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The bending problem for a cylindrical shell with oblique cuts is solved using the equations of a model based on the straight-line hypothesis. The two-dimensional boundary-value problem obtained is reduced by the spline-approximation method to one-dimensional one solved by the method of discrete orthogonalization. The results calculated are compared with those obtained using the classical theory. Shells with different values of the cut angles are analyzed.

An approach to solving static problems for ring plates with parameters varying in two coordinate directions is proposed. The system of equations and boundary conditions are formulated for displacements, forces, and moments. The two-dimensional boundary-value problem is reduced to one-dimensional one using the spline-collocation method. This problem is solved with the stable numerical method of discrete orthogonalization. The numerical results presented as a table are analyzed.

The problem of bending of beveled circular cylindrical shells is solved by parametrizing the shell and reducing the two-dimensional boundary-value problem to a one-dimensional one by the spline-collocation method. This problem is solved by the stable discrete-orthogonalization method. The effect of the variability of the geometrical parameters on the displacement fields of circular cylinders is analyzed

The study addresses cervical vertebral condition and myofascial pain syndrome as a contributor to arterial hypertension. 400 subjects working in a railways (locomotion brigades) of the Kuvbishev railway were examined. The effective system of prevention and combination therapy of hypertension with myofascial pain syndrome in introduced.

Irrational administration of antimicrobials, incorrect regimens and dosing provide occurrence of adverse effects with minimal therapeutic results and development of drug resistance including anti-tuberculosis drugs. The study was designed to detect information sources on drug therapy used by general practitioners and TB specialists, to establish stereotypical models of antibacterial drug administration in prevalent upper and lower airway diseases at the Samara region and to substantiate the supposition about unreasonable empiric administration of anti-tuberculosis drugs in a respiratory patient without microbiological confirmation as a probable cause of drug resistant tuberculosis. A cross-sectional study based on a special questionnaire was performed in 425 general practitioners in primary care facilities, hospitals and in TB specialists at the Samara region. The questionnaire contained several clinical situations and their solving and the respondents should choose the most suitable ones. Results demonstrated that majority of the practitioners (80 %, or 340 / 425 cases) widely use advertising information regarding antimicrobials. Several doctors (1.7 %) chose antibacterial drugs to treat acute respiratory viral infection, 0.8 to 1.6 % of doctors certainly decided to administer anti-tuberculotics in non-TB respiratory diseases such as acute bronchitis, chronic obstructive pulmonary disease, communityacquired pneumonia and acute tonsillitis, and approximately one fifth of the practitioners thought to administer antituberculotics in these diseases (18.4 % (78 / 425) – rifampicin, 21.2 % (90 / 425) – isoniasid).

An approach to the solution of problems of the statics of shallow orthotropic shells is proposed. It is based on reducing a two-dimensional boundary value problem to a one-dimensional one using the spline-collocation method and solution of the problem by the stable numerical method of discrete orthogonalization. Solutions are presented for problems on the stress state of orthotropic shells of double curvature for several values of the elastic constants of the material.

Since solving problems of the stressed-strained state of elastic bodies in an exact three-dimensional poses considerable mathematical and computational difficulties, only for a small number of problems have the results of the solution been put in numerical form [8, 10, 15, 16, 18]. The stressed-strained state of three-dimensional bodies must be known in order to evaluate the strength capabilities of structural elements, both as a reference for models of applied theories of shells and as solutions obtained by approximate methods. In this article we consider the class of problems of the stressed-strained state of transversely isotropic hollow cylinders of finite length under asymmetric loads applied to the lateral surfaces and with different boundary conditions at the ends. The solution of that class of problems is constructed on the basis of separation of variables in the circumferential coordinate and solution of the two-dimensional boundary-value problem by the spline-collocation and discrete orthogonalization methods [4, 5, 6, 12, 13]. This approach was used earlier [1, 2, 7, 11] to solve two-dimensional problems of the theory of shells in different formulations. The influence of boundary conditions on the displacement and stress distribution in cylinders is analyzed on the basis of the results obtained. We consider transversely isotropic hollow cylinders in which the plane of isotropy coincides with the tangent to the cylindrical surface and the mechanical characteristics vary only along the normal to it. Asymmetrically distributed loads are applied to the lateral surfaces of the cylinder and boundary conditions are given at the ends. The problem is described on the basis of the three-dimensional theory of elasticity in a cylindrical coordinate system

