Find the English equivalents for the following words and word combinations
Расплавленный металл, необходимый размер, не нагретый металл, механические свойства, максимум температуры. защищать поверхности, быстрое охлаждение. осуществлять контроль, препятствовать окислению, вступать в химическую реакцию, термообработка, бомбардировка электронами, зона термического [теплового] воздействия, общая потребляемая энергия.
Complete the following sentences.
1. A characteristic feature of fusion welding is …
a) molten metal
b) low-voltage discharge
c) inert atmosphere
2. Furnace heating is usually employed in …
a) friction joining
b) diffusion bonding
c) ultrasonic joining
3.The consumable electrode is made …
a) negative
b) positive
c) neither
4. Total energy input in all welding processes is …
a) is greater than required to produce a joint
b) is smaller than required to produce a joint
c) equals to required to produce a joint
5. Reactions of most metals with die atmosphere or other nearby metals can
a) improve the properties of a welded joint
b) make the properties of a welded joint worse
c) never influence the properties of a welded joint
6. The most common gas used in gas-shielded metal-arc and gas-shielded tungsten-arc welding is …
a) argon
b) oxygen
c) carbon dioxide
7. If not controlled, residual stress results in …
a) precipitation processes in welded structures
b) freezing of die weld-metal
c) bowing or distortion of the weldment
Say if the following sentences are true or false.
1.There is always a welding pool in solid-phase welding processes.
2.Total energy input in all welding processes is greater than needed to produce a weld.
3.Reactions of metals with the atmosphere or other nearby metals are favorable to the properties of a welded joint.
4.Fluxes and inert atmospheres play a protective role and prevent oxidation.
5.The heat-affected zone is a region with unaltered properties.
6.Residual stress is present in all welded structures.
ADDITIONAL TEXTS FOR READING AND DISCUSSION
Cold Forging
The cold forming process is similar to the cold heading process, however, the process uses vertical presses instead of horizontal cold heading machines. The cold forming process is also volume specific and the process uses dies and punches to convert a specific "slug" or blank of a given volume into a finished intricately shaped part of the exact same volume. The cold forming process generally compliments the cold heading process by adding more intricate shapes to the cold headed blank.
Cold forging is a reliable and cost efficient process. The main advantages are the following:
• savings in material and final machining,
• high productivity,
• excellent dimensional accuracy and surface quality of cold extruded parts,
• improvement of mechanical properties of extruded parts,
• favorable crystal grain flow increases toughness.
Cold forging encompasses many processes: bending, cold drawing, cold heading, coining, extrusion, punching, thread rolling and more to yield a diverse range of part shapes.
The main groups of produced cold forged parts are:
• Parts for starter motors (pinion, barrel, solenoid body, plunger, core…)
• Parts for alternators (claw pole…)
• Parts for switches, valves and other applications
• Parts for car seats
• Anti vibration parts, spiders, inner racks
• Parts for flywheel magnetos and other motorbike parts
• Hollow parts with stems and shafts
• Different gears and other parts etc.
Hot forging
Hot forging, also referred to as drop forging, is a process that can be used to produce a wide variety of parts in most metals. Generally, forging is the process of forming and shaping metals through the use of hammering, pressing or rolling. Forgings are produced in sizes ranging from a few millimeters maximum dimension up to 3 m or more in some cases.
The principles and practices of hot forging have been established since the last century, but improvements have obviously been made in equipment, lubricants and the ability to process the more difficult to forge materials since that time.
Hot forging is a plastic deformation of metal at a temperature and strain rate such that recrystallization occurs simultaneously with deformation, thus avoiding strain hardening. For this to occur, high workpiece temperature (matching the metal's recrystallization temperature) must be attained throughout the process.
A form of hot forging is isothermal forging, where materials and dies are heated to the same temperature. In nearly all cases, isothermal forging is conducted on super alloys in a vacuum or highly controlled atmosphere to prevent oxidation.
Because the metal is hot, it is easy to move it around, allowing for more elaborate shapes than cold forging. Hot forging is common for harder metals such as steel that would be difficult to shape when cold. The process begins with a cast ingot, which is heated to its plastic deformation temperature, then forged between dies to the desired shape and size. During this forging process, the cast, coarse grain structure is broken up and replaced by finer grains, achieved through the size reduction of the ingot.
