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🔗 Bose–Einstein Condensate
A Bose–Einstein condensate (BEC) is a state of matter (also called the fifth state of matter) which is typically formed when a gas of bosons at low densities is cooled to temperatures very close to absolute zero (-273.15 °C). Under such conditions, a large fraction of bosons occupy the lowest quantum state, at which point microscopic quantum phenomena, particularly wavefunction interference, become apparent macroscopically. A BEC is formed by cooling a gas of extremely low density, about one-hundred-thousandth (1/100,000) the density of normal air, to ultra-low temperatures.
This state was first predicted, generally, in 1924–1925 by Albert Einstein following a paper written by Satyendra Nath Bose, although Bose came up with the pioneering paper on the new statistics.
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- "Bose–Einstein Condensate" | 2020-02-05 | 58 Upvotes 20 Comments
🔗 Magdeburg Water Bridge
The Magdeburg Water Bridge (German: Kanalbrücke Magdeburg) is a large navigable aqueduct in central Germany, located near Magdeburg. The largest canal underbridge in Europe, it spans the river Elbe and directly connects the Mittellandkanal to the west and Elbe-Havel Canal to the east of the river, allowing large commercial ships to pass between the Rhineland and Berlin without having to descend into and then climb out of the Elbe itself.
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- "Magdeburg Water Bridge" | 2019-11-21 | 52 Upvotes 41 Comments
🔗 Compressed-Air Car
A compressed-air car is a compressed-air vehicle powered by pressure vessels filled with compressed air. It is propelled by the release and expansion of the air within a motor adapted to compressed air. The car might be powered solely by air, or combined (as in a hybrid electric vehicle) with other fuels such as gasoline, diesel, or an electric plant with regenerative braking.
Compressed-air cars use a thermodynamic process. Air cools when expanding and heats when compressed. Thermal energy losses in the compressor and tankage reduce the capacity factor of compressed air systems.
This technology might develop into an inexpensive, clean transportation technology. The energy, vehicles and compressors might be produced easily by decentralized methods, even circular industry. Using plastic might permit open source fabrication using numerical control, including additive manufacturing. The compressed air for such vehicles might be produced easily by common types of renewable energy. For example, multistage air compressors and intercoolers or hydraulic pumps might be attached directly to trompes, hydropower, VAWT wind turbines or stirling engines using a solar concentrator. Direct mechanical compression avoids the Carnot inefficiencies of heat engines. Insulated storage of compressed air avoids energy conversion and battery storage. Heat-based systems might use tankage of solar-heated molten salts driving a heat exchanger rather than an onboard heat recovery system. Electric energy, electric grids and their issues might be avoided.
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- "Compressed-Air Car" | 2025-05-24 | 14 Upvotes 6 Comments
🔗 3-6-3 Rule
The term 3-6-3 Rule describes how the United States retail banking industry operated from the 1950s to the 1980s. The name 3-6-3 refers to the impression that bankers had a stable, comfortable existence by paying 3 percent interest on deposits, lending money out at 6 percent, and being able to "tee off at the golf course by 3 p.m."
The implication was that the banks were less competitive during that period than in subsequent years due to tight regulations that limited the formation and location of banks as well as restrictions on interest rates that could be charged or paid. As a result, bankers had "power and prestige ... while profits were steady and certain". These regulations were loosened in the 1980s.
Richmond Federal Reserve senior economist John R. Walter argues that, although there is evidence that restrictions on banks before the 1980s did limit the competitiveness of banking markets and thereby granted some banks monopoly power, "the regulatory restrictions probably had a limited effect on competition" during the time in question. Chicago Federal Reserve researchers Robert DeYoung and Tara Rice argue that, "Like most good jokes, the 3-6-3 rule mixes a grain of truth with a highly simplified view of reality."
The rule has been noted positively following the late-2000s financial crisis as a preferable way for banks to operate following the bailout of major banks.
Australia's banking system, which was deregulated in the 1990s in a manner similar to that in the U.S., also came to be characterized in the same way as did the United Kingdom's.
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- "3-6-3 Rule" | 2021-08-25 | 14 Upvotes 1 Comments
🔗 Harvard Mark I
The IBM Automatic Sequence Controlled Calculator (ASCC), called Mark I by Harvard University’s staff, was a general purpose electromechanical computer that was used in the war effort during the last part of World War II.
