Tungsten filament

The invention: 



Metal filament used in the incandescent light bulbs

that have long provided most of the world’s electrical lighting.





The people behind the invention:



William David Coolidge (1873-1975), an American electrical

engineer

Thomas Alva Edison (1847-1931), an American inventor








The Incandescent Light Bulb



The electric lamp developed along with an understanding of

electricity in the latter half of the nineteenth century. In 1841, the

first patent for an incandescent lamp was granted in Great Britain.A

patent is a legal claim that protects the patent holder for a period of

time from others who might try to copy the invention and make a

profit from it. Although others tried to improve upon the incandescent

lamp, it was not until 1877, when Thomas Alva Edison, the famous

inventor, became interested in developing a successful electric

lamp, that real progress was made. The Edison Electric Light

Company was founded in 1878, and in 1892, it merged with other

companies to form the General Electric Company.

Early electric lamps used platinum wire as a filament. Because

platinum is expensive, alternative filament materials were sought.

After testing many substances, Edison finally decided to use carbon

as a filament material. Although carbon is fragile, making it difficult

to manufacture filaments, it was the best choice available at the time.



The Manufacture of Ductile Tungsten



Edison and others had tested tungsten as a possible material for

lamp filaments but discarded it as unsuitable. Tungsten is a hard,

brittle metal that is difficult to shape and easy to break, but it possesses

properties that are needed for lamp filaments. It has the highest

melting point (3,410 degrees Celsius) of any known metal; therefore,

it can be heated to a very high temperature, giving off a

relatively large amount of radiation without melting (as platinum

does) or decomposing (as carbon does). The radiation it emits when

heated is primarily visible light. Its resistance to the passage of electricity

is relatively high, so it requires little electric current to reach

its operating voltage. It also has a high boiling point (about 5,900 degrees

Celsius) and therefore does not tend to boil away, or vaporize,

when heated. In addition, it is mechanically strong, resisting breaking

caused by mechanical shock.

William David Coolidge, an electrical engineer with the General

Electric Company, was assigned in 1906 the task of transforming

tungsten from its natural state into a form suitable for lamp filaments.

The accepted procedure for producing fine metal wires was

(and still is) to force a wire rod through successively smaller holes in

a hard metal block until a wire of the proper diameter is achieved.

The property that allows a metal to be drawn into a fine wire by

means of this procedure is called “ductility.” Tungsten is not naturally

ductile, and it was Coolidge’s assignment to make it into a ductile

form. Over a period of five years, and after many failures, Coolidge

and his workers achieved their goal. By 1911, General Electric

was selling lamps that contained tungsten filaments.

Originally, Coolidge attempted to mix powdered tungsten with a

suitable substance, form a paste, and squirt that paste through a die

to form the wire. The paste-wire was then sintered (heated at a temperature

slightly below its melting point) in an effort to fuse the

powder into a solid mass. Because of its higher boiling point, the

tungsten would remain after all the other components in the paste

boiled away. At about 300 degrees Celsius, tungsten softens sufficiently

to be hammered into an elongated form. Upon cooling, however,

tungsten again becomes brittle, which prevents it from being

shaped further into filaments. It was suggested that impurities in

the tungsten caused the brittleness, but specially purified tungsten

worked no better than the unpurified form.

Many metals can be reduced from rods to wires if the rods are

passed through a series of rollers that are successively closer together.

Some success was achieved with this method when the rollers

were heated along with the metal, but it was still not possible to

produce sufficiently fine wire. Next, Coolidge tried a procedure

called “swaging,” in which a thick wire is repeatedly and rapidly

struck by a series of rotating hammers as the wire is drawn past

them. After numerous failures, a fine wire was successfully produced

using this procedure. It was still too thick for lamp filaments,

but it was ductile at room temperature.

Microscopic examination of the wire revealed a change in the

crystalline structure of tungsten as a result of the various treatments.

The individual crystals had elongated, taking on a fiber like

appearance. Now the wire could be drawn through a die to achieve

the appropriate thickness. Again, the wire had to be heated, and if

the temperature was too high, the tungsten reverted to a brittle

state. The dies themselves were heated, and the reduction progressed

in stages, each of which reduced the wire’s diameter by a

thousandth of an inch.

Finally, Coolidge had been successful.Pressed tungsten bars

measuring 1/4 x 3/8x6 inches were hammered and rolled into rods 1/8

inch , or 125/1000 inc, in diameter.

The unit 1/1000 inch is often called a “mil.”

These rods were then swaged to approximately 30 mil and

then passed through dies to achieve the filament size of 25 mil or

smaller, depending on the power output of the lamp in which the

filament was to be used. Tungsten wires of 1 mil or smaller are now

readily available.







Impact



Ductile tungsten wire filaments are superior in several respects

to platinum, carbon, or sintered tungsten filaments. Ductile filament

lamps can withstand more mechanical shock without breaking.

This means that they can be used in, for example, automobile

headlights, in which jarring frequently occurs. Ductile wire can also

be coiled into compact cylinders within the lamp bulb, which makes

for a more concentrated source of light and easier focusing. Ductile

tungsten filament lamps require less electricity than do carbon filament

lamps, and they also last longer. Because the size of the filament

wire can be carefully controlled, the light output from lamps

of the same power rating is more reproducible. One 60-watt bulb is

therefore exactly like another in terms of light production.

Improved production techniques have greatly reduced the cost

of manufacturing ductile tungsten filaments and of light-bulb man-

ufacturing in general. The modern world is heavily dependent

upon this reliable, inexpensive light source, which turns darkness

into daylight.





See also : Fluorescent lighting; Memory metal; Steelmaking process.

Tuberculosis vaccine

The invention: 



Vaccine that uses an avirulent (nondisease) strain

of bovine tuberculosis bacilli that is safer than earlier vaccines.





The people behind the invention:



Albert Calmette (1863-1933), a French microbiologist

Camille Guérin (1872-1961), a French veterinarian and

microbiologist

Robert Koch (1843-1910), a German physician and

microbiologist










Isolating Bacteria



Tuberculosis, once called “consumption,” is a deadly, contagious

disease caused by the bacterium Mycobacterium tuberculosis,

first identified by the eminent German physician Robert Koch in

1882. The bacterium can be transmitted from person to person by

physical contact or droplet infection (for example, sneezing). The

condition eventually inflames and damages the lungs, causing difficulty

in breathing and failure of the body to deliver sufficient oxygen

to various tissues. It can spread to other body tissues, where

further complications develop.Without treatment, the disease progresses,

disabling and eventually killing the victim. Tuberculosis

normally is treated with a combination of antibiotics and other

drugs.

Koch developed his approach for identifying bacterial pathogens

(disease producers) with simple equipment, primarily microscopy.

Having taken blood samples from diseased animals, he would

identify and isolate the bacteria he found in the blood. Each strain of

bacteria would be injected into a healthy animal. The latter would

then develop the disease caused by the particular strain.

In 1890, he discovered that a chemical released from tubercular

bacteria elicits a hypersensitive (allergic) reaction in individuals

previously exposed to or suffering from tuberculosis. This chemical,

called “tuberculin,” was isolated from culture extracts in which tubercular

bacteria were being grown.

When small amounts of tuberculin are injected into a person subcutaneously

(beneath the skin), a reddened, inflamed patch approximately

the size of a quarter develops if the person has been exposed

to or is suffering from tuberculosis. Injection of tuberculin into an

uninfected person yields a negative response (that is, no inflammation).

Tuberculin does not harm those being tested.