UDC 539.3 The problem of the interaction of the elastic elements of structures and their foundation is of central importance in the design of machines, space facilities, and engineering structures. A large number of studies have analyzed the work of structures without allowance for the elastic foundation. There have also been numerous investigations that have made allowance for same. However, most of them have used linear models both for the shells (the structural elements) and the foundation. For the latter, the model has usually been the classical Winkler model. The Winkler model presumes that the intensity of the reaction of the foundation is proportional to the deformation in the structure. The foundation is represented as a set of linear springs without mass that are deformed only in the normal direction [1, 2]. Also, researchers generally examine isotropic or orthotropic plates and cylindrical or spherical shells. At the same time, experience shows that in the case of large elastic displacements, the interaction of the structure with the foundation is described by a nonlinear function. This article analyzes the interaction of anisotropic shell systems with a nonlinear elastic foundation on the basis of the geometrically nonlinear theory of thin shells. We will examine the stress-strain state of elastic systems composed of a series of coaxial closed mnltilayered shells of revolution. The shells themselves are made up of an arbitrary number of anisotropic layers having a thickness that varies along the meridian. There is one plane of elastic symmetry at each point of the shell, this plane being parallel to its coordinate surface. The elastic characteristics do not change along the parallel. The elastic system is subjected to surface and contour loads such that it deforms while retaining its axial symmetry. We also assume that the system interacts with the elastic foundation without slip or separation and that the intensity of the reaction of the foundation is determined by the formula

The study of the stress-strain state of plates and shells subjected to various types of loads with different support conditions entails the formulation of boundary-value problems that generally involve systems of partial differential equations with variable coefficients. The complexity of solving these problems stems not only from the high order of the system and the variability of the coefficients, but also from the need to exactly satisfy prescribed boundary conditions. The use of a given method to obtains a solution with a satisfactorily high degree of accuracy depends to a significant extent on the geometric and mechanical parameters characterizing certain aspects of the problem and the type of boundary conditions. These factors sometimes limit the possibilities of solving problems in the important (in a practical sense) cases in which the stiffness of the shell or plate supports is also variable. In addition, problems of the shell theory entail local and edge effects, which imposes certain stiffness conditions on boundary-value problems related to the phenomenon of instability in the computation. Spline functions have recently come into wide use to solve such problems in the areas of computational mathematics, mathematical physics, and mechanics. The popularity of this approach stems from the advantagesmore » offered by spline functions compared to other methods. Among these advantages: the stability of splines in relation to local perturbations, i.e. the behavior of the spline in the neighborhood of a point has no effect on the behavior of the spline as a whole (which is not the case in a polynomial approximation); good convergence of a spline-interpolation, in contrast to a polynomial interpolation; simplicity and ease of use of algorithms that construct and calculate splines on computers. 65 refs., 5 figs., 7 tabs.« less

Spline functions have come into increasingly wide use recently in the solution of boundary-value problems of the theory of elasticity of plates and shells. This development stems from the advantages offered by spline approximations compared to other methods. Among the most important advantages are the following: (1) the behavior of the spline in the neighborhood of a point has no effect on the behavior of the spline as a whole; (2) spline interpolation converges well compared to polynomial interpolation; (3) algorithms for spline construction are simple and convenient to use. The use of spline functions to solve linear two-dimensional problems on the stress-strain state of shallow shells and plates that are rectangular in plan has proven their efficiency and made it possible to expand the range of problems that can be solved. The approach proposed in these investigations is based on reducing a linear two-dimensional problem to a unidimensional problem by the spline unidimensional problem by the method of discrete orthogonalization in the other coordinate direction. Such an approach makes it possible to account for local and edge effects in the stress state of plates and shells and obtain reliable solutions with complex boundary conditions. In the present study, wemore » take the above approach, employing spline functions to solve linear problems, and use it to also solve geometrically nonlinear problems of the statics of shallow shells and plates with variable parameters.« less

Geometrically nonlinear relationships of the theory of thin layered shells are applied to analyze axisymmetric strain of bimetallic shells of revolution in a temperature field. One-dimensional nonlinear boundary-value problems are solved by a combination of the linearization method and the discrete orthogonalization method. A numerical approach is proposed to solve the boundary-value problems in the supercritical strain region.

