Wyniki wyszukiwania - Biblioteka Nauki

1

Mathematical modeling of two-dimensional field development of temperature and moisture content in wood

100%

Dornyak O. R. , Shulman Z. P.

International Journal of Applied Mechanics and Engineering

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2005

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tom Vol. 10, no 4

593-604

EN

A mathematical model for studying the heat and mass transfer in wood during its modification is derived. The model is constructed on the basis of a continual approach within mechanics of heterogeneous medium. Wood is considered as transversal-isotropic unsaturated three-phase system. A numerical experiment for investigating the influence of phase transition and capillary effect on the moisture field is carried out. The analysis of heat and hydrodynamic regimes is conducted. It is shown that during a technological process of wood modification modeling it is necessary to calculate the coupled heat and mass transfer.

2

ER fluid application for chemical technology

100%

Korobko E. V. , Shulman Z. P.

Applied Mechanics and Engineering

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1999

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tom Vol. 4, no spec.

252-258

EN

The paper is an attempt to generalize the results of studies concerned with the "intelligent" fluids. Regularities of variation of mechanical (viscosity, elasticity, plasticity) properties of a class of liquid-disperse suspensions sensitive to an external electric field which are known as electrorheological fluids or "smart" fluids, are analyzed. The designs and operation principles of converters of electric energy to mechanical in power systems, and friction devices and others are described.

3

The rheodynamics factor in the thermoregulation model

100%

Shulman Z. P. , Makhaniok A.

Applied Mechanics and Engineering

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1999

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tom Vol. 4, no spec.

169-176

EN

The external or superficial heat or cold action has a strong influence on blood rheology and systemic and microvessels blood circulation. The tissue blood flow rate intensity is generally accepted to describe by Stolwijk's phenomenological model in the skin and Sekins's model in the muscle. We proposed an own model - a modification of Stolwijk's model, including influence of blood viscosity and vessel wall elasticity on the blood flow rate. A single equivalent vessel presents the arterioles and small arteries. The wall stress and the wall deformation of this vessel have described by Hook and Voigt-Kelvin models. The analytical expression has been obtained, which generalised Stolwijk and Sekins models. The quantitative analysis of the vessel wall elasticity influence on blood flow rate in the equivalent vessel has been performed out with the help of two dimensionless parameters, namely, the so-called "primary reaction" of the vessel at heating or cooling Dr and dimensionless complex p. The parameter 'DELTA''ro' is controlled by temperature. The p-complex is directly proportional to the transmural pressure value (Pinside-Poutside) and inverse proportional to elasticity modulus of the equivalent vessel wall. It has been found that the twofold increase of elasticity modulus decreases the blood flow rate on 30% at 'DELTA''ro' = 0,1 and < 1% at 'DELTA''ro' = 0,6. This means, that the elasticity modulus influence is increased with the stress relaxation of the vessel muscles. The new rheodynamics model of the thermoregulation was applied to the numerical simulation of the human body cooling process. The combined influence of vessel wall elasticity and temperature on blood flow rate and heat transfer for water hypothermia conditions has been considered. The tem-perature dependence of the apparent blood viscosity has been described by Arrenius' model. The results show the strong influence of blood viscosity and vessel wall elasticity alternations on blood flow rate and the heat transfer of man at moderate hypothermia (Tcore > 29-31oC). In the case water hypothermia at +10oC it has been shown that twofold increase of initial blood viscosity and wall elasticity modulus reduce the brain temperature on 3oC.

4

Simulation of non-steady flow of linear viscoplastic media

80%

Shulman Z. P. , Mansurov V. A. , Makhaniok A. A.

Inżynieria Chemiczna i Procesowa

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2000

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tom T. 21, z. 1

219-224

EN

The solution is given to a problem of non-steady (oscillating) flow of linear viscoplastic media in an annular gap of rotational viscometer: the outer cylinder moves stepwise, the inner one is fixed. It was shown that average shear rate on the surface of inner cylinder differed from its steady-state value by the factor t1/t2 (t1 is the motion length of time, t2 is the fall period of time).

PL

Przedstawiono rozwiązanie zagadnienia nieustalonego (oscylacyjnego) przepływu liniowych lepkosprężystych mediów w pierścieniowej szczelinie rotacyjnego wiskozymetru, w którym wewnętrzny cylinder porusza się skokowo, wewnętrzny zaś jest nieruchomy. Wykazano, że średnia prędkość ścinania na powierzchni wewnętrznego cylindra różni się od jej ustalonej wartości o czynnik t1/t2 (t1 jest czasem trwania ruchu, t2 - pełnym okresem czasu).

5

Field-induced structuring and light transmission in a gravitationally stratified ferrosuspension: an application in polymer film viscometry

80%

Shulman Z. P. , Kashevski S. B. , Prokhorov I. V.

International Journal of Applied Mechanics and Engineering

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2004

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tom Vol. 9, no 4

771-779

EN

The dynamics of structuring and light transmission in response to a transverse magnetic field applied to a gravitationally stratified layer of a ferromagnetic suspension is studied numerically and experimentally. The results obtained have been used to substantiate and implement in practice a magnetooptical method of measuring the fluid viscosity in thin films. This method is employed to investigate the viscosity kinetics of a polymer solution in a drying film.

6

Rheological changes in rat blood as a result of photodynamic treatment

61%

Shulman Z. P. , Makhaniok A. A. , Vilanskaya S. V. , Zhavrid E. A. , Istomin Y. P. , Sheleg S. V.

International Journal of Applied Mechanics and Engineering

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2003

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tom Vol. 8, no spec.

307-312

EN

The purpose of this study was experimental investigation of hemorheological changes under photodynamic therapy. The experiments were conducted on laboratory white purebred male rats under narcosis. Chlorin e6 as photosensitizer (PS) was used. Photodynamic exposure (PDE) was performed with semiconductor laser (wave length 670nm). The irradiated area was , and light exposure dose E was 22.5 to . Blood was sampled 1 hour after PDE completion and was heparin-conserved. The experimental study of PDE effect on the rheological properties of blood of tumour-free rats revealed that chlorin at a dose of body mass caused a significant increase in the hematocrit H. The flow curves were adequately described by the power law rheological model with independent of H and E. The correction to the parameter of blood consistency K in rats not exposed to PDE assumed the form . The exposure of rat skin to light at E 22.5 to resulted in an increase in the consistency parameter. The flow curves taking into account PDE are adequately described by the model . The results obtained from this study indicate that PDE at a concentrated chlorin dose of and light exposure dose of 22.5 to produces a significant increase in rat blood non-newtonian viscosity.