Tuberculosis’s Weaker Grandchildren





The first vaccine to prevent tuberculosis was developed in 1921

by two French microbiologists, Albert Calmette and Camille Guérin.

Calmette was a student of the eminent French microbiologist Louis

Pasteur at Pasteur’s Institute in Paris. Guérin was a veterinarian

who joined Calmette’s laboratory in 1897. At Lille, Calmette and

Guérin focused their research upon the microbiology of infectious

diseases, especially tuberculosis.

In 1906, they discovered that individuals who had been exposed to

tuberculosis or who had mild infections were developing resistance to

the disease. They found that resistance to tuberculosis was initiated by

the body’s immune system. They also discovered that tubercular bacteria

grown in culture over many generations become progressively

weaker and avirulent, losing their ability to cause disease.

From 1906 through 1921, Calmette and Guérin cultured tubercle

bacilli from cattle. With proper nutrients and temperature, bacteria

can reproduce by fission (that is, one bacterium splits into two bacteria)

in as little time as thirty minutes. Calmette and Guérin cultivated

these bacteria in a bile-derived food medium for thousands of

generations over fifteen years, periodically testing the bacteria for

virulence by injecting them into cattle. After many generations, the

bacteria lost their virulence, their ability to cause disease. Nevertheless,

these weaker, or “avirulent” bacteria still stimulated the animals’

immune systems to produce antibodies. Calmette and Guérin

had successfully bred a strain of avirulent bacteria that could not

cause tuberculosis in cows but could also stimulate immunity against

the disease.

There was considerable concern over whether the avirulent strain

was harmless to humans. Calmette and Guérin continued cultivating

weaker versions of the avirulent strain that retained antibody-

stimulating capacity. By 1921, they had isolated an avirulent antibody-

stimulating strain that was harmless to humans, a strain they

called “Bacillus Calmette-Guérin” (BCG).

In 1922, they began BCG-vaccinating newborn children against

tuberculosis at the Charité Hospital in Paris. The immunized children

exhibited no ill effects from the BCG vaccination. Calmette and

Guérin’s vaccine was so successful in controlling the spread of tuberculosis

in France that it attained widespread use in Europe and

Asia beginning in the 1930’s.



Impact



Most bacterial vaccines involve the use of antitoxin or heat- or

chemical-treated bacteria. BCG is one of the few vaccines that use

specially bred live bacteria. Its use sparked some controversy in

the United States and England, where the medical community

questioned its effectiveness and postponed BCG immunization

until the late 1950’s. Extensive testing of the vaccine was performed

at the University of Illinois before it was adopted in the

United States. Its effectiveness is questioned by some physicians to

this day.

Some of the controversy stems from the fact that the avirulent,

antibody-stimulating BCG vaccine conflicts with the tuberculin

skin test. The tuberculin skin test is designed to identify people

suffering from tuberculosis so that they can be treated. A BCGvaccinated

person will have a positive tuberculin skin test similar

to that of a tuberculosis sufferer. If a physician does not know that

a patient has had a BCG vaccination, it will be presumed (incorrectly)

that the patient has tuberculosis. Nevertheless, the BCG

vaccine has been invaluable in curbing the worldwide spread of

tuberculosis, although it has not eradicated the disease.





See also:



Antibacterial drugs; Birth control pill; Penicillin; Polio vaccine (Sabin);

Polio vaccine (Salk)

Transistor radio

The invention:



 Miniature portable radio that used transistors and

created a new mass market for electronic products.









The people behind the invention:



John Bardeen (1908-1991), an American physicist

Walter H. Brattain (1902-1987), an American physicist

William Shockley (1910-1989), an American physicist

Akio Morita (1921-1999), a Japanese physicist and engineer

Masaru Ibuka (1907-1997), a Japanese electrical engineer and

industrialist





A Replacement for Vacuum Tubes



The invention of the first transistor by William Shockley, John

Bardeen, andWalter H. Brattain of Bell Labs in 1947 was a scientific

event of great importance. Its commercial importance at the time,

however, was negligible. The commercial potential of the transistor

lay in the possibility of using semiconductor materials to carry out

the functions performed by vacuum tubes, the fragile and expensive

tubes that were the electronic hearts of radios, sound amplifiers,

and telephone systems. Transistors were smaller, more rugged,

and less power-hungry than vacuum tubes. They did not suffer

from overheating. They offered an alternative to the unreliability

and short life of vacuum tubes.

Bell Labs had begun the semiconductor research project in an effort

to find a better means of electronic amplification. This was

needed to increase the strength of telephone signals over long distances.

Therefore, the first commercial use of the transistor was

sought in speech amplification, and the small size of the device

made it a perfect component for hearing aids. Engineers from the

Raytheon Company, the leading manufacturer of hearing aids, were

invited to Bell Labs to view the new transistor and to help assess the

commercial potential of the technology. The first transistorized consumer

product, the hearing aid, was soon on the market. The early

models built by Raytheon used three junction-type transistors and

cost more than two hundred dollars. They were small enough to go

directly into the ear or to be incorporated into eyeglasses.

The commercial application of semiconductors was aimed largely

at replacing the control and amplification functions carried out by

vacuum tubes. The perfect vehicle for this substitution was the radio

set. Vacuum tubes were the most expensive part of a radio set

and the most prone to break down. The early junction transistors

operated best at low frequencies, and subsequently more research

was needed to produce a commercial high-frequency transistor.

Several of the licensees embarked on this quest, including the Radio

Corporation of America (RCA), Texas Instruments, and the Tokyo

Telecommunications Engineering Company of Japan.



Perfecting the Transistor



The Tokyo Telecommunications Engineering Company of Japan,

formed in 1946, had produced a line of instruments and consumer

products based on vacuum-tube technology. Its most successful

product was a magnetic tape recorder. In 1952, one of the founders

of the company, Masaru Ibuka, visited the United States to learn

more about the use of tape recorders in schools and found out that

Western Electric was preparing to license the transistor patent.With

only the slightest understanding of the workings of semiconductors,

Tokyo Telecommunications purchased a license in 1954 with

the intention of using transistors in a radio set.

The first task facing the Japanese was to increase the frequency

response of the transistor to make it suitable for radio use. Then a

method of manufacturing transistors cheaply had to be found. At

the time, junction transistors were made from slices of germanium

crystal. Growing the crystal was not an exact science, nor was the

process of “doping” it with impurities to form the different layers of

conductivity that made semiconductors useful. The Japanese engineers

found that the failure rate for high-frequency transistors was

extremely high. The yield of good transistors from one batch ran as

low as 5 percent, which made them extremely expensive and put the

whole project in doubt. The effort to replace vacuum tubes with

components made of semiconductors was motivated by cost rather

than performance; if transistors proved to be more expensive, then

it was not worth using them.

Engineers from Tokyo Telecommunications again came to the

United States to search for information about the production of

transistors. In 1954, the first high-frequency transistor was produced

in Japan. The success of Texas Instruments in producing the

components for the first transistorized radio (introduced by the Regency

Company in 1954) spurred the Japanese to greater efforts.

Much of their engineering and research work was directed at the

manufacture and quality control of transistors. In 1955, they introduced

their transistor radio, the TR-55, which carried the brand

name “Sony.” The name was chosen because the executives of the

company believed that the product would have an international appeal

and therefore needed a brand name that could be recognized

easily and remembered in many languages. In 1957, the name of the

entire company was changed to Sony.



Impact



Although Sony’s transistor radios were successful in the marketplace,

they were still relatively large and cumbersome. Ibuka saw a

consumer market for a miniature radio and gave his engineers the

task of designing a radio small enough to fit into a shirt pocket. The

realization of this design—“Transistor Six”—was introduced in 1957.

