Effect of Superimposed Vibrations on Droplet Oscillation Modes in Prilling Process

This article was aimed to solve an urgent problem of ensuring quality for prilling processes in vibrational prilling equipment. During the research, the need for the application of vibrational prilling to create a controlled impact on the process of jet decay on droplets with the proper characteristics was substantiated. Based on the experimental and theoretical studies of the process of decay of a liquid jet into drops, axisymmetric droplet oscillation modes for the different frequencies were observed. Frequency ranges of transition between modes of decay of a jet into drops were obtained. As a result, the mathematical model of the droplet deformation was refined. The experimental research data substantiated this model, and its implementation allowed determining the analytical dependencies for the components of the droplet deformation velocity. The proposed model explains the existence of different droplet oscillation modes depending on the frequency characteristics of the superimposed vibrational impact. Based on an analytical study of the droplet deformation velocity components, the limit values of the characteristics defining the transition between the different droplet oscillation modes were discovered. Analytical dependencies were also obtained to determine the diameter of the satellites and their total number.

Interaction of Creep and High Cycle Fatigue of IN 713LC Superalloy

The study deals with the interaction of creep and high cycle fatigue of cast polycrystalline nickel-based superalloy IN 713LC at high temperatures. Previous works indicated that creep lifetime of superalloy structures was un-affected or even slightly increased in the cases with superimposed vibrations. The reason for this behaviour was not well described up to now. Therefore, set of fatigue tests was conducted at high mean stresses level to observe this phenomenon. The mean stress was kept constant while the stress amplitudes were selected in order to measure wide range of conditions from pure creep to pure fatigue. Fractographic analysis by scanning electron microscopy (SEM) was done with the aim to identify governing damage mechanisms for particular test conditions as a preliminary evaluation of conducted tests.

Concurrent Repeated-Sprint and Resistance Training With Superimposed Vibrations in Rugby Players

Purpose:To examine the effect of repeated-sprint training (RST) vs combined RST and resistance training with superimposed vibrations on repeated-sprint ability (RSA) and lower-body power output in male rugby players.Methods:Players were divided into 2 training groups. One group performed RST (n = 10) 2 d/wk and the other performed RST 1 d/wk and squat resistance training with superimposed vibrations on the second day (RS+ST; n = 10). The squat training was carried out with a volume similar (ie, number of sets and repetitions) to that of the RST. The training period lasted 6 wk, and it was carried out as a supplement to the regular rugby training sessions.Results:Substantial improvements in RSA mean time (RSAmean; +2.3%/ES: 0.77 vs +4.1%/ES: 0.91), RSA percent decrement (%Dec; –25.6%/ES: 1.70 vs –23.2%/ES: 0.99), and squat absolute power output (+5.0%/ES:0.36 vs +17.2%/ES: 0.93) were obtained in RST and RS+ST, respectively. Substantial improvements in RSA best time (RSAbest; +2.6%/ES: 0.61) and squat power output normalized to body mass (+18.6%/ES: 0.76) only occurred in RS+ST. Both pretest and posttest RSAmean were largely correlated with the RSAbest. However, there were only unclear, small to moderate correlations between individual changes in squat power output and either RSAmean or RSAbest.Conclusion:Combined RST and resistance training induced improvements of greater magnitude in both repeated-sprint performance and muscle power output than the RST alone. The lack of substantial correlations between individual changes in repeated-sprint and muscle-power performance suggests that the same subjects were not systematically low or high responders to both RST and strength training.