The article presents th e computer system to determine fusibility of ash obtained from solid mineral fuels, which is a vital parameter for proper exploitation of power and heating plants boilers. The system is based on analysis of the image of a heated ash sample. In the beginning, we describe the way in which the ash specimen is prepared, as well as its thermal processing, and also give criteria for specifying the characteristic temperature points of phase transitions according to the ISO 1171 standard. Later, we present the scheme of the apparatus for automated determination of ash fusibility and the image acquisition method. Finally, we describe the chosen criteria of automated determination of characteristic points on the basis of selected sample image geometry coefficients. The ultimate determination of the values of those points on the basis of many calculated coeffici ents, fuzzy logic is applied.

This paper presents results from experiments using an ultrasonic gas flow meter measuring the speed of sound in air at varying air velocities, humidities and temperatures. The meter utilises the sing-around technique. The transducers in the meter are silicon-based ultrasonic transducers with a centre frequency of 800 kHz. In order to investigate the performance of the flow meter it was tested in a novel gas flow facility connected to a calibration facility for flow meters used for liquids. The Reynolds’ numbers for the investigated flow velocities ranged from 0 to 3,2·10⁴, the relative humidity varied from 40% to 80% RH and the temperature varied from 20°C to 46°C. It was found that the experimentally measured speed of sound corresponded well with the speed of sound obtained from theory. It is also concluded that the flow meter could potentially be used in determining the relative humidity in flowing air at atmospheric pressures using speed of sound and temperature measurements.

This paper presents a facility for humid air generation – the humidity generator. The generator was developed for calibration of hygrometers. The principle of operation is based on the two-temperature method for humid air generation and the open circuit flow mode is applied. Saturation of the air is achieved by the water atomization in air flow. The generator is designed to operate in the test chamber temperature range from 5°C to 85°C and in dew point temperature range from 2°C to 35°C. The paper makes a point to the possibility the system works in nonsaturation mode and the comparison method is applied for calibration purpose. The excellent dynamic characteristics are obtained by the fast changes of the quantity of water dispersed in air flow. Maintenance the intensity of the atomization and stationary temperature at the same time enables stationary air humidity circumstances in the test chamber. Dynamic and stationary characteristics of generator, as well as uniformity working area inside the test chamber is numerically and graphically presented. Analysis of the uncertainty using comparison calibration method is also reported. The software developed in LabVIEW environment supervises the system operation.

This study aims to develop a practical radiation thermometry system of metals moving through in a high temperature furnace. In order to achieve this study, two problems; emissivity compensation of a target and elimination of background radiation noise filled in a furnace must be sorted out. We have successfully developed a method for simultaneous measurement of emissivity and temperature by use of polarized directional properties of the radiance from the target, in this case, stainless steel, and moreover a technique to eliminate background radiation noise using a pseudo blackbody installed in a furnace.

Laser polarimetry has been used for years to obtain normal spectral emissivity measurements on pulseheated materials. The method is based on the FRESNEL equations that describe reflection and refraction at an ideally smooth interface between two isotropic media. However, polarimetry is frequently used with surfaces that clearly deviate from this ideal condition. Questions arise with respect to the applicability of the simple FRESNEL equations to non-specularly reflecting surfaces. On the other hand, reflectometry utilizing integrating spheres provides a measurement of the hemispherical spectral reflectance for normal incidence, from which the normal spectral emissivity can be derived, regardless of surface texture. In a first effort to explore the limits of polarimetry in terms of surface roughness, room temperature measurements were performed on a number of samples using both an integrating sphere reflectometer and a laser polarimeter. In this paper, the two methods are briefly described and the results of the comparison are discussed.