lecture 10 3/5/2014 energy update! today’s material: nuclear energy activity 3 next class...

Lecture 10 3/5/2014ENERGY UPDATE!

Today’s Material:Nuclear EnergyActivity 3

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Report: Good Thing World Has Unlimited Quantity Of OilWASHINGTON—According to a report published Monday by the Department of Energy, given current consumption habits and the dramatic projected increases in demand from developing countries, it is extremely fortunate that the planet has an inexhaustible supply of crude oil.

“Oil is the lifeblood of the world’s economies and global transportation networks, so the fact that our reserves are limitless, even in the face of exponential population growth, is exceptionally fortuitous in terms of maintaining our way of life and increasing our standard of living indefinitely,” the report read in part, while also noting how favorable it is that the world’s oil is spread evenly across the globe, thus eliminating any competition among nations who might otherwise squabble or even skirmish over the valuable yet thankfully infinite natural resource.

http://www.theonion.com/articles/report-good-thing-world-has-unlimited-quantity-of,35422/

© Copyright 2010 by Onion, Inc.

http://www.spacedaily.com/reports/A_cavity_that_you_want_999.html

A cavity that you wantNow, an international research team pushed the concept further by developing an optical "nanocavity" that boosts the amount of light that ultrathin semiconductors absorb. The advancement could lead to, among other things, more powerful photovoltaic cells and faster video cameras; it also could be useful for splitting water using energy from light, which could aid in the development of hydrogen fuel.

A rendering shows a beam of light interacting with an optical nanocavity. The nanocavity boosts light absorption in ultrathin semiconductors. Image courtesy Advanced Materials.

Semiconductors form the basis of modern electronics. They work by manipulating the flow of energy in electronic devices. The most common semiconductor material, silicon, is used to make microchips for cellular phones, computers and other electronic devices.

The problem, however, is that these ultrathin semiconductors do not absorb light as well as conventional bulk semiconductors. Therefore, there is an intrinsic tradeoff between the ultrathin semiconductors' optical absorption capacity and their ability to generate electricity

http://www.materialstoday.com/optical-materials/news/optical-nanocavity-to-boost-light-absorption/

Another article:

http://www.forbes.com/sites/jamesconca/2014/02/13/do-we-really-need-nuclear-fusion-for-power/?ss=business:energy

Do We Really Need Nuclear Fusion for Power?James Conca (opinion article!)Conca does not provide sources for his opinions. Read this article at your own risk.

In the end, nuclear energy, either fusion or fission, provides virtually limitless power. We know how to do fission right now. We aren’t yet there with fusion.

A new system developed by the Energy Department's Pacific Northwest National Laboratory (PNNL) converts natural gas and sunlight into a more energy-rich fuel called syngas, which will allow hybrid solar-gas power plants to use about 20 percent less natural gas to produce the same amount of electricity while also lowering the plant's greenhouse gas emissions.

http://energy.gov/articles/renewable-boost-natural-gas A Renewable Boost for Natural GasBen Dotson, Digital Reform

The system works through concentrating solar power, which uses a reflecting surface to concentrate the sun's rays like a magnifying glass. In the case of the new system from PNNL, a mirrored parabolic dish directs sunbeams to a central point, where a device absorbs the solar heat to make syngas.

“Solar system” model of the helium atom, with a nucleus consisting of two protons and two neutrons.

http://avonapbio.pbworks.com/w/page/9429249/Atomic%20Number%20and%20Atomic%20Mass

http://www.windows2universe.org/physical_science/physics/atom_particle/atomic_mass.html

Here you can see an example of atomic weight, atomic number, and mass number.The atomic number is the smaller number associated with the element and is equal to the number of protons in the nucleus.

https://np-apchemistry.wikispaces.com/chapter3

Decay of a radioactive sample containing initially 1,000 nuclei.

The curve of binding energy, a plot of binding energy per nucleon versus mass number. Individual isotopes may lie slightly off the general curve, as with He-4. Arrows indicate the energy-releasing paths of nuclear fusion and fission.

Neutron-induced fission. (a) A neutron strikes a heavy nucleus and is absorbed. (b) The nucleus begins to oscillate. (c) It takes on a dumbbell shape, and the repulsive electric force begins to dominate. (d) The nucleus fissions into two unequal middleweight nuclei, emitting several neutrons in the process.

A nuclear chain reaction. At left, a neutron strikes a U-235 nucleus, causing it to fission and, in this case, release two neutrons that go on to cause two additional fissions. Each of those fission events releases neutrons that cause more fission, and the chain reaction grows exponentially. This is what happens in a bomb. In a reactor, the neutrons are carefully controlled to ensure that, on average, each fission results in only one additional fission.

Nuclear fuel cycles. A once- through cycle is in black; additional steps in a reprocessing cycle are in gray. On-site storage involves pools of water for short-term storage of fresh, highly radioactive waste, followed by longer-term dry cask storage.

A hill-and-valley analogy for fusion. It takes substantial energy to get the ball up the hill, but a lot more is released when it drops into the valley.

The deuterium–tritium fusion reaction of Equation 7.3 produces a helium nucleus (He-4), a neutron, and energy.

Class Review:Nuclear Energy

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