Boiling is an essential process for many industrial applications, such as refrigeration, distillation, and chemical processes. The effectiveness of the heat transfer processes determines the efficiencies of these applications. This study presents the experimental data analysis for pool boiling performance of 0.10, 0.15, and 0.20 wt.% of multiwall carbon nanotubes/water nanofluid on smooth and straight, square, and circular grooved surfaces. According to the experimental results, the configuration S4 with a 30 mm deep circular groove inclined at a 45 angle and 33% higher than the base fluid on the smooth surface had the greatest enhancement in boiling heat transfer coefficient. The result indicated that the inclination of the circular groove had the potential to enhance significantly the pool boiling heat transfer process. Furthermore, this study demonstrated that analyzing the effectiveness of nanofluids in a variety of concentrations and geometrical configurations of heat transfer surfaces is still essential and desirable.

The purpose of this study is to understand electromyographic parameters of selected shoulder and arm muscles in water polo shots. The study was carried out with a group of 12 water polo players. Signals were recorded by surface electromyography (EMG) from the pectoralis major (PM), anterior deltoid (AD) and middle deltoid (MD), biceps brachii (BB), triceps brachii (TB), and wrist flexor (WF) muscles. The average and standard deviation of the normalized electrical activity and duration of the muscles were determined during four different water polo shots in water polo players. Post hoc analysis among muscles revealed that PM and AD showed significantly different amplitude values among water polo shots. Because the PM and AD must relax to perform the horizontal abduction necessary in the backhand shot, the amplitude was significantly lower than during overhead, push, or penalty shots. Similarly, the push shot requires elbow extension of a horizontally adducted and internally rotated shoulder; therefore, the AD has greater amplitude during this shot and TB was activated for longer periods of shots required for the elbow extension. There was little difference observed in WF and BB. Thus, this result suggests that these muscles played a similar role during penalty, overhead, and push shots. Therefore, coaches should emphasize the strength, endurance, and flexibility training of the PM and AD that may improve shooting velocity. However, the stabilizing role of the BB and TB is an important factor for overall performance and should also be considered.