The economic effects of 2018 U.S. Steel Tariffs: An Application of Event Study Methodology

In this essay I investigate the effect of United States March 2018 steel tariffs on producers’ capital. I use intertemporal event study methodology to appraise the effect of announcement of the tariffs on March 01, 2018 on the stock returns of major US steel companies listed at New York Stock Exchange. I use data from Yahoo finance and include 17 US based companies in the analysis. The results show that major steel manufacturers saw a positive shift in their returns due to the event. Steel consumer companies included in the study showed significantly negative returns on the event day. I include 5 US Tech firms in the control group. The event did not affect their returns. Our evidence shows that the efficient market hypothesis holds in this case. Further, as posited by the economic theory, the tariffs reduced overall efficiency in the market

Unsteady Helical Flows of a Size-Dependent Couple-Stress Fluid

The helical flows of couple-stress fluids in a straight circular cylinder are studied in the framework of the newly developed, fully determinate linear couple-stress theory. The fluid flow is generated by the helical motion of the cylinder with time-dependent velocity. Also, the couple-stress vector is given on the cylindrical surface and the nonslip condition is considered. Using the integral transform method, analytical solutions to the axial velocity, azimuthal velocity, nonsymmetric force-stress tensor, and couple-stress vector are obtained. The obtained solutions incorporate the characteristic material length scale, which is essential to understand the fluid behavior at microscales. If characteristic length of the couple-stress fluid is zero, the results to the classical fluid are recovered. The influence of the scale parameter on the fluid velocity, axial flow rate, force-stress tensor, and couple-stress vector is analyzed by numerical calculus and graphical illustrations. It is found that the small values of the scale parameter have a significant influence on the flow parameters