It was an immediate success. Sony sold the radios by the millions,

and numerous imitations were also marketed under brand names

such as “Somy” and “Sonny.” The product became an indispensable

part of popular culture of the late 1950’s and 1960’s; its low cost enabled

the masses to enjoy radio wherever there were broadcasts.

The pocket-sized radio was the first of a line of electronic consumer

products that brought technology into personal contact with

the user. Sony was convinced that miniaturization did more than

make products more portable; it established a one-on-one relationship

between people and machines. Sony produced the first alltransistor

television in 1960. Two years later, it began to market a

miniature television in the United States. The continual reduction in

the size of Sony’s tape recorders reached a climax with the portable

tape player introduced in the 1980’s. The SonyWalkman was a marketing

triumph and a further reminder that Japanese companies led

the way in the design and marketing of electronic products.





John Bardeen





The transistor reduced the size of electronic circuits and at

the same time the amount of energy lost from them as heat.

Superconduction gave rise to electronic circuits with practically

no loss of energy at all. John Bardeen helped unlock the secrets

of both.

Bardeen was born in 1908 in Madison,Wisconsin, where his

mother was an artist and his father was a professor of anatomy

at the University ofWisconsin. Bardeen attended the university,

earning a bachelor’s degree in electrical engineering in 1928

and a master’s degree in geophysics in 1929. After working as a

geophysicist, he entered Princeton University, studying with

Eugene Wigner, the leading authority on solid-state physics,

and received a doctorate in mathematics and physics in 1936.

Bardeen taught at Harvard University and the University of

Minnesota until World War II, when he moved to the Naval

Ordnance Laboratory. Finding academic salaries too low to

support his family after the war, he accepted a position at Bell

Telephone Laboratories. There, with Walter Brattain, he turned

William Shockley’s theory of semiconductors into a practical

device—the transfer resistor, or transistor.

He returned to academia as a professor at the University of

Illinois and began to investigate a long-standing mystery in

physics, superconductivity, with a postdoctoral associate, Leon

Cooper, and a graduate student, J. Robert Schrieffer. In 1956

Cooper made a key discovery—superconducting electrons

travel in pairs. And while Bardeen was in Stockholm, Sweden,

collecting a share of the 1956 Nobel Prize in Physics for his work

on transistors, Schrieffer worked out a mathematical analysis of

the phenomenon. The theory that the three men published since

became known as BCS theory from the first letters of their last

names, and as well as explain superconductors, it pointed toward

a great deal of technology and additional basic research.

The team won the 1972 Nobel Prize in Physics for BCS theory,

making Bardeen the only person to ever win two Nobel Prizes

for physics. He retired in 1975 and died sixteen years later.





See also :  Compact disc; FM radio; Radio; Radio crystal sets; Television;

Transistor;



Further Reading



Handy, Roger, Maureen Erbe, and Aileen Antonier. Made in Japan:

Transistor Radios of the 1950s and 1960s. San Francisco: Chronicle

Books, 1993.



Marshall, David V. Akio Morita and Sony. Watford: Exley, 1995.

Morita, Akio, with Edwin M. Reingold, and Mitsuko Shimomura.

Made in Japan: Akio Morita and Sony. London: HarperCollins, 1994.









Nathan, John. Sony: The Private Life. London: HarperCollins-

Business, 2001.

Transistor

The invention: 



A miniature electronic device, comprising a tiny

semiconductor and multiple electrical contacts, used in circuits

as an amplifier, detector, or switch, that revolutionized electronics

in the mid-twentieth century.



The people behind the invention:



William B. Shockley (1910-1989), an American physicist who led

the Bell Laboratories team that produced the first transistors

Akio Morita (1921-1999), a Japanese physicist and engineer who

was the cofounder of the Sony electronics company

Masaru Ibuka (1908-1997), a Japanese electrical engineer and

businessman who cofounded Sony with Morita








The Birth of Sony



In 1952, a Japanese engineer visiting the United States learned

that the Western Electric company was granting licenses to use its

transistor technology. He was aware of the development of this device

and thought that it might have some commercial applications.

Masaru Ibuka told his business partner in Japan about the opportunity,

and they decided to raise the $25,000 required to obtain a license.

The following year, his partner, Akio Morita, traveled to New

York City and concluded negotiations with Western Electric. This

was a turning point in the history of the Sony company and in the

electronics industry, for transistor technology was to open profitable

new fields in home entertainment.

The origins of the Sony corporation were in the ruins of postwar

Japan. The Tokyo Telecommunications Company was incorporated

in 1946 and manufactured a wide range of electrical equipment

based on the existing vacuum tube technology. Morita and Ibuka

were involved in research and development of this technology during

the war and intended to put it to use in the peacetime economy.

In the United States and Europe, electrical engineers who had done

the same sort of research founded companies to build advanced

audio products such as high-performance amplifiers, but Morita

and Ibuka did not have the resources to make such sophisticated

products and concentrated on simple items such as electric water

heaters and small electric motors for record players.

In addition to their experience as electrical engineers, both men

were avid music lovers, as a result of their exposure to Americanbuilt

phonographs and gramophones exported to Japan in the early

twentieth century. They decided to combine their twin interests by

devising innovative audio products and looked to the new field of

magnetic recording as a likely area for exploitation. They had learned

about tape recorders from technical journals and had seen them in

use by the American occupation force.

They developed a reel-to-reel tape recorder and introduced it in

1950. It was a large machine with vacuum tube amplifiers, so heavy

that they transported it by truck. Although it worked well, they had

a hard job selling it. Ibuka went to the United States in 1952 partly

on a fact-finding mission and partly to get some ideas about marketing

the tape recorder to schools and businesses. It was not seen as a

consumer product.

Ibuka and Morita had read about the invention of the transistor

inWestern Electric’s laboratories shortly after the war. John Bardeen

andWalter H. Brattain had discovered that a semiconducting material

could be used to amplify or control electric current. Their point

contact transistor of 1948 was a crude laboratory apparatus that

served as the basis for further research. The project was taken over

byWilliam B. Shockley, who had suggested the theory of the transistor

effect. A new generation of transistors was devised; they were

simpler and more efficient than the original. The junction transistors

were the first to go into production.





Ongoing Research



Bell Laboratories had begun transistor research becauseWestern

Electric, one of its parent companies along with American Telephone

and Telegraph, was interested in electronic amplification.

This was seen as a means to increase the strength of telephone signals

traveling over long distances, a job carried out by vacuum

tubes. The junction transistor was developed as an amplifier.Western

Electric thought that the hearing aid was the only consumer

product that could be based on it and saw the transistor solely as a

telecommunications technology. The Japanese purchased the license

with only the slightest understanding of the workings of

semiconductors and despite the belief that transistors could not be

used at the high frequencies associated with radio.

The first task of Ibuka and Morita was to develop a highfrequency

transistor. Once this was accomplished, in 1954, a method

had to be found to manufacture it cheaply. Transistors were made

from crystals, which had to be grown and doped with impurities to

form different layers of conductivity. This was not an exact science,

and Sony engineers found that the failure rate for high-frequency

transistors was very high. This increased costs and put the entire

project into doubt, because the adoption of transistors was based on

simplicity, reliability, and low cost.

The introduction of the first Sony transistor radio, the TR-55, in

1955 was the result of basic research combined with extensive industrial

engineering. Morita admitted that its sound was poor, but

because it was the only transistor radio in Japan, it sold well. These

were not cheap products, nor were they particularly compact. The

selling point was that they consumed much less battery power than

the old portable radios.

