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The Past and the Future of the Laser 12 глава
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one of the engines is lost. The CityHawk will have cruising speeds of 90-100 mph. The car is likely to be used as an air taxi, for news gathering and for traffic control.
The mass availability of flying cars can be very scary. Yet, if proper safeguards observed, flying cars will not only cut rush hours and traffic jams, but also they will allow us to live hundreds of miles farther from work and still make it to the office in no time.
III. Choose the correct option to complete the sentences.
1. The Wright Brothers' invention started the idea of flying....
a) horse carts; b) airplanes; c) cars.
2. The first developments of flying cars in the early 1900s were....
a) surprising; b) ineffective; c) successful.
3. The Skycar takes off and lands....
a) vertically; b) horizontally; c) spirally.
4. Without refuelling the Skycar can fly... miles.
a) 350; b) 400; c) 900.
5. The Skycar uses as much fuel as.....
a) the Harrier Jet; b) a medium-sized car; c) a GPS satellite.
6. The function of the Skyrider is....
a) to safely transport passengers; b) to sky fight;
c) to control traffic.
7. The CityHawk will be propelled by....
a) funs; b) fans; c)fins.
8. Flying cars will create problems of....
a) traffic jams and rush hours; b) safety;
c) moving away from polluted cities.
IV. Translation Check. Use the dictionary if necessary.
A New Form of City Transport?
Just don't call it a high-tech scooter! The Segway is the world's first self-balancing human transporter. It is quite stable on two wheels and runs on ordinary household electricity at the speed of 12 mph having the range of 15 miles. Four major elements of the Segway include the wheel and motor assembly, the sensor system, the circuit board brain and the operator control system. Balancing is controlled by a solid-state silicon gyroscope* system, which passes all tilt information to the two electronic controller circuit boards comprising 10 onboard
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microprocessors, which in total are three times as powerful as a typical PC. Their function is to adjust the speed of several electric motors according to the stability information. The motors, powered by a pair of rechargeable nickel metal hydride (NIMH) batteries, can turn each of the wheels independently at variable speeds. When the vehicle leans forward or backward, the motors spin both wheels forward or backward accordingly to keep from tilting over. When the rider operates the handlebar control to turn left or right, the motors spin one wheel faster than the other, or spin the wheels in opposite directions, so that the vehicle rotates. The machine is unlikely to replace the car but it is a superior option for the city.
*A basic gyroscope is a spinning wheel inside a stable frame. A spinning object resists changes to its axis of rotation. As the point of applied force moves along with the object itself, it ends up applying force on opposite ends of the wheel — the force balances itself out and the gyroscope maintains the stable position.
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TEXT 3
I. Scan the text to find answers to these questions.
1. What is a car?
2. Does the car have many applications?
3. What did the mass production of cars result in?
4. Is the car an efficient means of urban transportation?
5. What problems has the car caused?
6. How do environmentalists suggest improving transportation?
7. What fuel will the cars run on in the future?
II. Read the text attentively to learn more about the questions the cars pose.
Cars: Passion or Problem?
For many people, cars are more than a convenient form of transportation: they are a source of passion and pleasure. Yet cars can also be a source of many problems.
In 1903, Ford Motors became the first to mass-produce cars. This made the car available to large numbers of people. It has brought people much closer to places of work, study, and entertainment. Many people also work in car-related industries: fixing cars, washing cars, advertising cars and selling car products such as stereos and cellular phones.
Many Americans buy a new car every six years. In fact, there are more cars than people in the United States. In New York City, 2.5 million cars move in and out of the city each day. In this traffic, the average speed is sometimes 8.1 miles per hour. This speed could be easily reached by riding a horse instead of driving a car.
Environmentalists dream of turning parking lots into parks and replacing cars with bicycles. They insist on developing public transportation and point out that it saves fuel and does not damage the environment that much. Many people around the world people are unhappy with car traffic and pollution but they cannot imagine their life without driving.
Still, there is an important question that must be answered: What kind of fuel will be used when gasoline is no longer available? To solve this problem, car companies in Korea, Japan, Europe, and the US develop electric cars that will not require gasoline at all.
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The electric car is not a new idea. Being pollution-free, quiet and easy to start, it had a success with women in the 1900s. But gasoline-powered cars were faster and soon became much more popular. In the 1970s, when there were serious problems with the availability of oil, car companies began to plan for a future without gasoline again. Today's new interest in the electric car is partly related to a passion for speed and new technology. In 1987 a solar-powered car won a 2,000-mile race in Australia. Air-compressed cars, fuel cell cars, flying cars are currently under development. However, the importance of cars will not decrease, no matter how they change in the future.
