Uranium Glass
 |
| Powered by phpBay Pro |
Separating Twins To Generate Enormous Amount Of Energy
Uranium is the heaviest and last naturally occurring element on the periodic table. Uranium occurs near the beginning of the actinide family that consists of elements with atomic numbers 90 through 103. At one time, uranium was considered to be a relatively unimportant element. It had a few applications in the making of stains and dyes, in producing specialized steels, and in lamps. Its annual sales before World War II (1939-45) amounted to no more than a few hundred metric tons of the metal and its compounds. Then, a dramatic revolution occurred when scientists discovered that one form of uranium will undergo nuclear fission.
The first application of this discovery was in the making of nuclear weapons, such as the atomic bomb. After the war, nuclear power plants were built to make productive use of nuclear fission. Nuclear power plants convert the energy released by fission to electricity. Today, uranium is regarded as one of the most important elements for the future of the human race. Credit for the discovery of uranium is usually given to German chemist Martin Klaproth who was studying a common and well-known ore called pitchblende during the late 1780s. At the time, scientists thought that pitchblende was an ore of iron and zinc.
During his research, however, Klaproth found that a small portion of the ore did not behave the way iron or zinc would be expected to behave. He concluded that he had found a new element and suggested the name uranium for it. The name was given in honor of the Uranus, a planet that had been discovered only a few years earlier (in 1781). For some time, scientists believed that Klaproth had isolated uranium. Eventually they realized he had found uranium oxide (UO2), a compound of uranium. It was not until a half century later, in fact, that the pure element was prepared. In 1841, French chemist Eugène-Melchior Peligot (1811-90) produced pure uranium from uranium oxide. Early researchers did not know that uranium was radioactive. In fact, radioactivity, the tendency of an isotope or element to break down and give off radiation, was not discovered until 1898.
With melting point of 1,132.3°C (2,070.1°F), boiling point of about 3,818°C (6,904°F), and density of 19.05 grams per cubic centimeter, uranium is a silvery, shiny metal that is both ductile and malleable. Uranium is a relatively reactive element; It combines with nonmetals such as oxygen, sulfur, chlorine, fluorine, phosphorus, and bromine. It also dissolves in acids and reacts with water. It forms many compounds that tend to have yellowish or greenish colors. Uranium is a moderately rare element. Its abundance is estimated to be about 1 to 2 parts per million, making it about as abundant as bromine or tin.
The most common ore of uranium is pitchblende, although it also occurs in other minerals, such as uraninite, carnotite, uranophane, and coffinite. All isotopes of uranium are radioactive. Three of these: uranium-234, uranium-235, and uranium-238occur naturally. By far the most common is uranium-238, making up about 99.276% of uranium found in the Earth's crust. Uranium-238 also has the longest half life, about 4,468,000,000 years. If we imagine that the Earth's crust contains 100 million tonnes of uranium-238 today. Only half of a uranium-238 sample would remain 4,468,000,000 years from now (one half life). The remainder would have changed into other isotopes. About a dozen other isotopes of uranium have been made artificially.
Uranium compounds have been used to color glass and ceramics for centuries. Scientists have found that glass made in Italy as early as A.D. 79 was colored with uranium oxide. They have been able to prove that the coloring was done intentionally. Some uranium compounds were used for this purpose until quite recently. In fact, a popular type of dishware known as "Fiesta Ware" made in the 1930s and 1940s sometimes used uranium oxide as a coloring material. Other glassware, ceramics, and glazes also contained uranium oxide as a coloring agent.
Uranium compounds have had other limited uses. For example, they have been used as mordants in dyeing operations. Uranium oxide has also found limited application as an attachment to filaments in light bulbs. The compound reduces the speed at which an electric current enters the bulb. This reduces the likelihood of the filament heating too fast and breaking. None of these applications is of very much importance today, however.
