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Rupam sharma's Stashed Knowledge
Dissimilar Materials by Friction Stir Welding Pro
RESEARCH PAPER 1- Paper on Dissimilar Materials by Friction Stir Welding Process By Vuppula Prasanna1 , Shilpa2 Associate Professor1 , Assistant Professor2 Abstract: Recently many reports on Friction Stir Welding (FSW) of various dissimilar systems such as Aluminium to Copper and Aluminium to Brass been reported. FSW of Aluminium, Copper and Brass has captured important attention from manufacturing industries, such as Shipbuilding, Automotive, Railway and Aircraft production. Brass materials are widely used as engineering materials in industry because of their high electrical and thermal conductivity, high strength, and high corrosion resistance . Copper and its alloys are widely used in industrial applications due to their excellent electrical & thermal conductivities, good strength, corrosion & fatigue resistance. The aim of present study was analogy of the microstructures and mechanical properties of friction stir welded joint of Aluminium to Copper and Aluminium to Brass plates in 4mm thickness. Paper on Dissimilar Materials by Friction Stir Welding Process · Vertical milling machine of 7Kw is used to join the dissimilar plates · The plate size of Al6061 and pure copper are having 100mm length, 70mm width and 4mm thickness. · Work H13 tool is used. The tool is having tapered shoulder and pin. · The Vickers micro hardness was measured by using HARDWOOD HWMMT-X7 micro hardness tester. · Shoulder diameter(SD) -25mm · Pin diameter(PD)- 6mm · Pin length (PL) 3.6mm · Rotation Speed Rpm-Exp1- 710 ,900,1120 Exp2- 710,900,1120 · Transverse speed -10-60 mm/min · Material Dissimilar Thickness 4mm Length 100mm · Width 70mm · Rotational Speed 710,900 and 1120 rpm · Feed 15-30 mm/min · For 710 rpm Ultimate Tensile strength 37.69 N/mm² Yield Strength 29.808 N/mm² % Elongation 0.42% · For 900 rpm Ultimate Tensile strength- 55.89 N/mm² Yield Strength- 40.5 N/mm² · For 1120 rpm Ultimate Tensile strength -108.56 N/mm² Yield Strength -89.9 N/mm² % Elongation- 0.98% JOINING OF ALUMINIUM TO COPPER BY FRICTION STIR WELDING-Dhaval S. Chaudhari · Summary · The study has been aimed towards extracting mechanical properties and microstructures of friction stir welded joint of 6082 aluminium alloy and pure copper plates in 3 mm thickness. Zinc, Tin, Silicon Carbide have been used as filler materials. Welds were produced using High molybdenum high speed steel, with a cylindrical pin tool having 3 mm and 14 mm diameter of pin and shoulder respectively. Optical microscopy was used to study the microstructures and grain size in TMAZ, HAZ and NZ were analyzed. · Vickers hardness was used to study the hardness of the weld and tensile test were done to analyse the weakest portion of weld joints. · In conclusion, Microharness in NZ of Al/Al with Rare earth filler metal powder was lower than base metal. Tensile strength of Al/Cu ·with SiC and Al/Al with Zinc were good compares to others and all the welds were defect free. · Parameters: · Material: Aluminium and copper · plate size: 150 mm length, 100 mm width and 3 mm thickness · rotation speed: 1000 rpm · feed rate: 28 mm/min. · Tool material: high molybdenum high speed steel · Shape of tool: concave shoulder. · tool dimensions: shoulder diameter=14 mm with 2.7 mm pin length and 3 mm pin diameter. · tool pin: cylindrical. Weld-ability and mechanical properties of dissimilar aluminium–copper lap joints made by friction stir welding T. Saeida, A. Abdollah-zadehb, B. Sazgarib Summary · The rolled plates of 1060 aluminum alloy and commercially pure copper were used as the top and bottom plates of the lap joints.The experimental results of friction stir welding of 1060 aluminum alloy and commercially pure copper revealed that a dark area was formed in the aluminum close to the Al/Cu interface. In this area the intermetallic compounds of Al4Cu9 and