This work deals with the dynamic thermal conductivity (λ) measurements by hot wire method. This measurements are performed at unstationary state conditions (short time). Very thin (0.05 mm) manganin wire is supplied by DC electrical power and produces a thermal impulses which pass through the testing sample. Dynamics of this process depends on the type of the sample material. Temperature, electric power and time elapsed during the process are measured parameters from which thermal conductivity could be calculated. Measurement results are compared with those gained by the standard guarded hot plate (stationary) method. Testing samples are made from isotropic and homogenous materials.

A comparison of some defining temperature fixed-points on the ITS-90 was carried out at the National Institute of Standards using four calibrated SPRTs. The comparison was performed using large and small sealed cells from two different sources. The large cells, namely set1 cells and taken as reference cells were realized using the same technique used with the small cells (set2). The main task is to study the set2 cells and the possibility of using them instead of the large size (reference) cells. Measurements showed good results and some agreement between the two sets. The differences between the set2 cells and reference cells set1 were well within 2 mK.

The main purpose of this work is to present the manufacturing, calibration and validation of a system for wet and dry bulb temperature measurements obtained on a new psychrometer.
The calibration has lead to the adjustment of the appropriate psychrometer coefficient for the developed psychrometer, as a function of the wet bulb temperature, which fits best with experimental data, obtained on the range from 34% to 87% RH and 15°C to 30°C. Another set of experimental points on this range was used for evaluation of the psychrometer uncertainty.
An electronic hygrometer was calibrated simultaneously, and its calibration was also evaluated. The uncertainty of the Relative Humidity obtained in the calibration of the psychrometer was found to be only slightly higher than the uncertainty for the electronic hygrometer. For the wet-bulb temperature determination, the hygrometer presents itself as more precise, while the psychrometer was more accurate. Either could be used for technological development of the humidifier, but the psychrometer delivers a direct measurement of the wet-bulb temperature, independent of the local pressure and dry-bulb temperature, which affects the calculation obtained from the hygrometer data.

The problem of measurements of the thermal resistance (R_th) of monolithic switched regulators (MSR) is considered in the paper. A new method of measuring this thermal parameter is proposed and the proper measuring set is presented. The results of measurements of R_th of the considered devices are compared with the similar results obtained with two other known methods.

The present paper describes a simulation model for the operation of an automotive air conditioning system subjected to typical mechanical failures. A review identified the most common mechanical failures in automotive A/C systems. Simple mathematical models of two of the most common of these failures were developed and introduced in a simulation model of the vapor compression cycle. Simulated components of the cycle, operating trouble-free or under failure, included the compressor and the condenser. The evaporator, thermal expansion valve, filter-dryer, hoses and connections are also sources of failures and malfunctions. The modeling effort was employed to relate temperature and pressure field measurements with typical system failures. Uncertainties of these measurements and their effect in the predictions of the most probable system failures were studied with the simulation model, aiming at the standardization of mobile A/C system diagnosis procedures.