Random Articles (Page 4)
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π Naturally-Occurring Nuclear Reactors
A fossil natural nuclear fission reactor is a uranium deposit where self-sustaining nuclear chain reactions have occurred. This can be examined by analysis of isotope ratios. The conditions under which a natural nuclear reactor could exist had been predicted in 1956 by Paul Kazuo Kuroda. The phenomenon was discovered in 1972 in Oklo, Gabon by French physicist Francis Perrin under conditions very similar to what was predicted.
Oklo is the only known location for this in the world and consists of 16 sites at which self-sustaining nuclear fission reactions are thought to have taken place approximately 1.7 billion years ago, and ran for a few hundred thousand years, averaging probably less than 100 kW of thermal power during that time.
Discussed on
- "Natural Nuclear Fission Reactor" | 2022-05-07 | 10 Upvotes 1 Comments
- "Natural Nuclear Fission Reactor" | 2020-10-10 | 49 Upvotes 8 Comments
- "Natural Nuclear Fission Reactor" | 2019-07-03 | 60 Upvotes 16 Comments
- "Natural nuclear fission reactor" | 2018-07-08 | 71 Upvotes 18 Comments
- "Natural nuclear fission reactor" | 2009-11-04 | 14 Upvotes 2 Comments
π Privilegium Maius
The Privilegium maius (German: GroΓer Freiheitsbrief 'greater privilege') was a medieval document forged in 1358 or 1359 at the behest of Duke Rudolf IV of Austria (1358β65) of the House of Habsburg, claiming the family has the right to rule Rome because of land rights granted to them by Nero and Julius Caesar. It was essentially a modified version of the Privilegium minus issued by Emperor Frederick I Barbarossa in 1156, which had elevated the former March of Austria into a duchy. In a similar way, the Privilegium maius elevated the duchy into an Archduchy of Austria.
The privileges described in the document had great influence on the Austrian political landscape, and created a unique connection between the House of Habsburg and Austria.
Discussed on
- "Privilegium Maius" | 2023-04-02 | 38 Upvotes 17 Comments
π Zhou Qunfei
Zhou Qunfei (Chinese: ε¨ηΎ€ι£; born 1970) is a Chinese entrepreneur who founded the major touchscreen maker Lens Technology. After the public listing of her company on the Shenzhen ChiNext market in March 2015, her net worth reached US$10 billion, making her the richest woman in China. In 2018, she was named the world's richest self-made woman, with a net worth of $9.8 billion.
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- "Zhou Qunfei" | 2016-08-24 | 124 Upvotes 10 Comments
π Today I learned Epub is just HTML/CSS
EPUB is an e-book file format that uses the ".epub" file extension. The term is short for electronic publication and is sometimes styled ePub. EPUB is supported by many e-readers, and compatible software is available for most smartphones, tablets, and computers. EPUB is a technical standard published by the International Digital Publishing Forum (IDPF). It became an official standard of the IDPF in September 2007, superseding the older Open eBook standard.
The Book Industry Study Group endorses EPUB 3 as the format of choice for packaging content and has stated that the global book publishing industry should rally around a single standard. The EPUB format is implemented as an archive file consisting of XHTML files carrying the content, along with images and other supporting files. EPUB is the most widely supported vendor-independent XML-based (as opposed to PDF) e-book format; that is, it is supported by almost all hardware readers, except for Kindle.
Discussed on
- "Today I learned Epub is just HTML/CSS" | 2021-04-08 | 218 Upvotes 153 Comments
π Engines of Creation, by K. Eric Drexler (1986)
Engines of Creation: The Coming Era of Nanotechnology is a 1986 molecular nanotechnology book written by K. Eric Drexler with a foreword by Marvin Minsky. An updated version was released in 2007. The book has been translated into Japanese, French, Spanish, Italian, Russian, and Chinese.