Depending on the metal and the degree to which it was heated, the forging process itself might suffice to temper, or strengthen, the material. Usually, the product is additionally heat treated after it is hot forged.
One of America’s great machines comes back to life
TECHNOLOGYMARCH 2012 ATLANTIC MAGAZINE
APPROACHING ALCOA’S 50,000-TON forging press feels a bit like approaching an alp: it starts out incomprehensibly huge and keeps getting incomprehensibly huger. From a distance, the thing dominates the horizon of the hangar-like Cleveland Works facility; as you get nearer, catching glimpses through forests of girders and around cliffs of firebrick, it begins to dominate the air above. But even as you stand at its foot, being told that the eight steel bolts anchoring it are 40 inches thick, calculating in your head that that makes them 10 feet around — even then it’s still a bit out of reach. Only when you climb it, peer down from its sixth-floor summit, and realize that the puny machine next to it is, in fact, its 35,000-ton brother — well, then you finally appreciate the size of the thing. It’s big.
The Fifty, as it’s known in company shorthand, broke down three years ago, and there was talk of retiring it for good. Instead, it was overhauled and is scheduled to resume service early this year. One of the great machines of American industry has been reborn.
A forging press is — begging the forgiveness of the engineering gods — essentially a waffle iron for metal. An ingot, usually heated to increase its malleability, is placed on the lower of a pair of dies. The upper die is then gradually forced down against the ingot, and the metal flows to fill both dies and form the intended shape. In this way, extremely complex structures can be created quickly and with minimal waste.
What sets the Fifty apart is its extraordinary scale. Its 14 major structural components, cast in ductile iron, weigh as much as 250 tons each; those yard-thick steel bolts are also 78 feet long; all told, the machine weighs 16 million pounds, and when activated its eight main hydraulic cylinders deliver up to 50,000 tons of compressive force. If the logistics could somehow be worked out, the Fifty could bench-press the battleship Iowa, with 860 tons to spare.
It is this power, combined with amazing precision — its tolerances are measured in thousandths of an inch — that gives the Fifty its far-reaching utility. It has made essential parts for industrial gas turbines, helicopters, and spacecraft. Every manned U.S. military aircraft now flying uses parts forged by the Fifty. So does every commercial aircraft made by Airbus and Boeing.
The Fifty began its work in 1955, but its history goes back to 1919, when the Treaty of Versailles required Germany to relinquish some of its principal iron-producing regions but allowed it to keep its abundant magnesium reserves. Strong and lightweight, the metal also had one crucial drawback: it could not be worked by hammering, the way iron could. Smack iron, and it bends. Smack magnesium, and it cracks. So of necessity, German engineers developed a new technique for shaping the temperamental metal: press forging. Components made by German forges, using both magnesium and aluminum, helped build the Third Reich’s war machine. But at the end of that conflict, the Soviets took the most powerful forge home with them.
Meanwhile, in the U.S., Rosie the Riveter was still piecing together components out of layers of heavy steel plate. Finding itself suddenly at a disadvantage to the Soviets, the U.S. government decided to do something frankly Soviet in nature: it ordered the construction of a series of massive forges and directed industry in their production and use. The now-forgotten Heavy Press Program, inaugurated in 1950 and completed in 1957, would ultimately result in 10 forges built with taxpayer dollars: four presses (including the Fifty) and six extruders — giant toothpaste tubes squeezing out long, complex metal structures such as wing ribs and missile bodies.
At least eight of the forges are still working today. The Fifty will soon be supplying bulkheads for the Joint Strike Fighter, the U.S. military’s next-generation workhorse. Planned production of the plane extends to at least 2034, when the Fifty will be 79 years old. Alcoa expects it to keep working for at least 30 years beyond that.
Tim Heffernan is a writer in New York. He is currently working on a book about the Heavy Press Program.
ТИ-6
(Материаловедение и технологии материалов)
Designing with Protein
(1) How far off is such ability? Steps have been taken, but much work remains to be done. Biochemists have already mapped the structures of many proteins. With gene machines to help write DNA tapes, they can direct cells to build any protein they can design. But they still don't know how to design chains that will fold up to make proteins of the right shape and function. The forces that fold proteins are weak, and the number of plausible ways a protein might fold is astronomical, so designing a large protein from scratch isn't easy.