The TR-55 carried the brand name Sony, a relative of the Soni

magnetic tape made by the company and a name influenced by the

founders’ interest in sound. Morita and Ibuka had already decided

that the future of their company would be in international trade and

wanted its name to be recognized all over the world. In 1957, they

changed the company’s name from Tokyo Telecomunications Engineering

to Sony.

The first product intended for the export market was a small

transistor radio. Ibuka was disappointed at the large size of the TR-

55 because one of the advantages of the transistor over the vacuum

tube was supposed to be smaller size. He saw a miniature radio as a

promising consumer product and gave his engineers the task of designing

one small enough to fit into his shirt pocket.

All elements of the radio had to be reduced in size: amplifier,

transformer, capacitor, and loudspeaker. Like many other Japanese

manufacturers, Sony bought many of the component parts of its

products from small manufacturers, all of which had to be cajoled

into decreasing the size of their parts. Morita and Ibuka stated that

the hardest task in developing this new product was negotiating

with the subcontractors. Finally, the Type 63 pocket transistor radio

the “Transistor Six”—was introduced in 1957.





Impact



When the transistor radio was introduced, the market for radios

was considered to be saturated. People had rushed to buy them

when they were introduced in the 1920’s, and by the time of the

Great Depression, the majority of American households had one.

Improvements had been made to the receiver and more attractive

radio/phonograph console sets had been introduced, but these developments

did not add many new customers. The most manufacturers

could hope for was the replacement market with a few sales

as children moved out of their parents’ homes and established new

households.

The pocket radio created a new market. It could be taken anywhere

and used at any time. Its portability was its major asset, and it

became an indispensable part of youth-oriented popular culture of

the 1950’s and 1960’s. It provided an outlet for the crowded airwaves

of commercialAMradio and was the means to bring the new

music of rock and roll to a mass audience.

As soon as Sony introduced the Transistor Six, it began to redesign

it to reduce manufacturing cost. Subsequent transistor radios

were smaller and cheaper. Sony sold them by the millions, and millions

more were made by other companies under brand names such

as “Somy” and “Sonny.” By 1960, more than twelve million transistor

radios had been sold.

The transistor radio was the product that established Sony as an

international audio concern. Morita had resisted the temptation to

make radios for other companies to sell under their names. Exports

of Sony radios increased name recognition and established a bridgehead

in the United States, the biggest market for electronic consumer

products. Morita planned to follow the radio with other transistorized

products.

The television had challenged radio’s position as the mechanical

entertainer in the home. Like the radio, it stood in nearly every

American living room and used the same vacuum tube amplification

unit. The transistorized portable television set did for images

what the transistor radio did for sound. Sony was the first to develop

an all-transistor television, in 1959. At a time when the trend

in television receivers was toward larger screens, Sony produced

extremely small models with eight-inch screens. Ignoring the marketing

experts who said that Americans would never buy such a

product, Sony introduced these models into the United States in

1960 and found that there was a huge demand for them.

As in radio, the number of television stations on the air and

broadcasts for the viewer to choose from grew.Apersonal television

or radio gave the audience more choices. Instead of one machine in

the family room, there were now several around the house. The

transistorization of mechanical entertainers allowed each family

member to choose his or her own entertainment. Sony learned several

important lessons from the success of the transistor radio and

television. The first was that small size and low price could create

new markets for electronic consumer products. The second was that

constant innovation and cost reduction were essential to keep ahead

of the numerous companies that produced cheaper copies of original

Sony products.

In 1962, Sony introduced a tiny television receiver with a fiveinch

screen. In the 1970’s and 1980’s, it produced even smaller models,

until it had a TV set that could sit in the palm of the hand—the

Video Walkman. Sony’s scientists had developed an entirely new

television screen that worked on a new principle and gave better

color resolution; the company was again able to blend the fruits of

basic scientific research with innovative industrial engineering.

The transistorized amplifier unit used in radio and television sets

was applied to other products, including amplifiers for record players

and tape recorders. Japanese manufacturers were slow to take

part in the boom in high-fidelity audio equipment that began in the

United States in the 1950’s. The leading manufacturers of highquality

audio components were small American companies based

on the talents of one engineer, such as Avery Fisher or Henry Koss.

They sold expensive amplifiers and loudspeakers to audiophiles.

The transistor reduced the size, complexity, and price of these components.

The Japanese took the lead devising complete audio units based on transistorized

integrated circuits, thus developing the basic home stereo.

In the 1960’s, companies such as Sony and Matsushita dominated

the market for inexpensive home stereos. These were the basic

radio/phonograph combination, with two detached speakers.

The finely crafted wooden consoles that had been the standard for

the home phonograph were replaced by small plastic boxes. The

Japanese were also quick to exploit the opportunities of the tape cassette.

The Philips compact cassette was enthusiastically adopted by

Japanese manufacturers and incorporated into portable tape recorders.

This was another product with its ancestry in the transistor

radio. As more of them were sold, the price dropped, encouraging

more consumers to buy. The cassette player became as commonplace

in American society in the 1970’s as the transistor radio had

been in the 1960’s.





The Walkman



The transistor took another step in miniaturization in the Sony

Walkman, a personal stereo sound system consisting of a cassette

player and headphones. It was based on the same principles as the

transistor radio and television. Sony again confounded marketing

experts by creating a new market for a personal electronic entertainer.

In the ten years following the introduction of theWalkman in

1979, Sony sold fifty million units worldwide, half of those in the

United States. Millions of imitation products were sold by other

companies.

Sony’s acquisition of the Western Electric transistor technology

was a turning point in the fortunes of that company and of Japanese

manufacturers in general. Less than ten years after suffering defeat

in a disastrous war, Japanese industry served notice that it had lost

none of its engineering capabilities and innovative skills. The production

of the transistor radio was a testament to the excellence of

Japanese research and development. Subsequent products proved

that the Japanese had an uncanny sense of the potential market for

consumer products based on transistor technology. The ability to incorporate

solid-state electronics into innovative home entertainment

products allowed Japanese manufacturers to dominate the

world market for electronic consumer products and to eliminate

most of their American competitors.

The little transistor radio was the vanguard of an invasion of new

products unparalleled in economic history. Japanese companies

such as Sony and Panasonic later established themselves at the leading

edge of digital technology, the basis of a new generation of entertainment

products. Instead of Japanese engineers scraping together

the money to buy a license for an American technology, the

great American companies went to Japan to license compact disc

and other digital technologies.



William Shockley



William Shockley’s reputation contains extremes. He helped

invent one of the basic devices supporting modern technological

society, the transistor. He also tried to revive one of the most

infamous social theories, eugenics.

His parents, mining engineer William Hillman Shockley,

and surveyor May Bradford Shockley, were on assignment in

England in 1910 when he was born. The family returned to

Northern California when the younger William was three, and

they schooled him at home until he was eight. He acquired an

early interest in physics from a neighbor who taught at Stanford

University. Shockley pursed that interest at the California Institute

of Technology and the Massachusetts Institute of Technology,

which awarded him a doctorate in 1936.

Shockley went to work for Bell Telephone Laboratories in

the same year. While trying to design a vacuum tube that could

amplify current, it occurred to him that solid state components

might work better than the fragile tubes. He experimented with

the semiconductors germanium and silicon, but the materials

available were too impure for his purpose. World War II interrupted

the experiments, and he worked instead to improve radar

and anti-submarine devices for the military. Back at Bell

Labs in 1945, Shockley teamed with theorist John Bardeen and

experimentalistWalter Brattain. Two years later they succeeded

in making the first amplifier out of semiconductor materials

and called it a transistor (short for transfer resistor). Its effect on

the electronics industry was revolutionary, and the three shared



the 1956 Nobel Prize in Physics for their achievement.

