How Fiber Optics Was Invented

How Fiber Optics Was Invented Fiber optics is the contained transmission of light through long fiber rods of either glass or plastics. The light travels by process of internal reflection. The core medium of the rod or cable is more reflective than the material surrounding the core. That causes the light to keep being reflected back into the core where it can continue to travel down the fiber. Fiber optic cables are used for transmitting voice, images, and other data at close to the speed of light. Who Invented Fiber Optics? Corning Glass researchers  Robert Maurer, Donald Keck, and Peter Schultz  invented fiber optic wire or Optical Waveguide Fibers (patent #3,711,262) capable of carrying 65,000 times more information than copper wire, through which information carried by a pattern of light waves could be decoded at a destination even a thousand miles away.   Fiber optic communication methods and materials invented by  them opened the door to the commercialization of fiber optics. From long-distance telephone service to the internet and medical devices such as the endoscope, fiber optics are now a major part of modern life.   Timeline 1854: John Tyndall demonstrated to the Royal Society that light could be conducted through a curved stream of water, proving that a light signal could be bent.1880:  Alexander Graham Bell invented his Photophone, which transmitted a voice signal on a beam of light. Bell focused sunlight with a mirror and then talked into a mechanism that vibrated the mirror. At the receiving end, a detector picked up the vibrating beam and decoded it back into a voice the same way a phone did with electrical signals. However, many things - a cloudy day, for instance - could interfere with the Photophone, causing Bell to stop any further research with this invention.1880: William Wheeler invented a system of light pipes lined with a highly reflective coating that illuminated homes by using light from an electric arc lamp placed in the basement and directing the light around the home with the pipes.1888: The medical team of Roth and Reuss of Vienna used bent glass rods to illuminate body cavities.1 895: French engineer Henry Saint-Rene designed a system of bent glass rods for guiding light images in an attempt at early television. 1898: American David Smith applied for a patent on a bent glass rod device to be used as a surgical lamp.1920s: Englishman John Logie Baird and American Clarence W. Hansell patented the idea of using arrays of transparent rods to transmit images for television and facsimiles respectively.1930: German medical student Heinrich Lamm was the first person to assemble a bundle of optical fibers to carry an image. Lamms goal was to look inside inaccessible parts of the body. During his experiments, he reported transmitting the image of a light bulb. The image was of poor quality, however. His effort to file a patent was denied because of Hansells British patent.1954: Dutch scientist Abraham Van Heel and British scientist Harold H. Hopkins separately wrote papers on imaging bundles. Hopkins reported on imaging bundles of unclad fibers while Van Heel reported on simple bundles of clad fibers. He covered a bare fiber with a transparent cladding of a lower refractive index. This protected the f iber reflection surface from outside distortion and greatly reduced interference between fibers. At the time, the greatest obstacle to a viable use of fiber optics was in achieving the lowest signal (light) loss. 1961: Elias Snitzer of American Optical published a theoretical description of single-mode fibers, a fiber with a core so small it could carry light with only one waveguide mode. Snitzers idea was okay for a medical instrument looking inside the human, but the fiber had a light loss of one decibel per meter. Communications devices needed to operate over much longer distances and required a light loss of no more than ten or 20 decibels (a measurement of light) per kilometer.1964: A critical (and theoretical) specification was identified by Dr. C.K. Kao for long-range communication devices. The specification was ten or 20 decibels of light loss per kilometer, which established the standard. Kao also illustrated the need for a purer form of glass to help reduce light loss.1970: One team of researchers began experimenting with fused silica, a material capable of extreme purity with a high melting point and a low refractive index. Corning Glass researchers Robert Maurer, Donald Keck, and Peter Schultz invented fiber optic wire or Optical Waveguide Fibers (patent #3,711,262) capable of carrying 65,000 times more information than copper wire. This wire allowed for information carried by a pattern of light waves to be decoded at a destination even a thousand miles away. The team had solved the problems presented by Dr. Kao. 1975: The United States government decided to link the computers at the NORAD headquarters at Cheyenne Mountain using fiber optics to reduce interference.1977: The first optical telephone communication system was installed about 1.5 miles under downtown Chicago.  Each optical fiber carried the equivalent of 672 voice channels.By the end of the century, more than 80 percent of the worlds long-distance traffic was carried over optical fiber cables and 25 million kilometers of the cable. Maurer, Keck, and Schultz-designed cables have been installed worldwide. U.S. Army Signal Corp The following information was submitted by Richard Sturzebecher. It was originally published in the Army Corp publication Monmouth Message. In 1958, at the U.S. Army Signal Corps Labs in Fort Monmouth New Jersey, the manager of Copper Cable and Wire hated the signal transmission problems caused by lightning and water. He encouraged Manager of Materials Research Sam DiVita to find a replacement for copper wire. Sam thought glass, fiber, and light signals might work, but the engineers who worked for Sam told him a glass fiber would break. In September 1959, Sam DiVita asked 2nd Lt. Richard Sturzebecher if he knew how to write the formula for a glass fiber capable of transmitting light signals. DiVita had learned that Sturzebecher, who was attending the Signal School, had melted three triaxial glass systems using SiO2 for his 1958 senior thesis at Alfred University. Sturzebecher knew the answer. While using a microscope to measure the index-of-refraction on SiO2 glasses, Richard developed a severe headache. The 60 percent and 70 percent SiO2 glass powders under the microscope allowed higher and higher amounts of brilliant white light to pass through the microscope slide and into his eyes. Remembering the headache and the brilliant white light from high SiO2 glass, Sturzebecher knew that the formula would be ultra pure SiO2. Sturzebecher also knew that Corning made high purity SiO2 powder by oxidizing pure SiCl4 into SiO2. He suggested that DiVita use his power to award a federal contract to Corning to develop the fiber. DiVita had already worked with Corning research people. But he had to make the idea public because all research laboratories had a right to bid on a federal contract. So in 1961 and 1962, the idea of using high purity SiO2 for a glass fiber to transmit light was made public information in a bid solicitation to all research laboratories. As expected, DiVita awarded the contract to Corning Glass Works in Corning, New York in 1962. Federal funding for glass fiber optics at Corning was about $1,000,000 between 1963 and 1970. Signal Corps Federal funding of many research programs on fiber optics continued until 1985, thereby seeding this industry and making todays multibillion-dollar industry that eliminates copper wire in communications a reality. DiVita continued to come to work daily at the U.S. Army Signal Corps in his late 80s and volunteered as a consultant on nanoscience until his death at age 97 in 2010.

