374 18.Economic and Environmental Considerations 1.4 10 1.2 8 6 Sn 1.0 2 (punod/s) 0.8 60*70'80902000 0.6 0.4 0.2 Steel 0 1 1900*102030'40506070'80902000 Year FiGURE 18.1.The price per pound of some commonly used industrial materials from 1900 to 2000 in the United States.Prices are not cor- rected for inflation.For plastics,see Table 18.1.[Source:U.S.Bureau of Mines,U.S.Department of the Interior.] portation,and by the usage of leaner ores.Short-term fluctua- tions depend on speculators,supply and demand,and political factors such as strikes and wars.For example,the steep price in- creases in the late 1970s were caused by the OPEC oil embargo and by the removal of government price controls. It is interesting in this context to compare the prices of met- als with those of plastics.The prices of polymeric materials vary, however,with types and properties,and can therefore not be readily included in Figure 18.1.For this reason Table 18.1 lists the cost of plastics as published on August 4,2003.It is noticed that the cost of steel based on weight is essentially still lower than that for plastics.This is,however,not always true if the price is based on volume. 18.2.Production Volumes Figure 18.2 displays the production volumes of various materi- als over the past 16 years.It can be learned from this graph that timber and concrete are essentially the most widely used ma- terials in the United States.(It needs to be kept in mind thatportation, and by the usage of leaner ores. Short-term fluctua￾tions depend on speculators, supply and demand, and political factors such as strikes and wars. For example, the steep price in￾creases in the late 1970s were caused by the OPEC oil embargo and by the removal of government price controls. It is interesting in this context to compare the prices of met￾als with those of plastics. The prices of polymeric materials vary, however, with types and properties, and can therefore not be readily included in Figure 18.1. For this reason Table 18.1 lists the cost of plastics as published on August 4, 2003. It is noticed that the cost of steel based on weight is essentially still lower than that for plastics. This is, however, not always true if the price is based on volume. Figure 18.2 displays the production volumes of various materi￾als over the past 16 years. It can be learned from this graph that timber and concrete are essentially the most widely used ma￾terials in the United States. (It needs to be kept in mind that FIGURE 18.1. The price per pound of some commonly used industrial materials from 1900 to 2000 in the United States. Prices are not cor￾rected for inflation. For plastics, see Table 18.1. [Source: U.S. Bureau of Mines, U.S. Department of the Interior.] 374 18 • Economic and Environmental Considerations 1.4 1.2 1.0 0.8 0.6 Price ($/pound) 0.4 0.2 0 1900 ’10 ’60 2 4 6 8 Sn 10 ’70 ’80 ’90 2000 ’20 ’30 ’40 ’50 Year Steel Cu Sn Zn Al Pb Zn Al Cu ’60 ’70 ’80 ’90 2000 18.2 • Production Volumes