(2) The forces that stick proteins together to form complex machines are the same ones that fold the protein chains in the first place. The differing shapes and kinds of stickiness of amino acids - the lumpy molecular "beads" forming protein chains - make each protein chain fold up in a specific way to form an object of a particular shape. Biochemists have learned rules that suggest how an amino acid chain might fold, but the rules aren't very firm. Trying to predict how a chain will fold is like trying to work a jigsaw puzzle, but a puzzle with no pattern printed on its pieces to show when the fit is correct, and with pieces that seem to fit together about as well (or as badly) in many different ways, all but one of them wrong. False starts could consume many lifetimes, and a correct answer might not even be recognized. Biochemists using the best computer programs now available still cannot predict how a long, natural protein chain will actually fold, and some of them have despaired of designing protein molecules soon.
(3) Yet most biochemists work as scientists, not as engineers. They work at predicting how natural proteins will fold, not at designing proteins that will fold predictably. These tasks may sound similar, but they differ greatly: the first is a scientific challenge, the second is an engineering challenge. Why should natural proteins fold in a way that scientists will find easy to predict? All that nature requires is that they in fact fold correctly, not that they fold in a way obvious to people.
(4) Proteins could be designed from the start with the goal of making their folding more predictable. Carl Pabo, writing in the journal Nature, has suggested a design strategy based on this insight, and some biochemical engineers have designed and built short chains of a few dozen pieces that fold and nestle onto the surfaces of other molecules as planned. They have designed from scratch a protein with properties like those of melittin, a toxin in bee venom. They have modified existing enzymes, changing their behaviors in predictable ways. Our understanding of proteins is growing daily.
(5) In 1959, according to biologist Garrett Hardin, some geneticists called genetic engineering impossible; today, it is an industry. Biochemistry and computer-aided design are now exploding fields, and as Frederick Blattner wrote in the journal Science, "computer chess programs have already reached the level below the grand master. Perhaps the solution to the protein-folding problem is nearer than we think." William Rastetter of Genentech, writing in Applied Biochemistry and Biotechnology asks, "How far off is de novo enzyme design and synthesis? Ten, fifteen years?" He answers, "Perhaps not that long."
(6) Forrest Carter of the U.S. Naval Research Laboratory, Ari Aviram and Philip Seiden of IBM, Kevin Ulmer of Genex Corporation, and other researchers in university and industrial laboratories around the globe have already begun theoretical work and experiments aimed at developing molecular switches, memory devices, and other structures that could be incorporated into a protein-based computer. The U.S. Naval Research Laboratory has held two international workshops on molecular electronic devices, and a meeting sponsored by the U.S. National Science Foundation has recommended support for basic research aimed at developing molecular computers.
Fill in the gaps.
1) Much work … to be done.
a) remains b) ones c) can d) machines
2) Biochemists have already … the structures of many proteins.
a) mapped b) made c) mixed d) mined
2. Find the best translation:particular shape
a) практический контур b) определённая форма
c) практическое уменьшение d)сильно худеть
3. Which statement matches the text?
a)Proteins` research is important part of our science and industry.
b)Scientists work at predicting how natural proteins will fold.
c)Scientists work at designing proteins that will fold predictably.
d)Natural proteins will help us at designing proteins new substances and tissues.
4. Which statement matches the text?
a)Corporations and other industrial laboratories around the globe have begun theoretical work aimed at developing a new race of people.
b)Corporations and other industrial laboratories around the globe have begun theoretical work aimed at developing computer chess programs.
c)Industrial laboratories around the globe have begun work aimed at developing structures for genetic weapons.
d)Researchers have already begun experiments aimed at developing structures for a protein computer.
5. Which part of the text contains the idea?
U.S. Navy is interested in making research on molecular electronic devices.
a) 1 b) 2 c) 3 d) 4 e) 5 f) 6
6. Which part of the text answers the question?
Who has already begun experiments aimed at developing molecular computers?
a) 1 b) 2 c) 3 d) 4 e) 5 f) 6
7. Answer the questions:
1.Is it easy to designing a large protein from scratch? Why?
2.What makes each protein chain fold up in a specific way?
3.Do most biochemists work as scientists or as engineers?
4.What has Carl Pabo suggested?
5.Who has recommended support for basic research aimed at developing molecular computers?