Explain and show what determines the demand for labour by a perfectly Essay

Explain and show what determines the demand for labour by a perfectly competitive firm - Essay Example Labour, is one of the main inputs, along with land, capital and entrepreneurship. The demand for all inputs such as labour is a derived demand. Derived from the output the given factors are used to produce (Begg D., Fischer S. and Dornbusch R., 2000:176). Firms will use labour and capital and focus on either labour intensive method or capital-intensive methods for production. In the short run, it is assumed that capital is fixed and labour is variable. Accordingly, the demand for labour is based on the profit maximising condition, which can be stated in two ways (Begg D., Fischer S. and Dornbusch R., 2000:178). It can be seen that the MPP (which refers to the output of every extra unit of labour) increases from 0.8 to 1 when labour is increased from 1 worker to 2 workers. However, from the 3rd worker onwards MPP begins to decrease. This is explained by the law of diminishing returns, which states that if increasing quantities of variable input are applied to a given quantity of a fixed input, the marginal product, and the average product of the variable input will eventually decrease (Lipsey and Chrystal, 2004:135). However, the firm can continue to add up to 7 workers and still maintain a profit. Thus satisfying the profit maximising requirements since the MRP (obtained by multiplying the MPP by the unit price of the good, which is assumed as â‚ ¬ 500) is higher than Average Variable Cost, which is the wage rate. However, if an 8th worker were to be hired, the AVC will be higher than the MRP, thus the profit maximising condition would be violated. The firm will therefore not expand its labour force to 8 workers (7.5 units of MPP) since the cost of this expansion will be greater than the revenue. At point B, the MRP is at W1 and employment is at L1. The revenue generated by the extra employment is higher than the labour cost since it above the wage

