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"Thermite welding was a step forward for joining rails A thermite weld in progress. Exothermic welding, also known as exothermic bonding, thermite welding (TW), and thermit welding, is a welding process that employs molten metal to permanently join the conductors. The process employs an exothermic reaction of a thermite composition to heat the metal, and requires no external source of heat or current. The chemical reaction that produces the heat is an aluminothermic reaction between aluminium powder and a metal oxide. Overview In exothermic welding, aluminium dust reduces the oxide of another metal, most commonly iron oxide, because aluminium is highly reactive. Iron(III) oxide is commonly used: :\mathrm{Fe_2O_3 + 2 \ Al \longrightarrow 2 \ Fe + Al_2O_3} The products are aluminium oxide, free elemental iron, and a large amount of heat. The reactants are commonly powdered and mixed with a binder to keep the material solid and prevent separation. Commonly the reacting composition is five parts iron oxide red (rust) powder and three parts aluminium powder by weight, ignited at high temperatures. A strongly exothermic (heat-generating) reaction occurs that via reduction and oxidation produces a white hot mass of molten iron and a slag of refractory aluminium oxide. The molten iron is the actual welding material; the aluminium oxide is much less dense than the liquid iron and so floats to the top of the reaction, so the set-up for welding must take into account that the actual molten metal is at the bottom of the crucible and covered by floating slag. Other metal oxides can be used, such as chromium oxide, to generate the given metal in its elemental form. Copper thermite, using copper oxide, is used for creating electric joints: :\mathrm{3 \ Cu_2O + 2 Al \longrightarrow 6 \ Cu + Al_2O_3} Thermite welding is widely used to weld railway rails. One of the first railroads to evaluate the use of thermite welding was the Delaware and Hudson Railroad in the United States in 1935"Welding Rails Together Takes Out Clicks", Popular Mechanics, October 1935. The weld quality of chemically pure thermite is low due to the low heat penetration into the joining metals and the very low carbon and alloy content in the nearly pure molten iron. To obtain sound railroad welds, the ends of the rails being thermite welded are preheated with a torch to an orange heat, to ensure the molten steel is not chilled during the pour. Because the thermite reaction yields relatively pure iron, not the much stronger steel, some small pellets or rods of high-carbon alloying metal are included in the thermite mix; these alloying materials melt from the heat of the thermite reaction and mix into the weld metal. The alloying beads composition will vary, according to the rail alloy being welded. The reaction reaches very high temperatures, depending on the metal oxide used. The reactants are usually supplied in the form of powders, with the reaction triggered using a spark from a flint lighter. The activation energy for this reaction is very high however, and initiation requires either the use of a "booster" material such as powdered magnesium metal or a very hot flame source. The aluminium oxide slag that it produces is discarded. When welding copper conductors, the process employs a semi-permanent graphite crucible mould, in which the molten copper, produced by the reaction, flows through the mould and over and around the conductors to be welded, forming an electrically conductive weld between them. When the copper cools, the mould is either broken off or left in place. Alternatively, hand-held graphite crucibles can be used. The advantages of these crucibles include portability, lower cost (because they can be reused), and flexibility, especially in field applications. Properties An exothermic weld has higher mechanical strength than other forms of weld, and excellent corrosion resistance It is also highly stable when subject to repeated short-circuit pulses, and does not suffer from increased electrical resistance over the lifetime of the installation. However, the process is costly relative to other welding processes, requires a supply of replaceable moulds, suffers from a lack of repeatability, and can be impeded by wet conditions or bad weather (when performed outdoors). Applications Exothermic welding is usually used for welding copper conductors but is suitable for welding a wide range of metals, including stainless steel, cast iron, common steel, brass, bronze, and Monel. It is especially useful for joining dissimilar metals. The process is marketed under a variety of names such as Harger ULTRASHOT, American Rail Weld, ERICO CADWELD, Quikweld, Tectoweld, Ultraweld, Techweld, TerraWeld, Thermoweld, Ardo Weld, AmiableWeld, AIWeld, FurseWeld, CADWELL TVT and Kumwell. Because of the good electrical conductivity and high stability in the face of short-circuit pulses, exothermic welds are one of the options specified by §250.7 of the United States National Electrical Code for grounding conductors and bonding jumpers. It is the preferred method of bonding, and indeed it is the only acceptable means of bonding copper to galvanized cable. The NEC does not require such exothermically welded connections to be listed or labelled, but some engineering specifications require that completed exothermic welds be examined using X-ray equipment. Rail welding Tram tracks being joined Tram tracks recently joined History Modern thermite rail welding was first developed by Hans Goldschmidt in the mid-1890s as another application for the thermite reaction which he was initially exploring for the use of producing high-purity