By far the most important application is in nuclear weapons and nuclear power plants. The reason for this importance is that one isotope of uranium, uranium-235, undergoes nuclear fission, the process by which neutrons are fired at a target. The target is usually made of uranium atoms. When neutrons hit the target, they cause the nuclei of uranium atoms to break apart. Smaller elements are formed and very large amounts of energy are given off. When this reaction is carried out with no attempt to capture or control the energy, an enormous explosion takes place. This release of nuclear energy accounts for the power of a nuclear weapon such as an atomic bomb. However, when one wants to put this property to useful purposes in reactors, the energy released during fission is used to boil water. Steam is produced and is converted to electricity. The controlled release of nuclear energy takes place in a nuclear power plant.
Here it is worth noting that if neutrons are fired at a big block of uranium metal, neither would nuclear fission occur nor would this be the way to make an atomic bomb. Moreover we can not use this process in a nuclear power plant as only one isotope of uranium, uranium-235, undergoes nuclear fission while the most common isotope, uranium-238, does not. Hence there is no way to make a bomb or a nuclear power plant with a chunk of natural uranium metal. It is necessary is to increase the percentage of uranium-235 in the metal.
As a chunk of uranium metal containing more uranium-235, is more likely to undergo nuclear fission. In making a bomb or a power plant, then, the first step is to separate the isotopes of uranium from each other. The goal is to produce more uranium-235 and less uranium-238. Though the goal sounds easy, it is very difficult to do as all isotopes of uranium behave very much alike and have the same chemical properties. The only aspect in which they differ from each other is weight. An atom of uranium-238, for example, weighs about 1 percent more than an atom of uranium-235. That's not much of a difference.
Scientists separate these isotopes in a centrifuge in which heavier objects spin farther out than lighter objects. A mixture of uranium-235 and uranium-238 can be separated slightly in a centrifuge. But the separation is not very good because the isotopes weigh almost the same amount. In practice, a mixture of isotopes must be centrifuged many times. Each time, the separation gets better. Scientists prepare enriched uranium by this method. Enriched uranium contains more uranium-235 and less uranium-238. Initially enriched uranium was used to make atomic bombs but now it is being used in nuclear power plants. Today, over 400 nuclear power plants exist worldwide, producing about 17 percent of all electricity.
While many people believe that nuclear power will be more important in the future as the world's supply of coal, oil, and natural gas will eventually run out, others are concerned about the dangers of nuclear power. The radiation released and radioactive wastes produced by nuclear power plants have made them unpopular in the United States. No new nuclear generators have been built for over ten years. Uranium poses an exceptional risk in powdered form as in this form; it tends to catch fire spontaneously. Since it is a radioactive element, uranium must be handled with great care.
About the Author
Dr. Badruddin Khan teaches Chemistry in the University of Kashmir, Srinagar,India.
Uranium glass De La Rive tube
Uranium Glass
What Is Bulk Metallic Glass?
Bulk metallic glass, a.k.a. amorphous metal, appears to have a very bright future. Being twice as strong as titanium, tougher and more elastic than ceramics, and having excellent wear and corrosion resistance makes them attractive for a variety of applications. It can even be cast in a mold to near net shapes.
Conventional Metals
In an ordinary metal the atoms of the metal arrange themselves into a repeating pattern of crystals or grains with different sizes and shapes upon cooling from the liquid state. Because metals typically do not solidify into single crystals, they have inherent weaknesses.
The boundaries between the grains are weak spots and under high enough stress and temperature the grains will slide past each other resulting in metal deformation. In addition, extra atoms are often present in grains causing planes of distortion called dislocations. Dislocations easily move through metal that is under stress, again causing deformation. Grain boundaries and dislocations greatly lower a metals strength compared to its theoretical maximum.
Casting of conventional metals also requires more manufacturing steps than bulk metallic glass. Conventional metals shrink significantly as they cool in the mold from liquid to solid form and often develop surface roughness. Secondary steps are usually required to get at the final product, such as grinding and polishing.