SPE 565 Essay Example | Topics and Well Written Essays - 750 words

SPE 565 - Essay Example These are social-cognitive theory by Bandura, 1991, Theory of Planned Behaviour by Azjen, 1991 and Theory of Interpersonal Behaviour by Triandis, 1981. (Bandura, 1997) defined social-cognitive as a theory that "explains how people acquire and maintain certain behavioural patterns, while also providing the basis for intervention strategies" (n.p.). The factors to be considered to evaluate behavioural change are the people, environment, and behaviour. This social cognition model focuses on self-efficacy expectancies or beliefs about a person's ability to perform certain behaviour. A framework for designing, implementing and evaluating programs are being offered in social-cognitive theory. To better analyze this social cognition model, analysis of the pros and cons when this model is used should be presented. SCT is an important and effective means for educators in assisting the students to gain new supporting skills by developing feelings of self-efficacy from their own mastery experiences. SLT can help educators determine why certain learning activities work, and why other activities aren't very effective as the students may receive standard persuasive techniques to try to instil feelings of self-efficacy. ... It is believed that all of the people are able of doing critical thinking, in spite of their differences. Additionally, social cognitive theory encourages the use of non-traditional methods of learning instructions and evaluations, which involves a major time commitment on the part of the expert using the model. Theory of Planned Behaviour (TPB) evaluated: The theory of planned behaviour is a theory about the relation between behaviour and attitudes. It was projected by Icek Ajzen as an annex of the theory of reasoned action (TRA). It is one of the most prognostic persuasion theories. As (Wikipedia, 2007), "it has been applied to studies of the relations among beliefs, attitudes, behavioural intentions and behaviours in various fields such as advertising, public relations, campaigns, healthcare, etc." (n.p.). TPB can cover people's intentional behaviour which Theory of Reasoned Action cannot explain. TPB would help better forecast health-related behavioural intention as it improves the predictability of intentions. It can give explanation to individual's social behaviours by viewing social norms as important factors. However, TPB fails to notice emotional factors and may only provide limited assessment on these areas. Theory of Interpersonal Behaviour (TIB) - Triandis Theory This model is based on TRA and TPB although based on (Davis et al., 1992) "efforts towards developing models that incorporate a non-utilitarian aspect of technology acceptance have been made" (pp 1111-1132). Hence, it does not distinguish the emotional from the cognitive domain and promotes assumption that an individual is positioned on the dimension of both emotional and cognitive bipolar in terms of evaluation. Triandis theory of interpersonal