An approach is proposed to numerical analysis of the stress state of shells of revolution in the geometrically nonlinear setting. It is based on a combination of linearization and discrete orthogonalization methods. Stress concentration is analyzed for a flexible spherical shell with a central hole, depending on load intensity, hole size, and the boundary conditions on the contours in the precritical strain region.

Symptomatic lesions of the stomach in patients with chronic inspecific pulmonary diseases depend on the respiratory insufficiency gravity and blood gas composition changes. Hypoxemia promotes stomach mucous membrane atrophy, and hypercapnia reduces stomach mucous membrane resistance to the tion of different ulcerogenic factors including Неlicobacter pylori. The infection of the stomach mucous membrane with Helicobacter pylori is retained in the treatment of patients with chronic inspecific pulmonary diseases by antibiotics.

The paper presents a numerical analysis of the deformation of an infinitely long flexible cylindrical panel of variable thickness immersed in a liquid with a concentrated force applied along the panel generator in the symmetry plane. The nonlinear boundary-value problem is solved by the linearization method combined with the discrete orthogonalization method. We examine the effect of variable thickness on the deformation of the panel for various initial values of the radius of curvature.

The strength and stiffness characteristics of fiber composites are such as to permit their use in many sectors of technology in the manufacture of structural elements having the form of thin-walled shells of revolution of different shapes and structures. The studies [i, 2, 8, i0, ii] examined their stress-strain state, these investigations having solved problems with allowance for variability of the properties of the composites under different loading conditions in different types of structures. Shells of revolution made by the method of continuous winding are widely used as pressure cylinders, tanks, pipelines, and other structures. Most studies of the stress-strain state of such shell elements have been made in a linear formulation. Complicating the service conditions of the structures and increasing the loads while maintaining strict requirements in regard to reliability and weight characteristics make it necessary to use nonlinear models of deformation.

There were 73 patients with infectious-allergic bronchial asthma (stages I and 1-2-3 and II according to the classification of Ado and Bulatov). Among the patients there were 30 male and 43 female patients aged from 18 to 70 years. All patients were admitted to the hospital with exacerbation of the disease. Lung emphysema was diagnosed in 28 patients, respiratory failure degree I - in 12, II - in 28, III - in 26 patients (according to A.G. Dembo classification).

Depending on the hemodynamic type and state of the kallikreinkinin 'blood system, differential treatment of 246 hypertensive patients was carried out using the beta-blocker anaprilin and the peripheral arteriolar vasodilator apressin. A pronounced hypotensive effect was observed in 82.5% of patients. In patients who underwent differential treatment, a decrease in blood pressure was observed 3.2 days earlier than in patients who were treated empirically; hospitalization terms were reduced by an average of 2.5 bed-days.

The bending problem for laminated orthotropic trapezoidal plates of variable thickness is solved by parametrizing the domain of interest and reducing the two-dimensional boundary-value problem to one-dimensional using the spline-collocation method. The resulting problem is solved by the stable discrete-orthogonalization method. The influence of orthotropy and the variability of the thickness on the displacement and stress fields is analyzed

We studied functional state of adenohypophyseal-adrenal system in hypertensive patients. 127 patients with hypertension of I and II stages according to WHO classification (59 men and 68 women) aged 17-60 years (mean age 48,7 years) were investigated. Patients with Stage I hypertension (Group I) had systolic and diastolic BP of 22.61.1 and 13.00.6 kPa, respectively (mean duration of disease: 4 years). Arterial hypertension in stage II patients (group 2) was stable, 25.41.3 and 14.71.1 kPa (mean duration of illness - 11 years). The control group included 32 healthy individuals.

We studied the state of cardiac hemodynamics in patients with chronic pyelonephritis with and without arterial hypertension according to echocardiographic study (EchoCG). We have examined 149 patients with chronic pyelonephritis aged from 17 to 70 years (men-51, women-98). The average age of the patients was 43.9 years.