Inventions

Inventions have always been a driving force behind human progress.

noreply@blogger.com (Unknown) — Tue, 17 Jan 2023 01:42:00 -0800

Inventions have always been a driving force behind human progress.

From the invention of the wheel to the latest technological advancements, inventions have shaped our world in countless ways.

One of the most impactful inventions of all time is the printing press, invented by Johannes Gutenberg in the 15th century. This invention revolutionized the way information was disseminated, making it possible for books to be mass-produced and distributed to the masses. This led to an explosion of knowledge and education, and is considered one of the key factors in the development of the modern world.

Another important invention is the steam engine, invented by James Watt in the 18th century. This invention powered the Industrial Revolution and led to the development of new forms of transportation, such as trains and steamboats, as well as the creation of new manufacturing processes.

The invention of the telephone by Alexander Graham Bell in 1876 was another game-changer. It revolutionized communication and made it possible for people to talk to each other over long distances. In recent years, the invention of the internet has had an enormous impact on the way we live and work. It has made it possible for people to communicate and access information from anywhere in the world, and has greatly facilitated the growth of e-commerce and online business.

All of these inventions have had a profound impact on society and have changed the way we live. From the printing press to the internet, they have all played a crucial role in shaping the world we live in today.

Videocassette recorder

noreply@blogger.com (Unknown) — Wed, 15 Jun 2016 00:58:00 -0700

The invention:

A device for recording and playing back movies
and television programs, the videocassette recorder (VCR) revolutionized
the home entertainment industry in the late 1970’s.

The company behind the invention:

Philips Corporation, a Dutch Company

Videotape Recording

Although television sets first came on the market before World
War II, video recording on magnetic tape was not developed until
the 1950’s. Ampex marketed the first practical videotape recorder
in 1956. Unlike television, which manufacturers aimed at retail
consumers from its inception, videotape recording was never expected
to be attractive to the individual consumer. The first videotape
recorders were meant for use within the television industry.
Developed not long after the invention of magnetic tape recording
of audio signals, the early videotape recorders were large machines
that employed an open reel-to-reel tape drive similar to that
of a conventional audiotape recorder. Recording and playback heads
scanned the tape longitudinally (lengthwise). Because video signals
have a much wider frequency (“frequency” is the distance between
the tops and the bottoms of the signal waves) than audio signals do,
this scanning technique meant that the amount of recording time
available on one reel of tape was extremely limited. In addition,
open reels were large and awkward, and the magnetic tape itself
was quite expensive.
Still, within the limited application area of commercial television,
videotape recording had its uses. It made it possible to play
back recorded material immediately rather than having to wait for
film to be processed in a laboratory. As television became more popular
and production schedules became more hectic, with more material
being produced in shorter and shorter periods of time, videotape
solved some significant problems.

Helical Scanning Breakthrough

Engineers in the television industry continued to search for innovations
and improvements in videotape recording following
Ampex’s marketing of the first practical videotape recorder in the
1950’s. It took more than ten years, however, for the next major
breakthrough to occur. The innovation that proved to be the key to
reducing the size and awkwardness of video recording equipment
came in 1967 with the invention by the Philips Corporation of helical
scanning.
All videocassette recorders eventually employed multiple-head
helical scanning systems. In a helical scanning system, the record
and playback heads are attached to a spinning drum or head that rotates
at exactly 1,800 revolutions per minute, or 30 revolutions per
second. This is the number of video frames per second used in the
NTSC-TV broadcasts in the United States and Canada. The heads
are mounted in pairs 180 degrees apart on the drum. Two fields on
the tape are scanned for each revolution of the drum. Perhaps the
easiest way to understand the helical scanning system is to visualize
the spiral path followed by the stripes on a barber’s pole.
Helical scanning deviated sharply from designs based on audio
recording systems. In an audiotape recorder, the tape passes over
stationary playback and record heads; in a videocassette recorder,
both the heads and the tape move. Helical scanning is, however, one
of the few things that competing models and formats of videocassette
recorders have in common. Different models employ different
tape delivery systems and, in the case of competing formats such as
Beta and VHS, there may be differences in the composition of the
video signal to be recorded. Beta uses a 688-kilohertz (kHz) frequency,
while VHS employs a frequency of 629 kHz. This difference
in frequency is what allows Beta videocassette recorders (VCRs) to
provide more lines of resolution and thus a superior picture quality;
VHS provides 240 lines of resolution, while Beta has 400. (For this
reason, it is perhaps unfortunate that the VHS format eventually
dominated the market.)
In addition to helical scanning, Philips introduced another innovation:
the videocassette. Existing videotape recorders employed a
reel-to-reel tape drive, as do videocassettes, but videocassettes en-
close the tape reels in a protective case. The case prevents the tape
from being damaged in handling.
The first VCRs were large and awkward compared to later models.
Industry analysts still thought that the commercial television
and film industries would be the primary markets for VCRs. The
first videocassettes employed wide—3
4-inch or 1-inch—videotapes,
and the machines themselves were cumbersome. Although Philips
introduced a VCR in 1970, it took until 1972 before the machines actually
became available for purchase, and it would be another ten
years before VCRs became common appliances in homes.

Consequences

Following the introduction of the VCR in 1970, the home entertainment
industry changed radically. Although the industry did not
originally anticipate that the VCR would have great commercial potential
as a home entertainment device, it quickly became obvious
that it did. By the late 1970’s, the size of the cassette had been reduced
and the length of recording time available per cassette had
been increased from one hour to six. VCRs became so widespread
that advertisers on television became concerned with a phenomenon
known as “timeshifting,” which refers to viewers setting the
VCR to record programs for later viewing. Jokes about the complexity
of programming VCRs appeared in the popular culture, and an
inability to cope with the VCR came to be seen as evidence of technological
illiteracy.
Consumer demand for VCRs was so great that, by the late 1980’s,
compact portable video cameras became widely available. The same
technology—helical scanning with multiple heads—was successfully
miniaturized, and “camcorders” were developed that were not much
larger than a paperback book. By the early 1990’s, “reality television”—
that is, television shows based on actual events—began relying
on video recordings supplied by viewers rather than material
produced by professionals. The video recorder had completed a circle:
It began as a tool intended for use in the television studio, and it
returned there four decades later. Along the way, it had an effect no
one could have predicted; passive viewers in the audience had evolved
into active participants in the production process.

See also :
Cassette recording; Color television; Compact disc;
Dolby noise reduction; Television.

Vending machine slug rejector

noreply@blogger.com (Unknown) — Mon, 18 Jan 2016 01:05:00 -0800

The invention:

A device that separates real coins from counterfeits,
the slug rejector made it possible for coin-operated vending
machines to become an important marketing tool for many
products .

The people behind the invention:

Thomas Adams, the founder of Adams Gum Company
Frederick C. Lynde, an Englishman awarded the first American
patent on a vending machine
Nathaniel Leverone (1884-1969), a founder of the Automatic
Canteen Company of America
Louis E. Leverone (1880-1957), a founder, with his brother, of the
Automatic Canteen Company of America

The Growth of Vending Machines

One of the most imposing phenomena to occur in the United
States economy followingWorldWar II was the growth of vending
machines. Following the 1930’s invention and perfection of the slug
rejector, vending machines became commonplace as a means of
marketing gum and candy. By the 1960’s, almost every building had
soft drink and coffee machines. Street corners featured machines
that dispensed newspapers, and post offices even used vending machines
to sell stamps. Occasionally someone fishing in the backwoods
could find a vending machine next to a favorite fishing hole
that would dispense a can of fishing worms upon deposit of the correct
amount of money. The primary advantage offered by vending
machines is their convenience. Unlike people, machines can provide
goods and services around the clock, with no charge for the “labor”
of standing duty.
The decade of the 1950’s brought not only an increase in the number
of vending machines but also an increase in the types of goods
that were marketed through them. Before World War II, the major
products had been cigarettes, candy, gum, and soft drinks. The
1950’s brought far more products into the vending machine market.
The first recognized vending machine in history was invented in
the third century b.c.e. by the mathematician Hero. This first machine
was a coin-activated device that dispensed sacrificial water in
an Egyptian temple. It was not until the year 1615 that another
vending machine was recorded. In that year, snuff and tobacco
vending boxes began appearing in English pubs and taverns. These
tobacco boxes were less sophisticated machines than was Hero’s,
since they left much to the honesty of the customer. Insertion of a
coin opened the box; once it was open, the customer could take out
as much tobacco as desired. One of the first United States patents on
a machine was issued in 1886 to Frederick C. Lynde. That machine
was used to vend postcards.
If any one person can be considered the father of vending machines
in the United States, it would probably be Thomas Adams,
the founder of Adams Gum Company. Adams began the first successful
vending operation in America in 1888 when he placed gum
machines on train platforms in New York City.
Other early vending machines included scales (which vended a
service rather than a product), photograph machines, strength testers,
beer machines, and hot water vendors (to supply poor people
who had no other source of hot water). These were followed, around
1900, by complete automatic restaurants in Germany, cigar vending
machines in Chicago, perfume machines in Paris, and an automatic
divorce machine in Utah.
Also around 1900 came the introduction of coin-operated gambling
machines. These “slot machines” are differentiated from normal
vending machines. The vending machine industry does not
consider gambling machines to be a part of the vending industry
since they do not vend merchandise. The primary importance of the
gambling machines was that they induced the industry to do research
into slug rejection. Early machines allowed coins to be retrieved
by the use of strings tied to them and accepted counterfeit
lead coins, called slugs. It was not until the 1930’s that the slug
rejector was perfected. Invention of the slug rejection device gave
rise to the tremendous growth in the vending machine industry in
the 1930’s by giving vendors more confidence that they would be
paid for their products or services.
Soft drink machines got their start just prior to the beginning of
the twentieth century. By 1906, improved models of these machines
could dispense up to ten different flavors of soda pop. The
drinks were dispensed into a drinking glass or tin cup that was
placed near the machine (there was usually only one glass or cup
to a machine, since paper cups had not been invented). Public
health officials became concerned that everyone was drinking
from the same cup. At that point, someone came up with the idea
of setting a bucket of water next to the machine so that each customer
could rinse off the cup before drinking from it. The year 1909
witnessed one of the monumental inventions in the history of
vending machines, the pay toilet.

Impact

The 1930’s witnessed improved vending machines. Slug rejectors
were the most important introduction. In addition, change-making
machines were instituted, and a few machines would even say
“thank you” after a coin was deposited. These improved machines
led many marketers to experiment with automatic vending. Coinoperated
washing machines were one of the new applications of the
1930’s. During the Depression, many appliance dealers attached
coin metering devices to washing machines, allowing the user to accumulate
money to make the monthly payments by using the appliance.
This was a form of forced saving. It was not long before some
enterprising appliance dealer got the idea of placing washing machines
in apartment house basements. This idea was soon followed
by stores full of coin-operated laundry machines, giving rise to a
new kind of automatic vending business.
Following World War II, there was a surge of innovation in the
vending machine industry. Much of that surge resulted from the
discovery of vending machines by industrial management. Prior to
the war, the managements of most factories had been tolerant of
vending machines. Following the war, managers discovered that
the machines could be an inexpensive means of keeping workers
happy. They became aware that worker productivity could be increased
by access to candy bars or soft drinks. As a result, the demand
for machines exceeded the supply offered by the industry
during the late 1940’s.
Vending machines have had a surprising effect on the total retail
sales of the U.S. economy. In 1946, sales through vending machines
totaled $600 million. By 1960, that figure had increased to $2.5 billion;
by 1970, it exceeded $6 billion. The decade of the 1950’s began
with individual machines that would dispense cigarettes, candy,
gum, coffee, and soft drinks. By the end of that decade, it was much
more common to see vending machines in groups. The combination
of machines in a group could, in many cases, meet the requirements
to assemble a complete meal.
Convenience is the key to the popularity of vending machines.
Their ability to sell around the clock has probably been the major
impetus to vending machine sales as opposed to more conventional
marketing. Lower labor costs have also played a role in their popularity,
and their location in areas of dense pedestrian traffic prompts
impulse purchases.
Despite the advances made by the vending machine industry
during the 1950’s, there was still one major limitation to growth, to
be solved during the early 1960’s. That problem was that vending
machines were effectively limited to low-priced items, since the machines
would accept nothing but coins. The inconvenience of inserting
many coins kept machine operators from trying to market expensive
items; as they expected consumer reluctance. The early
1960’s witnessed the invention of vending machines that would accept
and make change for $1, $5, and $10 bills. This invention paved
the way for expansion into lines of grocery items and tickets.
The first use of vending machines to issue tickets was at an Illinois
race track, where pari-mutuel tickets were dispensed upon deposit of
$2. Penn Central Railroad was one of the first transportation companies
to sell tickets by means of vending machines. These machines,
used in high-traffic areas on the East Coast, permitted passengers to
deal directly with a computer when buying reserved-seat train tickets.
The machines would accept $1 bills and $5 bills as well as coins.

