Anisotropic elastodynamics in a half space: An analytic method for polynomial data

An initial boundary value problem for the dynamic system of anisotropic elasticity in a half space is studied in the paper. A novel method of finding an exact solution of this problem for a special polynomial form of initial data and inhomogeneous term of the system is described. On the base of this method the simulation of elastic waves in different homogeneous anisotropic half spaces is implemented.     

An algorithm for extracting and scanning attention points in a complex image

Encoding algorithms for constructing scanning trajectories of attention points in a complex image have been developed. Image fragments can be extracted and classified by using neuron-like media as well. The algorithms that we propose have been implemented in a program unit intended for use in more complicated hierarchical systems of pattern recognition.Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 9, pp. 1183–1194, September, 1994.     

Superposition of the Nadai and prandtl solutions for the system of two-dimensional ideal plasticity

A general algorithm is presented for transforming the exact solutions of the system of plane ideal plasticity of the Mises medium by using the superposition principle for solutions which arises as a corollary of the fact that the original system admits an infinite-dimensional symmetry group. As an example, there is considered the relation between the known exact solutions: the Prandtl solution for a thin layer compressed by rough solid plates and the Nadai solution for the radial distribution of stresses in a convergent channel in the shape of a flat wedge.     

The coffee-drop phenomenon and its time fluctuations: Self-sustained oscillations in colloidal liquids

The instant coffee model has been taken to study self-sustained oscillations in liquid dispersive media using dynamic self-organization processes in drying droplets that stay sessile on a solid wetted substrate. The width of the formed ring and the dynamics of mechanical properties of the drying sediment and the way they fluctuated over 11 h of the experiment have been measured. Analysis has shown a high degree of correlation between these indicators. This dynamics reflects processes that develop in the examined liquid medium. The possible mechanism of self-sustained oscillations, which is related to the aggregation–disaggregation of the colloidal phase and fluctuations of the interphase tension, has been discussed. The practical significance of this work is that fluctuation processes in liquid dispersive media need to be taken into account as a natural source of systematic measurement error.     

Research system of decision making by composite image fragments using neuron-like algorithms

Base models of homogeneous neuron-like media and the corresponding systems of spatiotemporal solutions are considered. Ways of using these models and solutions as the base models for designing hierarchic systems of parallel processing of complex information flows with the help of neuron-like algorithms are studied. The version of a decision-making system with tunable architecture at a coarsegrain level (for adapting the system to the processing purposes and type of image) and universal neuron-like subsystems at a fine-grain level (for providing a wide variety of operations needed to extract local and global features and to encode individual fragments or the whole of the image) is developed. Examples of the transformation processes in the images of biological objects (growing neurons, erythrocytes, fingerprints) in a hierarchic decision-making system are demonstrated.Institute of Applied Physics, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 8, pp. 961–986, August, 1994.     

Structural evolution of drying drops of biological fluids

Qualitative analysis of experimental data for the mechanisms of structuring in drying drops of biological fluids is carried out. It is shown that the structural evolution of the drying drops is a complex process in which two stages can be separated out by convention: events occurring during evaporation of free water and structuring due to evaporation of film water. Consideration of the structural evolution of drying drops on the basis of the physical chemistry of solutions, physics of polymers, mechanics, and materials science makes it possible to explain the phenomenology of the process in terms of well-known physical phenomena.     

Dynamics of phase transitions in drying drops of human serum protein solutions

The dynamics of structuring of protein solutions in drying drops and their morphology versus the composition of dissolved proteins are studied. An increase in the content of immunoglobulins and fibronectin is shown to have an effect on the physical properties of adsorption layers at the fluid-air interface and thereby changes the dynamic parameters of structuring in drying drops. These changes are embodied in the shape of the acoustomechanical impedance curves of drying drops and can be estimated numerically. Thus, experimental support is provided for the previous phenomenological data indicating that medical diagnosis based on recording the dynamics of the acoustomechanical impedance in drying drops of blood serum is a feasibility.     

Local thickness of a washing film in the entrance section

A method of graphic analysis is considered for the calculation of the local thickness of a liquid film in the entrance section of the transformation of slot flow into film flow over a vertical plate. The proposed method can also be used in calculating the local thicknesses of a thin layer during liquid flow over curved surfaces.

     

Noise immunity analysis of neuron-like algorithms in acoustic image processing

There exists the problem of pre-selection of the most noise-immune algorithms (including the neuron-like ones) when acoustic signals are proceesed in subwater acoustic vision systems. A software version is considered for choosing the parameters in the acoustic image processing algorithms which improve the noise immunity of the decision-making process. It is shown that the processing modes with improved noise immunity can be chosen in model experiments associated with threshold changes in the neuron-like transformation algorithms.Institute of Physics, Russian Academy of Sciences, Nizhny Novgorod. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 9, pp. 1214–1223, September, 1994.