III. Choose the correct option to complete the sentences.
1. The major function of the car is to serve as....
a) a means of transportation; b) a source of entertainment; c) a source of problems.
2. The mass production of cars made the cars....
a) large; b) practical; c) available.
3. The New Yorkers move at approximately 8.1 mph because they....
a) like horse riding; b) are not in a hurry;
c) stop in traffic jams.
4. Environmentalists object to....
a) replacing cars with bikes; b) polluting the environment; c) developing public transportation.
5. The topical question of the day is....
a) what fuel will replace gasoline; b) how much fuel will cost; c) when electric cars will appear.
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6. Electric cars are being developed because conventional fuel will
soon become....
a) expensive; b) unavailable; c) inefficient.
7. Electric cars lost popularity in the 1920s because they were....
a) pollution-free, quiet and easy to start; b) slow; c) driven by women.
8. Even if the cars totally change in the future, their importance will
not....
a) increase; b) decrease; c) change.
IV. Translation Check. Use the dictionary if necessary.
Why Bicycle?
A public bus trip here in Greifswald costs 1.50 Euro, the taxi is much more expensive. And it is environmentally dangerous! (Don't forget that Germany is one of the 'greenest' countries in Europe). Maybe that's why most people here prefer a healthy, pollution-free, cheap and convenient vehicle - the bicycle. Indeed, it's as difficult to imagine Greifswald without this kind of 'public transport' as it is hard to imagine this city without students!
The bicycle in Greifswald is a dream of every newcomer. Some of them are lucky to obtain it from their friends, but there are still those who are sadly looking at the daily bike traffic along the streets and go to their workshops on foot. According to unofficial statistics here in Greiswald every person has a bicycle or even two. It's as natural as eating sausages for breakfast. The average commercial price of an average make of a bicycle is around 200 Euro. The average price of a stolen bike at the local 'black market' is much lower -30 - 50 Euro. Here you even have a chance to buy your own bike, stolen last week, though already coloured from pink to blue. If you even don't have a Ferrari, having a new 'Adventure' (probably one of the best makes of a bicycle in Greifswald), sounds quite cool.
P.S.: One thing that every owner of a bike ought to remember: LOCK IT!!I
TEXT 4
I. Scan the text to find answers to these questions.
1. What is bicycle riding compared to?
2. What forces make the bicycle fall over?
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3. What force prevents you from falling when cornering?
4. How is riding 'hands off possible?
5. Why is a slowly moving bicycle stable?
6. How does the bicycle rider balance?
7. What should we consider in order to make the bicycle stable and
easy to ride?
II. Read the text attentively to learn more about bicycle riding laws.
Riding a Bicycle
Why is riding a bicycle so much easier than tight-rope walking if in both cases you are in contact with the ground through two very small areas? This is how physicists explain it.
The bicycle doesn't stay up on its own. It falls over under the influence of the weight (mg) acting vertically downwards through the centre of mass and the reaction (R) from the ground acting vertically upwards. Some extra forces to keep the bicycle up are clearly needed.
Steering into the direction of fall makes the bicycle travel in a curve. The resulting centrifugal force experienced by the bicycle and the rider pushes them upright again, so correcting the fall. This simple theory of balancing explains why the bicycle cannot be ridden with the front fork locked. However, it does not explain why it is possible to ride 'hands off.
The rotating wheel is observed to be much more stable than the stationary wheel as spinning stabilizes the motion due to the conservation of angular momentum. Also, the precession of the front wheel automatically steers even the riderless bicycle to keep it upright.
At slow walking speed the gyroscopic forces are definitely too weak and riding is controlled by the steering geometry of the bicycle concerning the head angle (the angle of the axis of rotation with the
ground) and the fork rake (it shows the relations of the wheel axle and the rotation axis). They control two important features to do with the bicycle stability. The first is the castor of the front wheel showing how far the point of contact with the ground is behind the steering axis. It determines how strongly steering is self-centering
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and stable. The second feature is the lowering of the centre of mass by means of turning the handlebars.
This addition to the theory of balance works as follows. As the bicycle begins to overbalance while moving, the handlebars automatically turn in the direction of lean to lower the potential energy. This makes the bicycle travel in the right sort of curve to correct the lean. The castor of the front wheel stops the handlebars from turning too far and forces them to straighten up when the bicycle is upright again. A combination of centrifugal force, gyroscopic action and correct steering geometry gives us a stable bicycle that is easy to ride.
