It starts from a planetary mechanism that generates hypocycloids and it is completed with an RPP dyad, so that transfer functions are generated, i.e. races along the x and y directions. Different hypocycloids (normal, elongated, shortened) are generated and transfer functions are established for these cases. The obtained curves and transfer functions are discussed, establishing some conclusions. All study includes various range of lengths for the cinematic links so the important and interesting trajectories are found. The related transfer functions can be used in a diversity of applications. These findings are useful for special devices for automatic lathes, horizontal forging machines, textile machinery, and kinetic art.

In this paper there are presented the influence of the various parameters which could be involved in the collapse of the roof concrete structures of the Cluj Sports Hall in February 15th 1961 soon after the total solar eclipse. This study takes into consideration the multiple causes for the collapse include the thermal shock due to the solar eclipse, the inappropriate projection of the roof and the cracks in the structure after winter and exactly the rain conditions in previous night of the collapse. This parameters where involved in modeling the structure with SCIA Engineer v16.0. The conclusions of this study reveals as a major factor for collapse the rising the weight of the roof structure due to water accumulation in the cracks of the roof and the secondary cause the superposition of the specific thermal field due to the total solar eclipse. Using the Energonics principles, the superposition of the two main loads (mechanical and thermal), there were performed a lot of iterations in ETABS analysis to determine the load which is responsible for collapse. In these days, the standards for roofs with these dimensions of openings are completely changed. The significance of this study is bonded with superposition of the natural effects above the structures and the partition of their influence. Also this study can be used as a critical analysis of the type of projecting the roof structures in 1960s. This paper presents also a hypothetical analysis with accumulation of snow beside of the other factors involved.

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