SOFTWARE

A PC computer in connection with the microprocessor unit is used for control of the measuring process and data acquisition. The menu-controlled software with on-line help system improves the efficiency of the instrument operation. Setting thickness and the diameter of the specimen as well as density and specimen shape (cylinder or rectangle), the system automatically optimize experimental parameters (energy and the width of the heat pulse). An isothermal regime at any temperature from 40C up to 200C or non-isothermal regime with heating or cooling rate within the range 0.02 up to 1.2C/min can be used. The experimental parameters can be adjusted manually, too to investigate data reliability in detail. 

Three different programs are offered:

  • Basic program represents "one shot" measuring regimes. This program includes procedures that estimates heat pulse energy and heat pulse width, the "tuning" procedure that optimize heat pulse energy and heat pulse width and, finally, the procedure that calculates specific heat, thermal diffusivity and thermal conductivity.

  • Advanced program includes the facilities of the Basic program. In addition the measurement can be realized in cycles automatically. Several measuring regimes can be used (statistics, isothermal or non-isothermal measuring regimes). The program outputs the data files. This version is estimated for customer that wants to use his own thermostat. Therefore the temperature regime (isotherm, non-isotherm) has to be set manually due to operation of the thermostat.

  • Professional program includes, possibilities of both previous programs. In addition this program cooperates with laboratory data - base. Program has, again, a choice of statistics, isothermal and non-isothermal measuring regime. Full information regarding specimen parameters, measuring regime, parameters of experiment and experimental data are stored online into laboratory data - base. Database environment allows comfortable data browsing and retrieving and analyzing data directly in graphical representation. Every measuring cycle that was stored in laboratory data base can be reconstructed ex post. This program allows fully automatic experiment, data storing and data analysis. This program helps to create laboratory "know how" on thermophysics. Several input tabs are constructed that helps to operate any of the programs mentioned above. Some of them are shown below:

Parameters tab. Setting shape of the specimen (circle/square) and diameter/cross-section and thickness of the specimen, estimation of heat pulse energy and heat pulse width is performed

Stabilization time has to be set that represents temperature equilibration after measurement was realized. The measuring time tmeas plus stabilization time tstab gives time of measuring cycle. Measuring time tmeas is automatically calculated. When auto tuning check box is active (checked) then the button "go" starts the tuning procedure

Result of this procedure is the optimized heat pulse width and heat pulse energy. The measurement using optimized parameters gives the correct data of specific heat, thermal diffusivity and thermal conductivity. The procedure can be repeated. Record of measured cycles can be found in the graph windows together with measured values.

Tab of statistical measurements. Variations of the heat pulse energy can be set 
in using this form. 

Tab of non-isotherm regime. This form allows set the parameters regarding automatic measurements (Professional version) using heating or cooling of the specimen. The initial temperature Tstart), heating or cooling rate and the final temperature (Tend) have to be set in.

Isotherm tab.

This form allows set the parameters regarding utomatic measurements (Professional version) at constant temperature. The waiting time for specimen temperature stabilization, temperature of the isotherm and time of the isotherm have to be set in.

The chosen measuring regimes can be stored into sequence container. A sequence corresponds to a set of measurement acts. Thus a combination of statistics, isotherms and non-isotherms can be realized. The instrument will execute consecutively the sequences that are stored in the sequence container.

Software includes laboratory data - base that, again, allows comfortable data browsing and retrieving, analyzing data directly in graphical representation, sorting data upon various criteria and calculations of mean values and standard deviations as well as correction of data for the case that the conditions of ideal model are not fulfilled.

The Internet page http://thermophys.savba.sk and the e-mail address ludovit.kubicar@savba.sk offer basic information and help in the instrument operation and data evaluation.

Recorded temperature response and the current and voltage on the planar heat source