Engineered proteins
(1) Engineered proteins will split and join molecules as enzymes do. Existing proteins bind a variety of smaller molecules, using them as chemical tools; newly engineered proteins will use all these tools and more.
(2) Further, organic chemists have shown that chemical reactions can produce remarkable results even without nanomachines to guide the molecules. Chemists have no direct control over the tumbling motions of molecules in a liquid, and so the molecules are free to react in any way they can, depending on how they bump together. Yet chemists nonetheless coax reacting molecules to form regular structures such as cubic and dodecahedral molecules, and to form unlikely-seeming structures such as molecular rings with highly strained bonds. Molecular machines will have still greater versatility in bondmaking, because they can use similar molecular motions to make bonds, but can guide these motions in ways that chemists cannot.
(3) Indeed, because chemists cannot yet direct molecular motions, they can seldom assemble complex molecules according to specific plans. The largest molecules they can make with specific, complex patterns are all linear chains. Chemists form these patterns (as in gene machines) by adding molecules in sequence, one at a time, to a growing chain. With only one possible bonding site per chain, they can be sure to add the next piece in the right place.
(4) But if a rounded, lumpy molecule has (say) a hundred hydrogen atoms on its surface, how can chemists split off just one particular atom (the one five up and three across from the bump on the front) to add something in its place? Stirring simple chemicals together will seldom do the job, because small molecules can seldom select specific places to react with a large molecule. But protein machines will be more choosy.
(5) A flexible, programmable protein machine will grasp a large molecule (the workpiece) while bringing a small molecule up against it in just the right place. Like an enzyme, it will then bond the molecules together. By bonding molecule after molecule to the workpiece, the machine will assemble a larger and larger structure while keeping complete control of how its atoms are arranged. This is the key ability that chemists have lacked.
(6) Like ribosomes, such nanomachines can work under the direction of molecular tapes. Unlike ribosomes, they will handle a wide variety of small molecules (not just amino acids) and will join them to the workpiece anywhere desired, not just to the end of a chain. Protein machines will thus combine the splitting and joining abilities of enzymes with the programmability of ribosomes. But whereas ribosomes can build only the loose folds of a protein, these protein machines will build small, solid objects of metal, ceramic, or diamond - invisibly small, but rugged.
(7) Where our fingers of flesh are likely to bruise or burn, we turn to steel tongs. Where protein machines are likely to crush or disintegrate, we will turn to nanomachines made of tougher stuff.
Fill in the gaps.
1) Engineered proteins will … and join molecules as enzymes do.
a) do b) split c) replace d) open
2) Chemists cannot yet … molecular motions.
a) move b) construct c) direct d)rename
3) Like an enzyme, … will then bond the molecules together.
a) machine b) flesh c) protein d) liquid
2. Which statement matches the text?
a)Like a machine, enzyme will bond the molecules together.
b)A protein machine will grasp a large molecule while bringing a small molecule up against it in just the right place.
c)A flexible, programmable protein machine will bring small molecules up to build objects of metal.
d)Any machine can grasp a large molecule while bringing a small molecule up against it in the right place.
3. Which part of the text contains the idea?
1) Chemists yet have no direct control over the tumbling motions of molecules, and so the molecules are free to react in any way they can.
a) 1 b) 2 c) 3 d) 4 e) 5 f) 6 g) 7
2) Nanomachines will handle molecules and will join them to the workpiece anywhere desired, not just to the end of a chain.
a) 1 b) 2 c) 3 d) 4 e) 5 f) 6 g) 7
4. Which part of the text answers the question?
What molecule has a hundred hydrogen atoms on its surface?
a) 1 b) 2 c) 3 d) 4 e) 5 f) 6 g) 7
5. Answer the questions:
1.How can chemists control the tumbling motions of molecules in a liquid?
2.How can chemists form patterns of complex molecules?
3.How will a programmable protein machine work?
4.Can ribosomes build only the loose folds of a protein?
5.What will turn us to nanomachines?
Existing Protein Machines
(1) These protein hormones and enzymes selectively stick to other molecules. An enzyme changes its target's structure, then moves on; a hormone affects its target's behavior only so long as both remain stuck together. Enzymes and hormones can be described in mechanical terms, but their behavior is more often described in chemical terms.