Al2Cu, and some micro-cracks were detected. The frequency of such micro-cracks decreased with increasing welding speed. . This can be related to both introduction of copper in small quantities and less intensive mixing condition at high welding speeds. Some of the copper fragments contain the layer structure while the others consist of fine grains of copper rich structure. On the other hand, at higher welding speeds of 118 and 190 mm/min, the cavity defects were formed inside the joints as a result of insufficient heat input. Decreasing the welding speed of a tool due to higher amount of micro-cracks reduced the tolerable shear load. · Furthermore, lower welding speed caused more vertical transport, while a higher welding speed caused less vertical transport on the retreating side.The results of tensile shear test revealed that the maximum tensile shear strength of joint was obtained at welding speed of 95 mm/min. At this welding speed, no cavity defects, and few micro-cracks were observed in the weld. · Parameters: · The rolled plates of 1060 aluminum alloy and commercially pure copper were · used as the top and bottom plates of the lap joints. Table 1 indicates chemical com- · position and thicknesses of these two materials. · Plate dimensions: 20 mm length and 10 mm · rotating tool material: quenched and tempered steel. · Tool dimensions: It has a 15 mm diameter shoulder and a left-hand threaded pin (-5 mm × 6.5 mm). · pin rotating speed: 1180 rpm · welding speed: 30, 60, 95, 118, 190, 300, and 375 mm/min. 2. APPLICATION OF RESISTANCE OF WELDING Resistance seam welding can be used to make gas- or fluid-tight joints in a variety of sheet metal fabrications. Steel fuel tanks for motor vehicles are a prime example. It is also used in making tin cans, steel drums and domestic radiators. The process lends itself particularly to welding seams which are straight or have a regular curvature: abrupt changes in the weld line in any plane should be avoided. Welding is not possible into internal corners or where other features of a component obstruct access for the wheel electrodes. Access to both sides of the joint is necessary, and a lap joint configuration is generally required. Components comprising two half shells may be welded, for example petrol tanks or domestic radiators. Alternatively, sheet can be rolled into tubular form and the longitudinal seam welded, as in tin cans or steel drums. § Resistance welding is widely used in automotive industries. § Projection welding is widely used in production of nut and bolt. § Seam welding is used to produce leak prove joint required in small tanks, boilers etc. § Flash welding is used to welding pipes and tubes. 1. SPОT: Resistance spоt welding SPОT: Resistance spоt welding is made by passing current, fоr a timed interval, thrоugh the wоrkpieces frоm electrоdes which apply the welding fоrce. 2. SEAM: Seam welding SEAM: Seam welding cоnsists оf making a series оf оverlapping spоt welds by using оne оr twо rоtating wheel electrоdes withоut оpening the electrоdes between spоts. 3. CRОSS WIRE: In practice, it usually cоnsists оf welding a number parallel wire at right angles tо оne оr mоre wires оr rоds. 4. UPSET: Is a resistance welding prоcess which prоduces cоalescence simultaneоusly оver the entire area оf abutting surfaces оr prоgressively alоng a jоint. 5. RESISTANCE BRAZING: Resistance brazing is a methоd оf lоw-temperature brazing by the applicatiоn оf heat and fоrce tо the parts tо be jоined using heat generated by the current in either the parts themselves, in the dies hоlding the parts оr the electrоdes making cоntact with the area tо be brazed, оr bоth.
Tanmay Paliwal
Design of transmission system
Available below are the notes for the course mechanical and subject production. The topics included in the documents are FLEXIBLE M/C ELEMENTS, ADVANTAGES OF BELT DRIVES, DRAWBACKS, DESIGN CONSIDERATION, BELT MATERIAL, TENSION FORCES, ADVANTAGES OF V-BELTS, etc.