chromium and manganese. The first rail line was welded using the process in Essen, Germany in 1899, and thermite welded rails gained popularity as they had the advantage of greater reliability with the additional wear placed on rails by new electric and high speed rail systems. Some of the earliest adopters of process were the cities of Dresden, Leeds, and Singapore. In 1904 Goldschmidt established his eponymous Goldschmidt Thermit Company (known by that name today) in New York City to bring the practice to railways in North America. In 1904, George E. Pellissier, an engineering student at Worcester Polytechnic Institute who had been following Goldschmidt's work, reached out to the new company as well as the Holyoke Street Railway in Massachusetts. Pellissier oversaw the first installation of track in the United States using this process on August 8, 1904, and went on to improve upon it further for both the railway and Goldschmidt's company as an engineer and superintendent, including early developments in continuous welded rail processes that allowed the entirety of each rail to be joined rather than the foot and web alone. Although not all rail welds are completed using the thermite process today, it still remains a standard operating procedure throughout the world today. Process Typically, the ends of the rails are cleaned, aligned flat and true, and spaced apart . This gap between rail ends for welding is to ensure consistent results in the pouring of the molten steel into the weld mold. In the event of a welding failure, the rail ends can be cropped to a gap, removing the melted and damaged rail ends, and a new weld attempted with a special mould and larger thermite charge. A two or three piece hardened sand mould is clamped around the rail ends, and a torch of suitable heat capacity is used to preheat the ends of the rail and the interior of the mould. The proper amount of thermite with alloying metal is placed in a refractory crucible, and when the rails have reached a sufficient temperature, the thermite is ignited and allowed to react to completion (allowing time for any alloying metal to fully melt and mix, yielding the desired molten steel or alloy). The reaction crucible is then tapped at the bottom. Modern crucibles have a self-tapping thimble in the pouring nozzle. The molten steel flows into the mould, fusing with the rail ends and forming the weld. The slag, being lighter than the steel flows last from the crucible and overflows the mould into a steel catch basin, to be disposed of after cooling. The entire setup is allowed to cool. The mould is removed and the weld is cleaned by hot chiselling and grinding to produce a smooth joint. Typical time from start of the work until a train can run over the rail is approximately 45 minutes to more than an hour, depending on the rail size and ambient temperature. In any case, the rail steel must be cooled to less than before it can sustain the weight of rail locomotives. When a thermite process is used for track circuits – the bonding of wires to the rails with a copper alloy, a graphite mould is used. The graphite mould is reusable many times, because the copper alloy is not as hot as the steel alloys used in rail welding. In signal bonding, the volume of molten copper is quite small, approximately and the mould is lightly clamped to the side of the rail, also holding a signal wire in place. In rail welding, the weld charge can weigh up to . The hardened sand mould is heavy and bulky, must be securely clamped in a very specific position and then subjected to intense heat for several minutes before firing the charge. When rail is welded into long strings, the longitudinal expansion and contraction of steel must be taken into account. British practice sometimes uses a sliding joint of some sort at the end of long runs of continuously welded rail, to allow some movement, although by using a heavy concrete sleeper and an extra amount of ballast at the sleeper ends, the track, which will be prestressed according to the ambient temperature at the time of its installation, will develop compressive stress in hot ambient temperature, or tensile stress in cold ambient temperature, its strong attachment to the heavy sleepers preventing buckling or other deformation. Current practice is to use welded rails throughout on high speed lines, and expansion joints are kept to a minimum, often only to protect junctions and crossings from excessive stress. American practice appears to be very similar, a straightforward physical restraint of the rail. The rail is prestressed, or considered "stress neutral" at some particular ambient temperature. This "neutral" temperature will vary according to local climate conditions, taking into account lowest winter and warmest summer temperatures. The rail is physically secured to the ties or sleepers with rail anchors, or anti-creepers. If the track ballast is good and clean and the ties are in good condition, and the track geometry is good, then the welded rail will withstand ambient temperature swings normal to the region. Remote welding Remote exothermic welding is a type of exothermic welding process for joining two electrical conductors from a distance. The process reduces the inherent risks associated with exothermic welding and is used in installations that require a welding operator to permanently join conductors from a safe distance from the superheated copper alloy. The process incorporates either an igniter for use with standard graphite molds or a consumable sealed drop-in weld metal cartridge, semi-permanent graphite crucible mold, and an ignition source that tethers to the cartridge with a cable that provides the safe remote ignition. See also * Rail lengths References External links * Exothermic Welding Powder - Learn how Exothermic Welding is done, AmiableWeld Category:History of Cleveland Category:Welding "
