Increasing concerns about the spread of airborne pathogens such as severe acute respiratory syndrome (SARS) and novel swine-origin influenza A (H1N1) have attracted public attention to bioaerosols and protection against them. The airborne pathogens are likely to be expelled from coughing or speaking, so the physical data of the exhaled particles plays a key role in analyzing the pathway of airborne viruses. The objective of this study was to analyze the initial velocity and the angle of the exhaled airflow from coughing and speaking of 17 males and 9 females using Particle Image Velocimetry (PIV) and acrylic indoor chamber. The results showed that the average initial coughing velocity was 15.3 m/s for the males and 10.6 m/s for the females, while the average initial speaking velocity was 4.07 m/s and 2.31 m/s respectively. The angle of the exhaled air from coughing was around 38° for the males and 32° for the females, while that of the exhaled air from speaking was around 49° and 78° respectively. Also, the linear relation between the tested subject's height and their coughing and speaking velocity was shown in this study.
We investigated the characteristics of charged aerosols produced by high-voltage power lines (HVPLs) to explore the effects on respiratory disease incidence among those who handle HVPLs. Charged aerosol currents and charged aerosol concentrations were measured over 24 h at 12 sites. Aerosol current effective levels were 2.7 times higher compared to exposed and control sites. This pattern of relative enhancement at exposed sites was seen consistently in all measurements and the difference was 1.7 higher at exposed sites. Correlation analysis among all important variables revealed strong positive correlations between currents and concentration, currents and magnetic field, humidity and concentration, and humidity and particles of 10 µm or less (PM), while negative correlations were observed between charged aerosol concentrations and wind velocity and between wind velocity and humidity. Estimated production of charged aerosols from HVPLs found that people who work with HVPLs are highly likely to be exposed to charged aerosols.
LiOH is known to be one of the most efficient CO2adsorbent because it reacts with CO2to form Li2CO3. However, LiOH still suffers from lack of enough hardness for practical use. In this study, various substrates, were modified with LiOH. Their X-ray diffraction patterns were investigated, and LiOH peak was observed from all prepared samples. CO2adsorption capacity of each prepared sample was measured by monitoring CO2concentration change during the adsorption process under constant CO2gas inflow condition. LiOH-modified Al2O3and zeolite 5A showed good CO2adsorption performance, while LiOH-modified AC and SiO2showed relatively poor CO2adsorption. Al2O3and zeolite 5A contains many basic functional groups of Al3+, which promote the neutralization reaction with acidic CO2. The effect of carrier gas, carrier gas flow rate, initial CO2concentration, and amount of LiOH-modified Al2O3loading was investigated. CO2 adsorption performance was better when the carrier gas was N2, because O2competes with CO2on LiOH. CO2adsorption performance was better with lower carrier gas flow rate, lower initial CO2concentration, and less loading of adsorbent due to the increase of contact time and contact points.
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