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Sparsha Saha'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
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
First day at job
So, it is your first day at your new job and you don't really know what to expect. You have been to the office before but only briefly at the interview and have got a first impression about the company. But, how much do you really know about the office etiquette and how you are expected to behave? Well, there are some simple rules and guidelines to abide by so that you will take to your new workplace like a duck to water. The basic behaviours that will be expected of a new starter are those that the current office will already practise. Adhering to the dress code will be demanded so ensure you know if the company encourages suit-wearing or smart casual as this will make you feel comfortable and prevent an embarrassing first day. It will feel awkward if you arrive for work in a three-piece suit to find your peers and boss in jeans and trainers or vice versa. As a new starter you will be expected to adapt to the office environment that you are joining. Don't think that you can just impose your personality on the workplace as this can appear as arrogance and may alienate you from certain members, if not all, of the office. Take your time when you start to monitor the other workers and get an understanding of how they work, speak and behave. Doing this will enable you to become a part of the office hierarchy as you smoothly integrate into the group. Many of your actions should be based upon those of the existing workforce. However, this doesn't mean that you should act sheepish and introverted and become an office clone. There may be various traditions that are followed so try to make yourself aware of these early on so you don't offend people when you flout these rules. An example of this could be communal tea runs, when the single cup-of-tea maker will be victim to whispers and gossip-mongering. Don't be afraid to be yourself as it will enable your new workmates to get to know you right from the start. Setting the tone and conveying your personality is an important part of making an impression, so do it in the right way and you will be a popular figure in no time at all. Respect is one of the cornerstones of a happy office so treat others with respect or risk becoming an eternal outcast. Talking over people, making personal calls and telling offensive jokes are all ways of making you disliked with little chance of reconciliation. First impressions are so important so be aware that your new office will be scrutinizing everything that you do in order to gauge a quick evaluation of what you're about. Your first day is likely to involve a lot of meeting new people, so ensure you sleep well the night before. Yawning or appearing disinterested and vacant when you are being shown around is not going to set you in good stead for your new career. Listen carefully to any important information and don't be afraid to ask questions when you don't understand. It will let your boss know that you are listening and that you are keen to learn. The key to becoming a fully-integrated member of your new workplace is simply to listen and observe to your new workmates. You will be spending more time with them than you will with your family so take the ime to get to know their quirks and beliefs. You will not want to seem invisible but you will also need to avoid standing out from the crowd for the wrong reasons. It will be hard to convince people that their first impressions were wrong. Starting you new job is an intimidating time for any person, but try not to be too nervous as this may affect your behaviour negatively. Be confident, without appearing arrogant, and get to know your new peers during breaks and conversations as this will further improve your chances of enjoying a happy working life. The new office could be your workplace for a very long time so it makes sense to make the effort to fit in without irritating too many people
abhishek singh
Arab The difficult world
It is not easy to be an Arab these days. If you are old, the place where you live is likely to have changed so much that little seems friendly and familiar. If you are young, years of rote learning in dreary state schools did not prepare you well for this new world. In your own country you have few rights. Travel abroad and they take you for a terrorist. Even your leaders don't count for much in the wider world. Some are big on money, others on bombast, but few are inspiring or visionary. These are gross generalisations, of course. Huge differences persist among 300m-odd Arabic speakers and 22 countries of the Arab League. With oil prices touching record highs, some Arab economies are booming. The gulf between a Darfuri refugee and a Porsche-driving financier in Dubai is as great as between any two people on earth. Yet, to travel through the Arab world right now is to experience a peculiar sameness of spirit. Particularly among people under 30, who make up the vast majority of Arabs, the mood is one of disgruntlement and doubt. Factors that contribute to the gloom include the discombobulating impact of one of the world's fastest population growth rates, failing public-education systems and the resilience of social traditions often ill-suited to the urban lifestyle that is now the Arab norm. But it is politics above all that shapes this generation's discontent. In the world at large, things have not looked good for the Arabs for a long time. The generation that emerged after the second world war came to believe in the inevitability of an Arab renaissance after centuries of domination by Ottoman Turks and European imperialists. Within this scheme of Arab progress, the problem of Palestine stuck out like a troublesome nail. Defeat in the 1967 war with Israel shattered many dreams. Yet, even after Israel's victory Palestine remained a touchstone for Arabs everywhere. Sooner or later, it was felt, justice would be done. That confidence has taken a beating of late. Few Arabs expect the peace initiative George Bush launched in Annapolis last November to achieve anything. And the schism between Hamas and Fatah has shaken underlying assumptions. If the Palestinians cannot unite in their own cause, why should other Arabs help them? And which side to support? For fellow Arabs, as for Palestinians themselves, the clash between a heart that cries "resist" and a head that counsels compromise has seldom been more perplexing. As in Palestine, so in Iraq. In 2003 America's invasion produced all but universal Arab outrage. From afar, Iraqi "resistance" looked both natural and noble. But as Iraq has grown messier, the rights and wrongs have grown harder for Arabs to disentangle. There are few heroes in a cast that includes mass killers from al-Qaeda, brutal Shia militias, criminal gangs, Kurdish separatists and corrupt politicians as well as American occupiers. Elsewhere in the region, it has become harder for thoughtful Arabs to blame the government-inspired slaughter in the Darfur region of Sudan or the stalemate between Lebanon's religious sects on a nefarious American foreign policy. Many Arabs still see Mr Bush's "war on terrorism" as a crusade against Islam. But many also note that al-Qaeda-style jihadism has killed more Muslims, from Morocco to Saudi Arabia to the squalid Palestinian refugee camps of Lebanon, than "infidels".