Limitations to Vending Machines

There are limitations to the use of vending machines. Primary
among these are mechanical failure and vandalism of machines.
Another limitation often mentioned is that not every product can be
sold by machine. There are several factors that make some goods
more vendable than others. National advertising and wide consumer
acceptance help. Product must have a high turnover in order
to justify the cost of a machine and the cost of servicing it. A third
factor in measuring the potential success of an item is where it will
be consumed or used. The most successful products are used within
a short distance of the machine; consumers must be made willing to
pay the usually higher prices of machine-bought products by the
convenience of machine location.
The automatic vending of merchandise plays the largest role in
the vending machine industry, but the vending of services also
plays a role. The largest percentage of service vending comes from
coin laundries. Other types of services are vended by weighing machines,
parcel lockers, and pay toilets. By depositing a coin, a person
can even get shoes shined. Some motel beds offer a “massage.” Even
the lowly parking meter is an example of a vending machine that
dispenses services. Coin-operated photocopy machines account for
a large portion of service vending.
A later advance in the vending machine industry is the use of
credit. The cashless society began to make strides with vending machines
as well as conventional vendors. As of the early 1990’s, credit
cards could be used to operate only a few types of vending machines,
primarily those that dispense transportation tickets. Vending machines
operated by banks dispense money upon deposit of a credit
card. Credit-card gasoline pumps reduced labor requirements at gasoline
stations, pushing the concept of self-service a step further. As
credit card transactions become more common in general and as the
cost of making them falls, use of credit cards for vending machines
will increase.
Thousands of items have been marketed through vending machines,
and firms must continue to evaluate the use of automatic retailing
as a marketing channel. Many products are not conducive to
automatic vending, but before dismissing that option for a particular
product, a marketer should consider the range of products sold
through vending machines. The producers of Band-Aid flexible plastic
bandages saw the possibilities in the vending field. The only product
modification necessary was to put Band-Aids in a package the
size of a candy bar, able to be sold from renovated candy machines.
The next problem was to determine areas where there would be a
high turnover of Band-Aids. Bowling alleys were an obvious answer,
since many bowlers suffered from abrasions on their fingers.
The United States is not alone in the development of vending machines;
in fact, it is not as advanced as some nations of the world. In
Japan, machines operated by credit cards have been used widely
since the mid-1960’s, and the range of products offered has been
larger than in the United States. Western Europe is probably the
most advanced area of the world in terms of vending machine technology.
Germany of the early 1990’s probably had the largest selection
of vending machines of any European country. Many gasoline
stations in Germany featured beer dispensing machines. In rural areas
of the country, vending machines hung from utility poles. These
rural machines provided candy and gum, among other products, to
farmers who did not often travel into town.
Most vending machine business in Europe was done not in individual
machines but in automated vending shops. The machines offered
a creative solution to obstacles created by regulations and
laws. Some countries had laws stating that conventional retail stores
could not be open at night or on Sundays. To increase sales and satisfy
consumer needs, stores built vending operations that could be
used by customers during off hours. The machines, or combinations
of them, often stocked a tremendous variety of items. At one German
location, consumers could choose among nearly a thousand
grocery items.

The Future

The future will see a broadening of product lines offered in vending
machines as marketers come to recognize the opportunities that
exist in automatic retailing. In the United States, vending machines
of the early 1990’s primarily dispensed products for immediate consumption.
If labor costs increase, it will become economically feasible
to sell more items from vending machines. Grocery items and
tickets offered the most potential for expansion.
Vending machines offer convenience to the consumer. Virtually
any company that produces for the retail market must consider
vending machines as a marketing channel. Machines offer an alter-
native to conventional stores that cannot be ignored as the range of
products offered through machines increases.
Vending machines appear to be a permanent fixture and have
only scratched the surface of the market. Although machines have a
long history, their popularization came from innovations of the
1930’s, particularly the slug rejector. Marketing managers came to
recognize that vending machine sales are more than a sideline. Increasingly,
firms established separate departments to handle sales
through vending machines. Successful companies make the best
use of all channels of distribution, and vending machines had become
an important marketing channel.

See also : Geiger counter; Sonar.

Velcro

noreply@blogger.com (Unknown) — Mon, 19 Oct 2015 01:04:00 -0700

The invention:

A material comprising millions of tiny hooks and
loops that work together to create powerful and easy-to-use fasteners
for a wide range of applications.

The person behind the invention:

Georges de Mestral (1904-1990), a Swiss engineer and inventor

From Cockleburs to Fasteners

Since prehistoric times, people have walked through weedy fields
and arrived at home with cockleburs all over their clothing. In 1948, a
Swiss engineer and inventor, Georges de Mestral, found his clothing
full of cockleburs after walking in the Swiss Alps near Geneva.Wondering
why cockleburs stuck to clothing, he began to examine them
under a microscope. De Mestral’s initial examination showed that
each of the thousands of fibrous ends of the cockleburs was tipped
with a tiny hook; it was the hooks that made the cockleburs stick to
fabric. This observation, combined with much subsequent work, led
de Mestral to invent velcro, which was patented in 1957 in the form of
two strips of nylon material. One of the strips contained millions of
tiny hooks, while the other contained a similar number of tiny loops.
When the two strips were pushed together, the hooks were inserted
into the loops, joining the two strips of nylon very firmly. This design
makes velcro extremely useful as a material for fasteners that is used
in applications ranging from sneaker fasteners to fasteners used to
join heart valves during surgery.

Making Velcro Practical

Velcro is not the only invention credited to de Mestral, who also
invented such items as a toy airplane and an asparagus peeler, but it
was his greatest achievement. It is said that his idea for the material
was partly the result of a problem his wife had with a jammed dress
zipper just before an important social engagement. De Mestral’s
idea was to design a sort of locking tape that used the hook-andloop
principle that he had observed under the microscope. Such a
tape, he believed, would never jam. He also believed that the tape
would do away with such annoyances as buttons that popped open
unexpectedly and knots in shoelaces that refused to be untied.
The design of the material envisioned by de Mestral took seven
years of painstaking effort. When it was finished, de Mestral named
it “velcro” (a contraction of the French phrase velvet crochet, meaning
velvet hook), patented it, and opened a factory to manufacture
it. Velcro’s design required that de Mestral identify the optimal
number of hooks and loops to be used. He eventually found that using
approximately three hundred per square inch worked best. In
addition, his studies showed that nylon was an excellent material
for his purposes, although it had to be stiffened somewhat to work
well. Much additional experimentation showed that the most effective
way of producing the necessary stiffening was to subject the
velcro to infrared light after manufacturing it.
Other researchers have demonstrated that velcrolike materials
need not be made of nylon. For example, a new micromechanical
velcrolike material (microvelcro) that medical researchers believe
will soon be used to hold together blood vessels after surgery is
made of minute silicon loops and hooks. This material is thought to
be superior to other materials for such applications because it will
not be redissolved prematurely by the body. Other uses for microvelcro
may be to hold together tiny electronic components in miniaturized
computers without the use of glue or other adhesives.Amajor
advantage of the use of microvelcro in such situations is that it is
resistant to changes of temperature as well as to most chemicals that
destroy glue and other adhesives.

Impact

In 1957, when velcro was patented, there were four main ways to
hold things together. These involved the use of buttons, laces, snaps,
and zippers (which had been invented by Chicagoan Whitcomb L.
Judson in 1892). All these devices had drawbacks; zippers can jam,
buttons can come open at embarrassing times, and shoelaces can
form knots that are difficult to unfasten. Almost immediately after
velcro was introduced, its use became widespread; velcro fasteners
can be found on or in clothing, shoes, watchbands, wallets, back-
packs, bookbags, motor vehicles, space suits, blood-pressure cuffs,
and in many other places. There is even a “wall jumping” game incorporating
velcro in which a wall is covered with a well-supported
piece of velcro. People who want to play put on jackets made of
velcro and jump as high as they can. Wherever they land on the wall,
the velcro will join together, making them stick.
Wall jumping, silly though it may be, demonstrates the tremendous
holding power of velcro; a velcro jacket can keep a twohundred-
pound person suspended froma wall. This great strength is
used in a more serious way in the design of the items used to anchor
astronauts to space shuttles and to buckle on parachutes. In addition,
velcro is washable, comes in many colors, and will not jam. No
doubt many more uses for this innovative product will be found.

Georges de Mestral

Georges de Mestral got his idea for Velcro in part during a
hunting trip on his estates and in part before an important formal
social function. These contexts are evidence of the high
standing in Swiss society held by de Mestral, an engineer and
manufacturer. In fact, de Mestral, who was born in 1904, came
from a illustrious line of noble landowners. Their prize possession
was one of Switzerland’s famous residences, the castle of
Saint Saphorin on Morges.
Built on the site of yet older fortifications, the castle was
completed by François-Louis de Pesme in 1710. An enemy of
King Louis XIV, de Pesme served in the military forces of Austria,
Holland, and England, rising to the rank of lieutenant general,
but he is best known for driving off a Turkish invasion fleet
on the Danube in 1695. Other forebears include the diplomat
Armand- François Louis de Mestral (1738-1805) and his father,
Albert-Georges-Constantin de Mestral (1878-1966), an agricultural
engineer.
The castle passed to the father’s four sons and eventually
into the care of the inventor. It in turn was inherited by Georges
de Mestral’s sons Henri and François when he died in 1990 in
Genolier, Switzerland.

See also : Artificial heart

Vat dye

noreply@blogger.com (Unknown) — Sat, 19 Sep 2015 00:16:00 -0700

The invention:

The culmination of centuries of efforts to mimic the
brilliant colors displayed in nature in dyes that can be used in
many products.

The people behind the invention:

Sir William Henry Perkin (1838-1907), an English student in
Hofmann’s laboratory
René Bohn (1862-1922), a synthetic organic chemist
Karl Heumann (1850-1894), a German chemist who taught Bohn
Roland Scholl (1865-1945), a Swiss chemist who established the
correct structure of Bohn’s dye
August Wilhelm von Hofmann (1818-1892), an organic chemist

Synthesizing the Compounds of Life

From prehistoric times until the mid-nineteenth century, all dyes
were derived from natural sources, primarily plants. Among the
most lasting of these dyes were the red and blue dyes derived from
alizarin and indigo.
The process of making dyes took a great leap forward with the
advent of modern organic chemistry in the early years of the nineteenth
century. At the outset, this branch of chemistry, dealing with
the compounds of the element carbon and associated with living
matter, hardly existed, and synthesis of carbon compounds was not
attempted. Considerable data had accumulated showing that organic,
or living, matter was basically different from the compounds
of the nonliving mineral world. It was widely believed that although
one could work with various types of organic matter in
physical ways and even analyze their composition, they could be
produced only in a living organism.
Yet, in 1828, the German chemist Friedrich Wöhler found that it
was possible to synthesize the organic compound urea from mineral
compounds. As more chemists reported the successful preparation
of compounds previously isolated only from plants or animals,
the theory that organic compounds could be produced only in a living
organism faded.

One field ripe for exploration was that committed to exploiting the
uses of coal tar. Here, August Wilhelm von Hofmann was an active
worker. He and his students made careful studies of this complex
mixture. The high-quality stills they designed allowed for the isolation
of pure samples of important compounds for further study.
Of greater importance was the collection of able students Hofmann
attracted. Among them was Sir William Henry Perkin, who is regarded
as the founder of the dyestuffs industry. In 1856, Perkin undertook
the task of synthesizing quinine (a bitter crystalline alkaloid
used in medicine) from a nitrogen-containing coal tar material
called toluidine. Luck played a decisive role in the outcome of his
experiment. The sticky compound Perkin obtained contained no
quinine, so he decided to investigate the simpler related compound
aniline.Asmall amount of the impurity toluidine in his aniline gave
Perkin the first synthetic dye, Mauveine.

Searching for Structure

From this beginning, the great dye industries of Europe, particularly
Germany, grew. The trial-and-error methods gave way to more
systematic searches as the structural theory of organic chemistry
was formulated.
As the twentieth century began, great progress had been made,
and German firms dominated the industry. Badische Anilin- und
Soda-Fabrik (BASF) was incorporated at Ludwigshafen in 1865 and
undertook extensive explorations of both alizarin and indigo. A
chemist, René Bohn, had made important discoveries in 1888, which
helped the company recover lost ground in the alizarin field. In
1901, he undertook the synthesis of a dye he hoped would combine
the desirable attributes of both alizarin and indigo.
As so often happens in science, nothing like the expected occurred.
Bohn realized that the beautiful blue crystals that resulted
from his synthesis represented a far more important product. Not
only was this the first synthetic vat dye, Indanthrene, ever prepared,
but also, by studying the reaction at higher temperature, a useful
yellow dye, Flavanthrone, could be produced.
The term vat dye is used to describe a method of applying the dye,
but it also serves to characterize the structure of the dye, because all
currently useful vat dyes share a common unit. One fundamental
problem in dyeing relates to the extent to which the dye is watersoluble.
Abeautifully colored molecule that is easily soluble in water
might seem attractive given the ease with which it binds with the fiber;
however, this same solubility will lead to the dye’s rapid loss in
daily use.
Vat dyes are designed to solve this problem by producing molecules
that can be made water-soluble, but only during the dyeing or
vatting process. This involves altering the chemical structure of the
dye so that it retains its color throughout the life of the cloth.
By 1907, Roland Scholl had showed unambiguously that the
chemical structure proposed by Bohn for Indanthrene was correct,
and a major new area of theoretical and practical importance was
opened for organic chemists.

