Mid-term Exam 2018 Autumn Term

1. Steel is tougher than pure iron because small amount of carbon is mixed into iron.

2. Cast iron contains more than steel to lower melting temperature so that it is easier to produce liquid iron for shape molding. It also further increases the hardness so to make it suitable for building iron bridges.

3. Steel is a metal and therefore easily bended, while dried harden is not bendable. Concrete with steel inside make combined structure resistant to load on a horizontal beam. That changes the appearance of modern cities.

4. High sky cranes are important tool to build sky scrapers, when constriction finished, they can be disassembled into components small enough to be sent back down to ground by lift (elevator).

5. Those pipe / tube / channel build deepest below surfaces are clean dirty water sewer pipe to make sure isolate from people living in that city.

6. When an arch shape bridge take loading from above, all internal components undergo and compression force, so steel, concrete and even rocks are all very suitable for building this type of bridges.

7. Treatment of fresh water require alum to be added into water.

8. Removal of toxic substance to plant and animals (including human) so the river and ocean will not be poisoned is the major purpose of domestic sewer water treatment in cities.

9. Sometime typhoon cause fresh water supply interrupted simply because the too high density mud and send in water intake, that is why water soil preservation is important at near water dam area.

10. Chlorine concentration in faucet water at the home user end should be as low as possible to keep people healthy, and this is how national standard set.

11. The only reason for using Extremely Ultra High Voltage to electricity from power plant to cities is to reduce energy lost during the transmission.