Conan Doyle detective fiction Essay Example for Free

Conan Doyle detective fiction Essay Some people say that one of the reasons they enjoy reading crime stories like Sherlock Holmes is that order is always restored, good always triumphs over evil. Crime fiction is popular still today because there are many programmes on T. V today i. e. A Touch of Frost, Taggart, and Wire in the Blood. It is also in books like the novels of Ian Paterson. The genre is so popular because people enjoy it and there is an atmosphere of expectation in most stories. Conan Doyle was popular with the Victorian audience because the criminals always got caught, and his stories were published in a magazine read in a parlour or on a train journey. The basic structure of a crime story is that at the beginning there is order and all is well. Soon, however something happens usually a crime to disrupt that order. Then the detective investigates and solves the case. Finally order is restored again as good has defeated evil. This structure is evident in The Man with the Twisted Lip. For example it begins orderly at the beginning of the story as we read about Dr Watson and his wife in the sitting room just before the hour that a man goes to bed. His wife is knitting and Dr Watson sat in his chair. Then the order is disrupted when the doorbell rings and one of Dr Watsons patients Kate Whitney is at the door and she tells whats up. Dr Watson then goes to find Kate Whitneys husband and whilst there, finds Sherlock Holmes in the Opium den. The crime Sherlock Holmes has to investigate is the apparent murder of Neville St Clair. He solves the case by realising that Neville St Clair is in disguise as Hugh Boone. Finally order has been restored because Holmes gets to Neville St Clair and undisguises him as evil is defeated. Conan Doyle uses all the right ingredients and description to his villains which strikes fear into any reader. Dr Roylott is a perfect example of this. Conan Doyle describes him as So tall was he that his hat actually brushed the cross-bar of the doorway, and his breadth seemed to span it across from side to side. A large face, seared with a thousand wrinkles, burned yellow with the sun, and marked with evil passion, was turned from one to the other of us, while his deep-set, bile-shot eyes, and the high thin fleshless nose, gave him somewhat the resemblance to a fierce old bird of prey. This shows the sheer size and fierce looks that he has. I am a dangerous man to fall foul of! See here He stepped swiftly, seized the poker, and bent it into a curve with his huge brown hands. This shows how strong Dr Roylott is and to warn Sherlock Holmes off because other people fear him. In The Speckled Band Conan Doyle describes how aggressive, violent and Greedy Dr Roylott and that he uses his knowledge of medicine for evil doings. Jim Browner is another Conan Doyle that is very well described. His aggression, jealousy and uncontrollable rage are shown here. I swore to my wife that I would kill her if I found her under in his company again, and I led her back with me, sobbing and trembling and as white as a piece of paper. His cunning ways are shown here I had a heavy oak stick in my hand, and I telly you I saw red from the first; but as I ran I got cunning and hung back a little to see them without being seen. His violence and vengeance is shown here Crushed his head like an egg. I would have spared her, perhaps, for all my madness, but she threw her arms around him crying out to him I was like a wild beast that had tasted blood. This also shows there is no stopping him and that he gives no mercy. Conan Doyle carefully describes his settings to create tension and suspense. An example in The Man with the Twisted Lip Conan Doyle describes the opium den internally and externally to brilliant effect. The modern reader knows this is a place where sinister events happen, a black gap like the mouth of a cave Out of the black shadows there glimmered little red circles of light. The Victorian reader very familiar with the atmosphere in London and would be gripped by Watsons struggle to see and all the detail that Conan Doyle describes the Opium Den with. Sir Conan Doyle uses great language to create a tense atmosphere in The Speckled Band. In section where Helen Stoner relays what happened on the night her sister mysteriously died, he uses the story within the story to great effect. Firstly an atmosphere of foreboding is created as the weather is described The wind was howling, animal imagery which creates the effect that there is a wild beast outside. The rain was beating and splashing against the window which is describing the weather to create atmosphere of foreboding and uses words like beating to show violent imagery. Conan Doyle uses sentence structures effectively to create different atmospheres. He uses short sentences to create drama and also short sharp sentences followed by an exclamation mark to create a scary and tense atmosphere. For example in The Speckled Band when Julia shouts Oh my God! Helen! It was the band! Another example of a short sentence is when Helen says I knew that it was my sisters voice. Conan Doyle is very successful in writing detective fiction that appeals to a modern reader because he uses all the right ingredients and structure. Conan Doyle uses very interesting characters and evil villains, which makes the readers addicted to his detective fiction stories. He uses different types of language and sentence structure, which is very appealing to the readers.

