Radiation Crosslinking of an Acrylamide–Sodium Acrylate Copolymer in Aqueous Solutions

The effect of concentration of an acrylamide–sodium acrylate copolymer in an aqueous solution on the crosslinking of macromolecules by the action of ionizing radiation was studied. It was shown that the efficiency of radiation crosslinking of the copolymer increased with an increase in the concentration of solution subject to irradiation, which was tentatively explained in terms of the existence of fluctuative entanglement network ensuring the approaching of macroradical sites and, thus, facilitating the combination reactions of macroradicals.     

Relationship between the fine structure of polyethylene and the mechanism of plastic deformation and fracture

The relationship between the mechanism of deformation and fracture of linear polyethylene and the details of its fine structure is investigated. It is shown that the clearly expressed localization of both processes is a result of the anisotropy of the properties of the structural elements composing the spherulite and is controlled by their initial orientation in the spherulite relative to the axis of the tensile stress. A spiral model of the structure of polymer crystals is proposed and justified and used to develop a dislocation theory of the deformation and fracture of crystalline polymers.Mekhanika Polimerov, Vol. 4, No. 1, pp. 3–10, 1968     

Lamellar structure and plasticity micromechanisms in bulk crystalline polymers. Communication 2

Conclusions 1. It has been experimentally established that the deformation of crystalline polymers is accompanied by the shear transitions between lamellar crystals of different orientations characteristic of martensitic structures.2. It is concluded that the reversibility of the large deformations of linear polymers is martensitic in nature.For communication 1 see [1].E. O. Paton Electrowelding Institute, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 6, pp. 963–969, November–December, 1976.     

The problem of phasing linear hydrophone arrays lying on a shallow ocean bottom

The problem of phasing linear hydrophone arrays lying on the bottom of the Barents Sea is discussed by using the results of a full-scale experiment. In the experiment, a pulsed pressure source was used as a source of sound and three linear hydrophone arrays positioned at different sites served as receivers. For signals at the array’s apertures, the spatial correlation interval is estimated. Output responses of the arrays are compared with and without allowance for the spatial correlation interval of the sound field.     

Experimental study of mode selection in shallow-water sea

The possibilities of matching low-frequency underwater sound pulses to the parameters of an oceanic waveguide are considered. The objective is to optimize the system of few-mode tomographic observation in a shallow-water sea. Experimental data are analyzed for two methods of selecting the low-frequency fewmode pulses propagating in a shallow-water sea. The first method excites probe pulses by vertically elongated arrays, with spatial filtering after vertical or horizontal arrays receive the pulses. The second method is based on exciting broadband signals with linear frequency modulation by a single transmitter. The selection of the few-mode signal is performed by time strobing the signals at the output of the matched filter after a horizontal array receives the pulses. The distance between the sound sources and receiving systems varied from 10 to 300 km.     

Aqueous Adhesives Based on Dextrin-Containing Polyacrylate Composites

Rheological and adhesion characteristics of water-soluble adhesive composites based on copolymer of acrylamide with sodium acrylate and corn dextrin were studied. The optimum composition of these composites in their use as label adhesives was determined.     

Monte Carlo Simulation of the TAIGA Hybrid Gamma-Ray Experiment

Physics of Atomic Nuclei - The TAIGA experiment (Tunka Advanced Instrument for cosmic ray physics and Gamma-ray Astronomy) combines heterogeneous arrays of imaging and non-imaging Cherenkov light...     

Electron-fractographic investigation of the brittle fracture of polyethylene

The results are presented of an electron-microscope investigation of the brittle fracture of linear polyethylene at the temperature of liquid nitrogen. It is shown that the physical nature of the structural details of the microrelief of the fracture surface is conditioned by local plastic deformation of the stratified lamellar structures in a thin layer adjacent to the fracture surface preceding and accompanying fracture. The possibility of local self-heating is discussed and a possible mechanism of plastic deformation of the crystal platelets at low temperatures is proposed.Mekhanika Polimerov, Vol. 3, No. 2, pp. 286–290, 1967     

High-frequency acoustical observation of inhomogeneities in shallow water oceanic waveguides with an irregular bottom in the presence of strong reverberation

Possibilities of high-frequency acoustical underwater observations of small-size objects in marine shelf zones are experimentally investigated using vertical and horizontal arrays radiating and receiving complex structure pulses in the presence of strong reverberation. Reconstruction of parameters of the observed objects yielded 35- to 40-dB weakening of the reverberation interferences due to medium-matched spatial, temporal, and Doppler filtering.