Washington — The Trump administration has begun erecting a 30-foot-high border wall that will cut through federally protected land in Arizona, despite warnings from Democratic lawmakers and activists ...

Flow control is important, but the impact element of impact barriers is most relevant when protecting stationary assets. In a busy warehouse yard, reversing accidents are all too common. Lighting ...

The classical concept of immune privilege as an exclusion of immune cells has been extended to include sites of immune tolerance induction, such as the intestine. Barriers can be grouped into three ...