Mechanism of occurrence of microcirculatory phenomena in a constant magnetic field

A motion-picture study of the capillary network of the interdigital membranes of frogs has been carried out in order to clarify a number of effects observed after individual parts of the body and the whole organism are placed in a constant magnetic field. A constant magnetic field is observed to have three principal effects on the blood flow. The intensified blood flow following exposure to the field is explained as a complex reflex response mechanism, in which a definite part is played by a change in blood particle potentials and by processes of aggregation with subsequent disaggregation.Paper presented at the First All-Union Conference on Engineering and Medical Biomechanics on the topic: Problems of Microcirculation and Mass Transfer, Riga, October, 1975.Riga Scientific-Research Institute of Traumatology and Orthopedics. Translated from Mekhanika Polimerov, No. 5, pp. 891–894, September–October, 1975.     

Propagation of ultrasonics in bones

Conclusions The possibility has been established of determining the propagation velocity of elastic waves in bones by an ultrasonic technique in order to study the healing of fracture. An experimental apparatus of new design is described, which has been developed and made for research purposes and diagnostic measurements. The apparatus enables a numerical evaluation of the propagation velocity of ultrasonics in a bone to be automatically portrayed on the counter display, and the complete wave pattern or its details to be watched on the oscilloscope screen. The trends and principles of the exploratory measurements and practical diagnostics are discussed and, after statistical processing, certain results from our determinations are also quoted.A paper presented to the First All-Union Conference on Engineering and Medical Biomechanics, Riga, October 28–31, 1975.Scientific-Research Institute of Traumatology, Brno, Czechoslavakian SSR. Translated from Mekhanika Polimerov, No. 6, 1084–1087, November–December, 1976.     

Connection between the mechanical characteristics of the human abdominal aorta and its biochemical composition

The basic characteristics of the mechanical properties of the subrenal portion of the abdominal aorta have been determined experimentally for biaxial stretching, and their change with increase in size has been established. Amounts of the five main biochemical components of the aorta wall have been determined and a correlational analysis between the mechanical characteristics and biochemical composition has been carried out.Paper presented at the First All-Union Conference on Engineering and Medical Biomechanics, Riga, October, 1975.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Riga Scientific-Research Institute of Traumatology and Orthopedics. Translated from Mekhanika Polimerov, No. 4, pp. 722–729, July–August, 1975.     

Effect of shear compliance in bending and torsion on the stress concentration in a transversely isotropic plate with a hole whose edge is supported

The stress concentration in shear-compliant, transversely isotropic plates with a hole whose edge is supported has been investigated in bending and torsion. Two variants of the boundary conditions are examined. It is shown that the use of the classical Kirchhoff model may lead to a number of qualitative discrepancies.Mathematical Physics Branch, Institute of Mathematics, Academy of Sciences of the Ukrainian SSR. Translated from Mekhanika Polimerov, No. 3, pp. 458–463, May–June, 1975.     

Construction of the functional model of B. S.-Nagy-C. Foias

Methodological paper: quick and simple construction of the Nagy—Foias functional model, using only elementary information about Hilbert spaces and operators on them. A formula is derived for a characteristic function. The account is based on an idea of B. S. Pavlov (Izv. Akad. Nauk SSSR, Ser. Mat.,39, No. 1, 123–148 (1975)) on symmetrization of the notation for a model space.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 73, pp. 16–23, 1977.     

Certain problems in developing a theory and design methods for anisotropic shells and plates with finite stiffness in shear. A survey

A survey is presented here of research on theory and design methods for shells and plates made of anisotropic materials, such as laminate reinforced plastics [4–13], compliant in shear. The report is based mainly on studies made at the Western Science Center, Academy of Sciences of the Ukrainian SSR during the last five years (after the previous survey [8] has been published), with the introduction of generalized Timoshenko-type theories.Branch of Mathematical Physics, Institute of Mathematics, Academy of Sciences of the Ukrainian SSR, L'vov. Translated from Mekhanika Polimerov, No. 2, pp. 269–284, March–April, 1975.     

Comparative performance of living and dead bony tissue under static and dynamic loading

The dependence of the mechanical properties of bony tissue on different conditions of storing the samples has been studied. As the performance characteristic under static loading we used the ultimate compressive strength of the bony tissue, and under dynamic loading we used the specific impact strength.Paper presented at the First All-Union Conference on Engineering and Medical Biomechanics, Riga, October, 1975.I. M. Sechenov First Moscow Medical Institute. Translated from Mekhanika Polimerov, No. 4, pp. 647–649, July–August, 1975.     

Experimental study of young's modulus of glass-plastics

The results of study of Young's modulus of glass-plastics in the 10^–1–10⁵-Hz frequency range are presented. A stepwise variation in the modulus, which governs the relaxation process corresponding to a low-temperature internal-friction peak in the filler, is obtained.Rybinsk Institute of Aircraft Technology. Translated from Mekhanika Polimerov, No. 6, pp. 1089–1091, November–December, 1975.     

Particular case of the deformation of a nine-atom model

The dependence of the tensile loading on the length of a nine-atom plane model is calculated. The shapes of the model in tension are determined.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 3, pp. 545–547, May–June, 1975.     

Elastic recovery of filled rubber mixtures after extrusion through round ducts

The results of an experimental study on the elastic recovery of filaments of filled rubber mixtures extruded through round ducts of various length are discussed. An empirical relationship which permits the effect of elastic recovery of filaments of a rubber mixture after extrusion from a round duct to be estimated as a function of the relative duct length has been established from the data measured.All-Union Scientific-Research and Technological Design Institute of the Rubber Industry, Volzhskii. Translated from Mekhanika Polimerov, No. 2, pp. 364–268, March–April, 1975.     

