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.     

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.     

Flow of a viscous fluid in a deformable valved tube in the presence of gravity

The problem of the flow of a viscous incompressible fluid in a tube of finite length with valves at the ends is solved numerically with allowance for gravity and elastic wall properties that vary periodically with time.Paper presented at the First All-Union Conference on Engineering and Medical Biomechanics, Riga, October, 1975.M. V. Lomonosov Moscow State University. Translated from Mekhanika Polimerov, No. 4, pp. 756–760, July–August, 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.     

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.     

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.     

Effect of the medium of a living organism on the vulcanization of silicone rubber

Conclusions The vulcanization process of SKTN silicone rubber in a living organism significantly depends on the chemical nature of the catalyst. The organism accelerates this process if cross-linking of the rubber occurs in the presence of tin dioctyldilaurate (Sn⁴⁺) and may retard this process if tin octoate (Sn²⁺) serves as the catalyst.Presented to the Second All-Union Conference on Biomechanics, Riga, April 1979.Translated from Mekhanika Kompozitnykh Materialov, No. 2, pp. 345–349, March–April, 1980.     

Circulation hydrodynamics in the organs of the abdominal cavity in the presence of extracorporeal perfusion

The general hemodynamics and circulation in the organs of the abdominal cavity have been investigated in the presence of artificial circulation at a calculated rate of perfusion. The effect of vasoactive preparations (noradrenaline, Arfonad) on these characteristics is analyzed. The behavior of the microcirculation in the presence of artificial circulation created by an artificial circulation apparatus equipped with automatic control systems of original design has been studied. It has been found that disturbances of the microcirculation are responsible for the development of a state of hypoxia in organs and tissues in the presence of artificial circulation at a calculated rate of perfusion under conditions of controlled vasoconstriction or controlled hypotension. Stabilization of the arterial pressure and the functional state of the vascular bed in the presence of artificial circulation had a positive effect on the tissue blood flow and oxygen metabolism in the organs of the abdominal cavity.Paper presented at the First All-Union Conference on Engineering and Medical Biomechanics on the topic: Problems of Circulatory Hydrodynamics, Riga, October, 1975.D. I. Ulyanov Kuibyshev Medical Institute. Translated from Mekhanika Polimerov, No. 5, pp. 871–874, September–October, 1975.     

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.     

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.     

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.     

Accelerated testing of polymeric materials operating in a vacuum in the presence of ionizing radiations

The effect of ionizing radiations on polymeric materials is considered and an accelerated method of determining the wear rate under these conditions is proposed.All-Union Scientific Research Institute of Optico-Physical Measurements, Moscow. Translated from Mekhanika Polimerov, No. 6, pp. 1105–1107, November–December, 1969.     

Synthesis and some properties of quick-hardening SKU-PFL polyurethane for possible use in endoprosthetics

Conclusions 1. The technique proposed for synthesizing SKU-PFL polyurethane excludes the thermal effect of the polymerization reaction on the tissues and enables the formation of the elastomer to be completed directly in the organism of the recipient.2. SKU-PFL polyurethane does not undergo biodegradation and is among the biologically inert polymers.3. The lack of toxicity, the chemical and physicome chanical stability, as well as the biological inertness, open up possibilities of using it in endoprosthetics.4. The advantage of quick-hardening SKU-PFL polyurethane is the possibility of its use for preparing endoprostheses directly in an organism of the recipient and also for making them outside the organism.S. V. Kurashov Kazan' State Medical Institute. Translated from Mekhanika Polimerov, No. 5, pp. 903–908, September–October, 1976.     

Investigation of the fiber packing density in a unidirectional composite

Recommendations are made for designing a unidirectional composite with an optimal arrangement of the fibers. The effect of the fiber diameter distribution law on the packing density is investigated.All-Union Scientific-Research Institute of Glass-Reinforced Plastics and Glass Fiber, Moscow. Moscow Institute of Electronic Machine-Building. Translated from Mekhanika Polimerov, No. 3, pp. 538–541, May–June, 1976.     

Creep of unidirectional glass-reinforced plastics based on new types of fibers

Theoretical and experimental compressive creep relations for a unidirectional glass-reinforced plastic based on hollow fibers are presented. The agreement between the theoretical and experimental data is shown to be satisfactory. The effect of fiber capillarity on the creep process is unimportant.All-Union Scientific-Research Institute of Glass-Reinforced Plastics and Fiber Glass, Moscow; Institute of Mechanics of Machines and Polymeric Materials, Academy of Sciences of the Georgian SSR, Tbilisi. Translated from Mekhanika Polimerov, No. 4, pp. 747–750, July–August, 1971.     

Effect of temperature on the mechanical properties of boron fibers

The effect of exposure to temperatures on the interval 20–600°C for up to 1000 h on the physicomechanical properties of boron fibers at room temperature has been investigated. Prolonged exposure to temperatures up to 200°C does not have much effect on the mechanical characteristics of the fibers, whereas heating for one hour at 300–350°C increases the strength of the fibers by 10–12%.All-Union Scientific Research Institute of Aviation Materials, Moscow. Translated from Mekhanika Polimerov, No. 2, pp. 329–332, March–April, 1971.     

Realization of the mechanical properties of fibers in high-modulus polymer composites

The effect of scatter in the strength and deformation properties of the high-modulus fibers, the degree of twist, and the presence of pores in the polymeric matrix on the degree of realization of the potential possibilities of these fibers in composite materials is briefly considered.All-Union Scientific-Research Institute of Aviation Materials, Moscow. Translated from Mekhanika Polimerov, No. 6, pp. 1123–1125, November–December, 1972.     

Mathematical model of muscular contraction with a ccount of excitability

A model of muscular contraetion has been developed which establishes the relationship between normal stresses and longitudinal deformations of the muscle tissue and takes into account its excitability. A transfer function has been proposed for the equation describing the behavior of the muscle as a dynamic system which is controlled by synegisms. The validity of the model has been tested experimentally. The model has been used to develop type-II Lagrange equations for the solution of the basic task of biomechanics for some movements of the human body.Paper presented at the FirstAll-Union Conference on Engineering and Medical Biomechanics, Riga, October, 1975.P. F. Lesgaft State Institute of Physical Culture, Leningrad. Translated from Mekhanika Polimerov, No. 4, pp. 608–612, July–August, 1975.     

Supermolecular structure and properties of polymers

Questions relating to methods of obtaining supermolecular structures and their effect on the properties of polymers are considered.Presented at 2nd All-Union Conference on Polymer Mechanics, Riga, November 10–12, 1971.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 3, pp. 409–415, May–June, 1972.     

A polymer film hardening effect

It is shown that a polyester film incapable of forced high-elastic deformation can be subjected to such deformation by stretching a film-substrate system. The resulting oriented structure is stable and on being measured from the substrate, the film exhibits a hardening effect. In this case contact with and adhesion to the substrate are a necessary condition for the development of the latent potential of the film.Lenin All-Union Electrical Engineering Institute, Moscow. Translated from Mekhanika Polimerov, No. 4, pp. 731–733, July–August, 1971.