Epidendrosaurus - Facts and Figures

Epidendrosaurus - Facts and Figures Name: Epidendrosaurus (Greek for lizard in the tree); pronounced EP-ih-DEN-dro-SORE-us Habitat: Woodlands of Asia Historical Period: Late Jurassic (150 million years ago) Size and Weight: About 6 inches long and a few ounces Diet: Probably omnivorous Distinguishing Characteristics: Tiny size; long arms with clawed hands About Epidendrosaurus Archaeopteryx gets all the headlines, but theres a convincing case to be made that Epidendrosaurus was the first reptile to be closer to a bird than to a dinosaur. This pint-sized theropod was less than half the size of its more famous cousin, and its a sure bet that it was covered with feathers. Most notably, Epidendrosaurus appears to have been adapted to an arboreal (tree-dwelling) lifestyleits small size would have made it a simple matter to hop from branch to branch, and its long, curved claws were likely used to pry insects from tree bark. So was the late Jurassic Epidendrosaurus really a bird rather than a dinosaur? As with all of the feathered dino-birds, as these reptiles are called, its impossible to say. Its better to think of the categories of bird and dinosaur as lying along a continuum, with some genera closer to either extreme and some smack in the middle. (By the way, some paleontologists believe that Epidendrosaurus should actually be subsumed under another dino-bird genus, Scansoriopteryx.)

The History and Importance of the Vacuum Tube

The History and Importance of the Vacuum Tube A vacuum tube, also called an electron tube, is a sealed-glass or metal-ceramic enclosure used in electronic circuitry to control the flow of electrons between the metal electrodes sealed inside the tubes. The air inside the tubes is removed by a vacuum. Vacuum tubes are used for amplification of a weak current, rectification of an alternating current to direct current (AC to DC), generation of oscillating radio-frequency (RF) power for radio and radar, and more. According to PV Scientific Instruments, The earliest forms of such tubes appeared in the late 17th century. However, it was not until the 1850s that sufficient technology existed to produce sophisticated versions of such tubes. This technology included efficient vacuum pumps, advanced glassblowing techniques, and the Ruhmkorff induction coil. Vacuum tubes were used widely in electronics in the early twentieth century, and the cathode-ray tube remained in use for televisions and video monitors before being supplanted by plasma, LCD, and other technologies. Timeline In 1875, American, G.R. Carey invented the phototube.In 1878, Englishman Sir William Crookes invented the Crookes tube, an early prototype of the cathode-ray tube.In 1895, German, Wilhelm Roentgen invented an early prototype Xray tube.In 1897, German, Karl Ferdinand Braun invents the cathode ray tube oscilloscope.In 1904, John Ambrose Fleming invented the first practical electron tube called the Fleming Valve. Leming invents the vacuum tube diode.In 1906, Lee de Forest invented the Audion later called the triode, an improvement on the Fleming Valve tube.In 1913, William D. Coolidge invented the Coolidge Tube, the first practical Xray tube.In 1920, RCA began the first commercial electron tube manufacturing.In 1921, American Albert Hull invented the magnetron electronic vacuum tube.In 1922, Philo T. Farnsworth develops the first tube scanning system for television.In 1923, Vladimir K Zworykin invented the iconoscope or the cathode-ray tube and the kinescope.In 1926, Hull and Williams c o-invented the tetrode electronic vacuum tube. In 1938, Americans Russell and Sigurd Varian co-invented the klystron tube.