Tejas Khot
Visionary behind Movies
Three years ago, Martin Scorsese, the New York director who has made street violence one of his signature traits, teamed up with Harvey Weinstein, co-chairman of Miramax Films and something of a street fighter himself. The goal was to make a stylized epic film about gang warfare in pre-Civil War Manhattan with enough mass appeal to score at the box office. But the making of that movie, Gangs of New York, has turned into an epic of its own. Stars like Robert DeNiro and Willem Dafoe have come and gone. Costs have overshot the original budget by about 25 per cent to soar above $100 million. Weinstein has fought for a streamlined, more commercial version. All the while, Scorsese has tried to stick to his artistic guns as the two have battled over taste and length. With hopes of promoting the film next month at Cannes, Miramax executives are pushing to have the final editing completed in the next few weeks so the complex task of mixing sound with film can begin. But Scorsese is still not satisfied with the ending. He has been considering reshooting it, some people involved in the film say. The film was initially supposed to hit theatres last December, but now is expected to be released later this year. Scorsese has not had a box-office smash since Cape Fear, which earned $79 million domestically in 1991. Weinstein, a domineering personality who, by his own admission, is spurned in Hollywood despite championing eclectic hits like The English Patient and Goodwill Hunting, has come under financial pressure of his own. In January he shut Talk magazine and more recently he shed 75 Miramax employees and contract workers to trim costs. Conflicts arise any time a director's vision collides with pressures to make a commercial hit. But Saul Zantez, the producer who battled with Weinstein over money after working with him on the Academy Award - winning The English Patient, said it was especially true with such strong-willed personalities. ''Marty is only interested in making the right picture,'' Mr. Zaentz said. ''He will make it no matter what he has to do. And he is strong enough to fight for what he believes in. Harvey's interest, on the other hand, is not the same as Marty's. It is about making money.'' The budget for ''Gangs'' has ballooned to more than $103 million from the original $83 million - some of which is being paid for by Mr. Scorsese and Mr. DiCaprio, who plays the lead character, according to two people involved in the film. At that price - high even by today's standards - it would be the most expensive movie in Miramax's 22-year history. Mr. Weinstein and Mr. Scorsese declined to be interviewed but released this statement: ''As the only two decision makers on 'Gangs of New York' we would be happy to discuss this film in the context of an art versus commerce article when the story is an informed one, which clearly hinges on the final film being screened.''
akash cha
Britain's queen mother
Nine days of state mourning at the passing away of Britain's queen mother, will mark a unique era because the racehorse loving, gin and tonic drinking 'grand old mum', as the Brits called her, literally lived through the entire 20th century. While TV channels put out some black and white archival footage from another age, the formerly reverential BBC attracted criticism because its newscasters did not wear black ties and they discussed the event with a frankness that would have been unthinkable a few years ago. She was widowed 50 years ago. A relic I still have in my possession amongst my naval memorabilia is a black, mourning armband issued to us when king George VI died on February 6, 1952. It was dispatched by Messrs Gieves of Old Bond Street in London, the naval tailors 'By appointment to the King'. I recall listening to the last Christmas day broadcast of King George VI, with his consort by his side, while sitting at a dinner to which my fellow cadet, Narinder Lal Khullar, and I were invited by an English family in Surrey and how by tradition they listened in rapt attention. Then a few weeks later we were to receive news of his death while we were at sea on board our training cruiser HMS Devonshire headed for the Caribbean. As we proceeded to drop anchor in Barbados harbour, we were struck first, by the magnificent sight of flying fish which kept darting across the placid blue waters, and then, by the great alacrity with which mourning bands were delivered to us for the funeral ceremonies. Inevitably, we were billed by 'Messrs Thieves' for five shillings, a princely sum then, because our pay was four shillings a day. Brought up as I was in a family known for thrift, I had put that piece of uniform safely away and which, as it happened, came in handy a year later following the death of the then queen mother, Mary. Our pay had doubled to eight shillings by then, we having been promoted as midshipmen, and the commander-in-chief in Malta was Louis Mountbatten. He was a close member of the royal family, a cousin of George VI and of course he and his wife Edwina flew to London for the funeral service in Westminster Abbey. But the formalities connected with a royal funeral were meticulously observed by all ships of the Mediterranean fleet and thus that black armband became an absolute necessity.
