David Terr's Website

 

Publications

“Fibonacci Expansions and ‘F-adic’ integers,” The Fibonacci Quarterly, v. 34, 1996

“On the Sums of Digits of Fibonacci Numbers,” The Fibonacci Quarterly, v. 35, 1996..

A Modification of Shanks’ Baby-Step Giant-Step Algorithm,” Mathematics of Computation, v. 69, 2000

Here's a copy of my resume

Alternate Forms of Energy

With the rapid depletion of fossil fuels, oil and natural gas in particular, and with their environmental hazards such as global warming, air pollution and acid rain, it is clear that we need to develop alternate forms of energy. Below I discuss several alternatives as well as their merits and drawbacks.

Renewable Sources

Hydroelectric Power
Hydroelectric power has been in use for a long time; the first hydroelectric plant was built in Rothbury, England in 1870. Today, hydroelectric power supplies 20% of the world's power and it is estimated that it is capable of providing 9 to 12 times as much energy as it currently does. However, there are environmental concerns regarding building new dams.

Solar Power
Solar power is a potentially very attractive form of energy, since it is plentiful and pollution-free. Just one tenth of a percent of the earth's surface potentially suffices to produce our current power needs. Nevertheless, there are several disadvantanges to solar power. Solar cells are only operable during the daytime when the sun is shining, and currently have an efficiency of only 7-18 percent. In order to be useful all the time, solar power must first be converted to another form of energy.

Wind Power
Wind power has been in use the longest of all renewable sources; the first use was in Persia around 200 BC for grinding grain. It currently accounts for less than 1% of worldwide energy use, though its use is growing quite fast. It is estimated that wind power can potentially produce about 5 times the world's current energy use.

Geothermal Power
Geothermal power is currently a rather limited renewable resource. Tidal power, one source of geothermal power, can potentially produce just one-quarter of the world's current power needs. The heat from the earth is plentiful, but most of it is not currently available.

Bioenergy
Bioenergy, including biomass, biofuel, and biogas, is a fairly new source of energy. Ethanol, a biofuel, was used by the Ford Model T from 1903 to 1926, until petroleum fuels became cheaper. Since the first energy crisis in 1973, there has been renewed interest in biofuels and other forms of bioenergy.

Non-Renewable Sources

Nuclear Power
Nuclear power is a non-renewable energy source. There are two potential forms of nuclear energy, fission and fusion, though no commercial fusion plants have yet been developed. Nuclear plants have been in use since 1954 and today they provide 7% of the world's energy. Nevertheless, nuclear power has several serious drawbacks. Nuclear power produces hazardous radioactive waste, and no viable solution has yet been offered on what to do with it. Also, there is serious potential risk of nuclear accidents, such as the meltdown at Chernobyl, Ukraine (formerly the USSR) in 1986. Furthermore, the amount of available uranium fuel is limited; it is estimated that available resources will last only 50 years at their current rate of use. Fusion power promises to alleviate nearly all the hazards of fission, but there are several obstacles in its development and it is estimated that it won't become commercially available until around 2050.