Impact

Bohn’s discovery led to the development of many new and useful
dyes. The list of patents issued in his name fills several pages in
Chemical Abstracts indexes.
The true importance of this work is to be found in a consideration
of all synthetic chemistry, which may perhaps be represented by
this particular event. More than two hundred dyes related to Indanthrene
are in commercial use. The colors represented by these substances
are a rainbow making nature’s finest hues available to all.
The dozen or so natural dyes have been synthesized into more than
seven thousand superior products through the creativity of the
chemist.
Despite these desirable outcomes, there is doubt whether there is
any real benefit to society from the development of new dyes. This
doubt is the result of having to deal with limited natural resources.
With so many urgent problems to be solved, scientists are not sure
whether to search for greater luxury. If the field of dye synthesis reveals
a single theme, however, it must be to expect the unexpected.
Time after time, the search for one goal has led to something quite
different—and useful.

William Henry Perkin

Born in England in 1838,William Henry Perkin saw a chemical
experiment for the first time when he was a small boy. He
found his calling there and then, much to the dismay of his father,
who wanted him to be a builder and architect like himself.
Perkin studied chemistry every chance he found as a teenager
and was only seventeen when he won an appointment as
the assistant to the German chemist August Wilhelm von Hofmann.
A year later, while trying to synthesize quinine at Hofmann’s
suggestion, Perkin discovered a deep purple dye—now
known as aniline purple or Mauveine, but popularly called
mauve. In 1857 he opened a small dyeworks by the Grand
Union Canal in West London, hoping to make his fortune by
manufacturing the dye.
He succeeded brilliantly. His ambitions were helped along
royally when Queen Victoria wore a silk gown dyed with Mauveine
to the Royal Exhibition of 1862. In 1869, he perfected a
method for producing another new dye, alizarin, which is red.
A wealthy man, he sold his business in 1874 when he was just
thirty-six years old and devoted himself to research, which included
isolation of the first synthetic perfume, coumarin, from
coal tar.
Perkin died in 1907, a year after receiving a knighthood, one
of his many awards and honors for starting the artificial dye industry.
His son William Henry Perkin, Jr. (1860-1927) also became
a well-known researcher in organic chemistry.

See also: Buna rubber; Color film; Neoprene.

Vacuum tube

noreply@blogger.com (Unknown) — Tue, 28 Jul 2015 01:54:00 -0700

The invention:

A sealed glass tube from which air and gas have
been removed to permit electrons to move more freely, the vacuum
tube was the heart of electronic systems until it was displaced
by transistors.

The people behind the invention:

Sir John Ambrose Fleming (1849-1945), an English physicist
and professor of electrical engineering
Thomas Alva Edison (1847-1931), an American inventor
Lee de Forest (1873-1961), an American scientist and inventor
Arthur Wehnelt (1871-1944), a German inventor

A Solution in Search of a Problem

The vacuum tube is a sealed tube or container from which almost
all the air has been pumped out, thus creating a near vacuum. When
the tube is in operation, currents of electricity are made to travel
through it. The most widely used vacuum tubes are cathode-ray
tubes (television picture tubes).
The most important discovery leading to the invention of the
vacuum tube was the Edison effect by Thomas Alva Edison in
1884. While studying why the inner glass surface of light bulbs
blackened, Edison inserted a metal plate near the filament of one
of his light bulbs. He discovered that electricity would flow from
the positive side of the filament to the plate, but not from the neg
ative side to the plate. Edison offered no explanation for the effect.
Edison had, in fact, invented the first vacuum tube, which was
later termed the diode; at that time there was no use for this device.
Therefore, the discovery was not recognized for its true significance.
Adiode converts electricity that alternates in direction (alternating
current) to electricity that flows in the same direction (direct
current). Since Edison was more concerned with producing
direct current in generators, and not household electric lamps, he
essentially ignored this aspect of his discovery. Like many other in-
ventions or discoveries that were ahead of their time—such as the
laser—for a number of years, the Edison effect was “a solution in
search of a problem.”
The explanation for why this phenomenon occurred would not
come until after the discovery of the electron in 1897 by Sir Joseph
John Thomson, an English physicist. In retrospect, the Edison effect
can be identified as one of the first observations of thermionic emission,
the freeing up of electrons by the application of heat. Electrons
were attracted to the positive charges and would collect on the positively
charged plate, thus providing current; but they were repelled
from the plate when it was made negative, meaning that no current
was produced. Since the diode permitted the electrical current to
flow in only one direction, it was compared to a valve that allowed a
liquid to flow in only one direction. This analogy is popular since
the behavior of water has often been used as an analogy for electricity,
and this is the reason that the term valves became popular for
vacuum tubes.

Same Device, Different Application

Sir John Ambrose Fleming, acting as adviser to the Edison Electric
Light Company, had studied the light bulb and the Edison effect
starting in the early 1880’s, before the days of radio. Many years
later, he came up with an application for the Edison effect as a radio
detector when he was a consultant for the Marconi Wireless Telegraph
Company. Detectors (devices that conduct electricity in one
direction only, just as the diode does, but at higher frequencies)
were required to make the high-frequency radio waves audible by
converting them from alternating current to direct current. Fleming
was able to detect radio waves quite effectively by using the Edison
effect. Fleming used essentially the same device that Edison had created,
but for a different purpose. Fleming applied for a patent on his
detector on November 16, 1904.
In 1906, Lee de Forest refined Fleming’s invention by adding a
zigzag piece of wire between the metal plate and the filament of the
vacuum tube. The zigzag piece of wire was later replaced by a
screen called a “grid.” The grid allowed a small voltage to control a
larger voltage between the filament and plate. It was the first com-
plete vacuum tube and the first device ever constructed capable of
amplifying a signal—that is, taking a small-voltage signal and making
it much larger. He named it the “audion” and was granted a U.S.
patent in 1907.
In 1907-1908, the American Navy carried radios equipped with
de Forest’s audion in its goodwill tour around the world. While useful
as an amplifier of the weak radio signals, it was not useful at this
point for the more powerful signals of the telephone. Other developments
were made quickly as the importance of the emerging
fields of radio and telephony were realized.

Impact

With many industrial laboratories working on vacuum tubes,
improvements came quickly. For example, tantalum and tungsten
filaments quickly replaced the early carbon filaments. In 1904, Arthur
Wehnelt, a German inventor, discovered that if metals were
coated with certain materials such as metal oxides, they emitted far
more electrons at a given temperature. These materials enabled
electrons to escape the surface of the metal oxides more easily. Thermionic
emission and, therefore, tube efficiencies were greatly improved
by this method.
Another important improvement in the vacuum tube came with
the work of the American chemist Irving Langmuir of the General
Electric Research Laboratory, starting in 1909, and Harold D. Arnold
of Bell Telephone Laboratories. They used new devices such as
the mercury diffusion pump to achieve higher vacuums. Working
independently, Langmuir and Arnold discovered that very high
vacuum used with higher voltages increased the power these tubes
could handle from small fractions of a watt to hundreds of watts.
The de Forest tube was now useful for the higher-power audio signals
of the telephone. This resulted in the introduction of the first
transamerican speech transmission in 1914, followed by the first
transatlantic communication in 1915.
The invention of the transistor in 1948 by the American physicists
William Shockley, Walter H. Brattain, and John Bardeen ultimately
led to the downfall of the tube.With the exception of the cathode-ray
tube, transistors could accomplish the jobs of nearly all vacuum tubes
much more efficiently. Also, the development of the integrated circuit
allowed the creation of small, efficient, highly complex devices that
would be impossible with radio tubes. By 1977, the major producers
of the vacuum tube had stopped making it.

John Ambrose Fleming

John Ambrose Fleming had a remarkably long and fruitful
scientific career. He was born in Lancaster, England, in 1849, the
eldest son of a minister. When he was a boy, the family moved
to London, which remained his home for the rest of his life. An
outstanding student, Fleming matriculated at University College,
London, graduating in 1870 with honors. Scholarships
took him to other colleges until his skill with electrical experiments
earned him a job as a lab instructor at Cambridge University
in 1880. In 1885, he returned to University College, London,
as professor of electrical technology. He taught there for the following
forty-one years, occasionally taking time off to serve as a
consultant for such electronics industry leaders as Thomas Edison
and Guglielmo Marconi.
Fleming’s passion was electricity and electronics, and he
was sought after as a teacher with a knack for memorable explanations.
For instance, he thought up the “right-hand” rule (also
called Fleming’s rule) to illustrate the relation of electromagnetic
forces during induction: When the thumb, index finger,
and middle finger of a human hand are held at right angles to
one another so that the thumb points in the direction of motion
through a magnetic field—which is indicated by the index finger—
then the middle finger shows the direction of induced
current. During his extensive research, Fleming investigated
transformers, high-voltage transmitters, electrical conduction,
cryogenic electrical effects, radio, and television, and also invented
the vacuum tube.
Advanced age hardly slowed him down. He wrote three
books and more than one hundred articles and remarried at
eighty-four. He also delivered public lectures—to audiences at
the Royal Institution and the Royal Society among other venues—
until he was ninety. He died in 1945, ninety-five years old,
having helped give birth to telecommunications.

See also: Color television; FM radio; Radar; Radio; Radio crystal
sets; Television; Transistor; Transistor radio.

Vacuum cleaner

noreply@blogger.com (Unknown) — Wed, 22 Jul 2015 00:13:00 -0700

The invention:

The first portable domestic vacuum cleaner successfully
adapted to electricity, the original machine helped begin
the electrification of domestic appliances in the early twentieth
century.

The people behind the invention:

H. Cecil Booth (1871-1955), a British civil engineer
Melville R. Bissell (1843-1889), the inventor and marketer of the
Bissell carpet sweeper in 1876
William Henry Hoover (1849-1932), an American industrialist
James Murray Spangler (1848-1915), an American inventor

From Brooms to Bissells

During most of the nineteenth century, the floors of homes
were cleaned primarily with brooms. Carpets were periodically
dragged out of the home by the boys and men of the family,
stretched over rope lines or fences, and given a thorough beating
to remove dust and dirt. In the second half of the century, carpet
sweepers, perhaps inspired by the success of street-sweepingmachines,
began to appear. Although there were many models, nearly
all were based upon the idea of a revolving brush within an outer
casing that moved on rollers or wheels when pushed by a long
handle.
Melville Bissell’s sweeper, patented in 1876, featured a knob for
adjusting the brushes to the surface. The Bissell Carpet Company,
also formed in 1876, became the most successful maker of carpet
sweepers and dominated the market well into the twentieth century.
Electric vacuum cleaners were not feasible until homes were
wired for electricity and the small electric motor was invented.
Thomas Edison’s success with an incandescent lighting system in
the 1880’s and Nikola Tesla’s invention of a small electric motor
that was used in 1889 to drive aWestinghouse Electric Corporation
fan opened the way for the application of electricity to household
technologies.

Cleaning with Electricity

In 1901, H. Cecil Booth, a British civil engineer, observed a London
demonstration of an American carpet cleaner that blew compressed
air at the fabric. Booth was convinced that the process
should be reversed so that dirt would be sucked out of the carpet. In
developing this idea, Booth invented the first successful suction
vacuum sweeper.
Booth’s machines, which were powered by gasoline or electricity,
worked without brushes. Dust was extracted by means of a
suction action through flexible tubes with slot-shaped nozzles.
Some machines were permanently installed in buildings that had
wall sockets for the tubes in every room. Booth’s British Vacuum
Cleaner Company also employed horse-drawn mobile units from
which white-uniformed men unrolled long tubes that they passed
into buildings through windows and doors. His company’s commercial
triumph came when it cleanedWestminster Abbey for the
coronation of Edward VII in 1902. Booth’s company also manufactured
a 1904 domestic model that had a direct-current electric motor
and a vacuum pump mounted on a wheeled carriage. Dust was
sucked into the nozzle of a long tube and deposited into a metal
container. Booth’s vacuum cleaner used electricity from overhead
light sockets.
The portable electric vacuum cleaner was invented in 1907 in the
United States by James Murray Spangler. When Spangler was a janitor
in a department store in Canton, Ohio, his asthmatic condition
was worsened by the dust he raised with a large Bissell carpet
sweeper. Spangler’s modifications of the Bissell sweeper led to his
own invention. On June 2, 1908, he received a patent for his Electric
Suction Sweeper. The device consisted of a cylindrical brush in the
front of the machine, a vertical-shaft electric motor above a fan in
the main body, and a pillowcase attached to a broom handle behind
the main body. The brush dislodged the dirt, which was sucked into
the pillowcase by the movement of air caused by a fan powered by
the electric motor. Although Spangler’s initial attempt to manufacture
and sell his machines failed, Spangler had, luckily for him, sold
one of his machines to a cousin, Susan Troxel Hoover, the wife of
William Henry Hoover.

