Jess+Emery

Week 2: Why do leeches Exist? Leeches are important to human being for so many reasons, which are: As food: Certain fishes, ducks, and other birds, turtles etc. eat leeches. Leeches are also used as bait to catch fish. Thus leeches form food of many animals which arc used as food by man. As pests : Man faces both direct and indirect problems because of leeches. (a) The leeches parasitic on fishes cause serious losses to fishery. (b) Cattles, especially buffaloes, which pass considerable time in ponds, suffer due to leeches. The wounds caused by leeches become infected with bacteria and this causes crippling effect and death of cattle. (c) Cattles and horses are often blinded by their attacks. (d) The bite of Indian land leeches (very common in forests) is very painful. Due to their attacks horses are driven wild and men suffer serious loss of blood. The soldiers of Napoleon were put to serious trouble by leeches. Medical importance: Leeches suck the blood of their hosts without causing pain. Due to this reason leeches were used extensively in the past for blood letting. It was believed in the past that removal of bad blood cures many diseases. Some tribal communities still use leeches for this purpose. Hirudin as an anticoagulant remained in use in hospitals for a long time. However, it is not used now. Leeches may be used in some hospitals now if an area is swollen with blood. For instance if a finger is cut off the main veins and arteries are re-c0nnected but it is impossible to connect every singly tiny vein and artery so a leech is attached to the finger to get rid of excess blood that builds up and encourage the body to re-establish a flow of blood as leech saliva inhibits blood coagulants.

Week 1: The ITER

[] -start at 2:42

The ITER (International Thermonuclear Experimental Reactor) is and international nuclear fusion project. ITER will be the world's largest experimental fusion reactor, located in the south of France. The ITER project aims to make the transition from experimental studies of plasma physics to full-scale electricity-producing power plants. The project is run by seven major entities; The European Union, India, Japan, China, Russia, South Korea, and the US. The ITER reactor is designed to produce 500 megawatts of power. It is designed to demonstrate the fusion property of giving off more energy than is put into it. The project was started in 2007 but had many delays and budget issue and is now projected to be complete by 2019. In 2020 the reactor will begin plasma experiments and is projected to perform full-out fusion by 2030.

__ITER Goals/Objectives__

 * ====**demonstrate feasibility of fusion power and show it can work without a negative impact**====
 * maintain fusion pulse of 480 seconds
 * ignite a self-sustaining plasma
 * maintenance by robots
 * refine neutron shield/heat conversion technologies

__Design__
Vacuum Vessel: Center of machine; double walled steel container where plasma is contained by magnetic fields

5,116 tons External diameter: 64 ft Internal diameter: 21 ft

The primary function of the vacuum vessel is to provide a sealed plasma container. Its main components are the main vessel, the port structures and the support system. The main vessel is a double walled structure with stiffening ribs between 60 millimeters (2.4 in) thick shells to reinforce the vessel structure. These ribs also form the flow passages for the cooling water. The space between the double walls will be filled with shield structures made of stainless steel. The inner surfaces of the vessel will be covered with blanket modules. These modules provide shielding from the high-energy neutrons produced by the fusion reactions.

Magnet System: The central solenoid(tightly packed helix-produces a uniform magnetic field in an area when an electrical current is passed through) coil will use superconducting niobium-tin(can withstand high magnetic field values-up to 30 teslas) to carry 46 kA(SI unit of electrical current) and produce a field of up to 13.5 teslas(SI unit of magnetic field strength). The 18 toroidal(doughnut shaped) field coil will also use niobium-tin. At their maximum field strength of 11.8 teslas, they will be able to store 41 gigajoules.

Cryostat: Large stainless steel structure surrounding the vacuum vessel and superconducting magnets. Provides a super-cool vacuum environment. 54 modules will be made

Cooling Systems: The ITER will use three interconnected cooling systems. Most heat will be removed by a primary water loop, cooled by water through a heat exchanger. The secondary cooling loop will be cooled by a larger cooling complex made up of a cooling tower, a 5 km pipe supplying water and basins that allow cooling water to be cooled and tested for chemical contamination. A liquid nitrogen system will provide another 1,300 kW of cooling to 80 K and a liquid helium system will provide a 75 kW of cooling to 4.5 K.

Major Problems
The number one technical concern is that the 14 MeV neutrons produced by the fusion reactions will damage the materials from which the reactor is built. Some say ITER is diverting money from research into more viable energy sources. Many green groups believe the money should be put towards finding practical energy solutions for the future.

As you can see ITER is trying to improve fusion energy but still the future of our planet is not coming into much consideration. This fusion plant will not help climate change or secure energy for the earth's future. This is very similar to many of the plans for nuclear energy. Countries are funding energy projects but no sustainable energy projects and most are not thinking of our future with global warming.

The French Nobel laureate in physics Pierre-Gilles de Gennes said of nuclear fusion, "We say that we will put the sun into a box. The idea is pretty. The problem is, we don't know how to make the box."