1.Superheterodyne Receiver
Armstrong improves radio technology.
It may not be the most eye-catching of names, but the superheterodyne receiver vastly improved radio technology in the early twentieth century by filtering out unwanted radio signals.
The "superhet," as it is commonly called, is the invention of Edwin Howard Armstrong (1890-1954). While working on ways to amplify radio signals during World War I, he hit upon a cunning idea. An incoming radio signal is mixed with an internal signal generated by the receiver (known as a local oscillator). The two signals are multiplied together. This creates two new signals: One is the sum of the two originals, and one is the difference. So, if you have an incoming radio frequency at 5 MHz and a local oscillator at 4 MHz, signals will be seen at 9 MHz and 1 MHz. This is known as heterodyning. A filter can be used to remove any signal that does not fit a narrow frequency range around the difference signal (here 1 MHz). The beauty of the system is that precise tuning can be achieved by varying the frequency of the local oscillator. For example, if you have a filter fixed at 1 MHz and radio stations broadcasting at 5, 6, and 7 MHz, the three stations can be "tuned in" by turning the dial-and therefore the local oscillator-to 4, 5, and 6 MHz respectively.
Armstrong patented the technique in 1918, and it was quickly adopted by the military. The superhet principle was later used to tune TV and radio broadcasts and is still widely used today. Armstrong went on to invent FM radio, but he also spent many years fighting patent lawsuits and eventually committed suicide.
2.Mass Spectrometer
Dempster devises an instrument essential to analysis of the physical world.
The mass spectrometer sorts ionized atoms emitted by specific heated substances according to their individual masses. The analysis is usually performed by passing these ions through a vacuum chamber placed in a strong magnetic field. The path of individual ions is a function of their mass, velocity, and charge.
The foundation of the technique was the investigation of the ions produced by cathode ray tubes, research that led to the discovery of isotopes by J.J. Thomson in 1913. An effective mass spectrometer was produced after World War I by Arthur J. Dempster (1886-1950), who used an electrical collector in 1918 at the University of Chicago. One year later Francis W.. Aston (1877-1945) used a photographic plate as a detector at the University of Cambridge. Aston discovered 212 naturaily occurring isotopes, and was awarded the Nobel Prize for Chemistry in 1922. By the 1940s mass spectrometers were being commercially manufactured and were being used by many experimenters-geologists, to measure the age of rocks by looking at their radioactive decay products; chemists, to analyze complex organic molecules; and space scientists, to analyze the composition of the upper atmosphere. Electron beams and lasers were used to excite the ions.
Miniature mass spectrometers were produced for portable medical applications, and versions were placed on spacecraft to analyze the atmospheres of Venus and Mars and the gases emitted from Halley's comet. Not only could the instruments measure minute samples, they could also measure the mass of an atom to the accuracy of one part in a billion.
3.Hydraulic Brake
Lougheed uses fluid to improve braking.
Before the invention of hydraulic brakes, various systems of levers and pads were developed, but thei main drawback was that they needed regula adjustment to maintain equal braking on all wheels Hydraulic brakes, invented in 1918 by Malcolm Lougheed, addressed this problem and gave much more responsive braking
Hydraulic brakes work by having a series of pistons connected to the brake pedal and the brake pads themselves. These are all interconnected by a central "reservoir of non-compressible fluid, initially a mix of water and alcohol. The differences in diameter of the pistons means that the same pressure inside the system magnifies the force applied to the brake pedal.
This greater force allowed the brakes to be applied
much more firmly and so bring cars to a quicker halt. The system was taken up by the Duesenberg motor company, and the first passenger car to use a hydraulic braking system-the "Model A-went into production in 1921. Despite the system's superiority to previous braking systems, other car manufacturers were slow to follow, possibly because of early problems with leaks: Gradually, however, as technology for lines and pistons improved, hydraulic brakes were introduced universally, and in 1938, Ford-the last manufacturer to catch on-finally switched over on all its cars.
4.Anthrax Vaccine
Smith reveals a breakthrough medication.
Before the invention of an effective vaccine for anthrax, the disease was a major agricultural problem and economic burden. Anthrax is a potentially fatal disease that affects animals and humans and is spread via airborne spores. Before it was fully understood, the illness was referred to as "ragpickers' disease or woolsorter's disease because it was mostly caught by people working closely with animal hides.
In 1877, the Prussian physician Robert Koch (1843 1910) finally made a link between anthrax infection and a spore-forming bacteria called Bacillus anthracis. In the late nineteenth century, renowned scientist Louis Pasteur (1822-1895) developed a two-dose vaccine for anthrax that he had tested on sheep. However, storage quickly reduced the efficacy of the vaccine, and its effect was sometimes fatal.
It was the Australian scientist John McGarvie Smith (1844-1918) and his research collaborator, John Gunn (1860-1910), who eventually developed a safe, single dose vaccine. Though the the two men shared an amicable relationship, neither one ever conceded that the other was responsible for the invention. Following Gunn's death in 1910, Smith refused to make the formula public and even resorted to setting up a laboratory in his own home to start production of the vaccine.
After years of resisting pressure by Australia's Minister of Agriculture, W. C. Grahame, to divulge the secret, Smith's health was deteriorating and he finally agreed to make his work public. In 1918, he handed over the desperately sought formula to Dr. Frank Edgar Wall on behalf of the State government. Smith also donated $10,000 to set up the John McGarvie Smith Institute where his vaccine could be mass-produced and distributed.
5.Pivoting Bed
Murphy improves one-room living with an ingenious space-saving bed.
In early twentieth-century San Francisco, William Murphy (1876-1959) found that he had a problem. He wanted to court a young opera singer from a good background, but he lived in a small one-room apartment with a bed taking up most of the floor space. Since it would not be proper to bring a young lady back to his bedroom, he began experimenting
with pivoting beds to make his room respectable. He applied for his first patent in 1900 and formed the Murphy Wall Bed Company that year. The company is still in business today, and is the secondoldest furniture company in America.
In the earliest and most familiar Murphy beds, the bed flips up at the head to be stored in a closet. In 1918 Murphy invented the pivoting bed that pivoted on a swinging arm around the door jamb of a closet, then lowered into a sleeping position. The beds were at the height of their popularity in the 1920s and 1930s, but declined after World War Il as the economy grew and single-family homes became more common. But with the recession of the 1970s, the beds came back into style as a way of making the most of limited space, and the business began to grow once more.
Murphy beds have provided countless opportunities for slapstick comedy throughout the years, regularly featuring in the films of Abbot and Costello, Laurel and Hardy, and Charlie Chaplin, always ready to spring from the wall to bonk someone on the head or suddenly fold up to leave someone trapped helplessly in the wall.
And Murphy's inventiveness paid off, too-he eventually married his musical sweetheart.
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