Electroosmotic Mixing of Non-Newtonian Fluid in a Microchannel with Obstacles and Zeta Potential Heterogeneity.

This paper investigates the electroosmotic micromixing of non-Newtonian fluid in a microchannel with wall-mounted obstacles and surface potential heterogeneity on the obstacle surface. In the numerical simulation, the full model consisting of the Navier-Stokes equations and the Poisson-Nernst-Plank equations are solved for the electroosmotic fluid field, ion transport, and electric field, and the power law model is used to characterize the rheological behavior of the aqueous solution. The mixing performance is investigated under different parameters, such as electric double layer thickness, flow behavior index, obstacle surface zeta potential, obstacle dimension. Due to the zeta potential heterogeneity at the obstacle surface, vortical flow is formed near the obstacle surface, which can significantly improve the mixing efficiency. The results show that, the mixing efficiency can be improved by increasing the obstacle surface zeta potential, the flow behavior index, the obstacle height, the EDL thickness.

Growth and Persistence of Place-Based Mortality in the United States: The Rural Mortality Penalty.

OBJECTIVES: To examine 47 years of US urban and rural mortality trends at the county level, controlling for effects of education, income, poverty, and race. METHODS: We obtained (1) Centers for Disease Control and Prevention WONDER (Wide-ranging ONline Data for Epidemiologic Research) data (1970-2016) on 104 million deaths; (2) US Census data on education, poverty, and race; and (3) Bureau of Economic Analysis data on income. We calculated ordinary least square regression models, including interaction models, for each year. We graphed standardized parameter estimates for 47 years. RESULTS: Rural-urban mortality disparities increased from the mid-1980s through 2016. We found education, race, and rurality to be strong predictors; we found strong interactions between percentage poverty and percentage rural, indicating that the largest penalty was in high-poverty, rural counties. CONCLUSIONS: The rural-urban mortality disparity was persistent, growing, and large when compared to other place-based disparities. The penalty had evolved into a high-poverty, rural penalty that rivaled the effects of education and exceeded the effects of race by 2016. Public Health Implications. Targeting public health programs that focus on high-poverty, rural locales is a promising strategy for addressing disparities in mortality.

Safer Roads Owing to Higher Gasoline Prices: How Long It Takes.

OBJECTIVES: We investigated how much time passes before gasoline price changes affect traffic crashes. METHODS: We systematically examined 2004 to 2012 Mississippi traffic crash data by age, gender, and race. Control variables were unemployment rate, seat belt use, alcohol consumption, climate, and temporal and seasonal variations. RESULTS: We found a positive association between higher gasoline prices and safer roads. Overall, gasoline prices affected crashes 9 to 10 months after a price change. This finding was generally consistent across age, gender, and race, with some exceptions. For those aged 16 to 19 years, gasoline price increases had an immediate (although statistically weak) effect and a lagged effect, but crashes involving those aged 25 to 34 years was seemingly unaffected by price changes. For older individuals (≥ 75 years), the lagged effect was stronger and lasted longer than did that of other age groups. CONCLUSIONS: The results have important health policy implications for using gasoline prices and taxes to improve traffic safety.