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π Codd's 12 rules
Codd's twelve rules are a set of thirteen rules (numbered zero to twelve) proposed by Edgar F. Codd, a pioneer of the relational model for databases, designed to define what is required from a database management system in order for it to be considered relational, i.e., a relational database management system (RDBMS). They are sometimes jokingly referred to as "Codd's Twelve Commandments".
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- "Codd's 12 rules" | 2009-09-03 | 15 Upvotes 2 Comments
π Vanadium redox battery
The vanadium redox battery (VRB), also known as the vanadium flow battery (VFB) or vanadium redox flow battery (VRFB), is a type of rechargeable flow battery that employs vanadium ions in different oxidation states to store chemical potential energy. The vanadium redox battery exploits the ability of vanadium to exist in solution in four different oxidation states, and uses this property to make a battery that has just one electroactive element instead of two. For several reasons, including their relative bulkiness, most vanadium batteries are currently used for grid energy storage, i.e., attached to power plants or electrical grids.
The possibility of creating a vanadium flow battery was explored by Pissoort in the 1930s, NASA researchers in the 1970s, and Pellegri and Spaziante in the 1970s, but none of them were successful in demonstrating the technology. The first successful demonstration of the all-vanadium redox flow battery which employed vanadium in a solution of sulfuric acid in each half was by Maria Skyllas-Kazacos at the University of New South Wales in the 1980s. Her design used sulfuric acid electrolytes, and was patented by the University of New South Wales in Australia in 1986.
The main advantages of the vanadium redox battery are that it can offer almost unlimited energy capacity simply by using larger electrolyte storage tanks; it can be left completely discharged for long periods with no ill effects; if the electrolytes are accidentally mixed, the battery suffers no permanent damage; a single state of charge between the two electrolytes avoids the capacity degradation due to a single cell in non-flow batteries; the electrolyte is aqueous and inherently safe and non-flammable; and the generation 3 formulation using a mixed acid solution developed by the Pacific Northwest National Laboratory operates over a wider temperature range allowing for passive cooling. VRFBs can be used at depth of discharge (DOD) around 90% and more, i.e. deeper DODs than solid-state batteries (e.g. lithium-based and sodium-based batteries, which are usually specified with DOD=80%). In addition, VRFBs exhibit very long cycle lives: most producers specify cycle durability in excess of 15,000-20,000 charge/discharge cycles. These values are far beyond the cycle lives of solid-state batteries, which is usually in the order of 4,000-5,000 charge/discharge cycles. Consequently, the levelized cost of energy (LCOE, i.e. the system cost divided by the usable energy, the cycle life, and round-trip efficiency) of present VRFB systems is typically in the order of a few tens of $ cents or β¬ cents, namely much lower than the LCOEs of equivalent solid-state batteries and close to the targets of $0.05 and β¬0.05, stated by the US Department of Energy and the European Commission Strategic Energy Technology (SET) Plan, respectively.
The main disadvantages with vanadium redox technology are a relatively poor energy-to-volume ratio in comparison with standard storage batteries, and the relatively poor round trip efficiency. Furthermore, the aqueous electrolyte makes the battery heavy and therefore only useful for stationary applications. Another disadvantage is the relatively high toxicity of oxides of vanadium (see vanadium Β§Β Safety).
Numerous companies and organizations involved in funding and developing vanadium redox batteries include Avalon Battery, Vionx (formerly Premium Power), UniEnergy Technologies and Ashlawn Energy in the United States; Renewable Energy Dynamics Technology in Ireland; Enerox GmbH (formerly Gildemeister energy storage) in Austria; Cellennium in Thailand; Rongke Power in China; Prudent Energy in China; Sumitomo in Japan; H2, Inc. in South Korea; redT in Britain., Australian Vanadium in Australia, and the now defunct Imergy (formerly Deeya). Lately, also several smaller size vanadium redox flow batteries were brought to market (for residential applications) mainly from StorEn Technologies (USA), Schmid Group, VoltStorage and Volterion (all three from Germany), VisBlue (Denmark) or Pinflow energy storage (Czechia).