Effect of γ radiation on the distribution of stresses in polymers

Infrared spectroscopy has been used to study the effect of -radiation on the distribution of an applied stress over the individual polymer chains. It has been shown that, as the irradiation dose is increased, the maximum stress on the bonds which are ruptured is attained at a lower value for the mean stress applied to the sample.V. I. Lenin Tadzhik State University, Dushanbe. Translated from Mekhanika Polimerov, No. 2, pp. 214–217, March–April, 1975.     

Micromechanical investigation of osteons with crossed lamellae

A micromechanical investigation of osteons with crossed lamellae has shown that they can be regarded as orthogonally reinforced material. The stress-strain curve has a break at low stresses. This effect can be explained by reference to the mechanical behavior of orthogonally reinforced laminates. It is assumed that a stress concentration develops at the fiber-matrix interface in the lamellae with transverse fibers oriented at 90° to the direction of loading, and that microfractures can develop in the osteon before the proportionality limit of the fibers parallel to the loading axis is reached.Study No. 73.00430.04 of the Italian National Research Council. Paper presented at the First All-Union Conference on Engineering and Medical Biomechanics, Riga, October, 1975.Rome University. Translated from Mekhanika Polimerov, No. 4, pp. 669–673, July–August, 1975.     

Mechanical properties of a carbon-fiber-reinforced plastic and the residual stresses in wound components made out of combined composites

A technique for calculating the residual stresses in wound components made out of mixed carbon-fiber-and glass-fiber-reinforced plastics and the results of the calculations are presented. The effect of the conditions under which the components are wound on the magnitude and nature of the residual stresses distribution in components made out of combined composites is investigated. The results of the calculations are compared with the experimental values.Translated from Mekhanika Polimerov, No. 6, pp. 996–1004, November–December, 1975.     

Effect of fiber tension on the unwinding resistance of hardening layers of glass-reinforced plastic

The shear fracture toughness characteristics of glass-reinforced plastics used for strengthening metal pressure vessels have been determined by testing metal-GRP rings. The shear fracture toughness characteristics are statistically estimated for a unidirectional GRP as a function of the winding tension.K. É. Tsiolkovskii Moscow Aviation Engineering Institute. Translated from Mekhanika Polimerov, No. 5, pp. 935–938, September–October, 1975.     

Fracture mechanism of amorphous polystyrene

The degradation products of polystyrene film specimens have been recorded and their accumulation kinetics in the presence of uniaxial tensile stresses have been studied at various temperatures. It is shown that the accumulation kinetics satisfy the Arrhenius equation for reactions in a mechanical field. The equation for the rupture life can be written in terms of the corresponding parameters of the mechanical degradation reactions. It is concluded that the rupture life and strength of polystyrene depend on the kinetics of mechanical degradation of the polymer chains.A. F. Ioffe Physicotechnical Institute, Academy of Sciences of the USSR, Leningrad. Translated from Mekhanika Polimerov, No. 3, pp. 541–544, May–June, 1975.     

Some postulates of general taxonomy

A logical analysis is made of the various assumptions underlying general taxonomy.The material in the article was used in Lyubishchev's report at the seminar of Apr. 24, 1972. The text itself goes back to 1947 (in this connection, it has been somewhat shortened). The logical analysis of the aspects being examined is carried out, in contrast to the other articles in this collection, at a premathematical level — Editors' Note.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 49, pp. 159–175, 1975.     

Determination of the elastic and damping properties of the human femur in bending

The results of an experimental investigation of the deflection of the human femur subjected to a bending moment are presented. The existence of two principal bending planes is established. The equivalent flexural rigidity of the dry bone is calculated for both static and dynamic loading. It is found that the human femur has a nonlinear elastic characteristic. The stiffness and damping properties obtained in static and dynamic testing are compared.Paper presented at the First All-Union Conference on Engineering and Medical Biomechanics, Riga, October, 1975.Moscow. Translated from Mekhanika Polimerov, No. 4, pp. 642–646, July–August, 1975.     

Forced axisymmetric oscillations of a viscoelastic cylindrical shell

The variational problem of forced oscillations of a cylindrical shell is reduced to a system of linear integrodifferential equations for which a periodic solution is constructed.Moscow Institute of Electronic Machinery. Translated from Mekhanika Polimerov, No. 6, pp. 1111–1114, November–December, 1975.     

Effect of compression on bone tissue crystals

The effect of compressive forces on the mineral components of bone tissue was studied. On the basis of x-ray diffraction analysis and the observed electrical and recrystallization effects, it is proposed that compression has a direct effect on the formation of callus through a definite means of compression osteosynthesis.Paper presented at the First All-Union Conference on Engineering and Medical Biomechanics, Riga, October, 1975.Orthopedic Clinic, Semmelweis Medical School, Budapest, Hungary. Translated from Mekhanika Polimerov, No. 4, pp. 664–668, July–August, 1975.     

Rate of resorption of polymeric implants in relation to biological fluid hydrodynamics

The dissociation of water-insoluble macromolecular complexes dissociating with the formation of soluble macromolecules is theoretically examined. The dissociation dynamics in static and open systems are compared (model media and the living organism, respectively). The effect of the rate of metabolic processes and the water-salt balance on the dissociation-association equilibrium in the organism is predicted. The effect of the tension in thread formed from a polycomplex on its life is analyzed for constant and relaxing stress. The use of the theory for predicting the resorption times of polymeric implants (sutures) in the living organism is demonstrated.Paper presented at the First All-Union Conference on Engineering and Medical Biomechanics, Riga, October, 1975.All-Union Scientific-Research Institute of Medical Polymers, Moscow. Translated from Mekhanika Polimerov, No. 4, pp. 740–743, July–August, 1975.