kushagra srivastava
GASOLINE DIRECT INJECTION
FUNDAMENTALS OF GDI.WORKING.
vinit dahiya
STATISTICAL PROCESS CONTROL
STATISTICAL PROCESS CONTROL SEVERAL TECHNIQUES AND GRAPHS METHODICAL PROCEDURE
soham biswas
Language in humans
Language in humans has evolved culturally rather than genetically, according to a study by the University College London and US researchers. By modeling the ways in which genes for language might have evolved alongside language itself, the study showed that genetic adaptation to language would be highly unlikely, as cultural conventions change much more rapidly than genes. Thus, the biological machinery upon which human language is built appears to predate the emergence of language. According to a phenomenon known as the Baldwin effect, characteristics that are learned or developed over a lifespan may become gradually encoded in the genome over many generations, because organisms with a stronger predisposition to acquire a trait have a selective advantage. Over generations, the amount of environmental exposure required to develop the trait decreases, and eventually no environmental exposure may be needed - the trait is genetically encoded. An example of the Baldwin effect is the development of calluses on the keels and sterna of ostriches. The calluses may initially have developed in response to abrasion where the keel and sterna touch the ground during sitting. Natural selection then favored individuals that could develop calluses more rapidly, until callus development became triggered within the embryo and could occur without environmental stimulation. The PNAS paper explored circumstances under which a similar evolutionary mechanism could genetically assimilate properties of language - a theory that has been widely favoured by those arguing for the existence of 'language genes'. The study modeled ways in which genes encoding language-specific properties could have coevolved with language itself. The key finding was that genes for language could have coevolved only in a highly stable linguistic environment; a rapidly changing linguistic environment would not provide a stable target for natural selection. Thus, a biological endowment could not coevolve with properties of language that began as learned cultural conventions, because cultural conventions change much more rapidly than genes. The authors conclude that it is unlikely that humans possess a genetic 'language module' which has evolved by natural selection. The genetic basis of human language appears to primarily predate the emergence of language. The conclusion is reinforced by the observation that had such adaptation occurred in the human lineage, these processes would have operated independently on modern human populations as they spread throughout Africa and the rest of the world over the last 100,000 years. If this were so, genetic populations should have coevolved with their own language groups, leading to divergent and mutually incompatible language modules. Linguists have found no evidence of this, however; for example, native Australasian populations have been largely isolated for 50,000 years but learn European languages readily. Professor Nick Chater, UCL Cognitive, Perceptual and Brain Sciences, says: "Language is uniquely human. But does this uniqueness stem from biology or culture? This question is central to our understanding of what it is to be human, and has fundamental implications for the relationship between genes and culture. Our paper uncovers a paradox at the heart of theories about the evolutionary origin and genetic basis of human language - although we appear to have a genetic predisposition towards language, human language has evolved far more quickly than our genes could keep up with, suggesting that language is shaped and driven by culture rather than biology. "The linguistic environment is continually changing; indeed, linguistic change is vastly more rapid than genetic change. For example, the entire Indo-European language group has diverged in less than 10,000 years. Our simulations show the evolutionary impact of such rapid linguistic change: genes cannot evolve fast enough to keep up with this 'moving target'.
