Convective and radiation heat transfer take place between various objects placed in open air space and their surroundings. These phenomena bring about heat losses from pipelines, building walls, roofs and other objects. One of the main tasks in energy auditing is the reduction of excessive heat losses. In the case of a low sky temperature, the radiation heat exchange is very intensive and the temperature of the top part of the horizontal pipelines or walls is lower than the temperature of their bottom parts. Quite often this temperature is also lower than the temperature of the surrounding atmospheric air. In the case of overhead heat pipelines placed in open air space, it is the ground and sky that constitute the surroundings. The aforementioned elements of surroundings usually have different values of temperature. Thus, these circumstances bring about difficulties during infrared inspections because only one ambient temperature which represents radiation of all surrounding elements must be known during the thermovision measurements. This work is aimed at the development of a method for determination of an equivalent ambient temperature representing the thermal radiation of the surrounding elements of the object under consideration placed in open air space, which could be applied at a fairly uniform temperature of the sky during the thermovision measurements as well as for the calculation of radiative heat losses.

Shape memory polymers (SMP) are new multifunctional materials raising increasing interest in various functional applications. Among them, polyurethane shape memory polymers (PU-SMP) are particularly attractive due to their combination of shape memory, high strength and biocompatible properties. Developing new applications for PU-SMP requires comprehensive research on their characteristics. This work involved investigating the structure and mechanical behavior as well as characterizing the energy storage and dissipation of a thermoplastic PU-SMP with a glass transition temperature (Tg) of 25_C during tensile loading-unloading. The process of energy storage and dissipation in the PU-SMP was investigated based on the stress-strain curves recorded by a quasi-static testing machine and the temperature changes, accompanying the deformation process, obtained by using a fast and sensitive infrared camera. The results showed that the thermomechanical behavior of the examined PU-SMP depends significantly on the strain rate. At a higher strain rate, there are higher stress and related temperature changes, which lead to greater energy dissipation. However, the energy storage values estimated during the deformation process turned out to be not significant, indicating that the work supplied to the PU-SMP structure during loading is mainly converted into heat. It should also be noted that the structural investigation revealed no crystalline phase in the investigated PU-SMP.