Overhead In County Slogi and Woman Work :: Woman Work Maya Angelou

"Woman Work" by Maya Angelou and "Overheard in County Sigo" by Gillian Clarke In this essay I am going to discuss two poems. "Woman Work" written by Maya Angelou, is about a woman who works all the time and just wants to rest. The second poem is called "overheard in County Sigo" written by Gillian Clarke which is about a married woman having a conversation with her friend about her life and looking back at what her ambitions were. "Woman Work" is a regular 5 stanza, rhyming poem, It is set in southern USA. We know this because of the way she talkes "The cane to be cut" Cane is grown in southern USA, "I gotta clean up this hut" Hut is what she calles her house "And the cotton to Pick" cotton also grows in USA. It's about this womanwho's either single or doesn't get any help from her partener/husband. She's always doing something, looking after the children - "I've got the children to tend", housework - "I gotta clean up this hut", shopping - "The food to shop" or farmwork, - "The cane to be cut", "And the cotton to pick". "Overheard in County Sligo" is another regular 5 stanza, rhyming poem. It is set in Ireland. It is about a married woman who "married a man from county Roscommon" and she's talking about what her ambitions were - "I had thaught to work on the Abbey Stage" "or have my name in a book". It doesn't sound like she's happy but she won't leave - "the freedom's there for the taking" but she never went. There are several themes in "Woman work", one of them being Work. We can see this in the first stanza . She lists all the things she's got to do. Another theme being lonleiness. We can see this by the fact that she only mentions her children there, she may want someone to talk to her or help her with all her work. Mainly she just wants a rest. The theme in "Overheard in county Sligo" is basically life, it's all about a woman having a conversation with a friend or someone she knows and someone else just happend to be listening. The housewife is telling her friend about herself, and the fact that she wanted to leave her life but she never did - "the freedoms there for the taking" In "Woman Work" the poet Maya Angelou has made it so the reader can see a womandoing all this work in the reader's head, and how life must have been like for her.

Mesothelioma

Mesothelioma is a malignant neoplasm that develops from the mesothelium tissue (a membrane that covers the internal organs present in the body).   It occurs very rarely and is more frequently caused by inhaling asbestos dust.   The incidence of the disease is slowly on the rise.   In the US, about 2000 new cases are reported every year.   About 70 to 80% of all cases with mesothelioma report exposure to asbestos (NCI, 2002).   Mesothelioma can develop in various sites of the body including the pleura (membranes that covers the lungs), peritoneum (membrane that covers the abdominal cavity), tunica vaginalis testis (membrane that covers the male internal reproductive organs) and tunica serosa uteri (membrane that covers the female internal reproductive organs) (NCI, 2002). It is made up of one layer of flat or cuboidal cells that surround a particular organ or an organ set belonging to a particular group (Weitz & Luxenberg, 2006).   In between these membranes a fluid is present that permits some amount of movement during physiologic functioning.   When the asbestos is inhaled, it gets deposited into parenchyma of the lungs from where it enters the immediate membrane that covers the lungs.   It may be carried soon to the other membrane of the lung.   The tumor usually begins as discrete plaques known as ‘malignant mesothelial plaques’ (Weitz & Luxenberg, 2006). These discrete masses soon combine to form a large sheet like lesion that spreads.   The exact process by which mesothelioma occurs is not understood clearly, however, it seems that chronic irritation of the membrane plays a very important role (Weitz & Luxenberg, 2006).   The chromosomes present in the cell are distorted (Tan, 2007).   One of the most frequent changes in the malignant cell was the loss of a copy of Chromosome 22. The chromosomal picture of the cell seems to be very complex (complex karyotype) and is rearranged (Tan, 2007).   Sometimes, the chromosome arms of 1p, 3p, 9p and 6q may also get structurally rearranged.   This may be brought about by close contact between the chromosomes or the structural proteins with the asbestos particles (Weitz & Luxenberg, 2006). The asbestos may get deposited in the peritoneum either through the lymphatic system or the due ingestion of the sputum from the lungs (Weitz & Luxenberg, 2006).   The long thin fibers of asbestos are more dangerous than the feathery fibers as they more easily cause cancer.   Once the fibers get deposited in the pleura, the cancer development process actually begins.   In experimental rats, it has been observed that when the pleura or the peritoneum are invaded by the asbestos particles, macrophages and the other cells of the body’s defense mechanism accumulate (Weitz & Luxenberg, 2006). As the disease progresses, the macrophages and immune cells continue to invade the lesion.   Slowly the cells get transformed into malignancy.   Studies have demonstrated that the asbestos particles may directly (through physical interaction) and indirectly (through accumulation of macrophages) bring about malignant transformation of the epithelium cells.   Indirectly, the macrophages begin to function abnormally.   They phagocyte the asbestos particles and release higher amounts of hydroxyl radicals. They may stimulate the cancer process by affecting the DNA present in the cell.   Several other substances are released from the macrophages such as mitogens, growth factors, etc, which may bring about chronic irritation.   They also alter entry of certain substances into the cell (by affecting the membrane) and reducing the effect of antioxidant action within the cells.   Asbestos is also known to suppress the action of the body’s defense mechanism by overcoming the action of the lymphocytes (Weitz & Luxenberg, 2006). Several structural and functional features have been observed in the cells affected with mesothelioma (which have asbestos particles within the cells): – 1.the suppressor genes against cancers present in the cells may get inactivated when the asbestos fibers enters the cells 2.other cancer-stimulating agents may get activated and affect the cell 3. the DNA of the cell gets altered due to the incorporation of a foreign DNA which encourages cancer formation 4. the DNA repair enzymes may get stimulated and frequently result in a faulty method of repair 5.the cell terminal processes may become abnormal resulting in immortality 6.the DNA sequence may be added at the ends of the cell which makes the cells immortal and results in abnormal functioning (Weitz & Luxenberg, 2006) References: NCI. Mesothelioma: Questions and Answers. 2002. NCI. 5 Apr. 2007 http://www.cancer.gov/cancertopics/factsheet/Sites-Types/mesothelioma Tan W.W. â€Å"Mesothelioma.† 2007. E-Medicine. 5 Apr. 2007 http://www.emedicine.com/med/topic1457.htm Weitz & Luxenberg. â€Å"The Pathophysiology of Mesothelioma.† 2006. Weitz & Luxenberg Inc. 5 Apr. 2007 http://www.weitzlux.com/mesothelioma/Pathophysiology_403723.html