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- "Vanadium redox battery" | 2018-07-28 | 35 Upvotes 31 Comments
π London Bridge (Lake Havasu)
London Bridge is a bridge in Lake Havasu City, Arizona. It was built in the 1830s and formerly spanned the River Thames in London, England. It was dismantled in 1967 and relocated to Arizona. The Arizona bridge is a reinforced concrete structure clad in the original masonry of the 1830s bridge, which was purchased by Robert P. McCulloch from the City of London. McCulloch had exterior granite blocks from the original bridge numbered and transported to America to construct the present bridge in Lake Havasu City, a planned community he established in 1964 on the shore of Lake Havasu. The bridge was completed in 1971 (along with a canal), and links an island in the Colorado River with the main part of Lake Havasu City.
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- "London Bridge (Lake Havasu)" | 2015-05-26 | 43 Upvotes 20 Comments
π Eroom's Law
Eroom's law is the observation that drug discovery is becoming slower and more expensive over time, despite improvements in technology (such as high-throughput screening, biotechnology, combinatorial chemistry, and computational drug design), a trend first observed in the 1980s. The cost of developing a new drug roughly doubles every nine years (inflation-adjusted). In order to highlight the contrast with the exponential advancements of other forms of technology (such as transistors) over time, the law was deliberately spelled as Moore's law spelled backwards.
The article proposing and naming the law attributes it to four main causes.
- the 'better than the Beatles' problem: the sense that new drugs only have modest incremental benefit over drugs already widely considered as successful, such as Lipitor, and treatment effects on top of already effective treatments are smaller than treatment effects versus placebo. The smaller size of these treatment effects mandates an increase in clinical trial sizes to show the same level of efficacy. This problem was phrased as "better than the Beatles" to highlight the fact that it would be difficult to come up with new successful pop songs if all new songs had to be better than the Beatles.
- the 'cautious regulator' problem: the progressive lowering of risk tolerance seen by drug regulatory agencies that makes R&D both costlier and harder. After older drugs (such as Thalidomide or Vioxx) are removed from the market due to safety reasons, the bar on safety for new drugs is increased.
- the 'throw money at it' tendency: the tendency to add human resources and other resources to R&D, which may lead to project overrun.
- the 'basic researchβbrute force' bias: the tendency to overestimate the ability of advances in basic research and brute force screening methods to show a molecule as safe and effective in clinical trials. From the 1960s to the 1990s (and later), drug discovery has shifted from whole-animal classical pharmacology testing methods (phenotypic screening) to reverse pharmacology target-approaches that result in the discovery of drugs that may tightly bind with high-affinity to target proteins, but which still often fail in clinical trials due to an under-appreciation of the complexity of the whole organism. Furthermore, drug discovery techniques have shifted from small-molecule and iterative low-throughput search strategies to target-based high-throughput screening (HTS) of large compound libraries. But despite being faster and cheaper, HTS approaches may be less productive.
While some suspect a lack of "low-hanging fruit" as a significant contribution to Eroom's law, this may be less important than the four main causes, as there are still many decades' worth of new potential drug targets relative to the number of targets which already have been exploited, even if the industry exploits 4 to 5 new targets per year. There is also space to explore selectively non-selective drugs (or "dirty drugs") that interact with several molecular targets, and which may be particularly effective as central nervous system (CNS) therapeutics, even though few of them have been introduced in the last few decades.
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- "Eroom's law" | 2018-04-14 | 120 Upvotes 34 Comments
π Memento Mori
Memento mori (Latin for 'remember that you [have to] die') is an artistic or symbolic trope acting as a reminder of the inevitability of death. The concept has its roots in the philosophers of classical antiquity and Christianity, and appeared in funerary art and architecture from the medieval period onwards.
The most common motif is a skull, often accompanied by one or more bones. Often this alone is enough to evoke the trope, but other motifs such as a coffin, hourglass and wilting flowers signified the impermanence of human life. Often these function within a work whose main subject is something else, such as a portrait, but the vanitas is an artistic genre where the theme of death is the main subject. The Danse Macabre and Death personified with a scythe as the Grim Reaper are even more direct evocations of the trope.
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- "Memento Mori" | 2022-11-16 | 226 Upvotes 154 Comments
π Wabi-sabi
In traditional Japanese aesthetics, wabi-sabi (δΎε―) is a world view centered on the acceptance of transience and imperfection. The aesthetic is sometimes described as one of beauty that is "imperfect, impermanent, and incomplete". It is a concept derived from the Buddhist teaching of the three marks of existence (δΈζ³ε°, sanbΕin), specifically impermanence (η‘εΈΈ, mujΕ), suffering (θ¦, ku) and emptiness or absence of self-nature (η©Ί, kΕ«).
