Fractional Heat Conduction Models and Thermal Diffusivity Determination

The contribution deals with the fractional heat conduction models and their use for determining thermal diffusivity. A brief historical overview of the authors who have dealt with the heat conduction equation is described in the introduction of the paper. The one-dimensional heat conduction models with using integer- and fractional-order derivatives are listed. Analytical and numerical methods of solution of the heat conduction models with using integer- and fractional-order derivatives are described. Individual methods have been implemented in MATLAB and the examples of simulations are listed. The proposal and experimental verification of the methods for determining thermal diffusivity using half-order derivative of temperature by time are listed at the conclusion of the paper

MODELING OF MATERIAL BALANCE FROM THE EXPERIMENTAL UCG

The underground coal gasification is a continually evolving technology, which converts coal to calorific gas. There are many important parameters in this technology, which are difficult to measure. These parameters include the underground cavity growth, amount gasified coal, and the leakage of input and output gaseous components into the surrounding layers during the coal gasification process. Mathematical modeling of this process is one of the possible alternatives for determining these unknown parameters. In this paper, the structure of the mathematical model of laboratory underground coal gasification process from the material balance aspect is presented. The material balance consists of mass components entering and leaving from the UCG process. The paper shows a material balance in the form of a general mass balance and atomic species balance. The material balance was testing by six UCG laboratory experiments, which were realized in two ex-situ reactors

Analysis of the Parameter of the Electro-discharge Texturing

This paper deals with analysis of the electro discharge texturing (EDT) parameter impact to micro-geometry of the cylinder surface. Micro-geometry of the cylinder surface results has significant influence to final quality of rolled metal plate used to different industry. Micro-geometry evaluate is based on measurement of the surface roughness average (Ra) and peak count (Pc). In this paper is evaluated electro discharge texturing parameters and their impact to Ra and Pc. From the measured values follow that value of the texturing current, impulse on-time and impulse off-time most influence to Ra and Pc. In this paper is described design, realization and results of the model for estimation of the texturing current, impulse time and technological pause for Ra or Pc required value

MODELING OF MATERIAL BALANCE FROM THE EXPERIMENTAL UCG

The underground coal gasification is a continually evolving technology, which converts coal to calorific gas. There are many important parameters in this technology, which are difficult to measure. These parameters include the underground cavity growth, amount gasified coal, and the leakage of input and output gaseous components into the surrounding layers during the coal gasification process. Mathematical modeling of this process is one of the possible alternatives for determining these unknown parameters. In this paper, the structure of the mathematical model of laboratory underground coal gasification process from the material balance aspect is presented. The material balance consists of mass components entering and leaving from the UCG process. The paper shows a material balance in the form of a general mass balance and atomic species balance. The material balance was testing by six UCG laboratory experiments, which were realized in two ex-situ reactors

Electronic realization of the fractional-order systems

This article is devoted to the electronic (analogue) realization of the fractional-order systems – controllers or controlled objects whose we earlier used, identified, and analyzed as a mathematical models only ��� namely a fractional-order differential equation, and solved numerically using a method based on the truncated version of the Grunwald - Letnikov formula for fractional derivative. The electronic realization of the fractional derivative is based on the continued fraction expansion of the rational approximation of the fractional differentiator from which we obtained the values of the resistors and capacitors of the electronic circuit. Along with the mathematical description are presented also simulation and measurement results

Comparison of the methods for discrete approximation of the fractional-order operator

In this paper we will present some alternative types of discretization methods (discrete approximation) for the fractional-order (FO) differentiator and their application to the FO dynamical system described by the FO differential equation (FDE). With analytical solution and numerical solution by power series expansion (PSE) method are compared two effective methods - the Muir expansion of the Tustin operator and continued fraction expansion method (CFE) with the Tustin operator and the Al-Alaoui operator. Except detailed mathematical description presented are also simulation results. From the Bode plots of the FO differentiator and FDE and from the solution in the time domain we can see, that the CFE is a more effective method according to the PSE method, but there are some restrictions for the choice of the time step. The Muir expansion is almost unusable

Combustion Process Modelling and Control

This paper deals with realization of combustion control system on programmable logic controllers. Control system design is based on analysis of the current state of combustion control systems in technological device of raw material processing area. Control system design is composed of two subsystems. First subsystem is represented by software system for measured data processing and for data processing from simulation of the combustion mathematical model. Outputs are parameters for setting of controller algorithms. Second subsystem consists from programme modules. The programme module is presented by specific control algorithm, for example proportional regulation, programmed proportional regulation, proportional regulation with correction on the oxygen in waste gas, and so on. According to the specific combustion control requirements it is possible built-up concrete control system by programme modules. The programme modules were programmed by Automation studio that is used for development, debugging and testing software for B&R controllers

THERMOCHEMICAL CALCULATIONS USING SERVICEORIENTED ARCHITECTURE IN THE WEB SERVICE FORM

The subject of this article is the service-oriented architecture utilization in the design and implementation of a web service that is intended to perform selected thermochemical calculations for chemical reactions. Computing functions allow the chemical reaction calculations, such as molar heat capacity, enthalpy, entropy and Gibbs free energy. In the next part, there is a description of each function, the method of service calling in the client application and the structure specification of outputs and error states of the service. In addition to computing functions, the web service also has a group of three information functions that characterize the purpose of the web service and its parameters, provide in tabular form a list of all web service functions and a list of all error states of the web service. The final section describes the presentation web service application with a demonstration of the specific calculations, the possibilities of using the service, and a further solution treatment