Leadership Theory And Situational Leadership - 1621 Words

Robert Fleming Lieutenant Colonel Michael G. LaFeve AS 301 30 October 2015 Midterm Paper Leadership is one of the human traits that are looked up to the most. When a task is at hand many people look around for someone to lead them and take charge. Leadership has been a part of The Air Force since it was created in 1947. Recently more emphasis and researching went into leadership and scholars provided leadership theories. Two of the theories are the Full Range Leadership model and the Situational Leadership model. Both of these theories provide ideas on how to lead and a strategy. The Full Range Leadership model shows many different ways of approaching leadership based on motivation and needs. The Situational Leadership model gives a†¦show more content†¦Laissez-faire leadership is a hands off approach. This approach leaves an absence of action or commands at time and leads to a very chaotic environment (Nath). The people in a group with a laissez-faire leader have very little guidance and experience a lot of freedom in their own decision-making ab ilities. This approach has many different positives and negatives. The benefits of this leadership style are that the group can be very successful when the group is skilled, motivated and capable of working on their own (Lewin). This model is negative when the group lacks their own knowledge in the area. Most people have trouble with setting their own deadlines and sticking to them. This could cause the group to fail and is a downside in laissez-faire leadership (Lewin). Transactional leadership is more involved with the day-to-day workings of the group. It is more contract based rather than inspiring them. This is where the reward systems come in and a leadership gets results by rewards and management of tasks (Nath). The only downfall to this type of leadership is the leader is not involved in their subordinate’s life and doesn’t really find out their driving motivation. Transformational leadership is the opposite, it focus’s on motivating the group and drive them to better themselves. This gives the subordinates to drive to do better and the leader acts more of a role model then a manager of