Search

Objective: To investigate the effect of music on heart rate recovery (HRR) and heart rate variability (HRV) after intense exertion. Methods: Five hundred male students enrolled at Yongin University, Korea, underwent a cycling test to assess aerobic capacity; 180 students with equal scores were selected for a music intervention, which was conducted after vigorous exercise. The 180 participants were randomized into three music groups and a control group; the participants in each music group listened to music at three different tempos: slow (lento) (n = 45), moderate (moderato) (n = 45), and fast (allegretto) (n = 45). The control group did not listen to music (n = 45). After the test, data on cardiac recovery and HRV were gathered and modeled. Results: The results revealed no significant variation in HRR and HRV indexes between the four cohorts (p >.05), and no significant differences were observed in the anaerobic power cycling indexes during strenuous exercise (p >.05). The music intervention had a significant impact on HR, low‐frequency power (LF), high‐frequency power (HF), normalized LF (LFnorm), normalized HF (HFnorm), and the LF/HF ratio during recovery (p <.05). Conclusion: After rigorous activity, listening to allegretto music improved HRR and restored HRV equilibrium, which is critical to preventing and minimizing arrhythmias and sudden cardiac death. [ABSTRACT FROM AUTHOR]

Recently, the stringent international regulations on ship energy efficiency and NOx emissions from ocean-going ships make energy conservation and emission reduction be the theme of the shipping industry. Due to its fuel economy and reliability, most large commercial vessels are propelled by a low-speed two-stroke marine diesel engine, which consumes most of the fuel in the ship. In the present work, a zero-dimensional model is developed, which considers the blow-by, exhaust gas bypass, gas exchange, turbocharger, and heat transfer. Meanwhile, the model is improved by considering the heating effect of the blow-by gas on the intake gas. The proposed model is applied to a MAN B&W low-speed two-stroke marine diesel engine and validated with the engine shop test data. The simulation results are in good agreement with the experimental results. The accuracy of the model is greatly improved after considering the heating effect of blow-by gas. The model accuracy of most parameters has been improved from within 5% to within 2%, by considering the heating effect of blow-by gas. Finally, the influence of blow-by area change on engine performance is analyzed with considering and without considering the heating effect of blow-by. [ABSTRACT FROM AUTHOR]

Two‐dimensional transition‐metal dichalcogenides (TMDs) have attracted widespread interests owing to their attractive physical and chemical properties. In particular, they are especially attractive in the field of electrochemical biosensors. In this study, the properties of TMDs ((molybdenum sulfide (MoS2), molybdenum diselenide (MoSe2) and molybdenum telluride (MoTe2)) on the glucose sensing were explored and compared. Exfoliated MoS2, MoSe2 and MoTe2 nanosheets with basically the same size were fabricated through controlling the ultrasonic power. The structure and morphological characteristics of MoS2, MoSe2 and MoTe2 were examined through scanning electron microscopy, transmission electron microscopy, X‐ray photoelectron spectroscopy and powder X‐ray diffractometer. Electrochemical properties were analyzed through cyclic voltammetry and differential pulse voltammetry. Results showed that all the three kinds of TMDs can enhance the electroconductibility of the electrodes. When incorporated into the construction of electrochemical biosensors for glucose detection, all of the three kinds of exfoliated TMDs modified electrodes possessed achieved analytical requirements of selectivity, wide linear ranges, as well as low limits of detection and quantification. In particular, MoS2‐based biosensor generated a higher specificity and lower detection limit than that of MoSe2 and MoTe2. This is imperative to showcase the real potential of TMDs in electrochemical biosensors. [ABSTRACT FROM AUTHOR]