环境科学交叉关系学科-课后题参考答案-第八、九章.docx

1. Early in human history, people began to use additional sources of energy to make their lives more comfortable. They domesticated plants and animals to provide a more dependable supply of food. Domesticated animals furnished a source of energy for transportation, farming, and other tasks. They provided people with a source of power other than their own muscles.

2. Transportation, Residential, commercial and industrial needs

3. Central to the Industrial Revolution was the invention of steam engine, which could convert heat energy into the energy of motion. The major heat energy producer is coal and the steam engine made possible the large-scale mining of coal. Nations without a source of coal or those possessing coal reserves that were not easily exploited thus didn’t participate in the Industrial Revolution.

4. Invention of steam engine, coal discovery and mining as well as wood shortages in densely populated areas.

5. The invention of the internal combustion engine and the automobile dramatically increased the demand for oil products. The prospering automobile industry and road construction lead to more energy consumption, creating more demand for oil.

6.
a. Government policy has kept the cost of energy artificially low and supported the automobile industry while removing support for bus and rail transport.
b. The convenience of rapid travel provided by automobiles.

7.
(1) Imposing taxes on energy
(2) Granting subsidies to energy producers

8. Electricity is both a way that energy is consumed and a way that it is supplied. (secondary energy) The transportation of electrical energy is simple and the uses to which it can be put are varied.

9.
a. The consumption of electricity
b. The government regulations
c. The availability of resources that could produce electricity

10. Residential and commercial energy use; industrial energy use; transportation energy use.

11. OPEC nations control over 75% of the world’s estimated oil reserves of 1,400 billion barrels of oil; Today’s economy is highly dependent on oil as a source of energy. Thus, OPEC countries can set the price of oil through collective action.

12.
Political:
Increased solidarity among OPEC countries and continuing political instability in the Middle East had made oil prices to peak at over US $147 per barrel in mid-2008.
Economic:
The worldwide economic recession that began about 2008 lowered the demands for energy use and people’s access to energy.

13. Despite the possibility that new rich reserves would be found, the price of nonrenewable energy would continue to rise as the availability of energy become less. But as new technologies develop and price of renewable energy goes down, maybe we can see the trend of transformation to “green industry”.

1. Coal, oil, natural gas.

2. A resource is a naturally occurring substance of use to humans that can potentially be extracted.
Reserves are known deposits from which material can be extracted profitably with existing technology under prevailing economic conditions.
Reserves are a portion of the total resource. The concept of reserves is an economic idea and is only loosely tied to the total quantity of a material present in the world.

3.
a. Discovery of new oil deposits.
b. Better drilling techniques that led to the discovery of deeper oil deposits, c. Offshore drilling that make use of oil under the ocean floor.

4. Coal was formed from plant material that had been subjected to heat and pressure. In many regions of the Earth 300 million years ago, there were many freshwater swamps, which resulted in large accumulations of plant material. And their decay was inhibited after their deaths under water. Thus, a spongy mass of organic material formed. It is thought that the chemical nature of these ancient plants and the lack of many kinds of decay organisms at that time also contributed to the accumulation. Due to geologic changes in the Earth, some of these organic deposits were submerged by seas. The plant material that had collected in the swamps was then covered by sediment. The weight of the sediment on top of the deposit compressed it and heat from the Earth caused the evaporation of water and other volatile compounds. Thus, the original plant material was transformed into coal.

5. Lignite coal has a high moisture content and is crumbly in nature. Subbituminous coal has a lower moisture content and a higher carbon content (46%-60%) than lignite. Bituminous coal has a low moisture content and a high carbon content (60%-86%). Anthracite coal is 86%-98% carbon and relatively rare.

6. Oil and natural gas probably originated from microscopic marine organisms. When these organisms died and accumulated on the ocean bottom and were buried by sediments, their breakdown released oil droplets. Gradually, the muddy sediment formed rock called shale, which contained dispersed oil droplets. In instances where a layer of porous sandstone formed on top of the oil-containing shale and an impermeable layer of rock formed on top of the sandstone, concentrations of oil often form. Natural gas, like oil, forms from fossil remains. If the heat generated within the Earth reached high enough temperatures, natural gas could have formed along with or instead of oil. This would have happened as the organic material changed to lighter, more volatile hydrocarbons than those found in oil.

