MODEL FOR PLANNING AND FORECASTING DECOMPRESSION DIVES USING THE CORRECTION METHOD

Author(s):  
Н.С. Сковпин ◽  
М.В. Паринов

В работе описана разработанная модель планирования и прогнозирования декомпрессионных погружений с помощью модифицированного метода Градиент-Фактор. В работе подробно описаны подмодели входящие в комплексную математическую модель планирования погружений. The paper describes the developed model for planning and forecasting decompression dives using the modified Gradient Factor method. The paper describes in detail the sub-models included in the complex mathematical model of diving planning.

One of the approaches to the development of a complex mathematical model of a production system is considered. Keywords mathematical model; target subsystem; quality criterion; controlling parameter; hierarchical structure


Author(s):  
Gennadiy Kryzhevich ◽  
Anatoliy Filatov

This paper studies marine structures made of steels and light alloys and exposed to cyclic operational loads. Stress-strain parameters of their joints were taken from mathematical simulations of loads and strains or from actual strain gauging data. The aim of this study is to develop recommendations on fatigue strength calculations: specifically, how to quite the complex mathematical model of multi-axial loading at critical structural points with fast fatigue wear in favour of a simplified stressstrain state description based on optimal assignment of design parameters (stresses) in fatigue failure criteria. Preferability of this approach depends on case-specific requirements to calculation accuracy and timeframes. Uniaxial description of stressed state instead of the three-axial one enables much faster calculation with acceptable drop in accuracy.


Author(s):  
Bakhtiyar Ismailov ◽  
Zhanat Umarova ◽  
Khairulla Ismailov ◽  
Aibarsha Dosmakanbetova ◽  
Saule Meldebekova

<p>At present, when constructing a mathematical description of the pyrolysis reactor, partial differential equations for the components of the gas phase and the catalyst phase are used. In the well-known works on modeling pyrolysis, the obtained models are applicable only for a narrow range of changes in the process parameters, the geometric dimensions are considered constant. The article poses the task of creating a complex mathematical model with additional terms, taking into account nonlinear effects, where the geometric dimensions of the apparatus and operating characteristics vary over a wide range. An analytical method has been developed for the implementation of a mathematical model of catalytic pyrolysis of methane for the production of nanomaterials in a continuous mode. The differential equation for gaseous components with initial and boundary conditions of the third type is reduced to a dimensionless form with a small value of the peclet criterion with a form factor. It is shown that the laplace transform method is mainly suitable for this case, which is applicable both for differential equations for solid-phase components and calculation in a periodic mode. The adequacy of the model results with the known experimental data is checked.</p>


Author(s):  
Alexander Babin ◽  
Alexey Kornaev ◽  
Alexey Rodichev ◽  
Leonid Savin

Research in the field of active fluid-film bearing has been recently getting more and more attention, integration of control systems becoming one of the most promising means of enhancement of rotor-bearing nodes' characteristics. It has been determined that the vast majority of papers published on active fluid-film bearing only consider radial bearings, and very few focus on thrust bearings. This lack of attention along with the obvious necessity to fill the said gap has triggered the present research. In cases of rotor machines that experience extensive axial loading due to various reasons, e.g. various turbine engines (aero and spacecraft) and hydraulic pumps (crude oil extraction facilities), such research could prove the feasibility of application of a control system to significantly increase the performance of the whole machine. Moreover, extensive wear during start up and shut down could be eliminated by means of rotor position control, thus life time of a rotor-bearing system could be significantly increased. The present paper features a complex mathematical model of an active thrust fluid-film bearing with a central feeding orifice, a developed test rig designed to verify the presented mathematical model allowing a series of numerical tests to be carried out. Numerical studies focus on the hypothesis of a possibility to use active control in thrust bearings to decrease power loss due to friction and extensive axial vibrations by means of identification of an energy efficient area of axial gaps based on the lubrication regime and its maintenance by means of application of controlled lubrication principles.


2014 ◽  
Vol 10 ◽  
pp. 236-243 ◽  
Author(s):  
Viacheslav A. Chuzlov ◽  
Nikita V. Chekantsev ◽  
Emilia D. Ivanchina

2021 ◽  
pp. 12-12
Author(s):  
Dusko Salemovic ◽  
Aleksandar Dedic ◽  
Bosko Jovanovic

The paper describes the flow of a suspension which is a mixture of two phases: liquid and solid granules. The continuum model with microstructure is introduced, which involves two independent kinematic quantities: the velocity vector and the micro-rotation vector. The physical analogy is based on the movement of the suspension between two coaxial cylinders. The inner cylinder is stationary and the outer one rotates with constant angular velocity. This physical analogy enabled a mathematical model in a form of two coupled differential equations with variable coefficients. The aim of the paper is to present the numerical aspect of the solution for this complex mathematical model. It is assumed that the solid granules are identically oriented and that under the influence of the fluid they move translationally or rotate around the symmetry axis but the direction of their symmetry axes does not change. The solution was obtained by the ordinary finite difference method, and then the corresponding sets of points (nodes) were routed by interpolation graphics.


The article examines the morphology of the Karakalpak language, which belongs to the Kipchak group of the Turkic language family. The forms of word formation in the Karakalpak language, their sequences and the affixes added to the core are analyzed. On the basis of the analyzed affixes and suffixes, a complex mathematical model of word formation in the Karakalpak language was developed. On the basis of the developed mathematical model, an algorithm for creating a complex word in the Karakalpak language was developed. Using the developed mathematical model, a four-stage scheme was created for creating complex words of the Karakalpak language.


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