Arizona Concrete
According to the Mine Faculty at the University of Arizona, cement is
manufactured primarily from suitable limestone and shale rocks. Arizona had two
dry-process cement plants in 1969, namely the Arizona Portland Cement Company
plant in Pima County, near Tucson, and the American Cement Corporation plant at
Clarkdale, in Yavapai County (52-53).
The use of cementing materials goes back to the ancient Egyptians and
Romans, but the invention of modern portland cement is usually attributed to
Joseph Aspdin, a builder in Leeds, England, who obtained a patent for it in 1824.
Currently, the annual world production of portland cement is around 700 million
metric tons (Danbury).
Many people use the words concrete and cement interchangeably, but
they're not. Concrete is to cement as a cake is to flour. Concrete is a mixture
of ingredients that includes cement but contains other ingredients also (Day 6-
7).
Portland cement is produced by pulverizing clinker consisting
essentially of hydraulic calcium silicates along with some calcium aluminates
and calcium aluminoferrites and usually containing one or more forms of calcium
sulfate (gypsum) as an interground addition. Materials used in the manufacture
of portland cement must contain appropriate proportions of calcium oxide, silica,
alumina, and iron oxide components. During manufacture, analyses of all
materials are made frequently to ensure a uniformly high quality cement.
Selected raw materials are crushed, milled, and proportioned in such a
way that the resulting mixture has the desired chemical composition. The raw
materials are generally a mixture of calcareous (calcium oxide) material, such
as limestone, chalk or shells, and an argillaceous (silica and alumina) material
such as clay, shale, or blast-furnace slag. Either a dry or a wet process is
used. In the dry process, grinding and blending operations are done with dry
materials. In the wet process, the grinding and blending are done with the
materials in slurry form. In other respects, the dry and wet processes are very
much alike.
After blending, the ground raw material is fed into the upper end of a
kiln. The raw mix passes through the kiln at a rate controlled by the slope and
rotational speed of the kiln. Burning fuel (powdered coal, oil, or gas) is
forced into the lower end of the kiln where temperatures of 2600°F to 3000°F
change the raw material chemically into cement clinker, grayish-black pellets
about the size of 1/2-in.-diameter marbles.
The clinker is cooled and then pulverized. During this operation a small
amount of gypsum is added to regulate the setting time of the cement. The
clinker is ground so fine that nearly all of it passes through a No.
R.W. Sears Watch Company. In one year he made so much money that he was able to
Ewald Georg von Kleist is a German scientist who created the capacitor in November of 1745. Regrettably, Kleist did not have the proper paper work to claim in the records that the design of the capacitor was his idea. Many months later, a Dutch professor named Pieter van Musschenbroek created the Leyden jar, the world’s first capacitor (on record). It was a simple jar that was half filled with water and metal above it. A metal wire was connected to it and that wire released charges. Benjamin Franklin created his own version of the Leyden jar, the flat capacitor. This was the same experiment for the more part, but it had a flat piece of glass inside of the jar. Michael Faraday was the first scientist to apply this concept to transport electric power over a large distance. Faraday created the unit of measurement for a capacitor, called Farad.
1926. http://library.duke.edu/digitalcollections/adaccess_BH0301/ (accessed April 10, 2011).
Samuel Morse also developed a marble-cutting machine, but he was unable to patent it due to it conflicted with the 1820 design by Thomas Blanchard.
In “Don’t Blame the Eater”, by David Zinczenko and in “What You Eat is Your Business”, by Radley Balko both authors discuss and make their stance’s clear on their believed cause of obesity in America. On one hand, Zinczenko argues that it is not the consumers fault for putting themselves at risk of becoming obese or being diagnosed with type 2 diabetes, but that it is the fast-food companies fault. While on the other hand, Balko argues that we as individuals hold responsibility on whether or not we are putting ourselves at risk for obesity.
the world. It was invented by Eli Whitney while America was still barely 10 years old. At that time
The concentrate is dried and sent into a reverberatory furnace. The minerals are partly oxidized and melted, resulting in isolated layers. The matte layer refers to the iron-copper sulfide mixture which sinks to the bottom. The slag, which refers to the remaining impurities, floats on top of the matte and the discarded. Sulfur dioxide gases are also collected and made into sulfuric acid for use in hydrometallurgical leaching. The matte is recovered and moved to the converter, a cylindrical vessel into which the copper is poured. Air, lime and silica are added to react with the metal oxide. The slag is removed and the Sulfur dioxide and converted into sulfuric acid, this forms blister copper which is 97-99% pure.
