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Recently, researchers proposed that a second-order effect, acoustic streaming, induced aerosol depositions as a noninvasive aerosol removal technique. However, the acoustic streaming patterns, which determined the deposition efficiencies, were merely observed but not investigated. This article studied this correlation by both experimental and numerical methods. By keeping the sound frequency and sound pressure level constant, the acoustic streaming field was varied by the dimensions of the air duct and ultrasonic radiating plate. The numerical model was validated by the experimental results on three accounts, acoustic streaming patterns, velocity vectors, and deposition trends. Two new parameters, acoustic deposition ratio and near wall vorticity magnitude, were introduced to measure and predict the correlation between variation of the acoustic fields and deposition efficiencies. It was found that the geometry that produced a high vorticity magnitude near the deposition surfaces provided the condition to induced high occurrence for aerosols depositions (up to 3.5 times the rate caused by nature deposition). The finding in this study provided a method to quantify acoustic streaming fields, and the correlation between such quantity and the related deposition performance. This provides a guideline for designing acoustic aerosol manipulation devices, which aims to cause deposit with a noninvasive method. Copyright © 2016 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

We developed a video-assisted gliding test to evaluate the gliding force and the flexion angle with unrestricted joint motion. Tendon adhesion was induced in a chicken model of flexor digitorum profundus (FDP) injury at the annular pulley region of the long toe. The chicken feet were harvested immediately after injury, and 2 weeks and 6 weeks after injury. During the gliding test, the injured FDP was pulled for 15 mm then returned to its initial position. The test was recorded using a video camera and registered to the gliding test mechanical data. The maximum flexion angle and gliding resistance were calculated. The maximum flexion angle was significantly decreased from 78 (SD 10) in controls to 42 (SD 22) in tendons with injury, while gliding resistance was significantly increased in week 2 (0.06, SD 0.05) and week 6 (0.07, SD 0.01) after injury. [ABSTRACT FROM PUBLISHER]

This paper proposes a new part clustering algorithm that uses the concept of ant-based clustering in order to resolve machine cell formation problems. The three-phase algorithm mainly utilizes distributed agents which mimic the way real ants collect similar objects to form meaningful piles. In the first phase, an ant-based clustering model is adopted to form the initial part families. For the purpose of part clustering, a part similarity coefficient is modified and used in the similarity density function of the model. In the second phase, the K-means method is employed in order to achieve a better grouping result. In the third phase, artificial ants are used again to merge the small, refined part families into larger part families in a hierarchical manner. This would increase the flexibility of determining the number of final part families for the factory layout designer. The proposed algorithm has been developed into a software system called the ant-based part clustering system (APCS). In addition to part family formation, APCS performs the tasks of machine assignment and performance evaluation. Finally, performance evaluation of the proposed algorithm was conducted by testing some well-known problems from literature. The evaluation results show that the algorithm is able to solve the cell formation problems effectively. [ABSTRACT FROM AUTHOR]

During the COVID-19 pandemic, WHO and CDC suggest people stay 1 m and 1.8 m away from others, respectively. Keeping social distance can avoid close contact and mitigate infection spread. Many researchers suspect that suggested distances are not enough because aerosols can spread up to 7-8 m away. Despite the debate on social distance, these social distances rely on unobstructed respiratory activities such as coughing and sneezing. Differently, in this work, we focused on the most common but less studied aerosol spread from an obstructed cough. The flow dynamics of a cough jet blocked by the backrest and gasper jet in a cabin environment was characterized by the particle image velocimetry (PIV) technique. It was proved that the backrest and the gasper jet can prevent the front passenger from droplet spray in public transportation where maintaining social distance was difficult. A model was developed to describe the cough jet trajectory due to the gasper jet, which matched well with PIV results. It was found that buoyancy and inside droplets almost do not affect the short-range cough jet trajectory. Infection control measures were suggested for public transportation, including using backrest/gasper jet, installing localized exhaust, and surface cleaning of the backrest., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 Elsevier Ltd. All rights reserved.)

Background: Expiratory droplets cause high infection risk to nearby passengers via airborne route., Methods: We built a two-row four-seat setup to simulate a public transport cabin. A cough generator and a nebulizer were used to simulate the cough and talk processes respectively. Exposure and infection risk of nearby passengers was studied. The effect of gasper jet and backrest on risk mitigation was investigated., Results: For the activity of coughing, the front passenger has much higher infection risk, which was around four times of that of other passengers, because of the concentration surge in the inhalation zone. For talking, the nearby passengers have similar infection risk because nearby passengers were all exposed to concentration surges with similar peak value. Gasper jet of the infected passenger and higher backrest can extinguish or reduce the concentration surge of front passengers and reduce the infection risk due to coughing and talking droplets., Conclusion: The passengers near the infected passenger have very high infection risk. The overhead gasper and a higher backrest can reduce the exposure and mitigate the risk of infection. It is believed that the control measures to protect nearby passengers are urgently needed in public transport cabins., (Copyright © 2022 Elsevier Ltd. All rights reserved.)