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πŸ”— Lee Felsenstein

πŸ”— Biography πŸ”— Biography/science and academia

Lee Felsenstein (born April 27, 1945) is an American computer engineer who played a central role in the development of personal computers. He was one of the original members of the Homebrew Computer Club and the designer of the Osborne 1, the first mass-produced portable computer.

Before the Osborne, Felsenstein designed the Intel 8080 based Sol-20 computer from Processor Technology, the PennyWhistle modem, and other early "S-100 bus" era designs. His shared-memory alphanumeric video display design, the Processor Technology VDM-1 video display module board, was widely copied and became the basis for the standard display architecture of personal computers.

Many of his designs were leaders in reducing costs of computer technologies for the purpose of making them available to large markets. His work featured a concern for the social impact of technology and was influenced by the philosophy of Ivan Illich. Felsenstein was the engineer for the Community Memory project, one of the earliest attempts to place networked computer terminals in public places to facilitate social interactions among individuals, in the era before the commercial Internet.

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πŸ”— Wardenclyffe Tower a.k.a. the Tesla Tower

πŸ”— Physics πŸ”— New York (state) πŸ”— National Register of Historic Places πŸ”— New York (state)/Long Island

Wardenclyffe Tower (1901–1917), also known as the Tesla Tower, was an early experimental wireless transmission station designed and built by Nikola Tesla in Shoreham, New York in 1901–1902. Tesla intended to transmit messages, telephony and even facsimile images across the Atlantic to England and to ships at sea based on his theories of using the Earth to conduct the signals. His decision to scale up the facility and add his ideas of wireless power transmission to better compete with Guglielmo Marconi's radio based telegraph system was met with refusal to fund the changes by the project's primary backer, financier J. P. Morgan. Additional investment could not be found, and the project was abandoned in 1906, never to become operational.

In an attempt to satisfy Tesla's debts, the tower was demolished for scrap in 1917 and the property taken in foreclosure in 1922. For 50 years, Wardenclyffe was a processing facility producing photography supplies. Many buildings were added to the site and the land it occupies has been trimmed down to 16 acres (6.5Β ha) but the original, 94 by 94Β ft (29 by 29Β m), brick building designed by Stanford White remains standing to this day.

In the 1980s and 2000s, hazardous waste from the photographic era was cleaned up, and the site was sold and cleared for new development. A grassroots campaign to save the site succeeded in purchasing the property in 2013, with plans to build a future museum dedicated to Nikola Tesla. In 2018 the property was listed on the National Register of Historic Places.

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πŸ”— Qanat

πŸ”— Civil engineering πŸ”— Water

A qanat or kariz is a gently sloping underground channel to transport water from an aquifer or water well to surface for irrigation and drinking, acting as an underground aqueduct. This is an old system of water supply from a deep well with a series of vertical access shafts. The qanats still create a reliable supply of water for human settlements and irrigation in hot, arid, and semi-arid climates, but the value of this system is directly related to the quality, volume, and regularity of the water flow. Traditionally qanats are built by a group of skilled laborers, muqannΔ«s, with hand labor. The profession historically paid well and was typically handed down from father to son. According to most sources, the qanat technology was developed in ancient Iran by the Persian people sometime in the early 1st millennium BCE, and spread from there slowly westward and eastward. However, some other sources suggest a Southeast Arabian origin.

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  • "Qanat" | 2023-11-11 | 423 Upvotes 100 Comments
  • "Qanat" | 2016-05-18 | 186 Upvotes 69 Comments

πŸ”— Datasaurus dozen – Different datasets with the same descriptive statistics

πŸ”— Mathematics πŸ”— Statistics

The Datasaurus dozen comprises thirteen data sets that have nearly identical simple descriptive statistics to two decimal places, yet have very different distributions and appear very different when graphed. It was inspired by the smaller Anscombe's quartet that was created in

πŸ”— SNAP-10A was an experimental nuclear reactor launched into space in 1965

πŸ”— Spaceflight

SNAP-10A (Systems for Nuclear, Auxiliary Power, aka Snapshot for Space Nuclear Auxiliary Power Shot, also known as OPS 4682, COSPAR 1965-027A) was a US experimental nuclear powered satellite launched into space in 1965 as part of the SNAPSHOT program. The test marked the world's first operation of a nuclear reactor in orbit, and also the first operation of an ion thruster system in orbit. It is the only fission reactor power system launched into space by the United States. The reactor stopped working after just 43 days due to a non-nuclear electrical component failure. The Systems Nuclear Auxiliary Power Program (SNAP) reactor was specifically developed for satellite use in the 1950s and early 1960s under the supervision of the U.S. Atomic Energy Commission.

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πŸ”— β€œSILEX is the only privately held information that is classified by the US gov.”

πŸ”— Physics

Separation of isotopes by laser excitation (SILEX) is a process for isotope separation that is being investigated to produce enriched uranium on an industrial scale using lasers. It was developed in the 1990s and is a variant of molecular laser isotope separation (MLIS). For uranium, it uses a cold molecular beam with UF6 in a carrier cas, in which the 235UF6 is selectively excited by an infrared laser near 16Β Β΅m. But in contrast to earlier MLIS techniques developed since the 1970s, it does not dissociate the molecule.

πŸ”— Utah Data Center

πŸ”— United States/U.S. Government πŸ”— United States πŸ”— Mass surveillance πŸ”— Espionage πŸ”— Cryptography πŸ”— Cryptography/Computer science πŸ”— United States/Utah

The Utah Data Center (UDC), also known as the Intelligence Community Comprehensive National Cybersecurity Initiative Data Center, is a data storage facility for the United States Intelligence Community that is designed to store data estimated to be on the order of exabytes or larger. Its purpose is to support the Comprehensive National Cybersecurity Initiative (CNCI), though its precise mission is classified. The National Security Agency (NSA) leads operations at the facility as the executive agent for the Director of National Intelligence. It is located at Camp Williams near Bluffdale, Utah, between Utah Lake and Great Salt Lake and was completed in May 2019 at a cost of $1.5 billion.

The Utah Data Center, code-named Bumblehive, is the first Intelligence Community Comprehensive National Cyber-security Initiative (IC CNCI) data center designed to support the US intelligence community. The "massive data repository" is designed to cope with the large increase in digital data that has accompanied the rise of the global internet.

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πŸ”— Isochronous Curves

πŸ”— Mathematics

A tautochrone or isochrone curve (from Greek prefixes tauto- meaning same or iso- equal, and chrono time) is the curve for which the time taken by an object sliding without friction in uniform gravity to its lowest point is independent of its starting point on the curve. The curve is a cycloid, and the time is equal to Ο€ times the square root of the radius (of the circle which generates the cycloid) over the acceleration of gravity. The tautochrone curve is related to the brachistochrone curve, which is also a cycloid.

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πŸ”— Isotype picture language

πŸ”— Constructed languages πŸ”— Graphic design

Isotype (International System of Typographic Picture Education) is a method of showing social, technological, biological, and historical connections in pictorial form. It consists of a set of standardized and abstracted pictorial symbols to represent social-scientific data with specific guidelines on how to combine the identical figures using serial repetition. It was first known as the Vienna Method of Pictorial Statistics (Wiener Methode der Bildstatistik), due to its having been developed at the Gesellschafts- und Wirtschaftsmuseum in Wien (Social and Economic Museum of Vienna) between 1925 and 1934. The founding director of this museum, Otto Neurath, was the initiator and chief theorist of the Vienna Method. Gerd Arntz was the artist responsible for realising the graphics. The term Isotype was applied to the method around 1935, after its key practitioners were forced to leave Vienna by the rise of Austrian fascism.

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