In the mid-1950’s Shockley left Bell Labs to start Shockley

Transistor, then switched to academia in 1963, becoming Stanford

University’s Alexander M. Poniatoff Professor of Engineering

and Applied Science. He grew interested in the relation

between race and intellectual ability. Teaching himself psychology

and genetics, he conceived the theory that Caucasians were

inherently more intelligent than other races because of their genetic

make-up. When he lectured on his brand of eugenics, he

was denounced by the public as a racist and by scientists for



shoddy thinking. Shockley retired in 1975 and died in 1989.







See also : 



Cassette recording; Color television; FM radio; Radio;Television;



Further Reading :



Lyons, Nick. The Sony Vision. New York: Crown Publishers, 1976.

Marshall, David V. Akio Morita and Sony. Watford: Exley, 1995.

Morita, Akio, with Edwin M. Reingold, and Mitsuko Shimomura.

Made in Japan: Akio Morita and Sony. London: HarperCollins,

1994.

Reid, T. R. The Chip: How Two Americans Invented the Microchip and

Launched a Revolution. New York: Simon and Schuster, 1984.

Riordan, Michael. Crystal Fire: The Invention of the Transistor and the

Birth of the Information Age. New York: Norton, 1998.

Scott, Otto. The Creative Ordeal: The Story of Raytheon. New York:

Atheneum, 1974.

Touch-tone telephone

The invention: 



A push-button dialing system for telephones that

replaced the earlier rotary-dial phone.



The person behind the invention:



Bell Labs, the research and development arm of the American

Telephone and Telegraph Company







Dialing Systems



A person who wishes to make a telephone call must inform the

telephone switching office which number he or she wishes to reach.

A telephone call begins with the customer picking up the receiver

and listening for a dial tone. The action of picking up the telephone

causes a switch in the telephone to close, allowing electric current to

flow between the telephone and the switching office. This signals

the telephone office that the user is preparing to dial a number. To

acknowledge its readiness to receive the digits of the desired number,

the telephone office sends a dial tone to the user. Two methods

have been used to send telephone numbers to the telephone office:

dial pulsing and touch-tone dialing.

“Dial pulsing” is the method used by telephones that have rotary

dials. In this method, the dial is turned until it stops, after which it is

released and allowed to return to its resting position. When the dial

is returning to its resting position, the telephone breaks the current

between the telephone and the switching office. The switching office

counts the number of times that current flow is interrupted,

which indicates the number that had been dialed.



Introduction of Touch-tone Dialing



The dial-pulsing technique was particularly appropriate for use

in the first electromechanical telephone switching offices, because

the dial pulses actually moved mechanical switches in the switching

office to set up the telephone connection. The introduction of

touch-tone dialing into electromechanical systems was made possi-

ble by a special device that converted the touch-tones into rotary

dial pulses that controlled the switches. At the American Telephone

and Telegraph Company’s Bell Labs, experimental studies were

pursued that explored the use of “multifrequency key pulsing” (in

other words, using keys that emitted tones of various frequencies)

by both operators and customers. Initially, plucked tuned reeds

were proposed. These were, however, replaced with “electronic

transistor oscillators,” which produced the required signals electronically.

The introduction of “crossbar switching” made dial pulse signaling

of the desired number obsolete. The dial pulses of the telephone

were no longer needed to control the mechanical switching process

at the switching office. When electronic control was introduced into

switching offices, telephone numbers could be assigned by computer

rather than set up mechanically. This meant that a single

touch-tone receiver at the switching office could be shared by a

large number of telephone customers.

Before 1963, telephone switching offices relied upon rotary dial

pulses to move electromechanical switching elements. Touch-tone

dialing was difficult to use in systems that were not computer controlled,

such as the electromechanical step-by-step method. In about

1963, however, it became economically feasible to implement centralized

computer control and touch-tone dialing in switching offices.

Computerized switching offices use a central touch-tone receiver

to detect dialed numbers, after which the receiver sends the

number to a call processor so that a voice connection can be established.

Touch-tone dialing transmits two tones simultaneously to represent

a digit. The tones that are transmitted are divided into two

groups: a high-band group and a low-band group. For each digit

that is dialed, one tone from the low-frequency (low-band) group

and one tone from the high-frequency (high-band) group are transmitted.

The two frequencies of a tone are selected so that they are

not too closely related harmonically. In addition, touch-tone receivers

must be designed so that false digits cannot be generated when

people are speaking into the telephone.

For a call to be completed, the first digit dialed must be detected

in the presence of a dial tone, and the receiver must not interpret

background noise or speech as valid digits. In order to avoid such

misinterpretation, the touch-tone receiver uses both the relative and

the absolute strength of the two simultaneous tones of the first digit

dialed to determine what that digit is.

A system similar to the touch-tone system is used to send telephone

numbers between telephone switching offices. This system,

which is called “multifrequency signaling,” also uses two tones to

indicate a single digit, but the frequencies used are not the same frequencies

that are used in the touch-tone system. Multifrequency

signaling is currently being phased out; new computer-based systems

are being introduced to replace it.



Impact



Touch-tone dialing has made new caller features available. The

touch-tone system can be used not only to signal the desired number

to the switching office but also to interact with voice-response

systems. This means that touch-tone dialing can be used in conjunction

with such devices as bank teller machines. Acustomer can also

dial many more digits per second with a touch-tone telephone than

with a rotary dial telephone.

Touch-tone dialing has not been implemented in Europe, and

one reason may be that the economics of touch-tone dialing change

as a function of technology. In the most modern electronic switching

offices, rotary signaling can be performed at no additional cost,

whereas the addition of touch-tone dialing requires a centralized

touch-tone receiver at the switching office. Touch-tone signaling

was developed in an era of analog telephone switching offices, and

since that time, switching offices have become overwhelmingly digital.

When the switching network becomes entirely digital, as will

be the case when the integrated services digital network (ISDN) is

implemented, touch-tone dialing will become unnecessary. In the

future, ISDN telephone lines will use digital signaling methods exclusively.



See also: Cell phone; Rotary dial telephone; Telephone switching.

Tidal power plant

The invention:



Plant that converts the natural ocean tidal forces

into electrical power.



The people behind the invention:



Mariano di Jacopo detto Taccola (Mariano of Siena, 1381-1453),

an Italian notary, artist, and engineer

Bernard Forest de Bélidor (1697 or 1698-1761), a French engineer

Franklin D. Roosevelt (1882-1945), president of the United States







Tidal Energy



Ocean tides have long been harnessed to perform useful work.

Ancient Greeks, Romans, and medieval Europeans all left records

and ruins of tidal mills, and Mariano di Jacopo included tidal power

in his treatise De Ingeneis (1433; on engines). Some mills consisted of

water wheels suspended in tidal currents, others lifted weights that

powered machinery as they fell, and still others trapped the high

tide to run a mill.

Bernard Forest de Bélidor’s Architecture hydraulique (1737; hydraulic

architecture) is often cited as initiating the modern era of

tidal power exploitation. Bélidor was an instructor in the French

École d’Artillerie et du Génie (School of Artillery and Engineering).

Industrial expansion between 1700 and 1800 led to the construction

of many tidal mills. In these mills, waterwheels or simple turbines

rotated shafts that drove machinery by means of gears or

belts. They powered small enterprises located on the seashore.