"Carmen Lucille Lowell is a main character in the book and film The Sisterhood of the Traveling Pants (film). She is sometimes called Carma and Carmabelle (her Instant Messaging username) or Carmeena in the book, and is a sensitive and caring half-Puerto Rican with a bad temper. Her parents are divorced, and she lives with her mother, Christina. She is the organized one, but sometimes she thinks too much. She is the one most insistent on keeping the sisters together through the Traveling Pants, which she first found. She is the "glue" keeping the Sisterhood together. She is portrayed by America Ferrera in the 2005 film adaptation of the first book, and the 2008 sequel, The Sisterhood of the Traveling Pants 2. Family Christina: Carmen has a close relationship with her mother, Christina, whom she has lived with since her parents' divorce. Carmen admits that she can be bratty with her mother, though Christina suggests this may be because she knows it is easier to get mad at people you love because you can trust them to still love you. Carmen can also be possessive of her mother and is worried both when Christina begins dating and when she gets pregnant. She does not want her mother to leave her. Albert: Carmen looks up to her father; she wanted to follow in his footsteps and go to Williams College. However, her parents' divorce hit her hard and she is initially concerned that his marrying Lydia was an attempt to replace her and Christina with a perfect, beautiful family. She resolves most of these issues in the first book and afterwards often calls her father for advice or guidance. David: Carmen's stepfather. She was originally hostile toward David when he began dating Christina because she thought her mother was making a fool of herself and rushing into the relationship too quickly. Though she doesn't develop a very close relationship with him, she admits that he makes her mother happy; her only complaint about him is that he is a workaholic. Lydia: Carmen's stepmother. Carmen does not know of her until she goes to stay with her dad during the first novel. She gets off on the wrong foot with her stepmother due to their many differences. Lydia is blonde, and a "Southern belle" who has a perfectly neat house and is very religious. Because of how different Lydia's lifestyle is from her mother's, Carmen is at first angry with Lydia and her father and feels she is being replaced. Later, she achieves a more civil relationship with her stepmother, especially after realizing that Lydia and Christina actually get along. Paul: Carmen's older stepbrother. Carmen gets along very well with Paul and admires his honesty and lack of egotism. She e-mails and phones him regularly. The books mention that Paul regards Carmen and her temper with a sort of awe, and never understands the motivations behind her insane outbursts. Carmen is originally nervous that if Paul falls in love with Lena, he will forget about her. However, after noticing how the two look at each other and how alike they are, she eventually encourages their relationship. She also keeps on talking to Lena about Paul. Krista: Carmen's younger stepsister. They originally talked very little as Krista's preppy, flaky, superficial attitude was very different from Carmen's explosive, colorful personality. She felt that since Krista was the direct opposite of her that her father was "upgrading." After confronting her father about the issue, she and Krista get along much better. Krista grows to admire Carmen's independent attitude; in the second book, she runs away from home and seeks sanctuary with Carmen and Christina. Ryan: Carmen's younger half- brother. She is slightly bad-tempered about his birth and jealous of her mother's attention to him. Later, she gets over this, enjoys being a big sister and role model to him. Friends Carmen is the youngest member of the sisterhood. Lena Kaligaris, Tibby Rollins, and Bridget Vreeland are the other members of the sisterhood. She considers herself "the Puerto Rican with the bad temper" in the group. She also sees herself as "the glue" that keeps the friends together. Ann Brashares says that she believes Carmen gets the bigger picture of their friendship, whereas the other girls are more "in the moment." Romantic Relationships Winthrop "Win" Sawyer: Carmen meets Win at the hospital with Lena's grandmother. She is initially attracted to him, and the two have several other chance meetings. Win is a volunteer at the hospital and is two years older. Carmen is initially worried that she is deceiving him, as he keeps catching her doing charitable things and is scared that he won't like her as much when he learns about her bad temper. She tells him about her worries, but he resolves that he likes her anyway and the two kiss in the hospital. She lets the relationship drop off on purpose due to confidence issues. Carmen also briefly dates a boy in the second book who had a massive crush on her, Porter, but she was too distracted by issues with her mother; Porter eventually decided that he was tired of being led on. She also maintained a flirtatious relationship with one of the actors she worked with in the fourth book. Their relationship is not focused on in this book, though it mentions that he often played with her hair, flirted with her, and kissed her before the play's opening night. This relationship is more prominent in the second movie. The Second Summer of the Sisterhood Christina starts to date a young attractive man named David. Carmen is jealous of the time