(2) But other proteins serve basic mechanical functions. Some push and pull, some act as cords or struts, and parts of some molecules make excellent bearings. The machinery of muscle, for instance, has gangs of proteins that reach, grab a "rope" (also made of protein), pull it, then reach out again for a fresh grip; whenever you move, you use these machines. Amoebas and human cells move and change shape by using fibers and rods that act as molecular muscles and bones. A reversible, variable-speed motor drives bacteria through water by turning a corkscrew-shaped propeller. If a hobbyist could build tiny cars around such motors, several billions of billions would fit in a pocket, and 150-lane freeways could be built through your finest capillaries.
(3) Simple molecular devices combine to form systems resembling industrial machines. In the 1950s engineers developed machine tools that cut metal under the control of a punched paper tape. A century and a half earlier, Joseph-Marie Jacquard had built a loom that wove complex patterns under the control of a chain of punched cards. Yet over three billion years before Jacquard, cells had developed the machinery of the ribosome. Ribosomes are proof that nanomachines built of protein and RNA can be programmed to build complex molecules.
(4) Then consider viruses. One kind, the T4 phage, acts like a spring-loaded syringe and looks like something out of an industrial parts catalog. It can stick to a bacterium, punch a hole, and inject viral DNA (yes, even bacteria suffer infections). Like a conqueror seizing factories to build more tanks, this DNA then directs the cell's machines to build more viral DNA and syringes. Like all organisms, these viruses exist because they are fairly stable and are good at getting copies of themselves made.
(5) Whether in cells or not, nanomachines obey the universal laws of nature. Ordinary chemical bonds hold their atoms together, and ordinary chemical reactions (guided by other nanomachines) assemble them. Protein molecules can even join to form machines without special help, driven only by thermal agitation and chemical forces. By mixing viral proteins (and the DNA they serve) in a test tube, molecular biologists have assembled working T4 viruses. This ability is surprising: imagine putting automotive parts in a large box, shaking it, and finding an assembled car when you look inside! Yet the T4 virus is but one of many self-assembling structures. Molecular biologists have taken the machinery of the ribosome apart into over fifty separate protein and RNA molecules, and then combined them in test tubes to form working ribosomes again.
(6) To see how this happens, imagine different T4 protein chains floating around in water. Each kind folds up to form a lump with distinctive bumps and hollows, covered by distinctive patterns of oiliness, wetness, and electric charge. Picture them wandering and tumbling, jostled by the thermal vibrations of the surrounding water molecules. From time to time two bounce together, then bounce apart. Sometimes, though, two bounce together and fit, bumps in hollows, with sticky patches matching; they then pull together and stick. In this way protein adds to protein to make sections of the virus, and sections assemble to form the whole.
Fill in the gaps.
1) An enzyme … its target's structure, then moves on.
a) opens b) space c) changes d) closes
2) A reversible, variable-speed motor drives bacteria through water by … a corkscrew-shaped propeller.
a) turning b) pass c) walk d) closed
3) Nanomachines built of protein and RNA can be programmed to build … molecules.
a) sophisticated b) smart c) complex d) clever
2. Which statement matches the text?
a)DNA directs the cell's machines to build more viral DNA and syringes.
b)Mixed together enzymes selectively stick to other molecules and improve them.
c)Mixed together DNA and enzymes selectively build the structures and prove them.
d)DNA mixes the cell's machines to build more viral DNA and syringes.
3. Which part of the text contains the idea?
1) Protein molecules can even join, driven only by thermal agitation and chemical forces.
a) 1 b) 2 c) 3 d) 4 e) 5 f) 6
2) Nanomachines obey the universal laws of nature
a) 1 b) 2 c) 3 d) 4 e) 5 f) 6
4. Which part of the text answers the question?
How do T4 viruses work?
a) 1 b) 2 c) 3 d) 4 e) 5 f) 6
5. Answer the questions:
1.How does hormone affect its target's behavior?
2.In what terms can Enzymes and hormones be described?
3.What basic mechanical functions do proteins serve?
4.What did Joseph-Marie Jacquard had built?
5.How does the T4 phage virus act?
Genetic materials
(1) Genetic engineers are already showing the way. Ordinarily, when chemists make molecular chains - called "polymers" - they dump molecules into a vessel where they bump and snap together haphazardly in a liquid. The resulting chains have varying lengths, and the molecules are strung together in no particular order.
