, for example, ₆₂ ¹⁴⁹ Sm, in order to obtain the most accurate bounds on the possible shift of the samarium resonance as a result of a change in the fundamental constants, is found for 700 K.__________Translated from Atomnaya Energiya, Vol. 98, No. 4, pp. 306–316, April, 2005.