Steam engines, however, soon began to replace tidal mills. Steam

could be generated wherever it was needed, and steam mills were

not dependent upon the tides or limited in their production capacity

by the amount of tidal flow. Thus, tidal mills gradually were abandoned,

although a few still operate in New England, Great Britain,

France, and elsewhere.



Electric Power from Tides



Modern society requires tremendous amounts of electric energy

generated by large power stations. This need was first met by

using coal and by damming rivers. Later, oil and nuclear power became

important. Although small mechanical tidal mills are inadequate

for modern needs, tidal power itself remains an attractive

source of energy. Periodic alarms about coal or oil supplies and

concern about the negative effects on the environment of using

coal, oil, or nuclear energy continue to stimulate efforts to develop

renewable energy sources with fewer negative effects. Every crisis—

for example, the perceived European coal shortages in the

early 1900’s, oil shortages in the 1920’s and 1970’s, and growing

anxiety about nuclear power—revives interest in tidal power.

In 1912, a tidal power plant was proposed at Busum, Germany.

The English, in 1918 and more recently, promoted elaborate schemes

for the Severn Estuary. In 1928, the French planned a plant at Aber-

Wrach in Brittany. In 1935, under the leadership of Franklin Delano

Roosevelt, the United States began construction of a tidal power

plant at Passamaquoddy, Maine. These plants, however, were never

built. All of them had to be located at sites where tides were extremely

high, and such sites are often far from power users. So

much electricity was lost in transmission that profitable quantities

of power could not be sent where they were needed. Also, large

tidal power stations were too expensive to compete with existing

steam plants and river dams. In addition, turbines and generators

capable of using the large volumes of slow-moving tidal water that

reversed flow had not been invented. Finally, large tidal plants inevitably

hampered navigation, fisheries, recreation, and other uses

of the sea and shore.

French engineers, especially Robert Gibrat, the father of the La

Rance project, have made the most progress in solving the problems

of tidal power plants. France, a highly industrialized country, is

short of coal and petroleum, which has brought about an intense

search by the French for alternative energy supplies.

La Rance, which was completed in December, 1967, is the first

full-scale tidal electric power plant in the world. The Chinese, however,

have built more than a hundred small tidal electric stations about the size of the old mechanical tidal mills, and the Canadians

and the Russians have both operated plants of pilot-plant size.

La Rance, which was selected from more than twenty competing

localities in France, is one of a few places in the world where the

tides are extremely high. It also has a large reservoir that is located

above a narrow constriction in the estuary. Finally, interference with

navigation, fisheries, and recreational activities is minimal at La

Rance.

Submersible “bulbs” containing generators and mounting propeller

turbines were specially designed for the La Rance project.

These turbines operate using both incoming and outgoing tides,

and they can pump water either into or out of the reservoir. These

features allow daily and seasonal changes in power generation to be

“smoothed out.” These turbines also deliver electricity most economically.

Many engineering problems had to be solved, however,

before the dam could be built in the tidal estuary.

The La Rance plant produces 240 megawatts of electricity. Its

twenty-four highly reliable turbine generator sets operate about 95

percent of the time. Output is coordinated with twenty-four other

hydroelectric plants by means of a computer program. In this system,

pump-storage stations use excess La Rance power during periods

of low demand to pump water into elevated reservoirs. Later,

during peak demand, this water is fed through a power plant, thus

“saving” the excess generated at La Rance when it was not immediately

needed. In this way, tidal energy, which must be used or lost as

the tides continue to flow, can be saved.



Consequences



The operation of La Rance proved the practicality of tide-generated

electricity. The equipment, engineering practices, and operating

procedures invented for La Rance have been widely applied. Submersible,

low-head, high-flow reversible generators of the La Rance

type are now used in Austria, Switzerland, Sweden, Russia, Canada,

the United States, and elsewhere.

Economic problems have prevented the building of more large

tidal power plants. With technological advances, the inexorable

depletion of oil and coal resources, and the increasing cost of nu-

clear power, tidal power may be used more widely in the future.

Construction costs may be significantly lowered by using preconstructed

power units and dam segments that are floated into place

and submerged, thus making unnecessary expensive dams and reducing

pumping costs.







See also : Compressed-air-accumulating power plant; Geothermal power; Nuclear power plant; Nuclear reactor; Solar thermal engine; Thermal cracking process.

Thermal cracking process

The invention: 



Process that increased the yield of refined gasoline

extracted from raw petroleum by using heat to convert complex

hydrocarbons into simpler gasoline hydrocarbons, thereby making

possible the development of the modern petroleum industry.



The people behind the invention:



William M. Burton (1865-1954), an American chemist

Robert E. Humphreys (1942- ), an American chemist










Gasoline, Motor Vehicles, and Thermal Cracking



Gasoline is a liquid mixture of hydrocarbons (chemicals made up

of only hydrogen and carbon) that is used primarily as a fuel for internal

combustion engines. It is produced by petroleum refineries

that obtain it by processing petroleum (crude oil), a naturally occurring

mixture of thousands of hydrocarbons, the molecules of which

can contain from one to sixty carbon atoms.

Gasoline production begins with the “fractional distillation” of

crude oil in a fractionation tower, where it is heated to about 400 degrees

Celsius at the tower’s base. This heating vaporizes most of the

hydrocarbons that are present, and the vapor rises in the tower,

cooling as it does so. At various levels of the tower, various portions

(fractions) of the vapor containing simple hydrocarbon mixtures become

liquid again, are collected, and are piped out as “petroleum

fractions.” Gasoline, the petroleum fraction that boils between 30

and 190 degrees Celsius, is mostly a mixture of hydrocarbons that

contain five to twelve carbon atoms.

Only about 25 percent of petroleum will become gasoline via

fractional distillation. This amount of “straight run” gasoline is not

sufficient to meet the world’s needs. Therefore, numerous methods

have been developed to produce the needed amounts of gasoline.

The first such method, “thermal cracking,” was developed in 1913

by William M. Burton of Standard Oil of Indiana. Burton’s cracking

process used heat to convert complex hydrocarbons (whose molecules

contain many carbon atoms) into simpler gasoline hydrocarbons

(whose molecules contain fewer carbon atoms), thereby increasing

the yield of gasoline from petroleum. Later advances in

petroleum technology, including both an improved Burton method

and other methods, increased the gasoline yield still further.





More Gasoline!



Starting in about 1900, gasoline became important as a fuel for

the internal combustion engines of the new vehicles called automobiles.

By 1910, half a million automobiles traveled American roads.

Soon, the great demand for gasoline—which was destined to grow

and grow—required both the discovery of new crude oil fields

around the world and improved methods for refining the petroleum

mined from these new sources. Efforts were made to increase

the yield of gasoline—at that time, about 15 percent—from petroleum.

The Burton method was the first such method.

At the time that the cracking process was developed, Burton was

the general superintendent of the Whiting refinery, owned by Standard

Oil of Indiana. The Burton process was developed in collaboration

with Robert E. Humphreys and F. M. Rogers. This three-person

research group began work knowing that heating petroleum

fractions that contained hydrocarbons more complex than those

present in gasoline—a process called “coking”—produced kerosene,

coke (a form of carbon), and a small amount of gasoline. The

process needed to be improved substantially, however, before it

could be used commercially.

Initially, Burton and his coworkers used the “heavy fuel” fraction

of petroleum (the 66 percent of petroleum that boils at a temperature

higher than the boiling temperature of kerosene). Soon, they

found that it was better to use only the part of the material that contained

its smaller hydrocarbons (those containing fewer carbon atoms),

all of which were still much larger than those present in gasoline.