7. Coal: Europe and Eurasia; Oil: Middle East; Natural gas: Middle East.

8.
A. Landscape Disturbance.
B. Acid Mine Drainage
C. Air pollution

9. Secondary recovery methods include pumping water or gas into the well to drive the oil out of the pores in the rock. Tertiary recovery methods include pumping steam into the well to lower the viscosity of the oil and allow it to more readily. Other techniques include more aggressive pumping of gases or chemicals into wells.
These methods have costs and can manifest in the price of oil.

10. Mainly oil leakage, which includes oil spills and oil entering the oceans results from natural seeps and pollution from the use of oil as lubricants and fuel in machinery and the residue from these uses that is washed into streams and carried to the oceans. The evaporation of oil products and the incomplete burning of oil fuels contribute to air pollution.

11. Of the three fossil fuels, natural gas is the least disruptive to the environment. A natural gas well does not produce any unsightly waste, although there may be local odor problems. Except for the danger of an explosion or fire, natural gas poses no harm to the environment during transport. Since it is clean burning, it causes almost no air pollution. The products of its combustion are carbon dioxide and water.

12. The acceptance of the threat of climate change has had major implications for nuclear power. Since nuclear power plants do not produce carbon dioxide, many people, including some environmental organizations, have reevaluated the value of nuclear power and see it as a continuing part of the energy equation.
As the cost of oil and natural gas has increased, electricity generation from these sources has become more costly, making nuclear power more attractive. Countries with few fossil fuel reserves and those with developing economies are most likely to build nuclear power plants.

13. Nuclear disintegration releases energy from the nucleus as radiation, of which there are three major types: alpha radiation; beta radiation; gamma radiation. In addition, when they disintegrate, the nuclei of a few kinds of atoms release neutrons.

14. An atom that has a nucleus that will split, it is said to be fissionable and the process of splitting is known as nuclear fission. If these splitting nuclei also release neutrons, they can strike the nuclei of other atoms, which also disintegrate, resulting in a continuous process called a nuclear chain reaction.

15. The generation of electricity is mainly about the generation of products that came from a nuclear chain reaction. In order to maintain a nuclear chain reaction the fast moving neutrons must be slowed. This is accomplished by a moderator substance. Control rods contain nonfissionable materials that absorb the neutrons produced by fissioning uranium and prevent the neutrons from splitting other atoms. In order to manage the large amount of heat produced within the nuclear reactor, a coolant material is needed to transfer the heat away. In the production of electricity, a nuclear reactor serves the same function as burning a fossil fuel. It produces heat, which converts water to steam to operate a turbine that generates electricity.

16. Mining, extracting the uranium from the ore, enriching U-235, fabricating the fuel rods, installing and using the fuel in a reactor, and disposing of the wastes.

17. When an alpha or beta particle or gamma radiation interacts with atoms, it can dislodge electrons from the atoms and cause the formation of ions. When ionization occurs in living tissue it can result in damage to DNA or other important molecules in cells. The degree and kind of damage vary with the kind of radiation, the amount of radiation, the duration of the exposure, and the types of cells irradiated. Ionizing radiation can cause mutations, which are changes in the genetic messages within cells. Mutations that occur in the ovaries or testes can form mutated eggs or sperm, which can lead to abnormal offspring. Mutations that occur in other tissues of the body may manifest themselves as abnormal tissue growths known as cancer.

18. Time, distance, and shielding are the basic principles of radiation protection.

19. Three Mile Island Chernobyl Fukushima Dai-ichi

20. Contaminations associated with the radiation produced by the fuel and the waste products of its use. Radiation would cause damages to people’s bodies and increase the possibility of abnormal babies. Explosions, leaks of nuclear plants would cause a long-term evacuation of a long distance from the plant since the half-lives of some radioactive isotopes are extremely long. Radioactive products may contaminate the rivers and oceans around it and thus, cause environmental problems all over the world. Any living thing around the plant would receive high exposures, which may lead to death or abnormality. The disposal of nuclear waste has also raised environmental concern.

21. Stage 1 involves removing fuel rods and water used in the reactor and properly storing or disposing of them. This removes 99% of the radioactivity.

22.
a. Decontaminate and dismantle the plant as soon as it is shut down.
b. Secure the plant for many years to allow radioactive materials that have a short half-life to disintegrate and then dismantle the plant. (However, this process should be completed within 60 years.)
c. Entomb the contaminated portions of the plant by covering the reactor with reinforced concrete and placing a barrier around the plant.