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π Muntz Metal
Muntz metal (also known as yellow metal) is an alpha-beta brass alloy composed of approximately 60% copper, 40% zinc and a trace of iron. It is named after George Fredrick Muntz, a metal-roller of Birmingham, England, who commercialised the alloy following his patent of 1832.
The alloy must be worked hot and is used today for corrosion-resistant machine parts. Alpha-beta (also called duplex) metals contain both the Ξ± and Ξ² phases. The Ξ± phase refers to a crystal structure that is face-centered cubic, while the Ξ² phase is body-centered cubic.
Its original application was as a replacement for copper sheathing on the bottom of boats, as it maintained the anti-fouling abilities of the pure copper at around two thirds of the price. It became the material of choice for this application and Muntz made his fortune. It was found that copper prevented any organism that attempted to attach itself to a hull sheathed in the metal. Thus, it was also used to sheathe the piles of piers in tropical seas, as a protection against teredo shipworms, and in locomotive tubes. After successful experimentation with the sheathing Muntz also took out a patent for bolts of the same composition. These too proved a success as they not only were cheaper but also very strong and lasted longer. A notable use of Muntz metal was in the hull of the Cutty Sark.
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- "Muntz Metal" | 2025-06-23 | 19 Upvotes 1 Comments
π Ted Kaczynski
Theodore John Kaczynski (; born May 22, 1942), also known as the Unabomber (), is an American domestic terrorist, anarchist, and former mathematics professor. He was a mathematics prodigy, but he abandoned his academic career in 1969 to pursue a more primitive lifestyle. Between 1978 and 1995, he killed three people and injured 23 others in an attempt to start a revolution by conducting a nationwide bombing campaign targeting people involved with modern technology.
In 1971, Kaczynski moved to a remote cabin without electricity or running water near Lincoln, Montana, where he lived as a recluse while learning survival skills in an attempt to become self-sufficient. He witnessed the destruction of the wilderness surrounding his cabin and concluded that living in nature was untenable; he began his bombing campaign in 1978. In 1995, he sent a letter to The New York Times and promised to "desist from terrorism" if the Times or The Washington Post published his essay Industrial Society and Its Future, in which he argued that his bombings were extreme but necessary to attract attention to the erosion of human freedom and dignity by modern technologies that require large-scale organization.
Kaczynski was the subject of the longest and most expensive investigation in the history of the Federal Bureau of Investigation. Before his identity was known, the FBI used the case identifier UNABOM (University and Airline Bomber) to refer to his case, which resulted in the media naming him the "Unabomber." The FBI and Attorney General Janet Reno pushed for the publication of Industrial Society and Its Future, which led to a tip from Kaczynski's brother David, who recognized the writing style.
After his arrest in 1996, Kaczynski tried unsuccessfully to dismiss his court-appointed lawyers because they wanted him to plead insanity in order to avoid the death penalty, whereas he did not believe that he was insane. In 1998, a plea bargain was reached under which he pleaded guilty to all charges and was sentenced to life in prison without possibility of parole.
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- "Ted Kaczynski" | 2020-06-04 | 24 Upvotes 6 Comments
π The Illiac IV Computer
The ILLIAC IV was the first massively parallel computer. The system was originally designed to have 256 64-bit floating point units (FPUs) and four central processing units (CPUs) able to process 1 billion operations per second. Due to budget constraints, only a single "quadrant" with 64 FPUs and a single CPU was built. Since the FPUs all had to process the same instruction β ADD
, SUB
etc. β in modern terminology the design would be considered to be single instruction, multiple data, or SIMD.
The concept of building a computer using an array of processors came to Daniel Slotnick while working as a programmer on the IAS machine in 1952. A formal design did not start until 1960, when Slotnick was working at Westinghouse Electric and arranged development funding under a US Air Force contract. When that funding ended in 1964, Slotnick moved to the University of Illinois and joined the Illinois Automatic Computer (ILLIAC) team. With funding from Advanced Research Projects Agency (ARPA), they began the design of a newer concept with 256 64-bit processors instead of the original concept with 1,024 1-bit processors.
While the machine was being built at Burroughs, the university began building a new facility to house it. Political tension over the funding from the US Department of Defense led to the ARPA and the University fearing for the machine's safety. When the first 64-processor quadrant of the machine was completed in 1972, it was sent to the NASA Ames Research Center in California. After three years of thorough modification to fix various flaws, ILLIAC IV was connected to the ARPANet for distributed use in November 1975, becoming the first network-available supercomputer, beating the Cray-1 by nearly 12 months.
Running at half its design speed, the one-quadrant ILLIAC IV delivered 50Β MFLOP peak, making it the fastest computer in the world at that time. It is also credited with being the first large computer to use solid-state memory, as well as the most complex computer built to date, with over 1 million gates. Generally considered a failure due to massive budget overruns, the design was instrumental in the development of new techniques and systems for programming parallel systems. In the 1980s, several machines based on ILLIAC IV concepts were successfully delivered.