The cracking procedure attempted first involved passing the

starting material through a hot tube. This hot-tube treatment vaporized

the material and broke down 20 to 30 percent of the larger hydrocarbons

into the hydrocarbons found in gasoline. Various tarry

products were also produced, however, that reduced the quality of

the gasoline that was obtained in this way.



Next, the investigators attempted to work at a higher temperature

by bubbling the starting material through molten lead. More

gasoline was made in this way, but it was so contaminated with

gummy material that it could not be used. Continued investigation

showed, however, that moderate temperatures (between those used

in the hot-tube experiments and that of molten lead) produced the

best yield of useful gasoline.

The Burton group then had the idea of using high pressure to

“keep starting materials still.” Although the theoretical basis for the

use of high pressure was later shown to be incorrect, the new

method worked quite well. In 1913, the Burton method was patented

and put into use. The first cracked gasoline, called Motor

Spirit, was not very popular, because it was yellowish and had a

somewhat unpleasant odor. The addition of some minor refining

procedures, however, soon made cracked gasoline indistinguishable

from straight run gasoline. Standard Oil of Indiana made huge

profits from cracked gasoline over the next ten years. Ultimately,

thermal cracking subjected the petroleum fractions that were

utilized to temperatures between 550 and 750 degrees Celsius, under

pressures between 250 and 750 pounds per square inch.



Impact



In addition to using thermal cracking to make gasoline for sale,

Standard Oil of Indiana also profited by licensing the process for use

by other gasoline producers. Soon, the method was used throughout

the oil industry. By 1920, it had been perfected as much as it

could be, and the gasoline yield from petroleum had been significantly

increased. The disadvantages of thermal cracking include a

relatively low yield of gasoline (compared to those of other methods),

the waste of hydrocarbons in fractions converted to tar and

coke, and the relatively high cost of the process.

A partial solution to these problems was found in “catalytic

cracking”—the next logical step from the Burton method—in which

petroleum fractions to be cracked are mixed with a catalyst (a substance

that causes a chemical reaction to proceed more quickly,

without reacting itself). The most common catalysts used in such

cracking were minerals called “zeolites.” The wide use of catalytic

cracking soon enabled gasoline producers to work at lower temperatures

(450 to 550 degrees Celsius) and pressures (10 to 50 pounds

per square inch). This use decreased manufacturing costs because

catalytic cracking required relatively little energy, produced only

small quantities of undesirable side products, and produced high quality

gasoline.

Various other methods of producing gasoline have been developed—

among them catalytic reforming, hydrocracking, alkylation,

and catalytic isomerization—and now about 60 percent of the petroleum

starting material can be turned into gasoline. These methods,

and others still to come, are expected to ensure that the world’s

needs for gasoline will continue to be satisfied—as long as petroleum

remains available.



See also: Fuel cell; Gas-electric car; Geothermal power; Internal

combustion engine; Oil-well drill bit; Solar thermal engine.

Tevatron accelerator

The invention: 



A particle accelerator that generated collisions between

beams of protons and antiprotons at the highest energies

ever recorded.



The people behind the invention:



Robert Rathbun Wilson (1914- ), an American physicist and

director of Fermilab from 1967 to 1978

John Peoples (1933- ), an American physicist and deputy

director of Fermilab from 1987








Putting Supermagnets to Use



The Tevatron is a particle accelerator, a large electromagnetic device

used by high-energy physicists to generate subatomic particles

at sufficiently high energies to explore the basic structure of matter.

The Tevatron is a circular, tubelike track 6.4 kilometers in circumference

that employs a series of superconducting magnets to accelerate

beams of protons, which carry a positive charge in the atom, and

antiprotons, the proton’s negatively charged equivalent, at energies

up to 1 trillion electron volts (equal to 1 teraelectronvolt, or 1 TeV;

hence the name Tevatron). An electronvolt is the unit of energy that

an electron gains through an electrical potential of 1 volt.

The Tevatron is located at the Fermi National Accelerator Laboratory,

which is also known as Fermilab. The laboratory was one of

several built in the United States during the 1960’s.

The heart of the original Fermilab was the 6.4-kilometer main accelerator

ring. This main ring was capable of accelerating protons to

energies approaching 500 billion electron volts, or 0.5 teraelectronvolt.

The idea to build the Tevatron grew out of a concern for the

millions of dollars spent annually on electricity to power the main

ring, the need for higher energies to explore the inner depths of the

atom and the consequences of new theories of both matter and energy,

and the growth of superconductor technology. Planning for a

second accelerator ring, the Tevatron, to be installed beneath the

main ring began in 1972.

Robert Rathbun Wilson, the director of Fermilab at that time, realized

that the only way the laboratory could achieve the higher energies

needed for future experiments without incurring intolerable

electricity costs was to design a second accelerator ring that employed

magnets made of superconducting material. Extremely powerful

magnets are the heart of any particle accelerator; charged particles

such as protons are given a “push” as they pass through an electromagnetic

field. Each successive push along the path of the circular

accelerator track gives the particle more and more energy. The enormous

magnetic fields required to accelerate massive particles such

as protons to energies approaching 1 trillion electronvolts would require

electricity expenditures far beyond Fermilab’s operating budget.

Wilson estimated that using superconducting materials, however,

which have virtually no resistance to electrical current, would

make it possible for the Tevatron to achieve double the main ring’s

magnetic field strength, doubling energy output without significantly

increasing energy costs.





Tevatron to the Rescue



The Tevatron was conceived in three phases. Most important,

however, were Tevatron I and Tevatron II, where the highest energies

were to be generated and where it was hoped new experimental findings

would emerge. Tevatron II experiments were designed to be

very similar to other proton beam experiments, except that in this

case, the protons would be accelerated to an energy of 1 trillion

electron volts. More important still are the proton-anti proton colliding

beam experiments of Tevatron I. In this phase, beams of protons

and antiprotons rotating in opposite directions are caused to collide

in the Tevatron, producing a combined, or center-of-mass, energy

approaching 2 trillion electron volts, nearly three times the energy

achievable at the largest accelerator at Centre Européen de Recherche

Nucléaire (the European Center for Nuclear Research, or CERN).

John Peoples was faced with the problem of generating a beam of

antiprotons of sufficient intensity to collide efficiently with a beam

of protons. Knowing that he had the use of a large proton accelerator—

the old main ring—Peoples employed the two-ring mode in

which 120 billion electron volt protons from the main ring are aimed

at a fixed tungsten target, generating antiprotons, which scatter

from the target. These particles were extracted and accumulated in a

smaller storage ring. These particles could be accelerated to relatively

low energies. After sufficient numbers of antiprotons were

collected, they were injected into the Tevatron, along with a beam of

protons for the colliding beam experiments. On October 13, 1985,

Fermilab scientists reported a proton-antiproton collision with a

center-of-mass energy measured at 1.6 trillion electron volts, the

highest energy ever recorded.





Consequences



The Tevatron’s success at generating high-energy proton antiproton

collisions affected future plans for accelerator development

in the United States and offered the potential for important

discoveries in high-energy physics at energy levels that no other accelerator

could achieve.

Physics recognized four forces in nature: the electromagnetic

force, the gravitational force, the strong nuclear force, and the weak

nuclear force. A major goal of the physics community is to formulate

a theory that will explain all these forces: the so-called grand

unification theory. In 1967, one of the first of the so-called gauge theories

was developed that unified the weak nuclear force and the

electromagnetic force. One consequence of this theory was that the

weak force was carried by massive particles known as “bosons.”

