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Early reentry-vehicle concepts visualized in shadowgraphs of high speed wind tunnel tests. The concept of the ablative heat shield was described as early as 1920 by Robert Goddard: "In the case of meteors, which enter the atmosphere with speeds as high as 30 miles (48 km) per second, the interior of the meteors remains cold, and the erosion is due, to a large extent, to chipping or cracking of ...
Hydrogen is extremely flammable. Some countries have banned the use of hydrogen as a lift gas for commercial vehicles but it is allowed for recreational free ballooning in the United States, United Kingdom and Germany. The Hindenburg disaster is frequently cited as an example of the safety risks posed by hydrogen. The extremely high cost of ...
In November 2022, Quizlet announced a new CEO, Lex Bayer, the former CEO of Starship Technologies. [23] In March 2023, Quizlet started to incorporate AI features with the release "Q-Chat", a virtual AI tutor powered by OpenAI's ChatGPT API. [24] [25] [26] Quizlet launched four additional AI powered features in August 2023 to assist with student ...
For instance, argon, krypton, and xenon form clathrates with hydroquinone, but helium and neon do not because they are too small or insufficiently polarizable to be retained. [61] Neon, argon, krypton, and xenon also form clathrate hydrates, where the noble gas is trapped in ice. [62] An endohedral fullerene compound containing a noble gas atom
A-25 (25% argon/75% helium) is used for nonferrous base when higher heat input and good weld appearance are needed. A-50 (50% argon/50% helium) is used for nonferrous metals thinner than 0.75 inch for high-speed mechanized welding. A-75 (75% argon/25% helium) is used for mechanized welding of thick aluminium. Reduces weld porosity in copper. [14]
Closed-cycle gas turbine schematic C compressor and T turbine assembly w high-temperature heat exchanger ʍ low-temperature heat exchanger ~ mechanical load, e.g. electric generator. A closed-cycle gas turbine is a turbine that uses a gas (e.g. air, nitrogen, helium, argon, [1] [2] etc.) for the working fluid as part of a closed thermodynamic ...
A gas cylinder quad, also known as a gas cylinder bundle, is a group of high pressure cylinders mounted on a transport and storage frame. There are commonly 16 cylinders, each of about 50 litres capacity mounted upright in four rows of four, on a square base with a square plan frame with lifting points on top and may have fork-lift slots in the ...
A compressed-air vehicle (CAV) is a transport mechanism fueled by tanks of pressurized atmospheric gas and propelled by the release and expansion of the gas within a pneumatic motor. CAV's have found application in torpedoes , locomotives used in situations where standard locomotives are a hazard, and early prototype submarines .