The aim of this research was to experimentally analyse the possibility of using a rubber hose placed inside a pipeline to mitigate the water hammer phenomenon. The experiments were conducted using a steel pipeline with an inner diameter of 53 mm and an EPDM rubber hose with a diameter of 6 mm. Hydraulic transients were induced by a rapid closure of the valve located at the downstream end of the pipeline system. In order to analyse the influence of steady-state flow conditions on the maximum pressure increase, measurements were carried out for different values of initial pressure and discharge. The experimental results indicate that placing a rubber hose inside a pipeline can substantially attenuate valve-induced pressure oscillations. It was observed that the initial pressure has a significant influence on the capacity of the rubber hose to dampen the water hammer phenomenon. Comparative numerical calculations were performed using the Brunone–Vitkovský instant acceleration-based model of unsteady friction. It was demonstrated that this approach does not allow satisfactory reproduction of the observed pressure oscillations due to the viscoelastic properties of the EPDM hose used in the tests.

Novel tendinopathy treatment protocols should be assessed for safety. The goal of this work was to compare differences in selected systemic inflammatory marker concentrations after two treatment protocols for collagenase induced Achilles tendinopathy in sheep. 14 sheep (aged 5 and 6 years, Polish Mountain Sheep breed, weight 60-70kg) were injected with bacterial collagenase type 1A-S (Clostridium histolyticum, C-5894, Sigma Aldrich, Poznań, Poland) bilaterally to Achilles tendons. Subsequently, the animals were injected with Platelet Rich Plasma (7 sheep) or Adipose Derived Stem Cells (7 sheep) to induced tendinopathy foci. Left limbs of all sheep were additionally treated with Radial Pressure Wave Therapy (RPWT) focused above the tendinopathy origins. Treatment progress was controlled by ultrasound scans, and tendon samples were taken on the 126th day of the experiment. Serum Amyloid A (SAA) concentration showed mild elevation before the experiment (2 sheep from group I, 4 sheep from group II) and two days after the intratendinous growth factors injection ( 4 sheep from group I, 3 sheep from group II) combined with RPWT (mean 22,63 mg/L and 53, 6 mg/L respectively). Haptoglobine (Hp) concentration increased from 0 to 0,01 g/L in 2 animals from group I two days after injection. These values declined to 0 during the course of the treatment. Fibrinogen (Fb) concentrations were within reference levels throughout the research, although mild elevation was observed before the treatment course in 6 sheep from group I and 1 sheep from group II. In conclusion, addition of RPWT to growth factors injections in the treatment of yatrogenic Achilles tendinopathy in sheep did not induce systemic inflammatory response.