Discussed on
- "Engines of Creation, by K. Eric Drexler (1986)" | 2019-07-28 | 19 Upvotes 10 Comments
π Credit card imprinter
A credit card imprinter, colloquially known as a ZipZap machine, click-clack machine or Knuckle Buster, is a manual device that was used by merchants to record payment card transactions before the advent of payment terminals.
The device works by placing the customerβs credit card into a bed in the machine, then layering carbon paper forms over the card. A bar is slid back and forth over the paper to create an impression of the embossed card data and the merchant information on the imprinter. The customer signs these paper forms, with one copy as the customer receipt and the other kept by the merchant.
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- "Credit card imprinter" | 2025-10-04 | 16 Upvotes 7 Comments
π Electrochemical RAM
Electrochemical Random-Access Memory (ECRAM) is a type of non-volatile memory (NVM) with multiple levels per cell (MLC) designed for deep learning analog acceleration. An ECRAM cell is a three-terminal device composed of a conductive channel, an insulating electrolyte, an ionic reservoir, and metal contacts. The resistance of the channel is modulated by ionic exchange at the interface between the channel and the electrolyte upon application of an electric field. The charge-transfer process allows both for state retention in the absence of applied power, and for programming of multiple distinct levels, both differentiating ECRAM operation from that of a field-effect transistor (FET). The write operation is deterministic and can result in symmetrical potentiation and depression, making ECRAM arrays attractive for acting as artificial synaptic weights in physical implementations of artificial neural networks (ANN). The technological challenges include open circuit potential (OCP) and semiconductor foundry compatibility associated with energy materials. Universities, government laboratories, and corporate research teams have contributed to the development of ECRAM for analog computing. Notably, Sandia National Laboratories designed a lithium-based cell inspired by solid-state battery materials, Stanford University built an organic proton-based cell, and International Business Machines (IBM) demonstrated in-memory selector-free parallel programming for a logistic regression task in an array of metal-oxide ECRAM designed for insertion in the back end of line (BEOL). In 2022, researchers at Massachusetts Institute of Technology built an inorganic, CMOS-compatible protonic technology that achieved near-ideal modulation characteristics using nanosecond fast pulses
π MIPS R3000
The R3000 is a 32-bit RISC microprocessor chipset developed by MIPS Computer Systems that implemented the MIPS I instruction set architecture (ISA). Introduced in June 1988, it was the second MIPS implementation, succeeding the R2000 as the flagship MIPS microprocessor. It operated at 20, 25 and 33.33Β MHz.
The MIPS 1 instruction set is small compared to those of the contemporary 80x86 and 680x0 architectures, encoding only more commonly used operations and supporting few addressing modes. Combined with its fixed instruction length and only three different types of instruction formats, this simplified instruction decoding and processing. It employed a 5-stage instruction pipeline, enabling execution at a rate approaching one instruction per cycle, unusual for its time.
This MIPS generation supports up to four co-processors. In addition to the CPU core, the R3000 microprocessor includes a Control Processor (CP), which contains a Translation Lookaside Buffer and a Memory Management Unit. The CP works as a coprocessor. Besides the CP, the R3000 can also support an external R3010 numeric coprocessor and two other external coprocessors.
The R3000 CPU does not include level 1 cache. Instead, its on-chip cache controller operates external data and instruction caches of up to 256Β KB each. It can access both caches during the same clock cycle.
The R3000 found much success and was used by many companies in their workstations and servers. Users included:
- Ardent Computer
- Digital Equipment Corporation (DEC) for their DECstation workstations and multiprocessor DECsystem servers
- Evans & Sutherland for their Vision (ESV) series workstations
- MIPS Computer Systems for their MIPS RISC/os Unix workstations and servers.
- NEC for their RISC EWS4800 workstations and UP4800 servers.