shrivignesh ss
asteroids
Asteroids are rocky, metallic objects that orbit around the Sun, but are too small to be considered planets. The largest known asteroid, Ceres, has a diameter of about 1,000 kilometres. The smallest asteroids are the size of pebbles. Millions are the size of boulders. Most are irregularly shaped - only a few are large enough for gravity to have made them into spheres. About 250 asteroids in the solar system are 100 kilometres in diameter, and at least 16 have a diameter of 240 kilometres or greater. Their orbits lie in a range that stretches from Earth's orbit to beyond Saturn's orbit. Tens of thousands of asteroids exist in a belt between the orbits of Mars and Jupiter. An asteroid that hits Earth's atmosphere is called a meteor or shooting star, because it burns and gives off a bright flash of light. Whatever does not completely burn falls to Earth as a meteorite. Between 1,000 and 10,000 tons of this material fall to Earth daily. Much is in the form of small grains of dust, but about 1,000 metallic or rocky bits fall to Earth each year. There has been much speculation about large meteors hitting the Earth. A large asteroid or comet is thought to have landed in Mexico about 65 million years ago. The impact may have led to the extinction of many species, including the dinosaurs, by throwing dust into the atmosphere, blocking the sunlight, and causing a climate change. The period of time between such a large meteor impacts is probably in the millions of years, but smaller meteors such as the one that caused the Metro's Carter in Arizona (about 1.2 kilometres in diameter), may hit the Earth every 50,000 to 100,000 years. There's no historical record of a person being killed by a meteorite. The only reported injury occurred on November 30, 1954, when an eight-pound meteorite that fell through the roof of her house bruised an Alabama woman.
aman hussain
The garbage island
If you were to sail due west from San Francisco, California, after about 2000km you would find yourself in a very strange place. This is an area of the Pacific Ocean technically referred to as the North Pacific Gyre, but a more descriptive term is the Great Pacific Garbage Patch. You heard correct. Decades of constant oceanic currents have resulted in a huge area of the Pacific that has become a veritable black hole of human-produced waste. Oceanic currents are largely steady over the period of centuries. Since the days of colonisation, Christopher Columbus and his friends had capitalised on reliable trade winds to propel them to and from the Americas. Within these swirling, connected currents lie a few select dead spots, where the motion of the ocean is effectively nil. There are five of these so-called gyres located throughout the world. The Floating Island of Garbage was discovered surprisingly recently. The story goes, a sailor named Charles Moore was returning to Los Angles after competing in a race. Normally, seamen avoid the North Parasitic Gyre like the plague. The absence of wind makes sailing impossible, and the dearth of large critters renders the area unprofitable for fishing. On this one particular occasion in 1997, Charles Moore had a little extra time, and an outboard motor on his sailboat. He decided to take a shortcut and cross through the normally-avoided area of the sea. What he saw was astounding: plastic, plastic everywhere. Moore would later return to the area to conduct thorough investigations to quantify the extent of the mess. The actual size and trash-density of the garbage patch is somewhat debatable. The general consensus is that it is around the size of the continental US and contains floating bits of plastic that are more concentrated than plankton in some areas. While the statistics are staggering, this description may paint an inaccurate picture. The mental image I first saw was a solid layer of bags, a few meters thick, that you could walk across. While I couldn't find a decent picture of it, in reality the garbage patch is not any sort of solid surface. Aside from just the mess, more disconcerting is that the plastic is starting to work its way into the food chain. For years, chemists have sought to make increasingly robust plastics, and they have succeeded. If you were to go out and buy a bag of frozen lima beans, it would likely stay fresh for quite a while. The downside is after you eat those lima beans, the discarded bag will stay on this planet longer than you will. Polyvinylchloride, polyethylene, etc, cannot be degraded by any normal organism. Sitting out in the Pacific, baking in the sun, these polymers undergo photodegradation instead. Sunlight breaks down polymers into smaller and smaller pieces, until they get to be so small that even microscopic plankton will eat them. When the bottom of the food chain starts to eat our garbage, it's just a matter of time before it works its way into fish, birds, and eventually onto our dinner plates. If the Floating Island of Garbage is left unchecked, eventually those frozen lima beans will contain parts of the bags they come in. Because the island was discovered only recently, it has become far too large to even consider cleaning up. Compare and contrast with another environmental disaster: the Exxon Valdez oil spill in 1989. There, the spill covered a mere 28 000km2 of the ocean's surface (about 100 times smaller than the garbage patch), and cost about £1 billion or so to clean up.There has been an interest within the chemical community to make polymers that are at least somewhat biodegradable. There hasn't been a major success so far, one reason being that some of the materials are a little too biodegradable. That is, you don't want a bottle of orange juice to dissolve before you get the chance to drink it. So there's no good solution for what to do about the garbage island, other than trying not to make it worse. I won't even try to evaluate the global political and economic changes that would be needed for that. But I can say for sure that next time I'm at the shop, I'll bring my own canvas bag.