One of the first programs to run on the Mark I was initiated on 29 March 1944 by John von Neumann. At that time, von Neumann was working on the Manhattan Project, and needed to determine whether implosion was a viable choice to detonate the atomic bomb that would be used a year later. The Mark I also computed and printed mathematical tables, which had been the initial goal of British inventor Charles Babbage for his "analytical engine".
The Mark I was disassembled in 1959, but portions of it are displayed in the Science Center as part of the Harvard Collection of Historical Scientific Instruments. Other sections of the original machine were transferred to IBM and the Smithsonian Institution.
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- "Harvard Mark I" | 2019-08-07 | 44 Upvotes 23 Comments
🔗 Lycurgus Cup
The Lycurgus Cup is a 4th-century Roman glass cage cup made of a dichroic glass, which shows a different colour depending on whether or not light is passing through it: red when lit from behind and green when lit from in front. It is the only complete Roman glass object made from this type of glass, and the one exhibiting the most impressive change in colour; it has been described as "the most spectacular glass of the period, fittingly decorated, which we know to have existed".
The cup is also a very rare example of a complete Roman cage-cup, or diatretum, where the glass has been painstakingly cut and ground back to leave only a decorative "cage" at the original surface-level. Many parts of the cage have been completely undercut. Most cage-cups have a cage with a geometric abstract design, but here there is a composition with figures, showing the mythical King Lycurgus, who (depending on the version) tried to kill Ambrosia, a follower of the god Dionysus (Bacchus to the Romans). She was transformed into a vine that twined around the enraged king and restrained him, eventually killing him. Dionysus and two followers are shown taunting the king. The cup is the "only well-preserved figural example" of a cage cup.
The dichroic effect is achieved by making the glass with tiny proportions of nanoparticles of gold and silver dispersed in colloidal form throughout the glass material. The process used remains unclear, and it is likely that it was not well understood or controlled by the makers, and was probably discovered by accidental "contamination" with minutely ground gold and silver dust. The glass-makers may not even have known that gold was involved, as the quantities involved are so tiny; they may have come from a small proportion of gold in any silver added (most Roman silver contains small proportions of gold), or from traces of gold or gold leaf left by accident in the workshop, as residue on tools, or from other work. The very few other surviving fragments of Roman dichroic glass vary considerably in their two colours.
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- "Lycurgus Cup" | 2021-01-15 | 16 Upvotes 2 Comments
🔗 El Corte Inglés, Europe’s Biggest Department Store
El Corte Inglés S.A. (Spanish pronunciation: [el ˈkoɾte iŋˈɡles]), headquartered in Madrid, is the biggest department store group in Europe and ranks third worldwide. El Corte Inglés is Spain's only remaining department store chain. El Corte Inglés has been a member of the International Association of department stores since 1998.
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- "El Corte Inglés, Europe’s Biggest Department Store" | 2021-12-13 | 13 Upvotes 2 Comments
🔗 Add oil
"Add oil" is a Hong Kong English expression used as an encouragement and support to a person. Derived from the Chinese phrase Gayau (or Jiayou; Chinese: 加油), the expression is literally translated from the Cantonese phrase. It is originated in Hong Kong and is commonly used by bilingual Hong Kong speakers.
"Add oil" can be roughly translated as "Go for it". Though it is often described as "the hardest to translate well", the literal translation is the result of Chinglish and was added to the Oxford English Dictionary in 2018.
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- "Add oil" | 2023-12-05 | 64 Upvotes 28 Comments
🔗 Scuttlebutt: Decentralised, off-grid, mesh network and self-hosted social media
Secure Scuttlebutt (SSB) is a peer-to peer communication protocol, mesh network, and self-hosted social media ecosystem. Each user hosts their own content and the content of the peers they follow, which provides fault tolerance and eventual consistency. Messages are digitally signed and added to an append-only list of messages published by an author. SSB is primarily used for implementing distributed social networks, and utilizes cryptography to assure that content remains unforged as it is propagated through the network.
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- "Secure Scuttlebutt" | 2023-01-22 | 151 Upvotes 82 Comments
- "Scuttlebutt: Decentralised, off-grid, mesh network and self-hosted social media" | 2021-09-22 | 31 Upvotes 3 Comments
🔗 Amygdala hijack
An amygdala hijack refers to a personal, emotional response that is immediate, overwhelming, and out of measure with the actual stimulus because it has triggered a much more significant emotional threat. The term was coined by Daniel Goleman in his 1996 book Emotional Intelligence: Why It Can Matter More Than IQ.
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- "Amygdala hijack" | 2021-05-11 | 61 Upvotes 20 Comments