Abhay Khera
The sceptic media
Every day, experts bombard us with their views on topics as varied as Iraqi insurgents, Bolivian coca growers, European central bankers, and North Korea's Politburo. But how much credibility should we attach to the opinions of experts? Skeptics, warn that the mass media dictate the voices we hear and are less interested in reasoned debate than in catering to popular prejudices. As a result, fame could be negatively, not positively, correlated with long-run accuracy. Until recently, no one knew who is right, because no one was keeping score. But the results of a 20-year research project now suggest that the skeptics are closer to the truth. I describe the project in detail in my book Expert Political Judgment: How good is it? How can we know? The basic idea was to solicit thousands of predictions from hundreds of experts about the fates of dozens of countries, and then score the predictions for accuracy. We find that the media not only fail to weed out bad ideas, but that they often favor bad ideas, especially when the truth is too messy to be packaged neatly. The evidence falls into two categories. First, as the skeptics warned, when hordes of pundits are jostling for the limelight, many are tempted to claim that they know more than they do. Boom and doom pundits are the most reliable over-claimers. Between 1985 and 2005, boomsters made 10-year forecasts that exaggerated the chances of big positive changes in both financial markets. They assigned probabilities of 65% to rosy scenarios that materialized only 15% of the time. In the same period, doomsters performed even more poorly, exaggerating the chances of negative changes in all the same places where boomsters accentuated the positive. They assigned probabilities of 70% to bleak scenarios that materialized only 12% of the time. Second, again as the skeptics warned, over-claimers rarely pay penalties for being wrong. Indeed, the media shower lavish attention on over-claimers while neglecting their humbler colleagues. We can see this process in sharp relief when, following the philosopher Sir Isaiah Berlin, we classify experts as "hedgehogs" or "foxes." Hedgehogs are big-idea thinkers in love with grand theories: libertarianism, Marxism, environmentalism, etc. Their self-confidence can be infectious. They know how to stoke momentum in an argument by multiplying reasons why they are right and others are wrong. That wins them media acclaim. But they don't know when to slam the mental brakes by making concessions to other points of view. They take their theories too seriously. The result: hedgehogs make more mistakes, but they pile up more hits on Google. Imagine your job as a media executive depends on expanding your viewing audience. Whom would you pick: an expert who balances conflicting arguments and concludes that the likeliest outcome is more of the same, or an expert who gets viewers on the edge of their seats over radical Islamists seizing control and causing oil prices to soar? At this point, uncharitable skeptics chortle that we get the media we deserve. But that is unfair. No society has yet created a widely trusted method for keeping score on the punditocracy. Even citizens who prize accuracy have little way of knowing that they are sacrificing it when they switch channels from boring foxes to charismatic hedgehogs. Here, then, is a modest proposal that applies to all democracies: the marketplace of ideas works better if it is easier for citizens to see the trade-offs between accuracy and entertainment, or between accuracy and party loyalty. Wouldn't they be more likely to read pundits with better track records?
kevin dudeja
News media buisness
News media businesses can no longer rely solely on making money from traditional advertising and must embrace the multiple commercial opportunities from online, according to magazine publisher and broadcaster Andrew Neil. The Press Holdings chairman, BBC presenter and former Sunday Times editor said the changes sweeping the media industry were "transformative and revolutionary" and that traditional ways of making money had all but eroded as increased competition and the explosion of online media erodes the exclusivity of advertising deals. Speaking at today's SIIA Global Information Industry Summit in London, Neil said that the internet was not a threat to the traditional printed media companies, but an "essential" opportunity to diversify and ultimately save them. "Sensible newspaper and magazine publishers do not see online as a threat or something they have to do because 'it is the future, so let's do it and grit our teeth'," he said. "Offline publications are still necessary for brand building and because people still like to hold a newspaper or particularly a magazine. But the revenues for that are in decline as search engines make classified ads increasingly irrelevant." Neil pointed out that his magazine websites (- he is also chairman of ITP Publishing, the Gulf's largest magazine publishers) were visited mainly by people who also read the print version and visit the site "for the additional material that is only online". He said The Spectator, owned by Press Holdings, had achieved great success with its Coffee House network of blogs, which has 200,000 unique users a month and will contribute "20 per cent of the bottom line" this year in terms of revenue. He also pointed out that the one of the biggest spikes in traffic for Telegraph.co.uk was around 10am every day, when the print readers had finished their Daily Telegraph and wanted to know what else its journalists were doing. "You now need to use online to do a whole host of things that you just could not before," he added. "It ceases to be an either-or situation." Neil admitted the going was tough for the media in a multi-platform world with complex revenue streams but it was, for him at least, "a lot more fun". He contrasted the UK market with the US, in which newspapers are run by big city monopolies that are unused to competition and "run for the journalists and not for the readers". In the UK many mainstream publishers grasped the need to diversify early on: "Most trends like this begin in the US but in this trend the British media are particularly much ahead of them," he said. "British newspapers have always been used to competition: it's the most competitive newspaper market in the world bar none."
Abhisekh Deshmukh
Observation vs Interpretation
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.
vipul sharma