Bulk Metallic Glass
The structure of metallic glass is very different from that of conventional metals. Rather than arranging themselves into repeating patterns of grains, the atoms of metallic glasses are "frozen" in a random, disordered structure, similar to regular window glass. It even has a smooth surface like glass. So smooth, in fact, that paint does not adhere well to metallic glass. It is this amorphous structure, lacking in grain defects, that gives metallic glasses their strength, toughness, hardness, elasticity and corrosion and wear resistance.
First discovered by Pol Duwez in 1960 at Caltech, the technique to create metallic glasses required undercooling a molten metal uniformly and rapidly. Rapidly as in 1,000,000°C per second! The molten metal reaches its glass transition temperature without enough time or energy to crystallize, and instead solidifies as metallic glass. Because the material did not conduct heat well, only thin ribbons of metallic glass could be created because of the uniformity and speed of cooling that was required.
Around 1990 Akihisa Inoue and his team at Tohoku University in Japan discovered new alloys that could form thicker metallic glasses at cooling rates as low at 1°C to 100°C, as long as three conditions were met:
1) Use three or more elements in the alloy
2) The atomic size of the elements must differ from each other by at least 12 percent
3) Use elements that have a strong affinity for each other
Soon after, William Johnson and Atakan Peker at Caltech did the same. The lower cooling rates allowed for thicker materials to be created, up to four inches. These thicker materials are referred to as bulk metallic glass (BMG).
Currently available bulk metallic glasses are malleable at around 400°C, compared to over 1000°C for steel. This allows the material to be processed similarly to polymers, with high volume production via casting up to a thickness of four inches. The material has low shrinkage during solidification and can therefore be cast in near-net shapes with microscale precision. The smooth shiny surface eliminates secondary finishing processes. Scalpels made from bulk metallic glass come out of the mold sharp and ready to use.
Some Disadvantages
As with any material, BMG cannot be everything to every application. Its plastic like manufacturability also means that it cannot be used in high temperature applications, i.e., above 260°C, because it becomes soft and weakened. Pure bulk metallic glasses also exhibit cyclic fatigue from repeated stress. Because of their high elasticity and low plasticity, catastrophic failure occurs after only a small amount of plastic deformation.
BMG Composites
New developments in BMG composites are helping to reduce the limitations of the material. In a BMG composite the BMG is the matrix and a ductile crystalline-phase is the reinforcement material. The reinforcement can either be an added material, such as metal or ceramic fibers, or internally created by precipitating ductile dendrites within the BMG, yielding partial crystallinity. These composites combine the ductility, fracture toughness and plasticity of conventional metals with the high strength of pure BMG.
Applications
BMGs are being examined for or currently used in a wide variety of applications including:
– Industrial coatings for improved wear and corrosion resistance – As a replacement for depleted uranium in Kinetic Energy Penetrators for the military. – Casings for cell phones – Scalpels – Sporting goods such as bats and tennis racquets – Jewelry
The Defense Advanced Research Projects Agency (DARPA) also funding a three-year program called Structural Amorphous Metals (SAM). The aim of the program is to demonstrate the viability of BMG in structural applications. Specific applications being investigated include "corrosion-resistant, reduced magnetic mass hull materials; moderate temperature, lightweight alloys for aircraft and rocket propulsion; and wear-resistant machinery components for ground, marine, and air vehicles."
U.S. Patent Situation
Upon examining several patents and class codes on amorphous metals it appears that the main U.S. patent classification codes for these materials are:
148/304 – Amorphous: Stock material which has no regular crystal structure but rather has a series of noncrystalline areas much like a glass.
148/403 – Amorphous, i.e., glassy: Stock material which has no regular crystal structure, but rather has a series of noncrystalline areas much like a glass.
148/561 – Passing through an amorphous state or treating or producing an amorphous metal or alloy: Process wherein a metal or metal alloy having no regular crystalline structure or periodicity (i.e., amorphous) in any amount is produced or treated by a process under the class definition or wherein a metal or metal alloy passes through a physical state having no regular crystalline structure or periodicity during the treatment of the metal or metal alloy.