The Hoover family was involved in the production of leather
goods, with an emphasis on horse saddles and harnesses. William
Henry Hoover, president of the Hoover Company, recognizing that
the adoption of the automobile was having a serious impact on the
family business, was open to investigating another area of production.
In addition, Mrs. Hoover liked the Spangler machine that she
had been using for a couple of months, and she encouraged her husband
to enter into an agreement with Spangler. An agreement made
on August 5, 1908, allowed Spangler, as production manager, to
manufacture his machine with a small work force in a section of
Hoover’s plant. As sales of vacuum cleaners increased, what began
as a sideline for the Hoover Company became the company’s main
line of production.
Few American homes were wired for electricity when Spangler
and Hoover joined forces; not until 1920 did 35 percent of American
homes have electric power. In addition to this inauspicious fact, the
first Spangler-Hoover machine, the Model O, carried the relatively
high price of seventy-five dollars. Yet a full-page ad for the ModelO
in the December, 1908, issue of the Saturday Evening Post brought a
deluge of requests. American women had heard of the excellent performance
of commercial vacuum cleaners, and they hoped that the
Hoover domestic model would do as well in the home.

Impact

As more and more homes in the United States and abroad became
wired for electric lighting, a clean and accessible power
source became available for household technologies. Whereas electric
lighting was needed only in the evening, the electrification of
household technologies made it necessary to use electricity during
the day. The electrification of domestic technologies therefore
matched the needs of the utility companies, which sought to maximize
the use of their facilities. They became key promoters of electric
appliances. In the first decades of the twentieth century, many
household technologies became electrified. In addition to fans and
vacuum cleaners, clothes-washing machines, irons, toasters, dishwashing
machines, refrigerators, and kitchen ranges were being
powered by electricity.
The application of electricity to household technologies came as
large numbers of women entered the work force. During and after
WorldWar I, women found new employment opportunities in industrial
manufacturing, department stores, and offices. The employment
of women outside the home continued to increase throughout the
twentieth century. Electrical appliances provided the means by which
families could maintain the same standards of living in the home while
both parents worked outside the home.
It is significant that Bissell was motivated by an allergy to dust
and Spangler by an asthmatic condition. The employment of the
carpet sweeper, and especially the electric vacuum cleaner, not only
made house cleaning more efficient and less physical but also led to
a healthier home environment. Whereas sweeping with a broom
tended only to move dust to a different location, the carpet sweeper
and the electric vacuum cleaner removed the dirt from the house.

H. Cecil Booth

Although Hubert Cecil Booth (1871-1955), an English civil
engineer, designed battleship engines, factories, and bridges, he
was not above working on homier problems when they intrigued
him. That happened in 1900 when he watched the demonstration
of a device that used forced air to blow the dirt out of
railway cars. It worked poorly, and the reason, it seemed to
Booth, was that blowing just stirred up the dirt. Sucking it into a
receptacle, he thought, would work better. He tested his idea by
placing a wet cloth over furniture upholstery and sucking through
it. The grime that collected on the side of the cloth facing the upholstery
proved him right.
He built his first vacuum cleaner—a term that he coined—in
1901. It cleaned houses, but only with considerable effort. Measuring
54 inches by 42 inches by 10 inches, it had to be carried in
a horse-driven van to the cleaning site. A team of workmen
from Booth’s Vacuum Cleaner Company then did the cleaning
with hoses that reached inside the house through windows and
doors. Moreover, the machine cost the equivalent of more than
fifteen hundred dollars. It was beyond the finances and physical
powers of home owners.
Booth marketed the first successful British one-person vacuum
cleaner, the Trolley-Vac, in 1906. Weighing one hundred
pounds, it was still difficult to wrestle into position, but it came
with hoses and attachments that made possible the cleaning of
different types of surfaces and hard-to-reach areas.

See also : Disposable razor; Electric refrigerator; Microwave cooking;

UNIVAC Computer

noreply@blogger.com (Unknown) — Wed, 8 Jul 2015 01:28:00 -0700

The invention:

The first commercially successful computer system.

The people behind the invention:

John Presper Eckert (1919-1995), an American electrical engineer
John W. Mauchly (1907-1980), an American physicist
John von Neumann (1903-1957), a Hungarian American
mathematician
Howard Aiken (1900-1973), an American physicist
George Stibitz (1904-1995), a scientist at Bell Labs

The Origins of Computing

On March 31, 1951, the U.S. Census Bureau accepted delivery of
the first Universal Automatic Computer (UNIVAC). This powerful
electronic computer, far surpassing anything then available in technological
features and capability, ushered in the first computer generation
and pioneered the commercialization of what had previously
been the domain of academia and the interest of the military. The fanfare
that surrounded this historic occasion, however, masked the turbulence
of the previous five years for the young upstart Eckert-
Mauchly Computer Corporation (EMCC), which by this time was a
wholly owned subsidiary of Remington Rand Corporation.
John Presper Eckert and John W. Mauchly met in the summer of
1941 at the University of Pennsylvania. A short time later, Mauchly,
then a physics professor at Ursinus College, joined the Moore School
of Engineering at the University of Pennsylvania and embarked on a
crusade to convince others of the feasibility of creating electronic digital
computers. Up to this time, the only computers available were
called “differential analyzers,” which were used to solve complex
mathematical equations known as “differential equations.” These
slow machines were good only for solving a relatively narrow range
of mathematical problems.
Eckert and Mauchly landed a contract that eventually resulted in
the development and construction of the world’s first operational
general-purpose electronic computer, the Electronic Numerical Integrator
and Calculator (ENIAC). This computer, used eventually
by the Army for the calculation of ballistics tables, was deficient in
many obvious areas, but this was caused by economic rather than
engineering constraints. One major deficiency was the lack of automatic
program control; the ENIAC did not have stored program
memory. This was addressed in the development of the Electronic
Discrete Variable Automatic Computer (EDVAC), the successor to
the ENIAC.

Fighting the Establishment

A symbiotic relationship had developed between Eckert and
Mauchly that worked to their advantage on technical matters.
They worked well with each other, and this contributed to their
success in spite of external obstacles. They both were interested in
the commercial applications of computers and envisioned uses for
these machines far beyond the narrow applications required by
the military.
This interest brought them into conflict with the administration
at the Moore School of Engineering as well as with the noted mathematician
John von Neumann, who “joined” the ENIAC/EDVAC
development team in 1945. Von Neumann made significant contributions
and added credibility to the Moore School group, which often
had to fight against the conservative scientific establishment
characterized by Howard Aiken at Harvard University and George
Stibitz at Bell Labs. Philosophical differences between von Neumann
and Eckert and Mauchly, as well as patent issue disputes with
the Moore School administration, eventually caused the resignation
of Eckert and Mauchly on March 31, 1946.
Eckert and Mauchly, along with some of their engineering colleagues
at the University of Pennsylvania, formed the Electronic
Control Company and proceeded to interest potential customers
(including the Census Bureau) in an “EDVAC-type” machine. On
May 24, 1947, the EDVAC-type machine became the UNIVAC. This
new computer would overcome the shortcomings of the ENIAC
and the EDVAC (which was eventually completed by the Moore
School in 1951). It would be a stored-program computer and would
allow input to and output from the computer via magnetic tape. The
prior method of input/output used punched paper cards that were
extremely slow compared to the speed at which data in the computer
could be processed.
A series of poor business decisions and other unfortunate circumstances
forced the newly renamed Eckert-Mauchly Computer
Corporation to look for a buyer. They found one in Remington Rand
in 1950. Remington Rand built tabulating equipment and was a
competitor of International Business Machines Corporation (IBM).
IBM was approached about buying EMCC, but the negotiations fell
apart. EMCC became a division of Remington Rand and had access
to the resources necessary to finish the UNIVAC.

Consequences

Eckert and Mauchly made a significant contribution to the advent
of the computer age with the introduction of the UNIVAC I.
The words “computer” and “UNIVAC” entered the popular vocabulary
as synonyms. The efforts of these two visionaries were rewarded
quickly as contracts started to pour in, taking IBM by surprise
and propelling the inventors into the national spotlight.
This spotlight shone brightest, perhaps, on the eve of the national
presidential election of 1952, which pitted war hero General Dwight
D. Eisenhower against statesman Adlai Stevenson. At the suggestion
of Remington Rand, CBS was invited to use UNIVAC to predict
the outcome of the election. Millions of television viewers watched
as CBS anchormanWalter Cronkite “asked” UNIVAC for its predictions.
A program had been written to analyze the results of thousands
of voting districts in the elections of 1944 and 1948. Based on
only 7 percent of the votes coming in, UNIVAC had Eisenhower
winning by a landslide, in contrast with all the prior human forecasts
of a close election. Surprised by this answer and not willing to
suffer the embarrassment of being wrong, the programmers quickly
directed the program to provide an answer that was closer to the
perceived situation. The outcome of the election, however, matched
UNIVAC’s original answer. This prompted CBS commentator Edward
R. Murrow’s famous quote, “The trouble with machines is
people.”
The development of the UNIVAC I produced many technical innovations.
Primary among these is the use of magnetic tape for input
and output. All machines that preceded the UNIVAC (with one
exception) used either paper tape or cards for input and cards for
output. These methods were very slow and created a bottleneck of
information. The great advantage of magnetic tape was the ability
to store the equivalent of thousands of cards of data on one 30-centimeter
reel of tape. Another advantage was its speed.

See also: Apple II computer; BINAC computer; Colossus computer;
ENIAC computer; IBM Model 1401 computer; Personal computer;
Supercomputer.

Ultrasound

noreply@blogger.com (Unknown) — Wed, 22 Apr 2015 00:25:00 -0700

The invention:

A medically safe alternative to X-ray examination,
ultrasound uses sound waves to detect fetal problems in pregnant
women.

The people behind the invention:

Ian T. Donald (1910-1987), a British obstetrician

Paul Langévin (1872-1946), a French physicist

Marie Curie (1867-1946) and Pierre Curie (1859-1906), the French husband-and-wife team that researched and developed the field of radioactivity

Alice Stewart, a British researcher

An Underwater Beginning

In the early 1900’s, two major events made it essential to develop
an appropriate means for detecting unseen underwater objects. The
first event was the Titanic disaster in 1912, which involved a largely
submerged, unseen, and silent iceberg. This iceberg caused the sinking
of the Titanic and resulted in the loss of many lives as well as
valuable treasure. The second event was the threat to the Allied
Powers from German U-boats duringWorldWar I (1914-1918). This
threat persuaded the French and English Admiralties to form a joint
committee in 1917. The Anti-Submarine Detection and Investigation
Committee (ASDIC) found ways to counter the German naval
developments. Paul Langévin, a former colleague of Pierre Curie
and Marie Curie, applied techniques developed in the Curies’ laboratories
in 1880 to formulate a crude ultrasonic system to detect submarines.
These techniques used beams of sound waves of very high
frequency that were highly focused and directional.
The advent ofWorldWar II (1939-1945) made necessary the development
of faster electronic detection technology to improve the efforts
of ultrasound researchers. Langévin’s crude invention evolved
into the sophisticated system called “sonar” (sound navigation ranging),
which was important in the success of the Allied forces. Sonar
was based on pulse echo principles and, like the system called “ra-
dar” (radio detecting and ranging), had military implications. This vital
technology was classified as a military secret and was kept hidden
until after the war.

An Alternative to X Rays

Ian Donald’s interest in engineering and the principles of
sound waves began when he was a schoolboy. Later, while he was
in the British Royal Air Force, he continued and maintained his
enthusiasm by observing the development of the anti-U-boat
warfare efforts. He went to medical school afterWorldWar II and
began a career in obstetrics. By the early 1950’s, Donald had em-
barked on a study of how to apply sonar technology in medicine.
He moved to Glasgow, Scotland, a major engineering center in
Europe that presented a fertile environment for interdisciplinary
research. There Donald collaborated with engineers and technicians
in his medical ultrasound research. They used inanimate
and tissue materials in many trials. Donald hoped to apply ultrasound
technology to medicine, especially to gynecology and obstetrics,
his specialty.
His efforts led to new pathways and new discoveries. He was interested
in adapting a certain type of ultrasound technology method
(used to probe metal structures and welds for cracks and flaws) to
medicine. Kelvin Hughes, the engineering manufacturing company
that produced the flaw detector apparatus, gave advice, expertise,
and equipment to Donald and his associates, who were then able to
devise water tanks with flexible latex bottoms. These were coated
with a film of grease and placed into contact with the abdomens of
pregnant women.
The use of diagnostic radiography (such as X rays) became controversial
when it was evident that it caused potential leukemias and other injuries to the fetus. It was realized from the earliest days
of radiology that radiation could cause tumors, particularly of the
skin. The aftereffects of radiological studies were recognized much
later and confirmed by studies of atomic bomb survivors and of patients
receiving therapeutic irradiation. The use of radiation in obstetrics
posed several major threats to the developing fetus, most
notably the production of tumors later in life, genetic damage, and
developmental anomalies in the unborn fetus.
In 1958, bolstered by earlier clinical reports and animal research
findings, Alice Stewart and her colleagues presented a major case
study of more than thirteen hundred children in England andWales
who had died of cancer before the age of ten between 1953 and 1958.
There was a 91 percent increase in leukemias in children who were
exposed to intrauterine radiation, as well as a higher percentage of
fetal death. Although controversial, this report led to a reduction in
the exposure of pregnant women to X rays, with subsequent reductions
in fetal abnormalities and death.
These reports came at a very opportune time for Donald: The development
of ultrasonography would provide useful information
about the unborn fetus without the adverse effects of radiation.
Stewart’s findings and Donald’s experiments convinced others of
the need for ultrasonography in obstetrics.