The search for three of these particles—the intermediate vector bosons

W+, W-, and Z0—led to the rush to conduct colliding beam experiments

to the early 1970’s. Because the Tevatron was in the planning

phase at this time, these particles were discovered by a team of

international scientists based in Europe. In 1989, Tevatron physicists

reported the most accurate measure to date of the Z0 mass.

The Tevatron is thought to be the only particle accelerator in the

world with sufficient power to conduct further searches for the elusive

Higgs boson, a particle attributed to weak interactions by University

of Edinburgh physicist Peter Higgs in order to account for

the large masses of the intermediate vector bosons. In addition, the

Tevatron has the ability to search for the so-called top quark. Quarks

are believed to be the constituent particles of protons and neutrons.

Evidence has been gathered of five of the six quarks believed to exist.

Physicists have yet to detect evidence of the most massive quark,

the top quark.



See also:



Atomic bomb; Cyclotron; Electron microscope; Field ion

microscope; Geiger counter; Hydrogen bomb; Mass spectrograph;

Neutrino detector; Scanning tunneling microscope; Synchrocyclotron.

Television

The invention:



System that converts moving pictures and sounds

into electronic signals that can be broadcast at great distances.



The people behind the invention:



Vladimir Zworykin (1889-1982), a Soviet electronic engineer and

recipient of the National Medal of Science in 1967

Paul Gottlieb Nipkow (1860-1940), a German engineer and

inventor

Alan A. Campbell Swinton (1863-1930), a Scottish engineer and

Fellow of the Royal Society

Charles F. Jenkins (1867-1934), an American physicist, engineer,

and inventor










The Persistence of Vision



In 1894, an American inventor, Charles F. Jenkins, described a

scheme for electrically transmitting moving pictures. Jenkins’s idea,

however, was only one in an already long tradition of theoretical

television systems. In 1842, for example, the English physicist Alexander

Bain had invented an automatic copying telegraph for sending

still pictures. Bain’s system scanned images line by line. Similarly,

the wide recognition of the persistence of vision—the mind’s

ability to retain a visual image for a short period of time after the image

has been removed—led to experiments with systems in which

the image to be projected was repeatedly scanned line by line. Rapid

scanning of images became the underlying principle of all television

systems, both electromechanical and all-electronic.

In 1884, a German inventor, Paul Gottlieb Nipkow, patented a

complete television system that utilized a mechanical sequential

scanning system and a photoelectric cell sensitized with selenium

for transmission. The selenium photoelectric cell converted the light

values of the image being scanned into electrical impulses to be

transmitted to a receiver where the process would be reversed. The

electrical impulses led to light of varying brightnesses being produced

and projected on to a rotating disk that was scanned to reproduce

the original image. If the system—that is, the transmitter and

the receiver—were in perfect synchronization and if the disk rotated

quickly enough, persistence of vision enabled the viewer to

see a complete image rather than a series of moving points of light.

For a television image to be projected onto a screen of reasonable

size and retain good quality and high resolution, any system employing

only thirty to one hundred lines (as early mechanical systems

did) is inadequate.A few systems were developed that utilized

two hundred or more lines, but the difficulties these presented

made the possibility of an all-electronic system increasingly attractive.

These difficulties were not generally recognized until the early

1930’s, when television began to move out of the laboratory and into

commercial production.

Interest in all-electronic television paralleled interest in mechanical

systems, but solutions to technical problems proved harder to

achieve. In 1908, a Scottish engineer, Alan A. Campbell Swinton,

proposed what was essentially an all-electronic television system.

Swinton theorized that the use of magnetically deflected cathode-ray

tubes for both the transmitter and receiver in a system was possible.

In 1911, Swinton formally presented his idea to the Röntgen

Society in London, but the technology available did not allow for

practical experiments.





Zworykin’s Picture Tube

In 1923, Vladimir Zworykin, a Soviet electronic engineer working

for the Westinghouse Electric Corporation, filed a patent application

for the “iconoscope,” or television transmission tube. On

March 17, 1924, Zworykin applied for a patent for a two-way system.

The first cathode-ray tube receiver had a cathode, a modulating

grid, an anode, and a fluorescent screen.

Zworykin later admitted that the results were very poor and the

system, as shown, was still far removed from a practical television

system. Zworykin’s employers were so unimpressed that they admonished

him to forget television and work on something more

useful. Zworykin’s interest in television was thereafter confined to

his non working hours, as he spent the next year working on photographic

sound recording.

It was not until the late 1920’s that he was able to devote his full

attention to television. Ironically, Westinghouse had by then resumed

research in television, but Zworykin was not part of the

team. After he returned from a trip to France, where in 1928 he had

witnessed an exciting demonstration of an electrostatic tube, Westinghouse

indicated that it was not interested. This lack of corporate

support in Pittsburgh led Zworykin to approach the Radio Corporation

of America (RCA). According to reports, Zworykin demonstrated

his system to the Institute of Radio Engineers at Rochester,

New York, on November 18, 1929, claiming to have developed a

working picture tube, a tube that would revolutionize television development.

Finally, RCA recognized the potential.



Impact





The picture tube, or “kinescope,” developed by Zworykin changed

the history of television. Within a few years, mechanical systems

disappeared and television technology began to utilize systems

similar to Zworykin’s by use of cathode-ray tubes at both ends of

the system. At the transmitter, the image is focused upon a mosaic

screen composed of light-sensitive cells.A stream of electrons sweeps

the image, and each cell sends off an electric current pulse as it is hit

by the electrons, the light and shade of the focused image regulating

the amount of current.

This string of electrical impulses, after amplification and modification

into ultrahigh frequency wavelengths, is broadcast by antenna

to be picked up by any attuned receiver, where it is retransformed

into a moving picture in the cathode-ray tube receiver. The

cathode-ray tubes contain no moving parts, as the electron stream is

guided entirely by electric attraction.

Although both the iconoscope and the kinescope were far from

perfect when Zworykin initially demonstrated them, they set the

stage for all future television development.





Vladimir Zworykin



Born in 1889, Vladimir Kosma Zworykin grew up in Murom,

a small town two hundred miles east of Moscow. His father ran

a riverboat service, and Zworykin sometimes helped him, but

his mind was on electricity, which he studied on his own while

aboard his father’s boats. In 1906, he entered the St. Petersburg

Institute of Technology, and there he became acquainted with

the idea of television through the work of Professor Boris von

Rosing.

Zworykin assisted Rosing in his attempts to transmit pictures

with a cathode-ray tube. He served with the Russian Signal

Corps during World War I, but then fled to the United States

after the Bolshevist Revolution. In 1920 he got a job at Westinghouse’s

research laboratory in Pittsburgh, helping develop radio

tubes and photoelectric cells. He became an American citizen

in 1924 and completed a doctorate at the University of

Pittsburgh in 1926. By then he had already demonstrated his

iconoscope and applied for a patent. Unable to interest Westinghouse

in his invention, he moved to the Radio Corporation

of America (RCA) in 1929, and later became director of its electronics

research laboratory. RCA’s president, David Sarnoff,

also a Russian immigrant, had faith in Zworykin and his ideas.

Before Zworykin retired in 1954, RCA had invested $50 million

in television.

Among the many awards Zworykin received for his culture changing

invention was the National Medal of Science, presented

by President Lyndon Johnson in 1966. Zworykin died on

his birthday in 1982





See also : Color television; Community antenna television; Communications

satellite; Fiber-optics; FM radio; Holography; Internet;

Radio; Talking motion pictures.