- Prime Computer
- Pyramid Technology
- Seiko Epson
- Silicon Graphics for their Professional IRIS, Personal IRIS and Indigo workstations, and the multiprocessor Power Series visualization systems
- Sony for their PlayStation and PlayStation 2 (SCPH-10000 to SCPH-700XX - clocked at 37.5Β MHz for use as an I/O CPU and at 33.8Β MHz for compatibility with PlayStation games) video game consoles, and NEWS workstations, as well as the Bemani System 573 Analog arcade unit, which runs on the R3000A.
- Tandem Computers for their NonStop Cyclone/R and CLX/R fault-tolerant servers
- Whitechapel Workstations for their Hitech-20 workstation
- New Horizons Probe
The R3000 was also used as an embedded microprocessor. When advances in technology rendered it obsolete for high-performance systems, it found continued use in lower-cost designs. Companies such as LSI Logic developed derivatives of the R3000 specifically for embedded systems.
The R3000 was a further development of the R2000 with minor improvements including larger TLB and a faster bus to the external caches. The R3000 die contained 115,000 transistors and measured about 75,000 square mils (48Β mm2). MIPS was a fabless semiconductor company, so the R3000 was fabricated by MIPS partners including Integrated Device Technology (IDT), LSI Logic, NEC Corporation, Performance Semiconductor, and others. It was fabricated in a 1.2Β ΞΌm complementary metalβoxideβsemiconductor (CMOS) process with two levels of aluminium interconnect.
Derivatives of the R3000 for non-embedded applications include:
- R3000A - A further development by MIPS introduced in 1989. It operated at clock frequencies up to 40Β MHz.
- PR3400 - Developed by Performance Semiconductor, introduced in May 1991, also at up to 40Β MHz. It integrated the Performance Semiconductor PR3000A and PR3010A onto a single die.
Derivatives of the R3000 for embedded applications include:
- PR31700 - A 75Β MHz microcontroller from Philips Semiconductors. Fabricated in a 0.35Β ΞΌm process, delivered in a 208-pin LQFP, it operated at 3.3Β V and dissipated only 0.35Β W.
- RISController - A family of low-end microcontrollers from IDT. Models include the R3041, R3051, R3052, and R3081.
- TX3900 - A microcontroller from Toshiba.
- Mongoose-V - A radiation-hardened and expanded 10β15Β MHz CPU for use on spacecraft, it is still in use today in applications such as NASA's New Horizons space probe.
Discussed on
- "MIPS R3000" | 2019-06-20 | 37 Upvotes 59 Comments
π Small-World Experiment
The small-world experiment comprised several experiments conducted by Stanley Milgram and other researchers examining the average path length for social networks of people in the United States. The research was groundbreaking in that it suggested that human society is a small-world-type network characterized by short path-lengths. The experiments are often associated with the phrase "six degrees of separation", although Milgram did not use this term himself.
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- "Small-World Experiment" | 2020-03-15 | 50 Upvotes 3 Comments
π iLoo
The iLoo (short for Internet loo) was a cancelled Microsoft project to develop a Wi-Fi Internet-enabled portable toilet. The iLoo, which was to debut at British summer festivals, was described as being a portable toilet with wireless broadband Internet, an adjustable plasma screen, a membrane wireless keyboard, a six-channel speaker system, and toilet paper embossed with popular web site addresses. The iLoo was also to have an extra screen and keyboard on the outside, and was to be guarded. It was intended as the next in a series of successful initiatives by MSN UK which sought to introduce the internet in unusual locations, including MSN Street, MSN Park Bench and MSN Deckchair.
The project was announced by MSN UK on April 30, 2003, and was widely ridiculed before being declared a hoax by Microsoft on May 12. On May 13, another Microsoft press release stated that although the project had not been a hoax, it had been cancelled because it would do little to promote the MSN brand. There has since been speculation as to whether the project was cancelled for fear of being sued by Andrew Cubitt, who had invented the similarly named product "i-Loo". The iLoo was described as a public relations "debacle" by Online Journalism Review.
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- "iLoo" | 2015-07-23 | 354 Upvotes 56 Comments