Materials Selection/Society Economy Environment

Question 1

What is the Embodied Energy of a material

Answer 1

the energy needed to produce 1kg of usable material (MJ/kg)

Question 2

Why is there a difference between thermodynamics of process and actual embodied energy?

Answer 2

1. Efficiencies of processes are low
2. Only part of the output is usable (don’t forget scrap)
3. Feedstock used in the extraction carries embodied energy
4. Transportation is involved
5. Production plant has to be lit, heated, and serviced
6. Energy used to construct the plant in the first place

Question 3

What are the stages in life cycle analysis?

Answer 3

Energy and raw materials as input are put into:
Materials production
Product manufacturing 
Product use
Product disposal 

In order to get outputs like:
usable products, air emissions, solid wastes, water effluents, etc

Question 4

What are the stages in life cycle analysis?

Answer 4

Energy and raw materials as input are put into:
Materials production
Product manufacturing 
Product use
Product disposal 

In order to get outputs like:
usable products, air emissions, solid wastes, water effluents, etc

Question 5

Primary production involves ____, secondary production involves_____

Answer 5

raw materials to be used first, whereas secondary production uses in general recycled products

Question 6

What is the idea behind recycling

Answer 6

1. prevents the need to extract more raw materials
2. no need to dispose of recycled materials
3. energy requirements for refining and processing materials are usually (but not always) less than counterparts
4. Cost of recycling material is (usually) less than primary materials

Question 7

What is considered an “ideal” material

Answer 7

one that is totally recyclable or completely biodegradable

Question 8

What is the recycling behind metals

Answer 8

Many metals are biodegradable (i.e. Fe, Cu) but others such as Al are very corrosion resistance and hence “nonbiodegradable” other materials such as lead are toxic so we have some motivation to recycle. Certain metallic paints can contaminate recycling stream and as a result not be recycleable

Question 9

What is the recycling behind glass

Answer 9

Glass is inert and not biodegradable. Salvaged glass is hard and expensive to recycle, and raw materials are very cheap

Question 10

What is the recycling behind plastics

Answer 10

Chemically and biologically inert and are not bio-degradable. The overall fraction of recycled materials is low. Change in oil and gas prices or regulation can lead to change