Context and question: Additionally, Somalia has several private television networks, including Horn Cable Television and Universal TV. Two such TV stations re-broadcast Al-Jazeera and CNN. Eastern Television Network and SBC TV air from Bosaso, the commercial capital of Puntland. The Puntland and Somaliland regions also each have one government-run TV channel, Puntland TV and Radio and Somaliland National TV, respectively.
What type of Tv startions replay AL=jazeera and CNN?
Answer: private television networks
Context and question: Bitumen was used in early photographic technology. In 1826 or 1827, it was used by French scientist Joseph Nicephore Niepce to make the oldest surviving photograph from nature. The bitumen was thinly coated onto a pewter plate which was then exposed in a camera. Exposure to light hardened the bitumen and made it insoluble, so that when it was subsequently rinsed with a solvent only the sufficiently light-struck areas remained. Many hours of exposure in the camera were required, making bitumen impractical for ordinary photography, but from the 1850s to the 1920s it was in common use as a photoresist in the production of printing plates for various photomechanical printing processes.[not in citation given]
During what period was bitumen used in printing processes?
Answer: 1850s to the 1920s
Context and question: Ion gauges are used in ultrahigh vacuum. They come in two types: hot cathode and cold cathode. In the hot cathode version an electrically heated filament produces an electron beam. The electrons travel through the gauge and ionize gas molecules around them. The resulting ions are collected at a negative electrode. The current depends on the number of ions, which depends on the pressure in the gauge. Hot cathode gauges are accurate from 103 torr to 1010 torr. The principle behind cold cathode version is the same, except that electrons are produced in a discharge created by a high voltage electrical discharge. Cold cathode gauges are accurate from 102 torr to 109 torr. Ionization gauge calibration is very sensitive to construction geometry, chemical composition of gases being measured, corrosion and surface deposits. Their calibration can be invalidated by activation at atmospheric pressure or low vacuum. The composition of gases at high vacuums will usually be unpredictable, so a mass spectrometer must be used in conjunction with the ionization gauge for accurate measurement.
What must be used for accurate measurement on the composition of gases at a high vacuums?
Answer:
mass spectrometer must be used in conjunction with the ionization gauge