III. Choose the correct option to complete the sentences.
1. Tight-rope walking is... bicycle riding.
a) much easier than; b) as easy as; c) more difficult than.
2. The bicycle falls over under the influence of....
a) the center of mass; b) mg and R; c) some extra forces.
3. The centrifugal force pushes the rider....
a) towards the centre; b) away from the centre;
c) along the circle.
4. The front fork locked....
a) causes the centrifugal force; b) makes riding impossible;
c) improves your balance.
5. Angular momentum and gyroscopic action make the bicycle....
a) stable; b) rotating; c) stationary.
6. At slow walking speed the stability of the bicycle is controlled by....
a) gyroscopic forces; b) the head angle and the fork rake;
c) the handlebars.
7. The negative castor means that the bicycle is....
a) very unstable; b) super-stable; c) lying flat on the ground.
8. Handlebars are used to....
a) increase the potential energy; b) raise the centre of mass;
c) correct the lean.
IV. Translation Check. Use the dictionary if necessary.
Bike Extremes
Understanding how a bicycle balances allows us to design the two extremes - an unridable bicycle and a super-stable bicycle. The first will have a very steep head angle and an enormous fork rake (a). This ensures a negative castor and the centre of mass rises when the
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handlebars are turned towards the lean. That is, the handlebars will try to turn in the wrong direction when the bicycle leans over. This bicycle is very difficult to ride. All your skill is needed just to stay upright, and you certainly couldn't ride hands off.
Just by reversing the design we could also make a super-stable bicycle. All we need is a small head angle combined with a negative fork rake as seen in picture (b). This bicycle is so stable that it will travel riderless until it almost stops. However, it is awful to ride. It is too stable to be steered in any direction desired and only an inert rider with no balancing reflexes and no sense of direction would be happy on such a machine.
The bicycles we normally ride are between these two extremes. For a bicycle to be maneuverable, it should not be too stable, but for safety and ease of use, it should not be unstable. Cycling connoisseurs get their frames hand-made to their own measurements. You can see now how steering geometry will affect the feel and the handling of the bicycle.
TEXT 5
I. Scan the text to find answers to these questions.
1.What is the carbon content of steel?
2.How does adding carbon influence the properties of steel?
3.How is tool steel produced?
4.Why are thick tools often soft inside?
5.What drawbacks do carbon steel tools have?
6.Do cooks use knives and other cutlery made of strong carbon steel?
7. In what ways is the quality of steel improved?
II. Read the text attentively to learn more about the developments in steel making.
Steel Quality
In order to understand tool quality, remember that steel is basically iron with a carbon content of 1.7 percent or less. Adding carbon makes the metal harder, but also more brittle, less malleable and less resistant to stress and shock. As tools differ, steel is matched with a suitable carbon content for each tool.
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Tool-quality steel must have at least 0.6 % of carbon content. This insures that the steel can be heat-treated. Traditionally, heat treating involves heating the metal to about 1,350 °F and then plunging it in to cool water. This abrupt cooling technique, called quenching, changes the carbon particles in the metal into hard carbide crystals. Heat treating produces a hard edge on tools. However, it only penetrates about 1/8" into the metal and thick tools retain a soft center.
Obviously, the quality of each tool depends on the skill of the smith, but many old tools are still in use today. These 'water-hardened steel' tools are made of carbon steel and hold a very keen edge. Yet, they have two serious drawbacks. These tools tend to rust easily and to lose their temper and edge at high temperatures: e.g. carbon-steel drill bits will dull quickly when used in an electric drill; a carbon-steel turning chisel, for use on a lathe, loses its edge when subjected to the friction of the rotating wood.
In order to make better steel, metallurgists experiment with various alloy ingredients. For example, adding tungsten or molybdenum results in high-speed steel resisting a great heat buildup. When buying drill bits, be sure to look for ones made of high-speed steel. Chromium and nickel make steel stainless or rustproof. Early stainless steel knives had one major drawback however; they could not hold a sharp edge the way carbon steel knives could. Chefs and serious cooks preferred carbon steel knives (even though they were prone to rusting) for this reason. Metallurgists gradually improved the quality of stainless steel having developed a grade for cutlery that is rust-resistant and can hold a keen edge.
