In the three years of the CC-STADUS Project more than thirty cross-curricular hundred single discipline models have been developed by project staff and participants. These models and their accompanying curriculum are intended to expose students to the use of system dynamics as a problem solving tool, as well as to address the problems presented in their specific content. Patterns have emerged that point out the dangers and advantages of both types of models. In part, these patterns are a result of the techniques used to teach the teachers basic modeling skills, as well as their needs in the classroom. The experiences of the CC-STADUS staff and participants lead to recommendations and suggestions for model development, model documentation, and training programs for teachers.
The recycling of automobiles in North America represents one of the most successful--if not the most successful--examples of material recovery. This activity is sustained by a large industry constituted by several parties: consumers, dismantlers, remanufactures, transportation companies, material recycling companies, metal enterprises, landfills, and to certain extent, the automobile. It is estimated that approximately 94% of the vehicles being retired are processed by the recycling industry. From these, approximately 75% of the total mass is recovered. The other 25% is normally sent to landfills. These recovery rates are even more impressive considering that approximately 10 million cars are disposed yearly in North America. This is an industry that processes almost ten million tons of material per year.
This paper will report ongoing studies of the dynamics of urban growth in Brasilia, the capital of Brazil. The study is related to the literature in urban dynamics, but it is centered upon the transient dynamics of a planned city. Today, only 35 years after its inauguration, Brasilia houses a population of almost two million people--nearly twice the number originally estimated by urban planners. The original plans for the city have obviously been replaced by the internal dynamics of growth in the area. No longer is the city's only mission to serve as the federal capital for the nation. The number of federal jobs has been stable for several years while the city's population continues to grow.