Consequences

Diagnostic ultrasound first gained clinical acceptance in obstetrics,
and its major contributions have been in the assessment of fetal
size and growth. In combination with amniocentesis (the study of
fluid taken from the womb), ultrasound is an invaluable tool in operative
procedures necessary to improve the outcomes of pregnancies.
As can be expected, safety has been a concern, especially for a developing,
vulnerable fetus that is exposed to high-frequency sound.
Research has not been able to document any harmful effect of ultrasonography
on the developing fetus. The procedure produces neither
heat nor cold. It has not been shown to produce any toxic or destructive
effect on the auditory or balancing organs of the
developing fetus. Chromosomal abnormalities have not been reported
in any of the studies conducted.
Ultrasonography, because it is safe and does not require surgery,
has become the principal means for obtaining information about fetal
structures. With this procedure, the contents of the uterus—as
well as the internal structure of the placenta, fetus, and fetal organs—
can be evaluated at any time during pregnancy. The use of
ultrasonography remains a most valued tool in medicine, especially
obstetrics, because of Donald’s work.

Ian Donald

Ian Donald was born in Paisley, Scotland, in 1910 and educated
in Edinburgh until he was twenty, when he moved to
South Africa with his parents. He graduated with a bachelor of
arts degree from Diocesan College, Cape Town, and then moved
to London to study medicine, graduating from the University of
London in 1937. DuringWorldWar II he served as a medical officer
in the Royal Air Force and received a medal for rescuing flyers
from a burning airplane. After the war he began his long
teaching career in medicine, first at St. Thomas Hospital Medical
School and then as the Regius Professor of Midwifery at Glasgow
University. His specialties were obstetrics and gynecology.
While at Glasgow he accomplished his pioneering work
with diagnostic ultrasound technology, but he also championed
laparoscopy, breast feeding, and the preservation of membranes
during the delivery of babies. In addition to his teaching
duties and medical practice he wrote a widely used textbook,
oversaw the building of the Queen Mother’s Hospital in Glasgow,
and campaigned against England’s 1967 Abortion Act.
His expertise with ultrasound came to his own rescue after
he had cardiac surgery in the 1960’s. He diagnosed himself as
having internal bleeding from a broken blood vessel. The cardiologists
taking care of him were skeptical until an ultrasound
proved him right. Widely honored among physicians, he died
in England in 1987.

See also:

Amniocentesis; Birth control pill; CAT scanner; Electrocardiogram;
Electroencephalogram; Mammography; Nuclear magnetic resonance;
Pap test; Sonar; Syphilis test

Ultramicroscope

noreply@blogger.com (Unknown) — Sat, 21 Feb 2015 00:00:00 -0800

The invention:

A microscope characterized by high-intensity illumination
for the study of exceptionally small objects, such as colloidal
substances.

The people behind the invention:

Richard Zsigmondy (1865-1929), an Austrian-born German
organic chemist who won the 1925 Nobel Prize in Chemistry
H. F. W. Siedentopf (1872-1940), a German physicist-optician
Max von Smouluchowski (1879-1961), a German organic
chemist.

Accidents of Alchemy

Richard Zsigmondy’s invention of the ultramicroscope grew out
of his interest in colloidal substances. Colloids consist of tiny particles
of a substance that are dispersed throughout a solution of another
material or substance (for example, salt in water). Zsigmondy
first became interested in colloids while working as an assistant to
the physicist Adolf Kundt at the University of Berlin in 1892. Although
originally trained as an organic chemist, in which discipline
he took his Ph.D. at the University of Munich in 1890, Zsigmondy
became particularly interested in colloidal substances containing
fine particles of gold that produce lustrous colors when painted on
porcelain. For this reason, he abandoned organic chemistry and devoted
his career to the study of colloids.
Zsigmondy began intensive research into his new field of interest
in 1893, when he returned to Austria to accept a post as lecturer at a
technical school at Graz. Zsigmondy became especially interested
in gold-ruby glass, the accidental invention of the seventeenth century
alchemist Johann Kunckle. Kunckle, while pursuing the alchemist’s
pipe dream of transmuting base substances (such as lead)
into gold, discovered instead a method of producing glass with a
beautiful, deep red luster by suspending very fine particles of gold
throughout the liquid glass before it was cooled. Zsigmondy also
began studying a colloidal pigment called “purple of Cassius,” the
discovery of another seventeenth century alchemist, Andreas Cassius.
Zsigmondy soon discovered that purple of Cassius was a colloidal
solution and not, as most chemists believed at the time, a chemical
compound. This fact allowed him to develop techniques for
glass and porcelain coloring with great commercial value, which led
directly to his 1897 appointment to a research post with the Schott
Glass Manufacturing Company in Jena, Germany. With the Schott
Company, Zsigmondy concentrated on the commercial production
of colored glass objects. His most notable achievement during this
period was the invention of Jena milk glass, which is still prized by
collectors throughout the world.

Brilliant Proof

While studying colloids, Zsigmondy devised experiments that
proved that purple of Cassius was colloidal. When he published the
results of his research in professional journals, however, they were
not widely accepted by the scientific community. Other scientists
were not able to replicate Zsigmondy’s experiments and consequently
denounced them as flawed. The criticism of his work in
technical literature stimulated Zsigmondy to make his greatest discovery,
the ultramicroscope, which he developed to prove his theories
regarding purple of Cassius.
The problem with proving the exact nature of purple of Cassius
was that the scientific instruments available at the time were not
sensitive enough for direct observation of the particles suspended
in a colloidal substance. Using the facilities and assisted by the staff
(especially H. F.W. Siedentopf, an expert in optical lens grinding) of
the Zeiss Glass Manufacturing Company of Jena, Zsigmondy developed
an ingenious device that permitted direct observation of individual
colloidal particles.
This device, which its developers named the “ultramicroscope,”
made use of a principle that already existed. Sometimes called “darkfield
illumination,” this method consisted of shining a light (usually
sunlight focused by mirrors) through the solution under the microscope
at right angles to the observer, rather than shining the light directly
from the observer into the solution. The resulting effect is similar
to that obtained when a beam of sunlight is admitted to a closed
room through a small window. If an observer stands back fromand at
right angles to such a beam, many dust particles suspended in the air
will be observed that otherwise would not be visible.
Zsigmondy’s device shines a very bright light through the substance
or solution being studied. From the side, the microscope then
focuses on the light shaft. This process enables the observer using
the ultramicroscope to view colloidal particles that are ordinarily
invisible even to the strongest conventional microscope. To a scientist
viewing purple of Cassius, for example, colloidal gold particles
as small as one ten-millionth of a millimeter in size become visible.

Impact

After Zsigmondy’s invention of the ultramicroscope in 1902,
the University of Göttingen appointed him professor of inorganic
chemistry and director of its Institute for Inorganic Chemistry.
Using the ultramicroscope, Zsigmondy and his associates quickly
proved that purple of Cassius is indeed a colloidal substance.
That finding, however, was the least of the spectacular discoveries
that resulted from Zsigmondy’s invention. In the next decade,
Zsigmondy and his associates found that color changes in colloidal
gold solutions result from coagulation—that is, from changes in the
size and number of gold particles in the solution caused by particles
bonding together. Zsigmondy found that coagulation occurs when
the negative electrical charge of the individual particles is removed
by the addition of salts. Coagulation can be prevented or slowed by
the addition of protective colloids.
These observations also made possible the determination of the
speed at which coagulation takes place, as well as the number of particles
in the colloidal substance being studied.With the assistance of
the organic chemist Max von Smouluchowski, Zsigmondy worked
out a complete mathematical formula of colloidal coagulation that is
valid not only for gold colloidal solutions but also for all other
colloids. Colloidal substances include blood and milk, which both coagulate,
thus giving Zsigmondy’s work relevance to the fields of
medicine and agriculture. These observations and discoveries concerning
colloids—in addition to the invention of the ultramicroscope—
earned for Zsigmondy the 1925 Nobel Prize in Chemistry.

Richard Zsigmondy

Born in Vienna, Austria, in 1865, Richard Adolf Zsigmondy
came from a talented, energetic family. His father, a celebrated
dentist and inventor of medical equipment, inspired his children
to study the sciences, while his mother urged them to
spend time outdoors in strenuous exercise. Although his father
died when Zsigmondy was fifteen, the teenager’s interest in
chemistry was already firmly established. He read advanced
chemistry textbooks and worked on experiments in his own
home laboratory.
After taking his doctorate at the University of Munich and
teaching in Berlin and Graz, Austria, he became an industrial
chemist at the glassworks in Jena, Germany. However, pure research
was his love, and he returned to it, working entirely on
his own after 1900. In 1907 he received an appointment as professor
and director of the Institute of Inorganic Chemistry at the
University of Göttingen, one of the scientific centers of the
world. There he accomplished much of his ground-breaking
work on colloids and Brownian motion, despite the severe
shortages that hampered him during the economic depression
in Germany following World War I. His 1925 Nobel Prize in
Chemistry, especially the substantial money award, helped him
overcome his supply problems. He retired in early 1929 and
died seven months later.

See also: Scanning tunneling microscope; Ultracentrifuge;

Ultracentrifuge

noreply@blogger.com (Unknown) — Sun, 4 Jan 2015 23:52:00 -0800

The invention:

Asuper-high-velocity centrifuge designed to separate
colloidal or submicroscopic substances, the ultracentrifuge
was used to measure the molecular weight of proteins and
proved that proteins are large molecules.

The people behind the invention:

Theodor Svedberg (1884-1971), a Swedish physical chemist and
1926 Nobel laureate in chemistry
Jesse W. Beams (1898-1977), an American physicist
Arne Tiselius (1902-1971), a Swedish physical biochemist and
1948 Nobel laureate in chemistry

Svedberg Studies Colloids

Theodor “The” Svedberg became the principal founder of molecular
biology when he invented the ultracentrifuge and used it to
examine proteins in the mid-1920’s. He began to study materials
called “colloids” as a Swedish chemistry student at the University
of Uppsala and continued to conduct experiments with colloidal
systems when he joined the faculty in 1907. A colloid is a kind of
mixture in which very tiny particles of one substance are mixed
uniformly with a dispersing medium (often water) and remain
suspended indefinitely. These colloidal dispersions play an important
role in many chemical and biological systems.
The size of the colloid particles must fall within a certain
range. The force of gravity will cause them to settle if they are too
large. If they are too small, the properties of the mixture change,
and a solution is formed. Some examples of colloidal systems include
mayonnaise, soap foam, marshmallows, the mineral opal,
fog, India ink, jelly, whipped cream, butter, paint, and milk.
Svedberg wondered what such different materials could have in
common. His early work helped to explain why colloids remain
in suspension. Later, he developed the ultracentrifuge to measure
the weight of colloid particles by causing them to settle in a controlled
way.