abhishek ghangas
Ravens
A woman from New Orleans who read the article on ravens that I wrote when I had just started to investigate whether and how ravens share, wrote me: "I did not have so much trouble as you did in showing that ravens share. I see them at my feeder - they even feed one another". There are no ravens in New Orleans, nor anywhere else in Louisiana. Perhaps what she actually saw were several large dark birds (crows? Grackles?), one of which fed another one or two (probably their grown offspring traveling along with them). People commonly confuse personal interpretations with factual observations. This tendency is a special bane in getting reliable observations on ravens because so much ingrained folklore about them exists that it is difficult to look at them objectively. I once read an article about a trapper/writer in Alaska. Knowing he would be familiar with ravens in the north, I wrote to ask him if he had seen ravens feeding in crowds. He had a lot of raven stories to tell. First, he said "everyone" he knew, knew that ravens share their food. He was surprised at the ignorance of us armchair scientists so far away, who would even question it. Ravens were "clever enough" to raid the fish he kept on racks for his dogs. They proved their cleverness by posting a "twenty-four-hour guard" at his cabin. (How did he distinguish this, I wondered, from birds waiting for an opportunity to feed?) As soon as he left the cabin, a raven was there to "spread the word". (Read: Flew away and/or called.) He claimed that one raven "followed" him all day. (Read: He occasionally saw a raven.) It then "reported back" to the others so that they could all leave just before he got back from his day on the trapline. (Read: He saw several leave together, and there were none when he got back to the cabin door.) Many of the birds "raided" (fed from?) his fish rack, and his idea of their "getting out the word" to ravens for miles around is that the one who discovers the food calls, and thereby summons all the birds in neighboring territories, who then also call in an ever-enlarging ring of information sharing. (An interesting thought).) It was no mystery to him why the birds would do this: they are "gossiping". "It seems obvious", he said, "that the birds get excited, and they simply cannot hold in their excitement - that lets others know". Any why should they evolve such transparent excitement? That, too, was "obvious": "Because it is best for the species". This stock answer explains nothing. It was disturbing to me to see anyone so facilely blur the distinction between the observations and interpretations and then even go so far as to make numerous deductions without the slightest shred of evidence. When I was very young and did not "see" what seemed obvious to adults, I often though I was stupid and unsuited for science. Now I sometimes wonder if that is why I make progress. I see the ability to invent interconnections as no advantage whatsoever where the discovery of truth is the objective. There are those who believe that science consists entirely of disproving alternative hypotheses, as if when you eliminate the alternative views, the one you have left is right. The problem is that there is no way to think of all the possible hypotheses that nature can devise. More than that, you have to prove which is the most reasonable. But any one hypothesis can, with a limited data set, be reasonable. There is at least a touch of truth in the idea that any variable affects another. If you look long and determinedly enough you will find that almost any variable element you choose to examine apparently affects the behavior you are studying. You have to be able to skim over what is not important or relevant to your problem, and to concentrate long enough on the prime movers to unearth sufficient facts that, presuming they are recognized, add up to something. Q. 6.
Sparsha Saha