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- "The Illiac IV Computer" | 2020-06-04 | 56 Upvotes 10 Comments
π Molle
MOLLE (pronounced , similar in pronunciation to the name Molly) is an acronym for Modular Lightweight Load-carrying Equipment. It is used to define the current generation of load-bearing equipment and backpacks used by a number of NATO armed forces, especially the British Army and the United States Army.
The system's modularity is derived from the use of Pouch Attachment Ladder System (PALS) webbing equipment as rows of heavy-duty nylon stitched onto the vest to allow for the attachment of various compatible pouches and accessories. This method of attachment has become a de facto standard for modular tactical gear, replacing the All-purpose Lightweight Individual Carrying Equipment (ALICE) system used in the earliest modular vest systems (which is still in use with many police forces).
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- "Molle" | 2022-04-03 | 12 Upvotes 2 Comments
π The Overton Window
The Overton window is the range of policies politically acceptable to the mainstream population at a given time. It is also known as the window of discourse. The term is named after Joseph P. Overton, who stated that an idea's political viability depends mainly on whether it falls within this range, rather than on politicians' individual preferences. According to Overton, the window frames the range of policies that a politician can recommend without appearing too extreme to gain or keep public office given the climate of public opinion at that time.
π The quick brown fox jumps over the lazy dog
"The quick brown fox jumps over the lazy dog" is an English-language pangramβa sentence that contains all of the letters of the alphabet. It is commonly used for touch-typing practice, testing typewriters and computer keyboards, displaying examples of fonts, and other applications involving text where the use of all letters in the alphabet is desired. Owing to its brevity and coherence, it has become widely known.
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- "The quick brown fox jumps over the lazy dog" | 2010-06-14 | 14 Upvotes 5 Comments
π Toilet Paper Orientation
Toilet paper when used with a toilet roll holder with a horizontal axle parallel to both the wall and the floor has two possible orientations: the toilet paper may hang over (in front of) or under (behind) the roll.
Some people hold strong opinions on the matter; advice columnist Ann Landers said that the subject was the most responded to (15,000 letters in 1986) and controversial issue in her column's history. Defenders of either position cite advantages ranging from aesthetics, hospitality, and cleanliness to paper conservation, ease of detaching sheets, and compatibility with pets. Some writers have proposed connections to age, sex, or political philosophy, and survey evidence has shown a correlation with socioeconomic status.
Solutions where the views of household members differ include using separate dispensers or separate bathrooms and ignoring the issue. One man advocates a plan under which his country will standardize on a single forced orientation, and at least one inventor hopes to popularize a new kind of toilet roll holder which swivels from one orientation to the other.
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- "Toilet Paper Orientation" | 2020-05-15 | 67 Upvotes 73 Comments
π Public Universal Friend
The Public Universal Friend (born Jemima Wilkinson; November 29, 1752 β July 1, 1819) was an American preacher born in Cumberland, Rhode Island, to Quaker parents. After suffering a severe illness in 1776, the Friend claimed to have died and been reanimated as a genderless evangelist named the Public Universal Friend, and afterward shunned both birth name and gendered pronouns. In androgynous clothes, the Friend preached throughout the northeastern United States, attracting many followers who became the Society of Universal Friends.
The Public Universal Friend's theology was broadly similar to that of most Quakers. The Friend stressed free will, opposed slavery, and supported sexual abstinence. The most committed members of the Society of Universal Friends were a group of unmarried women who took leading roles in their households and community. In the 1790s, members of the Society acquired land in Western New York where they formed the township of Jerusalem near Penn Yan, New York. The Society of Universal Friends ceased to exist by the 1860s. Many writers have portrayed the Friend as a woman, and either a manipulative fraudster, or a pioneer for women's rights; others have viewed the preacher as transgender or non-binary and a figure in trans history.
π Comparison of X Window Managers
This article compares variety of different X window managers. For an introduction to the topic, see X Window System.
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- "Comparison of X Window Managers" | 2019-10-18 | 85 Upvotes 89 Comments
π Kessler Syndrome
The Kessler syndrome (also called the Kessler effect, collisional cascading, or ablation cascade), proposed by NASA scientist Donald J. Kessler in 1978, is a theoretical scenario in which the density of objects in low Earth orbit (LEO) due to space pollution is high enough that collisions between objects could cause a cascade in which each collision generates space debris that increases the likelihood of further collisions. One implication is that the distribution of debris in orbit could render space activities and the use of satellites in specific orbital ranges difficult for many generations.
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- "Kessler Syndrome" | 2020-02-13 | 57 Upvotes 57 Comments
- "Kessler Syndrome" | 2018-11-01 | 63 Upvotes 62 Comments