No abstract

The relationship between noise and human performance is a crucial topic in ergonomic research. However, the brain dynamics of the emotional arousal effects of background noises are still unclear. The current study employed meaningless speech noises in the n-back working memory task to explore the changes of event-related potentials (ERPs) elicited by the noises with low arousal level vs. high arousal level. We found that the memory performance in low arousal condition were improved compared with the silent and the high arousal conditions; participants responded more quickly and had larger P2 and P3 amplitudes in low arousal condition while the performance and ERP components showed no significant difference between high arousal and silent conditions. These findings suggested that the emotional arousal dimension of background noises had a significant influence on human working memory performance, and that this effect was independent of the acoustic characteristics of noises (e.g., intensity) and the meaning of speech materials. The current findings improve our understanding of background noise effects on human performance and lay the ground for the investigation of patients with attention deficits.

This is a repository copy of Experimental study on operating characteristics of a dual compensation chamber loop heat pipe in periodic acceleration fields.

Murine models have been widely used to investigate the mechanobiology of aortic atherosclerosis and dissections, which develop preferably at different anatomic locations of aorta. Based MRI and finite element analysis with fluid–structure interaction, we numerically investigated factors that may affect the blood flow and structural mechanics of rat aorta. The results indicated that aortic root motion greatly increases time‐averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), displacement of the aorta, and enhances helical flow pattern but has limited influence on effective stress, which is highly modulated by blood pressure. Moreover, the influence of the motion component on these indicators is different with axial motion more obvious than planar motion. Surrounding fixation of the intercostal arteries and the branch vessels on aortic arch would reduce the influence of aortic root motion. The compliance of the aorta has different influences at different regions, leading to decrease in TAWSS and helical flow, increase in OSI, RRT at the aortic arch, but has reversed effects on the branch vessels. When compared with the steady flow, the pulsatile blood flow would obviously increase the WSS, the displacement, and the effective stress in most regions. In conclusion, to accurately quantify the blood flow and structural mechanics of rat aorta, the motion of the aortic root, the compliance of aortic wall, and the pulsation of blood flow should be considered. However, when only focusing on the effective stress in rat aorta, the motion of the aortic root may be neglected.

In this article, a combined experimental and theoretical study has been conducted to investigate the operating characteristics of a dual compensation chamber loop heat pipe (DCCLHP) with ammonia as the working fluid under acceleration force conditions. The DCCLHP with nickel wick consists of a cylindrical evaporator and dual compensation chambers at both ends of evaporator. In the current study, a new DCCLHP test rig was setup which can provide the acceleration up to 11 g. Two types of loading mode were utilized for applying heat load prior to acceleration. The heat load ranges from 25 W to 300 W. Comparisons of operating performance of the DCCLHP were carried out under both gravity and acceleration conditions. A novel centrifugal force assist concept is proposed to address the observed operating behavior.Experimental results show that: (i) the acceleration effect with the proposed orientation could improve the operation performance of the DCCLHP which may operates at the centrifugal force driven mode and capillary-centrifugal force co-driven mode. The operating temperature profile at different heat loads shows "/-shape" oblique line with the increase of the acceleration; (ii) the transition heat load from centrifugal force driven mode to capillary-centrifugal force co-driven mode changes with the variation of acceleration magnitude at both loading modes; (iii) the acceleration effect on the operating temperature is remarkably significant as the heat load is less than 100 W. The operating temperature under acceleration conditions is apparently lower than that under terrestrial gravity; (iv) the coupling change of the loop pressure, vapor-liquid distribution, two-phase flow and heat transfer caused by acceleration effect leads to the unique operation performance of the DCCLHP.