In addition to creating alloys, manufacturers also improve the techniques of steel making. They have developed special heat-treating ovens and slow-quenching methods so that temper and hardness could be accurately controlled.
III. Choose the correct option to complete the sentences.
1. Basic steel contains... 1.7 percent of carbon.
a) exactly; b) no more than; c) no less than.
2. Steel with a high carbon content is....
a) hard and brittle; b) malleable; c) shock and stress resistant.
3. Different tools are made from steels with... carbon content.
a) the same; b) different; c) similar.
4. Heat treating produces a hard edge on tools as a result of carbon....
a) heating; b) quenching; c) crystallizing.
5. 'Water-hardened ' or carbon steel tools have the advantage of
being....
a) wear-proof; b) rustproof; c) temperature-proof.
6. The best drill bits are likely to be made of... steel.
a) carbon; b) stainless; c) high-speed.
7. Earlier chefs and serious cooks preferred carbon steel knives
because they were....
a) sharp; b) rusty; c) stainless.
8. The new techniques in steel making aim at....
a)creating special heat-treating ovens;
b)developing slow-quenching methods;
c) controlling temper and hardness accurately.
IV. Translation Check. Use the dictionary if necessary.
The Rins of Steel
Ancient metal smiths realized that tools would last longer if the hard shell could somehow be inserted in the core of the metal. In Damascus they developed the technique of folding the metal again and again, then hammering it into a solid piece of laminated steel. This method was so successful that Damascus steel became prized throughout the ancient world. The lamination technique was perfected to manufacture samurai swords and continues today in tool making in Japan. However, the Damascus process took time. Each piece had to be tested for quality and there were many rejects. The process was eventually replaced by a less complicated technique. The smith shaped the tool, heated it in the forge, and then quenched it. By carefully limiting the thickness of the tool, the blacksmith could create a tool with the right combination of toughness and hardness.
Are modern tools superior to those of past generations? In general yes, but there are cheap exceptions. Such tools are case-hardened so that the hard exterior is only a fraction of an inch thick. When the tool is sharpened, the hard exterior is ground off; and the tool cannot hold an edge. Some tools look like stainless steel, but they are only nickel-plated. As soon as the plating wears off, the tool begins to rust. You get what you pay for. When it comes to tools, it pays to buy good quality products.
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TEXT 6
I. Scan the text to find answers to these questions.
1. What is weathering?
2. What are the main chemical weathering processes?
3. Are there any chemical weathering agents more active than pure
water?
4. How does hydrolysis work?
5. Can limestone dissolve in pure water?
6. What role does water play in weathering?
7. What form of weathering is dominant in the desert areas?
II. Read the text attentively and say what new things you have learnt about weathering.
Weathering
Weathering is the general term used to describe the breakdown and alteration of materials near the Earth's surface into products that are more in balance with the physical and chemical conditions experienced there. No rock material can escape the impact of weathering.
Considering the processes that alter rock at the Earth's surface, we usually distinguish chemical and physical weathering, with water playing the major role. The main chemical processes include solution, hydrolysis, carbonation, oxidation and chelation.
Solution is the process in which minerals simply dissolve in water. It is controlled by the amount of water available and the solubility of material. Although some minerals will dissolve in pure water, the weak acids formed when certain substances (e.g. sulphur dioxide) dissolve in water are more effective weathering agents - remember acid rains!
Hydrolysis describes the direct reaction between water and a mineral in which the material is replaced by hydrogen from water.
Carbonation occurs as follows. Small quantities of carbon dioxide can be dissolved by rainwater to form weak carbonic acid. Additional carbon dioxide can be picked up as water drains through the soil. Carbonic acid is a very effective solvent of carbonate-rich rocks such as limestone, which are only slightly soluble in pure water.
Oxidation describes the reaction of a mineral with oxygen. The oxidation of iron, common in most rock minerals, creates characteristic reddish weathering profiles.
Biological processes (e.g. the decomposition of plant matter) can extract metal cations that would otherwise be insoluble. This process is called chelation.
The chemical processes involved in rock breakdown are complex, but the dominant factor is the supply of water. In desert environments chemical weathering is limited by the lack of available moisture.
Physical, or mechanical, weathering involves changing in volume of within the rock mass causing the pressure release, which normally results in breaking off blocks of the rock. It is evident that physical and chemical weathering processes are closely interrelated.
III. Choose the correct option to complete the sentences.
1. Weathering is the process of breaking and... materials near the
Earth's surface.
a) creating; b) changing; c) developing.