Characteristics of the wabi-sabi aesthetic include asymmetry, roughness, simplicity, economy, austerity, modesty, intimacy, and appreciation of the ingenuous integrity of natural objects and processes.
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- "Wabi-Sabi" | 2023-07-23 | 26 Upvotes 8 Comments
- "Wabi-Sabi" | 2021-10-11 | 19 Upvotes 3 Comments
- "Wabi-sabi" | 2013-10-16 | 63 Upvotes 33 Comments
π Tell HN: Perseids: "Last Chance" for Best Meteor Viewing Tonight
The Perseids are a prolific meteor shower associated with the comet SwiftβTuttle. The meteors are called the Perseids because the point from which they appear to hail (called the radiant) lies in the constellation Perseus.
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- "Tell HN: Perseids: "Last Chance" for Best Meteor Viewing Tonight" | 2009-08-12 | 20 Upvotes 13 Comments
π Word spacing
Word spacing in typography is space between words, as contrasted with letter-spacing (space between letters of words) and sentence spacing (space between sentences). Typographers may modify the spacing of letters or words in a body of type to aid readability and copy fit, or for aesthetic effect. In web browsers and standardized digital typography, word spacing is controlled by the CSS1 word-spacing property.
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- "Word spacing" | 2025-12-05 | 46 Upvotes 47 Comments
π KFC's Original Recipe
The KFC Original Recipe is a secret mix of ingredients that fast food restaurant chain KFC uses to produce fried chicken.
By the very late 1930s, Harland Sanders' gas station in Corbin, Kentucky was so well known for its fried chicken that Sanders decided to remove the gas pumps and build a restaurant and motel in their place. While perfecting his secret recipe with 11 herbs and spices, Sanders found that pan frying chicken was too slow, requiring 30 minutes per order. Deep frying the chicken required half the time but produced dry, unevenly done chicken. In 1939, he found that using a pressure fryer produced tasty, moist chicken in eight or nine minutes. By July 1940, Sanders finalized what came to be known as his Original Recipe.
After Sanders formed a partnership with Pete Harman, they began marketing the chicken in the 1950s as Kentucky Fried Chicken; the company shipped the spices already mixed to restaurants to preserve the recipe's secrecy. He claimed that the ingredients "stand on everybody's shelf".
Sanders used vegetable oil for frying chicken. By 1993, for economic reasons, many KFC outlets had chosen to use a blend of palm and soybean oil. In Japan, the oil used is mainly the more expensive cottonseed and corn oil, as KFC Japan believes that this offers superior taste quality.
π Bisbee Deportation
The Bisbee Deportation was the illegal kidnapping and deportation of about 1,300 striking mine workers, their supporters, and citizen bystanders by 2,000 members of a deputized posse, who arrested them beginning on July 12, 1917, in Bisbee, Arizona. The action was orchestrated by Phelps Dodge, the major mining company in the area, which provided lists of workers and others who were to be arrested to the Cochise County sheriff, Harry C. Wheeler. Those arrested were taken to a local baseball park before being loaded onto cattle cars and deported 200 miles (320Β km) to Tres Hermanas in New Mexico. The 16-hour journey was through desert without food and with little water. Once unloaded, the deportees, most without money or transportation, were warned against returning to Bisbee. The US government soon brought in members of the US Army to assist with relocating the deportees to Columbus, New Mexico.
As Phelps Dodge, in collusion with the sheriff, had closed down access to outside communications, it was some time before the story was reported. The company presented their action as reducing threats to United States interests in World War I in Europe, largely because the wartime demand for copper was heavy. The Governor of New Mexico, in consultation with President Woodrow Wilson, provided temporary housing for the deportees. A presidential mediation commission investigated the actions in November 1917, and in its final report, described the deportation as "wholly illegal and without authority in law, either State or Federal (Page 6)." Nevertheless, no individual, company, or agency was ever convicted in connection with the deportations. Arizona and Cochise County never prosecuted the case, and in United States v. Wheeler (1920), the Supreme Court ruled that the Constitution by itself does not give the federal government the power to stop kidnappings, even ones involving moving abductees across state lines on federally-regulated railroads.
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- "Bisbee Deportation" | 2025-08-05 | 17 Upvotes 1 Comments