State legislatures and school boards across the country have begun banning snacks and sodas from school campus and vending machines...Congress is now considering menu-labeling legislation, which would force restaurants to send every menu item to the laboratory for nutritional testing” (page 396-397). In a rebuttal, the article ‘What You Eat Is Your Business’ Radley Balko states that politicians and government officials are working so much on ways to manipulate and infuse healthy eating and living habits in all Americans that they are taking away the ability of ownership and responsibility, we Americans, fought for. “This collective ownership of private health then paves the way for even more federal restrictions on consumer choice and civil liberties. A society where everyone is responsible for everyone else’s well-being is society more apt to accept government regulations” (Page 397). Balko introduces the claim that Americans are becoming less responsible for their health and well-being, and more responsible for everyone else’s. Health Care policies in the United States has been pushed so far into the public sector that the health and well-being of a person is no longer their responsibility but now the responsibility of the government and health care officials. Balko then begins to state that the more control we give government officials with our health care, the more obligated they will feel
In David Zinczenko's article “Don't Blame the Eater”, argues that the reason behind individuals turning to fast-food for affordable meals is because there are a lack of alternatives to browse for a healthier way of life. He also raises the question "Where, exactly, are consumers - particularly teenagers – supposed to find alternatives?" David also claims that there are big number of fast-food restaurant all over the country illustrating by giving the example of McDonald’s restaurants. So fast-food is easily available food at any place. David also argues that the fast-food restaurants are the least expensive and most convenient nutrition option we have. David also blames fast-food restaurants for not giving calorie information charts on packages. On the basis of David’s point of view clearly
In the beginning of the play, King Hamlet is poisoned by Claudius, who then gains the title of king and marries Hamlet's mother Gertrude. Much like in The Lion King, Mufasa is killed by his brother Scar, who then goes on to become King of the Pridelands and leader of the lions , he then marry's Simba's mother, Sarobi. In Hamlet, Hamlet is missing for the majority of the main events because he is away at college. He only returns home when something needs to happen and he feels that he is the only one that can solve it. Simba also is not in the area that most of the issues are occurring , but rather in the jungle, when Scar is King and causes problems back in the Pridelands . He only returns when he is most needed. Both Princes return to claim their rightful place on the
The protagonists (heroes), Hamlet and Simba both learn that their fathers has been killed by the antagonists (villains), Claudius and Scar. In the ‘Lion King’ Simba runs away from pride rock in fear and grief after putting the blame on himself with the help of Scar. Simba finds his father’s ghost who tells him that Scar has betrayed him and killed him. Simba’s actions after leaving Pride Rock and seeing his father’s ghost show the audience that he wants to avenge his father’s death. In ‘Hamlet’ the main character, Hamlet, also sees his father’s ghost and tells him that he has also been back stabbed by his own brother, Claudius. Hamlet, furious after hearing that he has been betrayed, sets his uncle up too see if he really did kill his own brother to become the new king. Both Simba and Hamlet are trying to make their own legacy in seeking vengeance on their
The crucible and lid are heated at the beginning of the experiment before being weighed so that any moisture in the crucible is burned away.
Acid mine drainage refers to water (leachate, drainage or seepage) that has come into contact with oxidised rocks or overburden that contains sulphide material (coal, zinc, copper, lead). (Keller, 2000; U.S.G.S.; U.S.E.P.A., 2002). A common sulphide is pyrite, or iron disulfide (FeS2), and throughout this essay it will be pyrite that will be the primary sulphide considered. Acid mine drainage is not a new phenomenon, early mining techniques utilized gravity to avoid water pooling, resulting in the water becoming polluted by acid, iron, sulphur and aluminium (U.S.E.P.A., 2002). It is most commonly associated with coal mining, especially with soft coal, coal that has high sulphur content. The pyrite that is present in coal seams will be accessible after surface mining when the overlying surfaces are removed or in deep mines that allow oxygen access to the previously inaccessible pyrite-containing coal (D.E.P. 1, 1997). After pyrite is exposed to air and water, sulphuric acid and iron hydroxide are formed, creating an acidic runoff (D.E.P. 1, 1997; 2 2002).
Left behind are tailings, which are large piles of crushed rock left over when minerals have been extracted from rocks that once contained them. These tailings are then left prone to wind dispersion and water erosion. This wind dispersion occurs since the sand-like tailings are easily swept up by the atmosphere by wind and spread throughout the environment as dust particles. Figure 1 shows the wind erosion of a mine tailings pile being blow up into the air, creating dust. These tailings contain metal contaminants like arsenic, lead, and cadmium, which creates a problem for the environment and they can persist for decades due to the low pH levels and can cause problems in soil stabilization (arizona.edu, 2008).