Svedberg Builds an Ultracentrifuge

Svedberg was a successful chemistry professor at the University
of Uppsala in Sweden when he had the idea that colloids could be
made to separate from suspension by means of centrifugal force.
Centrifugal force is caused by circular motion and acts on matter
much as gravity does. Aperson can feel this force by tying a ball to a
rope and whirling it rapidly in a circle. The pull on the rope becomes
stronger as the ball moves faster in its circular orbit. A centrifuge
works the same way: It is a device that spins balanced containers of
substances very rapidly.
Svedberg figured that it would take a centrifugal force thousands
of times the force of gravity to cause colloid particles to settle. How
fast they settle depends on their size and weight, so the ultracentrifuge
can also provide a measure of these properties. Centrifuges were
already used to separate cream from whole milk and blood corpuscles
from plasma, but these centrifuges were too slow to cause the
separation of colloids. An ultracentrifuge—one that could spin samples
much faster—was needed, and Svedberg made plans to build one.
The opportunity came in 1923, when Svedberg spent eight months
as visiting professor in the chemistry department of the University
ofWisconsin at Madison and worked with J. Burton Nichols, one of
the six graduate students assigned to assist him. Here, Svedberg announced
encouraging results with an electrically driven centrifuge—
not yet an ultracentrifuge—which attained a rotation equal
to about 150 times the force of gravity. Svedberg returned to Sweden
and, within a year, built a centrifuge capable of generating 7,000
times the force of gravity. He used it with Herman Rinde, a colleague
at the University of Uppsala, to separate the suspended particles
of colloidal gold. This was in 1924, which is generally accepted
as the date of the first use of a true ultracentrifuge. From 1925 to
1926, Svedberg raised the funds to build an even more powerful ultracentrifuge.
It would be driven by an oil turbine, a machine capable
of producing more than 40,000 revolutions per minute to generate
a force 100,000 times that of gravity.
Svedberg and Robin Fahraeus used the new ultracentrifuge to
separate the protein hemoglobin from its colloidal suspension. Together
with fats and carbohydrates, proteins are one of the most
abundant organic constituents of living organisms. No protein had
been isolated in pure form before Svedberg began this study, and it
was uncertain whether proteins consisted of molecules of a single
compound or mixtures of different substances working together in
biological systems. The colloid particles of Svedberg’s previous
studies separated at different rates, some settling faster than others,
showing that they had different sizes and weights. Colloid particles
of the protein, however, separated together. The uniform separation
observed for proteins, such as hemoglobin, demonstrated for the
first time that each protein consists of identical well-defined molecules.
More than one hundred proteins were studied by Svedberg
and his coworkers, who extended their technique to carbohydrate
polymers such as cellulose and starch.

Impact

Svedberg built more and more powerful centrifuges so that smaller
and smaller molecules could be studied. In 1936, he built an ultracentrifuge
that produced a centrifugal force of more than a halfmillion
times the force of gravity. JesseW. Beams was an American
pioneer in ultracentrifuge design. He reduced the friction of an airdriven
rotor by first housing it in a vacuum, in 1934, and later by
supporting it with a magnetic field.
The ultracentrifuge was a central tool for providing a modern understanding
of the molecular basis of living systems, and it is employed
in thousands of laboratories for a variety of purposes. It is
used to analyze the purity and the molecular properties of substances
containing large molecules, from the natural products of the biosciences
to the synthetic polymers of chemistry. The ultracentrifuge is
also employed in medicine to analyze body fluids, and it is used in biology
to isolate viruses and the components of fractured cells.
Svedberg, while at Wisconsin in 1923, invented a second, very
different method to separate proteins in suspension using electric
currents. It is called “electrophoresis,” and it was later improved by
his student, Arne Tiselius, for use in his famous study of the proteins
in blood serum. The technique of electrophoresis is as widespread
and important as is the ultracentrifuge.

Typhus vaccine

noreply@blogger.com (Unknown) — Tue, 23 Dec 2014 07:27:00 -0800

The invention:

The first effective vaccine against the virulent typhus
disease.

The person behind the invention:

Hans Zinsser (1878-1940), an American bacteriologist and
immunologist

Studying Diseases

As a bacteriologist and immunologist, Hans Zinsser was interested
in how infectious diseases spread. During an outbreak of typhus
in Serbia in 1915, he traveled with a Red Cross team so that he
could study the disease. He made similar trips to the Soviet Union
in 1923, Mexico in 1931, and China in 1938. His research showed
that, as had been suspected, typhus was caused by the rickettsia, an
organism that had been identified in 1916 by Henrique da Rocha-
Lima. The organism was known to be carried by a louse or a rat flea
and transmitted to humans through a bite. Poverty, dirt, and overcrowding
led to environments that helped the typhus disease to
spread.
The rickettsia is a microorganism that is rod-shaped or spherical.
Within the insect’s body, it works its way into the cells that line the
gut. Multiplying within this tissue, the rickettsia passes from the insect
body with the feces. Since its internal cells are being destroyed,
the insect dies within three weeks after it has been infected with the
microorganism. As the infected flea or louse feeds on a human, it
causes itching. When the bite is scratched, the skin may be opened,
and the insect feces, carrying rickettsia, can then enter the body.
Also, dried airborne feces can be inhaled.
Once inside the human, the rickettsia invades endothelial cells
and causes an inflammation of the blood vessels. Cell death results,
and this leads to tissue death. In a few days, the infected person may
have a rash, a severe headache, a fever, dizziness, ringing in the ears,
or deafness. Also, light may hurt the person’s eyes, and the thinking
processes become foggy and mixed up. (The word “typhus” comes
from a Greek word meaning “cloudy” or “misty.”) Without treatment,
the victim dies within nine to eighteen days.
Medical science now recognizes three forms of typhus: the epidemic
louse-borne, the Brill-Zinsser, and the murine (or rodentrelated)
form. The epidemic louse-borne (or “classical”) form is the
most severe. The Brill-Zinsser (or “endemic”) form is similar but
less severe. The murine form of typhus is also milder then the epidemic
type.
In 1898, a researcher named Brill studied typhus among immigrants
in New York City; the form of typhus he found was called
“Brill’s disease.” In the late 1920’s, Hermann Mooser proved that
Brill’s disease was carried by the rat flea.
When Zinsser began his work on typhus, he realized that what
was known about the disease had never been properly organized.
Zinsser and his coworkers, including Mooser and others, worked to
identify the various types of typhus. In the 1930’s, Zinsser suggested
that the typhus studied by Brill in New York City had actually
included two types: the rodent-associated form and Brill’s disease.
As a result of Zinsser’s effort to identify the types of typhus
disease, it was renamed Brill-Zinsser disease.

Making a Vaccine

Zinsser’s studies had shown him that the disease-causing organism
in typhus contained some kind of antigen, most likely a polysaccharide.
In 1932, Zinsser would identify agglutinins, or antibodies,
in the blood serum of patients who had the murine and classical
forms of typhus. Zinsser believed that a vaccine could be developed
to prevent the spread of typhus. He realized, however, that a large
number of dead microorganisms was needed to help people develop
an immunity.
Zinsser and his colleagues set out to develop a method of growing
organisms in large quantities in tissue culture. The infected tissue
was used to inoculate large quantities of normal chick tissue,
and this tissue was then grown in flasks. In this way, Zinsser’s team
was able to produce the quantities of microorganisms they needed.
The type of immunization that Zinsser developed (in 1930) is
known as “passive immunity.” The infecting organisms carry anti-
gens, which stimulate the production of antibodies. The antigens
can elicit an immune reaction even if the cell is weak or dead.
“B” cells and macrophages, both of which are used in fighting
disease organisms, recognize and respond to the antigen. The B cells
produce antibodies that can destroy the invading organism directly
or attract more macrophages to the area so that they can attack the
organism. B cells also produce “memory cells,” which remain in the
blood and trigger a quick second response if there is a later infection.
Since the vaccine contains weakened or dead organisms, the
person who is vaccinated may have a mild reaction but does not actually
come down with the disease.

Impact

Typhus is still common in many parts of the world, especially
where there is poverty and overcrowding. Classical typhus is quite
rare; the last report of this type of typhus in the United States was in
1921. Endemic and murine typhus are more common. In the United
States, where children are vaccinated against the disease, only about
fifty cases are now reported each year. Antibiotics such as tetracycline
and chloramphenicol are effective in treating the disease, so
few infected people now die of the disease in areas where medical
care is available.
The work of Zinsser and his colleagues was very important in
stopping the spread of typhus. Zinsser’s classification of different
types of the disease meant that it was better understood, and this
led to the development of cures. The control of lice and rodents and
improved cleanliness in living conditions helped bring typhus under
control. Once Zinsser’s vaccine was available, even people who
lived in crowded inner cities could be protected against the disease.
Zinsser’s research in growing the rickettsia in tissue culture also
inspired further work. Other researchers modified and improved
his technique so that the use of tissue culture is now standard in laboratories.

See also : Birth control pill; Penicillin; Polio
vaccine (Sabin); Polio vaccine (Salk); Tuberculosis vaccine;

Turbojet

noreply@blogger.com (Unknown) — Mon, 8 Dec 2014 03:15:00 -0800

The invention:

A jet engine with a turbine-driven compressor that
uses its hot-gas exhaust to develop thrust.

The people behind the invention:

Henry Harley Arnold (1886-1950), a chief of staff of the U.S.
Army Air Corps
Gerry Sayer, a chief test pilot for Gloster Aircraft Limited
Hans Pabst von Ohain (1911- ), a German engineer
Sir Frank Whittle (1907-1996), an English Royal Air Force
officer and engineer

Developments in Aircraft Design

On the morning of May 15, 1941, some eleven months after
France had fallen to Adolf Hitler’s advancing German army, an experimental
jet-propelled aircraft was successfully tested by pilot
Gerry Sayer. The airplane had been developed in a little more than
two years by the English company Gloster Aircraft under the supervision
of Sir Frank Whittle, the inventor of England’s first jet engine.
Like the jet engine that powered it, the plane had a number of
predecessors. In fact, the May, 1941, flight was not the first jetpowered
test flight: That flight occurred on August 27, 1939, when a
Heinkel aircraft powered by a jet engine developed by Hans Pabst
von Ohain completed a successful test flight in Germany. During
this period, Italian airplane builders were also engaged in jet aircraft
testing, with lesser degrees of success.
Without the knowledge that had been gained from Whittle’s experience
in experimental aviation, the test flight at the Royal Air
Force’s Cranwell airfield might never have been possible. Whittle’s
repeated efforts to develop turbojet propulsion engines had begun
in 1928, when, as a twenty-one-year-old Royal Air Force (RAF)
flight cadet at Cranwell Academy, he wrote a thesis entitled “Future
Developments in Aircraft Design.” One of the principles of Whittle’s
earliest research was that if aircraft were eventually to achieve
very high speeds over long distances, they would have to fly at very
high altitudes, benefiting from the reduced wind resistance encountered
at such heights.
Whittle later stated that the speed he had in mind at that time
was about 805 kilometers per hour—close to that of the first jetpowered
aircraft. His earliest idea of the engines that would be necessary
for such planes focused on rocket propulsion (that is, “jets” in
which the fuel and oxygen required to produce the explosion needed
to propel an air vehicle are entirely contained in the engine, or, alternatively,
in gas turbines driving propellers at very high speeds).
Later, it occurred to him that gas turbines could be used to provide
forward thrust by what would become “ordinary” jet propulsion
(that is, “thermal air” engines that take from the surrounding atmosphere
the oxygen they need to ignite their fuel). Eventually, such
ordinary jet engines would function according to one of four possible
systems: the so-called athodyd, or continuous-firing duct; the
pulsejet, or intermittent-firing duct; the turbojet, or gas-turbine jet;
or the propjet, which uses a gas turbine jet to rotate a conventional
propeller at very high speeds.

Passing the Test

The aircraft that was to be used to test the flight performance
was completed by April, 1941. On April 7, tests were conducted
on the ground at Gloster Aircraft’s landing strip at Brockworth
by chief test pilot Sayer. At this point, all parties concerned tried
to determine whether the jet engine’s capacity would be sufficient
to push the aircraft forward with enough speed to make it
airborne. Sayer dared to take the plane off the ground for a limited
distance of between 183 meters and 273 meters, despite the
technical staff’s warnings against trying to fly in the first test
flights.
On May 15, the first real test was conducted at Cranwell. During
that test, Sayer flew the plane, now called the Pioneer, for seventeen
minutes at altitudes exceeding 300 meters and at a conservative test
speed exceeding 595 kilometers per hour, which was equivalent to
the top speed then possible in the RAF’s most versatile fighter
plane, the Spitfire.
Once it was clear that the tests undertaken at Cranwell were not
only successful but also highly promising in terms of even better
performance, a second, more extensive test was set for May 21, 1941.
It was this later demonstration that caused the Ministry of Air Production
(MAP) to initiate the first steps to produce the Meteor jet
fighter aircraft on a full industrial scale barely more than a year after
the Cranwell test flight.

Impact

Since July, 1936, the Junkers engine and aircraft companies in
Hitler’s Germany had been a part of a new secret branch dedicated
to the development of a turbojet-driven aircraft. In the same period,
Junkers’ rival in the German aircraft industry, Heinkel, Inc., approached
von Ohain, who was far enough along in his work on the
turbojet principle to have patented a device very similar to Whittle’s
in 1935.Alater model of this jet engine would power a test aircraft in
August, 1939.
In the meantime, the wider impact of the flight was the result of
decisions made by General Henry Harley Arnold, chief of staff of
the U.S. Army Air Corps. Even before learning of the successful
flight in May, he made arrangements to have one of Whittle’s engines
shipped to the United States to be used by General Electric
Company as a model for U.S. production. The engine arrived in
October, 1941, and within one year, a General Electric-built engine
powered a Bell Aircraft plane, the XP-59 A Airacomet, in its
maiden flight.
The jet airplane was not perfected in time to have any significant
impact on the outcome ofWorldWar II, but all of the wartime experimental
jet aircraft developments that were either sparked by the
flight in 1941 or preceded it prepared the way for the research and
development projects that would leave a permanent revolutionary
mark on aviation history in the early 1950’s.