she spends with him and also embarrassed because Christina's relationship is so passionate. She believes her mother is humiliating herself and falling in love too quickly. Carmen sabotages the relationship out of spite, but once she realizes how happy David makes her mother, she helps the two get together. A subplot during this book is Carmen's relationship with a boy, Porter, from her school. She goes on several dates with him but neglects him during each date due to her worries about her mother. Carmen is originally optimistic about the relationship because she has the Traveling Pants for their first date, but Porter becomes tired of Carmen "stringing him along" and stops dating her. On her final date with him, she brings Paul and a heartbroken Lena along. She notices how attracted Paul is to Lena and gives Lena the pants, encouraging her to go after Paul and Paul to see Lena. Girls in Pants: The Third Summer of the Sisterhood Carmen learns that Christina is pregnant with David's child. Carmen is originally hostile, believing that since the baby will be born just after she leaves for college that she is being replaced. Carmen also gets a job looking after Valia, Lena's grandmother, and meets a guy named Win 'Winthrop' at the hospital. She and Win maintain a flirtatious relationship, but she believes that she is deceiving him because he keeps catching her doing charitable things, and that he will be disappointed when he learns about her arguments with her mother. Carmen eventually realizes that since David works so much, she will have to be there for the child and makes amends with her mom. At the end of the book, Christina goes into labor four weeks early while David is away on business. Carmen and Win go hunting for David to bring him home. Meanwhile, Tibby helps Christina give birth. Carmen returns to the hospital where she meets her baby brother and tells Win that she doesn't think she deserves him. Win announces that it doesn't matter, and the two share a kiss. Forever in Blue: The Fourth Summer of the Sisterhood Carmen arrives at college where she falls into a sort of depression. She has let the relationship with Win drop off due to confidence issues. She gains weight and shrinks away from making new friends and from the sisterhood. She befriends a beautiful and sophisticated actress named Julia Beckwith; together, they go to a special acting camp. Carmen mistakenly auditions for the main play, although she originally tagged along only to be with Julia and work on sets. She wins the sought-after lead role in a play with several professional actors, and Julia becomes bad-tempered and surly. Julia tries to "help" Carmen with the part but really gives her bad advice in an attempt to sabotage an inexperienced Carmen. As a result, Carmen becomes depressed again, but finally realizes that Julia was not a friend to her because she fed off of Carmen's insecurities to boost her own confidence. Carmen stars in the play brilliantly and confronts Julia. Sisterhood Everlasting Carmen is a semi-successful actress in New York who is engaged (to a sometimes pretentious man her friends dislike). She is now obsessed with her work, worries about her wedding and her busy schedule. On her long trip to an audition, she meets a man named Roberto Moyo who is traveling with his two young children. Carmen befriends Roberto and is struck by his sad story, she also grows very fond of his kids. At the end of the book, Carmen breaks off her engagement. She is the only one of her friends who is not romantically involved with anyone; however, she is very satisfied with her life. She is very sad when Tibby died. Other References In the novel 3 Willows, Jo mentions babysitting a toddler named Ryan; this is Carmen's little brother. Category:Characters in American novels of the 21st century Category:Literary characters introduced in 2001 Category:Fictional actors Category:Drama film characters "
"Adam Fawer (born 1970 in New York City) is an American novelist. Improbable, his first novel, has been translated into eighteen languages and won the 2006 International Thriller Writers Award for best first novel. His second novel, Empathy, has been published in 2008 in German, Japanese and Turkish. His third novel, Oz, has been published in 2016 in Turkish only. Unlike the first two novels, it received generally negative reviews from critics and readers. Early life and education Fawer holds undergraduate and master's degrees from the University of Pennsylvania and the Wharton School of the University of Pennsylvania and received an MBA from the Stanford Graduate School of Business. Career During his corporate career, Fawer worked for a variety of companies including Sony Music, J.P. Morgan, and most recently, About.com, where he was the chief operating officer. Awards and honours In 2007, Fawer won the International Thriller Writers award for Best First Novel. Personal life Fawer lives in New York City with his partner and two sons. Bibliography *Improbable, 2005 *Gnosis, also published as Empathy, 2008 *Oz, 2016 See also * Laplace's demon ReferencesExternal links * Official Website for Adam Fawer * A review of Improbable by Judi Clark * Adam Fawer's backstory for IMPROBABLE Category:1970 births Category:Living people Category:21st-century American novelists Category:University of Pennsylvania alumni Category:Writers from New York City Category:Stanford Graduate School of Business alumni Category:American science fiction writers Category:American chief operating officers Category:American male novelists Category:21st- century American male writers Category:Wharton School of the University of Pennsylvania alumni Category:Novelists from New York (state) "