Computer modeling of melt spinning from a crystallizing polymer. Part I. The mathematical model

Polimery ◽  
2001 ◽  
Vol 46 (05) ◽  
pp. 335-343
Author(s):  
LESZEK JARECKI
2021 ◽  
Vol 2021 ◽  
pp. 1-23
Author(s):  
Karpenko Vasily Nikolaevich ◽  
Yuriy Starodub ◽  
Andrii Havrys

In the article, investigation is given of the developed mathematical models of nonequilibrium in time and distributed in space thermodynamic state of Earth’s matter from its center to its surface depending on the cases of the presence and absence of an internal source of thermal energy concentrated in the center of mass taking into account known geophysical data about the nucleus, mantle, lithosphere and atmosphere, and endogenous and exogenous heat fluxes. The objects of research are as follows: mathematical models of geothermal energy of the Earth, its internal source, and heat balance of endogenous and exogenous heat fluxes on the Earth’s surface. Research methods used are as follows: thermometry in deep wells, ground and remote sensing of heat fluxes of the Earth and the planets of the Solar System, mathematical modeling of heat exchange and thermoelastic processes from compression of Earth’s matter by gravitational field energy information and classical physical and mathematical methods, and computer modeling. The aim of research: in computer modeling to provide new mathematical models that determine the geophysical parameters of geothermal energy, which are aimed on solving problems of energy, environmental and economic security of society, using modern technical means of calculating ground and remote sensing data development of geothermal resources, and regulation of the heat balance of the ecosystem, namely: (i) study of the geological structure of the lithosphere to a depth of 10 km by remote sensing to determine the physical parameters of its layers more accurately than ground methods; (ii) development of projects of geothermal power plants on the basis of single isolated wells of a given depth with a capacity of up to 2 ÷ 3 mW of electricity on continents of the globe; (iii) real-time monitoring and forecasting of the temperature field of the atmosphere according to its physical and chemical composition. The novelty of the obtained research results: (i) developed the mathematical model of the physical process of origin and distribution in the bowels of the density of geothermal energy of the Earth from the surface to its center, which is the density of internal energy of an elementary geological object, and which increases when approaching the center of the planet; (ii) developed the mathematical model of the thermal energy source of infrared (IR) waves of the elementary geophysical object of the Earth’s interior depending on the depth of its occurrence, which allows to determine the stable generation of geothermal energy by rocks in a deep well for extraction and conversion into electricity and to study the geological structure and physical properties of the Earth’s interior; (iii) the mathematical model of heat exchange between the layers of the Earth’s subsoil with the thermal energy of infrared waves according to the laws of Fourier thermal conductivity and Stefan–Boltzmann heat transfer, which together with the geothermal energy source model allows to determine a thermal capacity of rocks in a deep well; (iv) developed the mathematical model of stable action of a source of thermal energy in the center of mass of the Earth, in the absence of which it is hard to explain the power of its endogenous infrared heat flux, parameters of geothermal energy distribution in the Earth, and the current thermodynamic state of the atmosphere, and the change in temperature of which depends on the thermophysical parameters of the physical-chemical composition of the atmosphere more than on changes in the thermal activity of the Sun; (v) determination of new numerical values: thermophysical parameters of the Earth’s interior; kinetic, potential and own gravitational energy of the Earth and own gravitational energy of the planets of the Solar System.


2011 ◽  
Vol 383-390 ◽  
pp. 2968-2973
Author(s):  
Xue Hui Gan ◽  
Qiang Liu ◽  
Xiao Jian Ma ◽  
Chun Hong Jia ◽  
Chong Chang Yang

From the rheological theory, the combination of the rheological characteristic of melt spinning and principle of spinning, the paper researches the mathematical model of the velocity distribution and shear rate distribution when the melt flow in composite spinning sheath-core orifices. According to the mathematical model, the melt flow velocity and pressure characteristic of the composite spinning micropore are researched with the software of CFD-Fluent. The results for the design of composite spinning technology and components provide a good theoretical basis.


Author(s):  
Olexandr Pavlenko ◽  
Serhii Dun ◽  
Maksym Skliar

In any economy there is a need for the bulky goods transportation which cannot be divided into smaller parts. Such cargoes include building structures, elements of industrial equipment, tracked or wheeled construction and agricultural machinery, heavy armored military vehicles. In any case, tractor-semitrailer should provide fast delivery of goods with minimal fuel consumption. In order to guarantee the goods delivery, tractor-semitrailers must be able to overcome the existing roads broken grade and be capable to tow a semi-trailer in off-road conditions. These properties are especially important for military equipment transportation. The important factor that determines a tractor-semitrailer mobility is its gradeability. The purpose of this work is to improve a tractor-semitrailer mobility with tractor units manufactured at PJSC “AutoKrAZ” by increasing the tractor-semitrailer gradeability. The customer requirements for a new tractor are determined by the maximizing the grade to 18°. The analysis of the characteristics of modern tractor-semitrailers for heavy haulage has shown that the highest rate of this grade is 16.7°. The factors determining the limiting gradeability value were analyzed, based on the tractor-semitrailer with a KrAZ-6510TE tractor and a semi-trailer with a full weight of 80 t. It has been developed a mathematical model to investigate the tractor and semi-trailer axles vertical reactions distribution on the tractor-semitrailer friction performances. The mathematical model has allowed to calculate the gradeability value that the tractor-semitrailer can overcome in case of wheels and road surface friction value and the tractive force magnitude from the engine. The mathematical model adequacy was confirmed by comparing the calculations results with the data of factory tests. The analysis showed that on a dry road the KrAZ-6510TE tractor with a 80 t gross weight semitrailer is capable to climb a gradient of 14,35 ° with its coupling mass full use condition. The engine's maximum torque allows the tractor-semitrailer to overcome a gradient of 10.45° It has been determined the ways to improve the design of the KrAZ-6510TE tractor to increase its gradeability. Keywords: tractor, tractor-semitrailer vehicle mobility, tractor-semitrailer vehicle gradeability.


