The paper proposes three multi-criteria decision-making (MCDM) methods for the selection

of an industrial robot for a universal, flexible assembly station, taking into consideration the

technical and performance parameters of the robot. Fuzzy versions of AHP and TOPSIS

methods as well as SMART were chosen from the variety of MCDM methods as they represent

different attitudes to analysis. In order to minimise the impact of the method applied on

the final decision, a list of results of the analyses has been developed and a final classification

has been made based on decision makers’ preferences concerning selected parameters of the

robot.

This study aims to investigate and compare the thermal performance of a solar air heater using a passive technique to enhance heat transfer between the absorber plate and the flowing fluid. The technique involves generating turbulence near the heat transferring surface through the use of artificial rib roughness. The study focuses on two different novel roughness geome-tries: full symmetrical arc rib roughness and half symmetrical arc rib roughness. By introducing additional gaps and varying the number of gaps in the roughness geometries, the study examines their effects on the solar air heaters thermal performance. The artificially roughened surface creates different turbulent zones, which are essential to the development of different types of turbulence in the vicinity of the heat transferring surface. The study finds that an optimal escalation in Nusselt number and friction factor by 2.36 and 3.45 times, respectively, occurs at certain gap numbers as 6 and ng as 5 for full symmetrical arc rib roughness. The maximum thermal-hydraulic performance parameter of 1.66 is attained at a Reynolds number of 6 000. The study also conducts correlation, mathematical modeling, and performance prediction under different operating circumstances.