2. Weathering influences... rock materials.
a) all; b) some; c) no.
3. Solution, hydrolysis, carbonation, oxidation and chelation are...
weathering processes.
a) physical; b) chemical; c) mechanical.
4. Acid rains are the result of... of certain gases in water.
a) solution; b) chelation; c) hydrolysis.
5. Carbonic acid is a very effective solvent of....
a) carbon; b) rocks; c) limestone.
6. Reddish weathering profiles are produced by the oxidation of....
a) sulphur; b) iron; c) carbon-rich rocks
7.... is the main component of all chemical weathering processes.
a) solution; b) balance; c) water.
8. Physical, or mechanical, weathering normally results in... pieces
of rock.
a) breaking off; b) pressing; c) releasing.
IV. Translation Check. Use the dictionary if necessary.
The Influence of Weathering
Given that all the rocks are heading towards breakdown, weathering poses a number of opportunities and problems for humans. The breakdown of rock material is essential for the
operation of other processes at the Earth's surface. Weathering produces materials, which are then transported by rivers, rain or wind. It also releases minerals from rocks, which are essential in the soil formation. The layer of altered rock created by weathering (termed regolith) contains various minerals that can be concentrated to become economically workable for mining. Bauxite deposits, which are a major source of aluminium ore, are created by tropical chemical weathering. At the same time weathering can create problems for human activity, especially through the damage it causes to building materials. The conservation of our architectural heritage requires action against the effects of weathering. In natural landscapes too, weathering can impose hazards, particularly where it is responsible for weakening rock so that it becomes dangerous. And yet, although the 'breakdown' may imply a negative impact but in fact weathering is the adjustment of materials to more stable states. As such, weathering is an essential link in the cycle of Earth surface materials.
TEXT 7
I. Scan the text to find answers to these questions.
1. What qualities are given to spiders in legends?
2. What are the properties of spider silk?
3. How is the super-strength of spider silk proved?
4. What is silk made of?
5. Where do spiders obtain amino acids?
6. Is the structure of the cobweb homogeneous?
7. Why is the spider's spinning technique environmentally friendly?
Il. Read the text attentively to learn more about the secrets of spiders.
Spiders' Webs
In myths and legends, spiders and their silk webs have equally fabulous properties. Today scientists are trying to solve the secrets of spider silk. Their discoveries may eventually lead to the biosynthesis of a new generation of materials.
Spider silk has extraordinary properties. The web of the garden spider is so fine that we only see it when covered with dew. However, the threads of spider silk are estimated to be much stronger than steel threads of identical
thickness. Experimenting proves that if the web were scaled up, with threads as thick as a pencil, it would be certain to stop a Boeing 747 in full flight. The cobweb is not only strong; it is also able to absorb the energy of the flying object without giving it back. If they did, the web would behave like a trampoline. Instead the recoil is buffered by a mechanism built into the fibre. Engineers could make very good use of a fibre with such amazing qualities. The secret must lie in the structure of silk.
Silk is a protein. Its molecules are made up of long chains of amino acids covalently linked together. Spiders are known to feed on insect protein, which they break down by digestion to amino acids used in the synthesis of silk. Each particular protein has a unique sequence of amino acids. Some chains of protein form nanocrystals making silk fibres smooth and strong. Between the crystals, other lengths of the protein chain form a mass of coils making the web soft and rubbery in order to stretch and absorb the energy of an impact.
Chemists envy the spider's spinning technique because, unlike the processes for making artificial fibres, it is environmentally friendly. Kelvar, the high-tech fibre used in body armour, is spun from concentrated sulphuric acid heated almost to the boiling point. By contrast, spider protein produced as a water jelly by the glands inside the spider is somehow turned into a water-insoluble fibre at the temperature of the spider's surroundings. Besides, the web being broken easily, the spider often has to create a new one. Always efficient, it recycles the protein by eating the old silk and proposing researchers another mystery to be solved.
III. Choose the correct option to complete the sentences.
1. The secrets of spider silk....
a) have fabulous properties; b) haven't been solved yet;
c) are kept well.
2. Spider silk has extraordinary properties of being....
a) fine and invisible; b) strong and non-resistant;
c) like a trampoline.
3. Steel threads are... spider silk threads.
a) as strong as; b) much stronger than; c) far less stronger than.
4. The web does not behave like a trampoline because....
a) it absorbs the energy of an impact;
b) it can stop a Boeing 747 in full flight;
c) it is made of protein.
5. Spider protein consists of....
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