(2) But in modern gene synthesis machines, genetic engineers build more orderly polymers - specific DNA molecules - by combining molecules in a particular order. These molecules are the nucleotides of DNA (the letters of the genetic alphabet) and genetic engineers don't dump them all in together. Instead, they direct the machine to add different nucleotides in a particular sequence to spell out a particular message. They first bond one kind of nucleotide to the chain ends, then wash away the leftover material and add chemicals to prepare the chain ends to bond the next nucleotide. They grow chains as they bond on nucleotides, one at a time, in a programmed sequence. They anchor the very first nucleotide in each chain to a solid surface to keep the chain from washing away with its chemical bathwater. In this way, they have a big clumsy machine in a cabinet assemble specific molecular structures from parts a hundred million times smaller than itself.
(3) But this blind assembly process accidentally omits nucleotides from some chains. The likelihood of mistakes grows as chains grow longer. Like workers discarding bad parts before assembling a car, genetic engineers reduce errors by discarding bad chains. Then, to join these short chains into working genes (typically thousands of nucleotides long), they turn to molecular machines found in bacteria. These protein machines, called restriction enzymes, "read" certain DNA sequences as "cut here." They read these genetic patterns by touch, by sticking to them, and they cut the chain by rearranging a few atoms. Other enzymes splice pieces together, reading matching parts as "glue here" - likewise "reading" chains by selective stickiness and splicing chains by rearranging a few atoms. By using gene machines to write, and restriction enzymes to cut and paste, genetic engineers can write and edit whatever DNA messages they choose.
(4) But by itself, DNA is a fairly worthless molecule. It is neither strong like Kevlar, nor colorful like a dye, nor active like an enzyme, yet it has something that industry is prepared to spend millions of dollars to use: the ability to direct molecular machines called ribosomes. In cells, molecular machines first transcribe DNA, copying its information to make RNA "tapes." Then, much as old numerically controlled machines shape metal based on instructions stored on tape, ribosomes build proteins based on instructions stored on RNA strands. And proteins are useful.
(5) Proteins, like DNA, resemble strings of lumpy beads. But unlike DNA, protein molecules fold up to form small objects able to do things. Some are enzymes, machines that build up and tear down molecules (and copy DNA, transcribe it, and build other proteins in the cycle of life). Other proteins are hormones, binding to yet other proteins to signal cells to change their behavior. Genetic engineers can produce these objects cheaply by directing the cheap and efficient molecular machinery inside living organisms to do the work. Whereas engineers running a chemical plant must work with vats of reacting chemicals (which often misarrange atoms and make noxious byproducts), engineers working with bacteria can make them absorb chemicals, carefully rearrange the atoms, and store a product or release it into the fluid around them.
(6) Genetic engineers have now programmed bacteria to make proteins ranging from human growth hormone to rennin, an enzyme used in making cheese. The pharmaceutical company Eli Lilly (Indianapolis) is now marketing Humulin, human insulin molecules made by bacteria.
Fill in the gaps.
1) Genetic engineers have now … bacteria to make proteins
a) made b) programmed c) worked d) arranged
2) Genetic engineers build more … polymers by combining molecules in a particular order.
a) slowly b) specifically c) orderly d) hardly
3) Genetic engineers can produce these objects … by directing the cheap molecular machinery inside living organisms.
a) weekly b) badly c) strongly d) cheaply
2. Which part of the text contains the idea?
1) Genetic engineers grow chains as they bond on nucleotides, one at a time, in a programmed sequence.
a) 1 b) 2 c) 3 d) 4 e) 5 f) 6
2) Protein molecules fold up to form small objects able to do things.
a) 1 b) 2 c) 3 d) 4 e) 5 f) 6
3) DNA is a fairly worthless molecule.
a) 1 b) 2 c) 3 d) 4 e) 5 f) 6
3. Which part of the text answers the question?
How can genetic engineers write and edit DNA messages?
a) 1 b) 2 c) 3 d) 4 e) 5 f) 6
4. Answer the questions:
1.How do genetic engineers build specific DNA molecules?
2.When does the likelihood of mistakes grow?
3.How do genetic engineers reduce errors?
4.What is the value of DNA molecule?
5.How can Genetic engineers produce proteins are hormones?