See also : Airplane; Dirigible; Rocket; Stealth aircraft; Supersonic
passenger plane;

Tupperware

noreply@blogger.com (Unknown) — Sun, 9 Nov 2014 23:24:00 -0800

The invention:

Trademarked food-storage products that changed
the way Americans viewed plastic products and created a model
for selling products in consumers homes.

The people behind the invention:

Earl S. Tupper (1907-1983), founder of Tupperware
Brownie Wise, the creator of the vast home sales network for
Tupperware
Morison Cousins (1934-2001), a designer hired by Tupperware
to modernize its products in the early 1990’s

“The Wave of the Future”?

Relying on a belief that plastic was the wave of the future and
wanting to improve on the newest refrigeration technology, Earl S.
Tupper, who called himself “a ham inventor and Yankee trader,”
created an empire of products that changed America’s kitchens.
Tupper, a self-taught chemical engineer, began working at Du Pont
in the 1930’s. This was a time of important developments in the
field of polymers and the technology behind plastics. Wanting to
experiment with this new material yet unable to purchase the
needed supplies, Tupper went to his employer for help. Because of
the limited availability of materials, major chemical companies
had been receiving all the raw goods for plastic production. Although
Du Pont would not part with raw materials, the company
was willing to let Tupper have the slag.
Polyethylene slag was a black, rock-hard, malodorous waste
product of oil refining. It was virtually unusable. Undaunted,
Tupper developed methods to purify the slag. He then designed
an injection molding machine to form bowls and other containers
out of his “Poly-T.” Tupper did not want to call the substance plastic
because of a public distrust of that substance. In 1938, he
founded the Tupper Plastics Company to pursue his dream. It was
during those first years that he formulated the design for the famous
Tupperware seal.
Refrigeration techniques had improved tremendously during
the first part of the twentieth century. The iceboxes in use prior to
the 1940’s were inconsistent in their interior conditions and were
usually damp inside because of melting of the ice. In addition, the
metal, glass, or earthenware food storage containers used during
the first half of the century did not seal tightly and allowed food to
stay moist. Iceboxes allowed mixing of food odors, particularly evident
with strong-smelling items such as onions and fish.

Electric Refrigerators

In contrast to iceboxes, the electric refrigerators available starting
in the 1940’s maintained dry interiors and low temperatures. This
change in environment resulted in food drying out and wilting.
Tupper set out to alleviate this problem through his plastic containers.
The key to Tupper’s solution was his containers’ seal. He took
his design from paint can lids and inverted it. This tight seal created
a partial vacuum that protected food from the dry refrigeration process
and kept food odors sealed within containers.
In 1942, Tupper bought his first manufacturing plant, in Farnumsville,
Massachusetts. There he continued to improve on his designs.
In 1945, Tupper introduced Tupperware, selling it through
hardware and department stores as well as through catalog sales.
Tupperware products were made of flexible, translucent plastic.
Available in frosted crystal and five pastel colors, the new containers
were airtight and waterproof. In addition, they carried a lifetime
warranty against chipping, cracking, peeling, and breaking in normal
noncommercial use. Early supporters of Tupperware included
the American Thermos Bottle Company, which purchased seven
million nesting cups, and the Tek Corporation, which ordered fifty
thousand tumblers to sell with toothbrushes.
Even though he benefited from this type of corporate support,
Tupper wanted his products to be for home use. Marketing the new
products proved to be difficult in the early years. Tupperware sat on
hardware and department store shelves, and catalog sales were
nearly nonexistent. The problem appeared to involve a basic distrust
of plastic by consumers and an unfamiliarity with how to use
the new products. The product did not come with instructions on
how to seal the containers or descriptions of how the closed container
protected the food within. BrownieWise, an early direct seller
and veteran distributor of Stanley Home Products, stated that it
took her several days to understand the technology behind the seal
and the now-famous Tupperware “burp,” the sound made when air
leaves the container as it seals.
Wise and two other direct sellers, Tom Damigella and Harvey
Hollenbush, found the niche for selling Tupperware for daily use—
home sales.Wise approached Tupper with a home party sales strategy
and detailed how it provided a relaxed atmosphere in which to
learn about the products and thus lowered sales resistance. In April,
1951, Tupper took his product off store shelves and hired Wise to
create a new direct selling system under the name of Tupperware
Home Parties, Inc.

Impact

Home sales had already proved to be successful for the Fuller
Brush Company and numerous encyclopedia publishers, yet Brownie
Wise wanted to expand the possibilities. Her first step was to found
a campus-like headquarters in Kissimmee, Florida. There, Tupper and
a design department worked to develop new products, and Tupperware
Home Parties, Inc., under Wise’s direction, worked to develop
new incentives for Tupperware’s direct sellers, called hostesses.
Wise added spark to the notion of home demonstrations. “Parties,”
as they were called, included games, recipes, giveaways, and other
ideas designed to help housewives learn how to use Tupperware
products. The marketing philosophy was to make parties appealing
events at which women could get together while their children were
in school. This fit into the suburban lifestyle of the 1950’s. These parties
offered a nonthreatening means for home sales representatives
to attract audiences for their demonstrations and gave guests a chance
to meet and socialize with their neighbors. Often compared to
the barbecue parties of the 1950’s, Tupperware parties were social,
yet educational, affairs. While guests ate lunch or snacked on desserts,
the Tupperware hostess educated them about the technology
behind the bowls and their seals as well as suggesting a wide variety
of uses for the products. For example, a party might include
recipes for dinner parties, with information provided on how
party leftovers could be stored efficiently and economically with
Tupperware products.
While Tupperware products were changing the kitchens of America,
they were also changing the women who sold them (almost all the
hosts were women). Tupperware sales offered employment for women
at a time when society disapproved of women working outside the
home. Being a hostess, however, was not a nine-to-five position. The
job allowed women freedom to tailor their schedules to meet family
needs. Employment offered more than the economic incentive of 35
percent of gross sales. Hostesses also learned new skills and developed
self-esteem. An acclaimed mentoring program for new and advancing
employees provided motivational training. Managers came only from
the ranks of hostesses; moving up the corporate ladder meant spending
time selling Tupperware at home parties.
The opportunity to advance offered incentive. In addition, annual
sales conventions were renowned for teaching new marketing
strategies in fun-filled classes. These conventions also gave women
an opportunity to network and establish contacts. These experiences
proved to be invaluable as women entered the workforce in
increasing numbers in later decades.

Expanding Home-Sales Business

The tremendous success of Tupperware’s marketing philosophy
helped to set the stage for other companies to enter home sales.
These companies used home-based parties to educate potential customers
in familiar surroundings, in their own homes or in the
homes of friends. The Mary Kay Cosmetics Company, founded in
1963, used beauty makeovers in the home party setting as its chief
marketing tool. Discovery Toys, founded in 1978, encouraged guests
to get on the floor and play with the toys demonstrated at its home
parties. Both companies extended the socialization aspects found in
Tupperware parties.
In addition to setting the standard for home sales, Tupperware
is also credited with starting the plastic revolution. Early plastics
were of poor quality and cracked or broke easily. This created distrust
of plastic products among consumers. Earl Tupper’s demand
for quality set the stage for the future of plastics. He started with
high-quality resin and developed a process that kept the “Poly-T”
from splitting. He then invented an injection molding machine that
mass-produced his bowl and cup designs. His standards of quality
from start to finish helped other companies expand into plastics.
The 1950’s saw a wide variety of products appear in the improved
material, including furniture and toys. This shift from wood, glass,
and metal to plastic continued for decades.
Maintaining the position of Tupperware within the housewares
market meant keeping current. As more Americans were able to purchase
the newest refrigerators, Tupperware expanded to meet their
needs. The company added new products, improved marketing
strategies, and changed or updated designs. Over the years, Tupperware
added baking items, toys, and home storage containers for such
items as photographs, sewing materials, and holiday ornaments. The
1980’s and 1990’s brought microwaveable products.
As women moved into the work force in great numbers, Tupperware
moved with them. The company introduced lunchtime parties
at the workplace and parties at daycare centers for busy working
parents. Tupperware also started a fund-raising line, in special colors,
that provided organizations with a means to bring in money
while not necessitating full-fledged parties. New party themes developed
around time-saving techniques and health concerns such
as diet planning. Beginning in 1992, customers too busy to attend a
party could call a toll-free number, request a catalog, and be put in
contact with a “consultant,” as “hostesses” now were called.
Another marketing strategy developed out of a public push for
environmentally conscious products. Tupperware consultants stressed
the value of buying food in bulk to create less trash as well as saving
money. To store these increased purchases, the company developed
a new line for kitchen staples called Modular Mates. These stackable
containers came in a wide variety of shapes and sizes to hold everything
from cereal to flour to pasta. They were made of see-through
plastic, allowing the user to see if the contents needed replenishing.
Some consultants tailored parties around ideas to better organize
kitchen cabinets using the new line. Another environmentally conscious
product idea was the Tupperware lunch kit. These kits did
away with the need for throwaway products such as paper plates,
plastic storage bags, and aluminum foil. Lunch kits marketed in
other countries were developed to accommodate the countries’ particular
needs. For example, Japanese designs included chopsticks,
while Latin American styles were designed to hold tortillas.

Design Changes

Tupperware designs have been well received over the years.
Early designs prompted a 1947 edition of House Beautiful to call the
product “Fine Art for 39 cents.” Fifteen of Tupper’s earliest designs
are housed in a permanent collection at the Museum of Modern Art
in New York City. Other museums, such as the Metropolitan Museum
of Art and the Brooklyn Museum, also house Tupperware designs.
Tupperware established its own Museum of Historic Food
Containers at its international headquarters in Florida. Despite this
critical acclaim, the company faced a constant struggle to keep
product lines competitive with more accessible products, such as
those made by Rubbermaid, that could be found on the shelves of
local grocery or department stores.
Some of the biggest design changes came with the hiring of
Morison Cousins in the early 1990’s. Cousins, an accomplished designer,
set out to modernize the Tupperware line. He sought to return
to simple, traditional styles while bringing in time-saving aspects.
He changed lid designs to make them easier to clean and
rounded the bottoms of bowls so that every portion could be scooped
out. Cousins also added thumb handles to bowls.
Backed by a knowledgeable sales force and quality product, the
company experienced tremendous growth. Tupperware sales reached
$25 million in 1954. By 1958, the company had grown from seven
distributorships to a vast system covering the United States and
Canada. That same year, BrownieWise left the company, and Tupper
Plastics was sold to Rexall Drug Company for $9 million. Rexall
Drug changed its name to Dart Industries, Inc., in 1969, then merged
with Kraft, Inc., eleven years later to become Dart and Kraft, Inc.
During this time of parent-company name changing, Tupperware
continued to be an important subsidiary. Through the 1960’s and
1970’s, the company spread around the world, with sales inWestern
Europe, the Far East, and Latin America. In 1986, Dart and Kraft,
Inc., split into Kraft, Inc., and Premark International, Inc., of which
Dart (and therefore Tupperware) was a subsidiary. Premark International
included other home product companies such as West
Bend, Precor, and Florida Tile.
By the early 1990’s, annual sales of Tupperware products reached
$1.1 billion. Manufacturing plants in Halls, Tennessee, and Hemingway,
South Carolina, worked to meet the high demand for Tupperware
products in more than fifty countries. Foreign sales accounted
for almost 75 percent of the company’s business. By meeting the
needs of consumers and keeping current with design changes, new
sales techniques, and new products, Tupperware was able to reach
90 percent of America’s homes.

Earl S. Tupper

Born in 1907, Earl Silas Tupper came from a family of go-getters.
His mother, Lulu Clark Tupper, kept a boardinghouse and
took in laundry, while his father, Earnest, ran a small farm and
greenhouse in New Hampshire. The elder Tupper was also a
small-time inventor, patenting a device for stretching out chickens
to make cleaning them easier. Earl absorbed the family’s
taste for invention and enterprise.
Fresh out of high school in 1925, Tupper vowed to turn himself
into a millionaire by the time he was thirty. He started a
landscaping and nursery business in 1928, but the Depression
led his company, Tupper Tree, into bankruptcy in 1936. Tupper
was undeterred. He hired on with Du Pont the next year. Du
Pont taught him a great deal about the chemistry and manufacturing
of plastics, but it did not give him scope to apply his
ideas, so in 1938 he founded the Earl S. Tupper Company. He
continued to work as a contractor for Du Pont to make the
fledgling company profitable, and during World War II the
company made plastic moldings for gas masks and Navy signal
lamps. Finally, in the 1940’s Tupper could devote himself to
his dream—designing plastic food containers, cups, and such
small household conveniences as cases for cigarette packs.
Thanks to aggressive, innovative direct marketing, Tupper’s
kitchenware, Tupperware, became synonymous with plastic
containers during the 1950’s. In 1958 Tupper sold his company
to Rexall for $16 million, having finally realized his youthful
ambition to make himself wealthy through Yankee wit and
hard work. He died in 1983.

