Sphagnum riparium (Bryophyta) is recorded and described from the Wedel Jarlsberg Land on Spitsbergen, the Arctic Svalbard Archipelago. It is the northernmost known population of the species in the Northern Hemisphere. The distribution of the two known Sphagnum species in the Hornsund area, viz. S. riparium and S. squarrosum is mapped and described.

The method of the calculation of strain distribution is based on the measurements of the displacements along the length and transverse cross-section of the conical working zone. Two measuring methods have been used. In the "classical" method the typical measuring microscope equipped with goniometric table has been used. The second method based on the photogrammetric analysis of the pictures has been elaborated and proved by authors. The special computer program has been elaborated for the photograrnmetric image analysis and the later final results receiving. This method can be recommended as the best for using in the practice of researches carried out at the real object. The experiments carried out during the rolling of condenser tubes using pilgering process show that the each transverse section of input tube is twisted during successive working cycles.