Author(s):  
Oleksii Timkov ◽  
Dmytro Yashchenko ◽  
Volodymyr Bosenko

The article deals with the development of a physical model of a car equipped with measuring, recording and remote control equipment for experimental study of car properties. A detailed description of the design of the physical model and of the electronic modules used is given, links to application libraries and the code of the first part of the program for remote control of the model are given. Atmega microcontroller on the Arduino Uno platform was used to manage the model and register the parameters. When moving the car on the memory card saved such parameters as speed, voltage on the motor, current on the motor, the angle of the steered wheel, acceleration along three coordinate axes are recorded. Use of more powerful microcontrollers will allow to expand the list of the registered parameters of movement of the car. It is possible to measure the forces acting on the elements of the car and other parameters. In the future, it is planned to develop a mathematical model of motion of the car and check its adequacy in conducting experimental studies on maneuverability on the physical model. In addition, it is possible to conduct studies of stability and consumption of electrical energy. The physical model allows to quickly change geometric dimensions and mass parameters. In the study of highway trains, this approach will allow to investigate the various layout schemes of highway trains in the short term. It is possible to make two-axle road trains and saddle towed trains, three-way hitched trains of different layout. The results obtained will allow us to improve not only the mathematical model, but also the experimental physical model, and move on to further study the properties of hybrid road trains with an active trailer link. This approach allows to reduce material and time costs when researching the properties of cars and road trains. Keywords: car, physical model, experiment, road trains, sensor, remote control, maneuverability, stability.


Author(s):  
Serhii Kovbasenko ◽  
Andriy Holyk ◽  
Serhii Hutarevych

The features of an advanced mathematical model of motion of a truck with a diesel engine operating on the diesel and diesel gas cycles are presented in the article. As a result of calculations using the mathematical model, a decrease in total mass emissions as a result of carbon monoxide emissions is observed due to a decrease in emissions of nitrogen oxides and emissions of soot in the diesel gas cycle compared to the diesel cycle. The mathematical model of a motion of a truck on a city driving cycle according to GOST 20306-90 allows to study the fuel-economic, environmental and energy indicators of a diesel and diesel gas vehicle. The results of the calculations on the mathematical model will make it possible to conclude on the feasibility of converting diesel vehicles to using compressed natural gas. Object of the study – the fuel-economic, environmental and energy performance diesel engine that runs on dual fuel system using CNG. Purpose of the study – study of changes in fuel, economic, environmental and energy performance of vehicles with diesel engines operating on diesel and diesel gas cycles, according to urban driving cycle modes. Method of the study – calculations on a mathematical model and comparison of results with road tests. Bench and road tests, results of calculations on the mathematical model of motion of a truck with diesel, working on diesel and diesel gas cycles, show the improvement of environmental performance of diesel vehicles during the converting to compressed natural gas in operation. Improvement of environmental performance is obtained mainly through the reduction of soot emissions and nitrogen oxides emissions from diesel gas cycle operations compared to diesel cycle operations. The results of the article can be used to further develop dual fuel system using CNG. Keywords: diesel engine, diesel gas engine, CNG


1998 ◽  
Vol 2 ◽  
pp. 23-30
Author(s):  
Igor Basov ◽  
Donatas Švitra

Here a system of two non-linear difference-differential equations, which is mathematical model of self-regulation of the sugar level in blood, is investigated. The analysis carried out by qualitative and numerical methods allows us to conclude that the mathematical model explains the functioning of the physiological system "insulin-blood sugar" in both normal and pathological cases, i.e. diabetes mellitus and hyperinsulinism.


2001 ◽  
Vol 6 (1) ◽  
pp. 9-19 ◽  
Author(s):  
A. Buikis ◽  
J. Cepitis ◽  
H. Kalis ◽  
A. Reinfelds ◽  
A. Ancitis ◽  
...  

The mathematical model of wood drying based on detailed transport phenomena considering both heat and moisture transfer have been offered in article. The adjustment of this model to the drying process of papermaking is carried out for the range of moisture content corresponding to the period of drying in which vapour movement and bound water diffusion in the web are possible. By averaging as the desired models are obtained sequence of the initial value problems for systems of two nonlinear first order ordinary differential equations. 


2011 ◽  
Vol 2 (1) ◽  
pp. 1-12
Author(s):  
A. Hegyi ◽  
H. Vermeşan ◽  
V. Rus

Abstract In this paper we wish to present the numerical model elaborated in order to simulate some physical phenomena that influence the general deterioration of steel, whether hot dip galvanized or not, in reinforced concrete. We describe the physical and mathematical models, establishing the corresponding equation system, the initial and boundary conditions. We have also presented the numeric model associated to the mathematical model and the numeric methods of discretization and solution of the differential equations system that describes the mathematical model.


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