Guideline examined patents assigned to these codes that were granted during the period from 1987 to 2003. We then compared the top patent holders for the above class codes in terms of number of patents published from 1987 to 2003.
Top BMG Patent Holders from '87 to '03
55 patents – YKK Corp.
43 patents – Honeywell
33 patents – Tsuyoshi Masumoto & Unitika Ltd.
26 patents – Akihisa Inoue
15 patents – Alps Electric Co.
14 patents – Koji Hashimoto
13 patents – California Institute of Technology
13 patents – Nippon Steel Corp.
11 patents – Hitachi Ltd.
11 patents – Kabushiki Kaisha Toshiba
One method Guideline uses to compare patent holders is by calculating an index referred to as Technology Influence. Technology Influence represents how often an assignee's patents from the previous five years (in this case, 1998-2002) are referenced by patents published in the year of comparison (in this case 2003). A Technology Influence value of 1 represents the average. This shows how much a patent holder's past technology developments are influencing current development. From this analysis Guideline determined that Caltech's work has been most influential as their Technology Influence value is 5.06, whereas the next closest value is only 1.46, held by Alps Electric.
Applied Science is another calculation used to compare patent holders. This refers to the average number of non-patent references cited by a patent holder's patents, such as scientific papers from journals, conference proceedings, etc. This gives an indication of which companies are working on the leading edge. Again, Caltech stands out as a clear leader with an Applied Science value of 7.3. This makes sense considering that Caltech is known to be one of the leaders in developing this technology. As mentioned earlier, metallic glass was first discovered at Caltech.
An analysis of patent assignees and inventors revealed that Akihisa Inoue has done extensive work and collaboration. He is listed as an inventor or co-inventor on a little over 60 patents with about 120 other Japanese researchers. All of this work was done with the following Japanese organizations, and this is only in regards to U.S. patents.
– Tsuyoshi Masumoto and Unitika, Limited – Teikoku Piston Ring Company Limited – Alps Electric Co., Ltd. – YKK Corporation – Honda Motor Co., Ltd. – Yamaha Corporation – Japan Science and Technology Corporation – Unitika Ltd. – Toyota Jidosha Kabushiki Kaisha – Research Development Corporation of Japan – Japan Metals & Chemicals Co., Ltd. – Sumitomo Rubber Industries, Ltd. – Mitsubishi Materials Corporation
Indeed, Inoue led a five year project sponsored by the Japanese government (Inoue Supercooled Liquid Glass Project), which reported the development of a less expensive copper alloy based BMG with a tensile strength over 2 Gpa. Currently Inoue is leading a five-year project sponsored by the Japanese New Energy and Industrial Technology Development Organization.
Although Inoue has done the most extensive work in terms of U.S. patenting on amorphous and glassy metal technology, the work being done by William Johnson's group at Caltech appears to be having a larger impact on the overall body of work in U.S. patents over recent years.
About the Author
Brian Reuter is Director of Product Realization at Guideline, Inc. Guideline provides research,
product realization
,
expert witness and consulting
services. Learn more at
www.intota.com
.
Who is this guy, Photo/Chem Story?
there is a story where a photoagrapher developes his picture in his darkroom but somehow the pictures were exposed to light, so he tried to develope them at his friends house it worked. he figured that it was one of the chemicals in the darkroom that was giving off light. so he finally figured out it was the Uranium Oxide giving off radiation hence giving off light to mess up his pictures.
My question is who was this photoagrapher, his name?
( this guy is back in the day, glass photo's...)
idk
Uranium Glass Shined with UV Flash Light and BluRay Laser
|
 Vintage Art Deco 30s Uranium glass dressing table set 5  US $173.83
|
 RARE VINTAGE CHROME ART DECO NUDE LADY GREEN URANIUM GLASS CAKEPLATE CENTREPIECE US $172.50
|
| Powered by phpBay Pro |