The report describes a laboratory test method to predict the initial retroreflectivity of pavement markings in the field based on the quality of the applied glass beads.
TRB's National Cooperative Highway Research Program (NCHRP) Research Results Digest 346: Optical Sizing and Roundness Determination of Glass Beads Used in Traffic Markings summarizes the results of a project that examined the precision and bias of both optical and traditional mechanical methods for different glass bead types. The project also compared the precision and bias of various measurement methods, and explored development of a practice for the use of computerized optical methods and equipment to measure the size and roundness of glass beads used in traffic markings. The final report on this project was published as NCHRP Web-Only Document 156.
This is a review of 190 years of literature on copper and its alloys. It integrates information on pigments, corrosion and minerals, and discusses environmental conditions, conservation methods, ancient and historical technologies.
Visitors to Yellowstone National Park are drawn to the spectacular scenery, unique thermal features, and the large numbers of wild animals easily observed in their natural habitat. The thoughtful visitor to the park cannot help but be captivated by the unparalleled breadth of scientific knowledge needed to understand the intricate interrelationships that make up the yellowstone landscape. Knowing Yellowstone explores how scientists discover what they know about America's first national park and the surrounding lands. The chapter authors are scientists who represent the best of their fields of study. The science they describe is leading the way to our understanding of complex ecosystems worldwide.