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The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a power ratio of 10 1/10 (approximately 1.26) or root-power ratio of 10 1/20 (approximately 1.12). [1] [2]
A sound level meter (also called sound pressure level meter ( SPL )) is used for acoustic measurements. It is commonly a hand-held instrument with a microphone. The best type of microphone for sound level meters is the condenser microphone, which combines precision with stability and reliability. [ 1] The diaphragm of the microphone responds to ...
Unit 731 (Japanese: 731部隊, Hepburn: Nana-san-ichi Butai), [note 1] short for Manchu Detachment 731 and also known as the Kamo Detachment [3]: 198 and the Ishii Unit, [5] was a covert biological and chemical warfare research and development unit of the Imperial Japanese Army that engaged in lethal human experimentation and biological weapons manufacturing during the Second Sino-Japanese War ...
The plots at the bottom show the signal intensity in the indicated row of the image (red: original signal, blue: with noise). Signal-to-noise ratio ( SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to noise power ...
The deepest underground laboratory in the United States, it houses multiple experiments in areas such as dark matter and neutrino physics research, biology, geology and engineering. There are currently 28 active research projects housed within the facility. Sanford Lab is managed by the South Dakota Science and Technology Authority (SDSTA).
Historically, the definition of a scientific instrument has varied, based on usage, laws, and historical time period. [1] [2] [3] Before the mid-nineteenth century such tools were referred to as "natural philosophical" or "philosophical" apparatus and instruments, and older tools from antiquity to the Middle Ages (such as the astrolabe and pendulum clock) defy a more modern definition of "a ...
Columbus is a science laboratory that is part of the International Space Station (ISS) and is the largest single contribution to the ISS made by the European Space Agency (ESA). Like the Harmony and Tranquility modules, the Columbus laboratory was constructed in Turin, Italy by Thales Alenia Space. The functional equipment and software of the ...
TL. v. t. e. Sound pressure or acoustic pressure is the local pressure deviation from the ambient (average or equilibrium) atmospheric pressure, caused by a sound wave. In air, sound pressure can be measured using a microphone, and in water with a hydrophone. The SI unit of sound pressure is the pascal (Pa).