Ivo Špička

On Experimental Thermal Analysis of Solid Materials

Abstract The paper is devoted to the presentation of a method for measurement of thermal conductivity k, specific heat capacity cp, and thermal diffusivity applying the lumped capacitance model (LCM) as a special case of Newton’s model of cooling. At the specific experimental conditions resulting from the theoretical analysis of the used model, we present a method for experimental determination of all three above mentioned thermal parameters for materials with different thermal transport properties. The input experimental data provide a cooling curve of the tested material. The evaluation of experimental data is realized by software, the fundamental features of which are presented here. The statistical analysis of experimental data was performed.

Incremental PIC controller with handled limit states and manual settings

A proportional-integral-derivative controller (PID controller) is a basic control loop feedback controller widely used in industrial control systems. An “error” value as the difference between a measured output system variable and a desired setpoint is calculated. The controller role is to minimize the error by adjusting the system inputs. For best performance, the PID parameters must be tuned according to the controlled system parameters.

Influence of Gama Prime Changes on the Heat Transport Phenomena of a Nickel Super Alloy

The paper deals with the influence of microstructural changes of the nickel superalloy (NiS) on heat transport changes in MAR-M247. The dissolving annealing within the temperature interval of 900 – 1240°C and cooling in water has been applied to enhance structural changes. It has been shown that the narrow connection between the γ’ phase morphology changes, as well as values of density, thermal conductivity and specific heat capacity. In the dissolving annealing process, the γ’ particles change in certain cycles from fine to rough and back to fine one. Obtained results of changes of thermal conductivity, density and specific heat capacity correlate with image analysis and electron microscopy observation.

Lumped Capacitance Model in Thermal Analysis of Solid Materials

The paper is devoted to the presentation of a method for measurement of thermal conductivity k, specific heat capacity cp and thermal diffusivity α applying the lumped capacitance model (LCM) as a special case of Newtons model of cooling. At the specific experimental conditions resulting from the theoretical analysis of the used model, we present relatively very precise method for experimental determination of all three above mentioned thermal parameters for materials with different thermal transport properties. The input experimental data provide a cooling curve of the tested material obtained in special experimental arrangement. The evaluation of experimental data is realized by software the fundamental features of which are presented here. The statistical analysis of experimental data was performed (99% confidence interval P99).

Infrared Monitoring of Inner Defects in Glass Laminates

In this paper, we present some distinguished methods of the digital thermograms software treatment which allows the visualization of hidden defects in glass fabric laminates, which are not usually visible in standard raw thermograms. The results of the software treatment are tested on artificial defects in glass laminate plates.