Voluntary physical distancing is essential for preventing the spread of COVID-19. We assessed the role of political partisanship in individuals’ compliance with physical distancing recommendations of political leaders using data on mobility from a sample of mobile phones in 3,100 counties in the United States during March 2020, county-level partisan preferences, information about the political affiliation of state governors, and the timing of their communications about COVID-19 prevention. Regression analyses examined how political preferences influenced the association between governors’ COVID-19 communications and residents’ mobility patterns. Governors’ recommendations for residents to stay at home preceded stay-at-home orders and led to a significant reduction in mobility that was comparable to the effect of the orders themselves. Effects were larger in Democratic- than in Republican-leaning counties, a pattern more pronounced under Republican governors. Democratic-leaning counties also responded more strongly to recommendations from Republican than from Democratic governors. Political partisanship influences citizens’ decisions to voluntarily engage in physical distancing in response to communications by their governor.

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A novel paraffin-based blends fuel prepared from pure paraffin wax of the alkane family with polyethylene of the alkene family is proposed and tested in a slab motor to visualize the droplet entrainment mechanism followed by a hybrid rocket motor test to analyze its combustion characteristics. The mechanical strength of the proposed blended fuel is investigated by increasing the polyethylene weight percent. The overall regression rate of 5 wt % of polyethylene with 95 wt % of pure paraffin is found to be 3.9 factors higher than that of a pure polyethylene. Improved combustion efficiency under the condition of a similar oxidizer mass flow rate range is achieved with respect to pure paraffin fuel in which performance gain is comparable to that of the SP-1a fuel of Stanford University. Spectrum analysis of the chamber pressure shows no critical instability mode for the range of this study. The blend fuel is found to be comparatively effective for the hybrid rocket fuel in terms of mechanical strength, combustion efficiency, combustion instability, and combustion performance. Nomenclature A f = cross-sectional area of final chamber, m 2 A i = cross-sectional area of initial chamber, m 2 A pf = cross-sectional area of final grain port, m 2 A pi = cross-sectional area of initial grain port, m 2 A t = exhaust nozzle throat area, m 2 a = regression rate coefficient c exp = experimental characteristic velocity, m∕s c theo = theoretical characteristic velocity, m∕s D pf = diameter of final grain port, m D pi = diameter of initial grain port, m G o = time-space-averaged oxidizer mass flux, kg∕m 2 -s H f = height of final slab fuel grain, m H i = height of initial slab fuel grain, m L f = fuel grain length, m _ m ent = entrained mass flux from fuel surface, kg∕m 2 -s _ m o = time-averaged oxidizer mass flow rate, g∕s n = oxidizer mass flux exponent P c = chamber pressure, MPa _ r = time-space-averaged fuel regression rate, mm∕s t b = burning time, s W f = fuel grain width, m α = dynamic pressure exponent β = thickness exponent γ = viscosity exponent η c = efficiency of characteristic velocity μ l = liquid layer viscosity, Pa-s π = surface tension exponent ρ f = fuel grain density, kg∕m 3 σ = surface tension, N∕m

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