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πŸ”— Electrochemical RAM

πŸ”— Technology πŸ”— Computing πŸ”— Electronics πŸ”— Engineering

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

πŸ”— Umbral Calculus

πŸ”— Mathematics

In mathematics before the 1970s, the term umbral calculus referred to the surprising similarity between seemingly unrelated polynomial equations and certain "shadowy" techniques used to "prove" them. These techniques were introduced by John BlissardΒ (1861) and are sometimes called Blissard's symbolic method. They are often attributed to Γ‰douard Lucas (or James Joseph Sylvester), who used the technique extensively.

πŸ”— Pessimism Porn

πŸ”— Economics πŸ”— Futures studies

Pessimism porn is a neologism coined in 2009 during the 2007–2012 global financial crisis to describe the alleged eschatological and survivalist thrill some people derive from predicting, reading and fantasizing about the collapse of civil society through the destruction of the world's economic system.

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πŸ”— Object Linking and Embedding

πŸ”— Computing πŸ”— Microsoft Windows πŸ”— Microsoft Windows/Computing πŸ”— Computing/Software πŸ”— Microsoft πŸ”— Microsoft/.NET

Object Linking & Embedding (OLE) is a proprietary technology developed by Microsoft that allows embedding and linking to documents and other objects. For developers, it brought OLE Control Extension (OCX), a way to develop and use custom user interface elements. On a technical level, an OLE object is any object that implements the IOleObject interface, possibly along with a wide range of other interfaces, depending on the object's needs.

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πŸ”— Gay Bomb

πŸ”— Military history πŸ”— Military history/Military science, technology, and theory πŸ”— Military history/Weaponry πŸ”— LGBT studies

The "gay bomb" and "halitosis bomb" are formal names for two non-lethal psychochemical weapons that a United States Air Force research laboratory speculated about producing. The theories involve discharging female sex pheromones over enemy forces in order to make them sexually attracted to each other.

In 1994 the Wright Laboratory in Ohio, a predecessor to today's United States Air Force Research Laboratory, produced a three-page proposal on a variety of possible nonlethal chemical weapons, which was later obtained by the Sunshine Project through a Freedom of Information Act request.

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πŸ”— Crookes Radiometer

πŸ”— Technology πŸ”— Physics πŸ”— Energy

The Crookes radiometer (also known as a light mill) consists of an airtight glass bulb containing a partial vacuum, with a set of vanes which are mounted on a spindle inside. The vanes rotate when exposed to light, with faster rotation for more intense light, providing a quantitative measurement of electromagnetic radiation intensity.

The reason for the rotation was a cause of much scientific debate in the ten years following the invention of the device, but in 1879 the currently accepted explanation for the rotation was published. Today the device is mainly used in physics education as a demonstration of a heat engine run by light energy.

It was invented in 1873 by the chemist Sir William Crookes as the by-product of some chemical research. In the course of very accurate quantitative chemical work, he was weighing samples in a partially evacuated chamber to reduce the effect of air currents, and noticed the weighings were disturbed when sunlight shone on the balance. Investigating this effect, he created the device named after him.

It is still manufactured and sold as an educational aid or for curiosity.

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πŸ”— Musth

πŸ”— Mammals

Musth or must (an Urdu word, from Persian, lit. drunk) is a periodic condition in bull (male) elephants characterized by highly aggressive behavior and accompanied by a large rise in reproductive hormones.

Testosterone levels in an elephant in musth can be on average 60 times greater than in the same elephant at other times (in specific individuals these testosterone levels can even reach as much as 140 times the normal). However, whether this hormonal surge is the sole cause of musth, or merely a contributing factor, is unknown.

Scientific investigation of musth is problematic because even the most placid elephants become highly violent toward humans and other elephants during musth.

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  • "Musth" | 2020-04-06 | 77 Upvotes 15 Comments

πŸ”— How trains avoid colliding with each other

πŸ”— Trains πŸ”— Trains/Operations

Signalling block systems enable the safe and efficient operation of railways by preventing collisions between trains. The basic principle is that a route is broken up into a series of sections or "blocks". Only one train may occupy a block at a time, and the blocks are sized to allow a train to stop within them. That ensures that a train always has time to stop before getting dangerously close to another train on the same line. The block system is referred to in the UK as the method of working, in the US as the method of operation, and in Australia as safeworking.

In most situations, a system of signals is used to control the passage of trains between the blocks. When a train enters a block, signals at both ends change to indicate that the block is occupied, typically using red lamps or indicator flags. When a train first enters a block, the rear of the same train has not yet left the previous block, so both blocks are marked as occupied. That ensures there is slightly less than one block length on either end of the train that is marked as occupied, so any other train approaching that section will have enough room to stop in time, even if the first train has stopped dead on the tracks. The previously-occupied block will only be marked unoccupied when the end of the train has entirely left it, leaving the entire block clear.

Block systems have the disadvantage that they limit the number of trains on a particular route to something fewer than the number of blocks. Since the route has a fixed length, increasing the number of trains requires the creation of more blocks, which means the blocks are shorter and trains have to operate at lower speeds in order to stop safely. As a result, the number and size of blocks are closely related to the overall route capacity, and cannot be changed easily because expensive alterations to the signals along the line would be required.

Block systems are used to control trains between stations and yards, but not normally within the yards, where some other method is used. Any block system is defined by its associated physical equipment and by the application of a relevant set of rules. Some systems involve the use of signals while others do not. Some systems are specifically designed for single track railways, on which there is a danger of both head-on and rear-end collision, as opposed to double track, on which the main danger is rear-end collisions.

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πŸ”— Phillis Wheatley

πŸ”— United States πŸ”— Biography πŸ”— Africa πŸ”— Poetry πŸ”— Women's History πŸ”— Women writers πŸ”— United States/Massachusetts πŸ”— African diaspora πŸ”— United States History πŸ”— United States/Massachusetts - Boston πŸ”— Africa/Gambia

Phillis Wheatley, also spelled Phyllis and Wheatly (c. 1753 – December 5, 1784) was the first African-American woman to publish a book of poetry. Born in West Africa, she was sold into slavery at the age of seven or eight and transported to North America. She was purchased by the Wheatley family of Boston, who taught her to read and write and encouraged her poetry when they saw her talent.

On a 1773 trip to London with her master's son, seeking publication of her work, she was aided in meeting prominent people who became patrons. The publication in London of her Poems on Various Subjects, Religious and Moral on September 1, 1773, brought her fame both in England and the American colonies. Figures such as George Washington praised her work. A few years later, African-American poet Jupiter Hammon praised her work in a poem of his own.

Wheatley was emancipated (set free) by the Wheatleys shortly after the publication of her book. She married in about 1778. Two of her children died as infants. After her husband was imprisoned for debt in 1784, Wheatley fell into working poverty and died of illness. Her last infant son died soon after.

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πŸ”— Webvan

πŸ”— California πŸ”— Companies πŸ”— California/San Francisco Bay Area πŸ”— Internet πŸ”— Food and drink

Webvan was a dot-com company and grocery business that filed for bankruptcy in 2001 after 3 years of operation. It was headquartered in Foster City, California, United States. It delivered products to customers' homes within a 30-minute window of their choosing. At its peak, it offered service in ten US markets: the San Francisco Bay Area; Dallas; Sacramento; San Diego; Los Angeles; Orange County, California; Chicago; Seattle; Portland, Oregon; and Atlanta, Georgia. The company had hoped to expand to 26 cities by 2001.

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