Discuss this Article. They dilated my daughter's eyes 18 hours ago, and they're still dilated. Anyone that says the eyes are back to normal in 6 hours does not know what they're talking about. The job of an eye doctor is not let their patients go blind. Retinal issues are the number one cause of blindness in north america, and most limiting factor of seeing the retina is the size of the pupil.
A truss bridge is a bridge composed of connected elements (typically straight) which may be stressed from tension, compression, or sometimes both in response to loads. Truss bridges are one of the oldest types of modern bridges. The basic types of truss bridges are shown below.
A beam or girder bridge is the simplest and most inexpensive kind of bridge. According to Craig Finley of Finley/McNary Engineering, they're basically the vanillas of the bridge world. In its most basic form, a beam bridge consists of a horizontal beam that is supported at each end by piers.