See also : Electric refrigerator; Food freezing; Freeze-drying; Microwave
cooking; Plastic; Polystyrene;Tupperware;Teflon

Tungsten filament

noreply@blogger.com (Unknown) — Sat, 18 Oct 2014 03:26:00 -0700

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 ,Tungsten filament

Tuberculosis vaccine

noreply@blogger.com (Unknown) — Thu, 25 Sep 2014 23:13:00 -0700

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

noreply@blogger.com (Unknown) — Tue, 26 Aug 2014 06:59:00 -0700

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

noreply@blogger.com (Unknown) — Wed, 16 Jul 2014 00:39:00 -0700

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

noreply@blogger.com (Unknown) — Sun, 8 Jun 2014 23:57:00 -0700

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

noreply@blogger.com (Unknown) — Sat, 7 Jun 2014 02:48:00 -0700

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

noreply@blogger.com (Unknown) — Fri, 25 Apr 2014 23:05:00 -0700

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 ; Thermal cracking process

Tevatron accelerator

noreply@blogger.com (Unknown) — Thu, 3 Apr 2014 00:18:00 -0700

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

noreply@blogger.com (Unknown) — Mon, 10 Feb 2014 00:17:00 -0800

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.

Telephone switching

noreply@blogger.com (Unknown) — Thu, 23 Jan 2014 00:33:00 -0800

The invention:

The first completely automatic electronic system
for switching telephone calls.

The people behind the invention:

Almon B. Strowger (1839-1902), an American inventor
Charles Wilson Hoover, Jr. (1925- ), supervisor of memory
system development
Wallace Andrew Depp (1914- ), director of Electronic
Switching
Merton Brown Purvis (1923- ), designer of switching
matrices

Electromechanical Switching Systems

The introduction of electronic switching technology into the telephone
network was motivated by the desire to improve the quality
of the telephone system, add new features, and reduce the cost of
switching technology. Telephone switching systems have three features:
signaling, control, and switching functions. There were several
generations of telephone switching equipment before the first
fully electronic switching “office” (device) was designed.
The first automatic electromechanical (partly electronic and partly
mechanical) switching office was the Strowger step-by-step switch.
Strowger switches relied upon the dial pulses generated by rotary
dial telephones to move their switching elements to the proper positions
to connect one telephone with another. In the step-by-step process,
the first digit dialed moved the first mechanical switch into position,
the second digit moved the second mechanical switch into
position, and so forth, until the proper telephone connection was established.
These Strowger switching offices were quite large, and
they lacked flexibility and calling features.
The second generation of automatic electromechanical telephone
switching offices was of the “crossbar” type. Initially, crossbar
switches relied upon a specialized electromechanical controller called
a “marker” to establish call connections. Electromechanical telephone
switching offices had difficulty implementing additional features
and were unable to handle large numbers of incoming calls.

Electronic Switching Systems

In the early 1940’s, research into the programmed control of
switching offices began at the American Telephone and Telegraph
Company’s Bell Labs. This early research resulted in a trial office being
put into service in Morris, Illinois, in 1960. The Morris switch
used a unique memory called the “flying spot store.” It used a photographic
plate as a program memory, and the memory was accessed
optically. In order to change the memory, one had to scratch
out or cover parts of the photographic plate.
Before the development of the Morris switch, gas tubes had been
used to establish voice connections. This was accomplished by applying
a voltage difference across the end points of the conversation.
When this voltage difference was applied, the gas tubes would
conduct electricity, thus establishing the voice connection. The Morris
trial showed that gas tubes could not support the voltages that
the new technology required to make telephones ring or to operate
pay telephones.
The knowledge gained from the Morris trial led to the development
of the first full-scale, commercial, computer-controlled
electronic switch, the electronic switching system 1 (ESS-1). The
first ESS-1 went into service in New Jersey in 1965. In the ESS-1,
electromechanical switching elements, or relays, were controlled
by computer software. A centralized computer handled call processing.
Because the telephone service of an entire community
depends on the reliability of the telephone switching office, the
ESS-1 had two central processors, so that one would be available
if the other broke down. The switching system of the ESS-1 was
composed of electromechanical relays; the control of the switching
system was electronic, but the switching itself remained mechanical.
Bell Labs developed models to demonstrate the concept of integrating
digital transmission and switching systems. Unfortunately,
the solid state electronics necessary for such an undertaking had not
developed sufficiently at that time, so the commercial development
of digital switching was not pursued. New versions of the ESS continued
to employ electromechanical technology, although mechanical
switching elements can cause impulse noise in voice signals and
are larger and more difficult to maintain than electronic switching
elements. Ten years later, however, Bell Labs began to develop a digital
toll switch, the ESS-4, in which both switching and control functions
were electronic.
Although the ESS-1 was the first electronically controlled switching
system, it did not switch voices electronically. The ESS-1 used
computer control to move mechanical contacts in order to establish
a conversation. In a fully electronic switching system, the voices are
digitized before switching is performed. This technique, which is
called “digital switching,” is still used.
The advent of electronically controlled switching systems made
possible features such as call forwarding, call waiting, and detailed
billing for long-distance calls. Changing these services became a
matter of simply changing tables in computer programs. Telephone
maintenance personnel could communicate with the central processor
of the ESS-1 by using a teletype, and they could change numbers
simply by typing commands on the teletype. In electromechanically
controlled telephone switching systems, however, changing numbers
required rewiring.

Consequences

Electronic switching has greatly decreased the size of switching
offices. Digitization of the voice prior to transmission improves
voice quality. When telephone switches were electromechanical, a
large area was needed to house the many mechanical switches that
were required. In the era of electronic switching, voices are switched
digitally by computer. In this method, voice samples are read into a
computer memory and then read out of the memory when it is time
to connect a caller with a desired number. Basically, electronic telephone
systems are specialized computer systems that move digitized
voice samples between customers.
Telephone networks are moving toward complete digitization.
Digitization was first applied to the transmission of voice signals.
This made it possible for a single pair of copper wires to be shared
by a number of telephone users. Currently, voices are digitized
upon their arrival at the switching office. If the final destination of
the telephone call is not connected to the particular switching office,
the voice is sent to the remote office by means of digital circuits.
Currently, voice signals are sent between the switching office and
homes or businesses. In the future, digitization of the voice signal
will occur in the telephone sets themselves. Digital voice signals
will be sent directly from one telephone to another. This will provide
homes with direct digital communication. Anetwork that provides
such services is called the “integrated services digital network”
(ISDN).

See also : Cell phone; Long-distance telephone; Rotary dial telephone;

Teflon

noreply@blogger.com (Unknown) — Thu, 24 Oct 2013 00:25:00 -0700

The invention:

Afluorocarbon polymer whose chemical inertness
and physical properties have made it useful for many applications,
from nonstick cookware coatings to suits for astronauts.

The person behind the invention:

Roy J. Plunkett (1910-1994), an American chemist

Nontoxic Refrigerant Sought

As the use of mechanical refrigeration increased in the late 1930’s,
manufacturers recognized the need for a material to replace sulfur
dioxide and ammonia, which, although they were the commonly
used refrigerants of the time, were less than ideal for the purpose.
The material sought had to be nontoxic, odorless, colorless, and not
flammable. Thomas Midgley, Jr., and Albert Henne of General Motors
Corporation’s Frigidaire Division concluded, from studying
published reports listing properties of a wide variety of chemicals,
that hydrocarbon-like materials with hydrogen atoms replaced by
chlorine and fluorine atoms would be appropriate.
Their conclusion led to the formation of a joint effort between the
General Motors Corporation’s Frigidaire Division and E. I. Du Pont
de Nemours to research and develop the chemistry of fluorocarbons.
In this research effort, a number of scientists began making
and studying the large number of individual chemicals in the general
class of compounds being investigated. It fell to Roy J. Plunkett
to do a detailed study of tetrafluoroethylene, a compound consisting
of two carbon atoms, each of which is attached to the other as
well as to two fluorine atoms.

The “Empty” Tank

Tetrafluoroethylene, at normal room temperature and pressure,
is a gas that is supplied to users in small pressurized cylinders. On
the morning of the day of the discovery, Plunkett attached such a
tank to his experimental apparatus and opened the tank’s valve. To
his great surprise, no gas flowed from the tank. Plunkett’s subsequent
actions transformed this event from an experiment gone
wrong into a historically significant discovery. Rather than replacing
the tank with another and going on with the work planned for
the day, Plunkett, who wanted to know what had happened, examined
the “empty” tank. When he weighed the tank, he discovered
that it was not empty; it did contain the chemical that was listed on
the label. Opening the valve and running a wire through the opening
proved that what had happened had not been caused by a malfunctioning
valve. Finally, Plunkett sawed the cylinder in half and
discovered what had happened. The chemical in the tank was no
longer a gas; instead, it was a waxy white powder.
Plunkett immediately recognized the meaning of the presence of
the solid. The six-atom molecules of the tetrafluoroethylene gas had
somehow linked with one another to form much larger molecules.
The gas had polymerized, becoming polytetrafluoroethylene, a solid
with a high molecular weight. Capitalizing on this occurrence,
Plunkett, along with other Du Pont chemists, performed a series of
experiments and soon learned to control the polymerization reaction
so that the product could be produced, its properties could be
studied, and applications for it could be developed.
The properties of the substance were remarkable indeed. It was
unaffected by strong acids and bases, withstood high temperatures
without reacting or melting, and was not dissolved by any solvent
that the scientists tried. In addition to this highly unusual behavior,
the polymer had surface properties that made it very slick. It was so
slippery that other materials placed on its surface slid off in much
the same way that beads of water slide off the surface of a newly
waxed automobile.
Although these properties were remarkable, no applications were
suggested immediately for the new material. The polymer might
have remained a laboratory curiosity if a conversation had not
taken place between Leslie R. Groves, the head of the Manhattan
Project (which engineered the construction of the first atomic bombs),
and a Du Pont chemist who described the polymer to him. The
Manhattan Project research team was hunting for an inert material
to use for gaskets to seal pumps and piping. The gaskets had to be
able to withstand the highly corrosive uranium hexafluoride with
which the team was working. This uranium compound is fundamental
to the process of upgrading uranium for use in explosive devices
and power reactors. Polytetrafluoroethylene proved to be just
the material that they needed, and Du Pont proceeded, throughout
World War II and after, to manufacture gaskets for use in uranium
enrichment plants.
The high level of secrecy of the Manhattan Project in particular
and atomic energy in general delayed the commercial introduction
of the polymer, which was called Teflon, until the late 1950’s. At that
time, the first Teflon-coated cooking utensils were introduced.

Impact

Plunkett’s thoroughness in following up a chance observation
gave the world a material that has found a wide variety of uses, ranging
from home kitchens to outer space. Some applications make use
of Teflon’s slipperiness, othersmake use of its inertness, and others take
advantage of both properties.
The best-known application of Teflon is as a nonstick coating for cookware.
Teflon’s very slippery surface initially was troublesome, when it proved to be
difficult to attach to other materials. Early versions of Teflon-coated cookware
shed their surface coatings easily, even when care was taken to avoid scraping it off.
A suitable bonding process was soon developed, however, and the present coated
surfaces are very rugged and provide a noncontaminating coating that can be cleaned
easily.
Teflon has proved to be a useful material in making devices that
are implanted in the human body. It is easily formed into various
shapes and is one of the few materials that the human body does not
reject. Teflon has been used to make heart valves, pacemakers, bone
and tendon substitutes, artificial corneas, and dentures.
Teflon’s space applications have included its use as the outer skin
of the suits worn by astronauts, as insulating coating on wires and
cables in spacecraft that must resist high-energy cosmic radiation,
and as heat-resistant nose cones and heat shields on spacecraft.

Roy J. Plunkett

Roy J. Plunkett was born in 1910 in New Carlisle, Ohio. In
1932 he received a bachelor’s degree in chemistry from Manchester
College and transferred to Ohio State University for
graduate school, earning a master’s degree in 1933 and a doctorate
in 1936. The same year he went to work for E. I. Du Pont
de Nemours and Company as a research chemist at the Jackson
Laboratory in Deepwater, New Jersey. Less then two years later,
when he was only twenty-seven years old, he found the strange
polymer tetrafluoroethylene, whose trade name became Teflon.
It would turn out to be among Du Pont’s most famous products.
In 1938 Du Pont appointed Plunkett the chemical supervisor
at its largest plant, the Chamber Works in Deepwater, which
produced tetraethyl lead. He held the position until 1952 and
afterward directed the company’s Freon Products Division. He
retired in 1975. In 1985 he was inducted into the Inventor’s Hall
of Fame, and after his death in 1994, Du Pont created the
Plunkett Award, presented to inventors who find new uses for
Teflon and Tefzel, a related fluoropolymer, in

See also :

Buna rubber; Neoprene; Nylon; Plastic; Polystyrene;