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🔗 Electronics

The Williamson amplifier is a four-stage, push-pull, Class A triode-output valve audio power amplifier designed by D. T. N. Williamson during World War II. The original circuit, published in 1947 and addressed to the worldwide do it yourself community, set the standard of high fidelity sound reproduction and served as a benchmark or reference amplifier design throughout the 1950s. The original circuit was copied by hundreds of thousands amateurs worldwide. It was an absolute favourite on the DIY scene of the 1950s, and in the beginning of the decade also dominated British and North American markets for factory-assembled amplifiers.

The Williamson circuit was based on the 1934 Wireless World Quality Amplifier by Walter Cocking, with an additional error amplifier stage and a global negative feedback loop. Deep feedback, triode-connected KT66 power tetrodes, conservative choice of standing currents, and the use of wide-bandwidth output transformer all contributed to the performance of the Williamson. It had a modest output power rating of 15 Watts but surpassed all contemporary designs in having very low harmonic distortion and intermodulation, flat frequency response throughout the audible frequency range, and effective damping of loudspeaker resonances. The 0.1% distortion figure of the Williamson amplifier became the criterion for high fidelity performance that remains valid in the 21st century.

The Williamson amplifier was sensitive to selection and matching of passive components and valves, and prone to unwanted oscillations at infrasonic and ultrasonic frequencies. Enclosing four valve stages and an output transformer in a negative feedback loop was a severe test of design, resulting in a very narrow phase margin or, quite often, no margin at all. Attempts to improve stability of the Williamson could not fix this fundamental flaw. For this reason, and due to high costs of required quality components, manufacturers soon abandoned the Williamson circuit in favour of inherently more stable, cheaper and efficient three-stage, ultralinear or pentode-output designs.

🔗 Psychology

The Johari window is a technique designed to help people better understand their relationship with themselves and others. It was created by psychologists Joseph Luft (1916–2014) and Harrington Ingham (1916–1995) in 1955, and is used primarily in self-help groups and corporate settings as a heuristic exercise. Luft and Ingham named their model "Johari" using a combination of their first names.

🔗 Computing

A dial box is a computer peripheral for direct 3D manipulation e.g. to interactively input the rotation and torsion angles of a model displayed on a computer screen. Dial boxes were common input tools in the first years of interactive 3D graphics and they were available for Silicon Graphics (SGI) or Sun Microsystems and sold with their workstations. Currently they have been replaced by standard computer mouse interaction techniques.

Standard dial box has 8 dials mounted on a plate. The plate is set upright with the help of a stand and usually located next to the computer screen for convenient access. The connection to a computer is made via the serial port (RS-232).

One of the fields of application for dial boxes was molecular graphics.

🔗 Military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/Weaponry 🔗 Italy 🔗 Architecture 🔗 Military history/Early Modern warfare 🔗 Military history/Maritime warfare 🔗 Ships 🔗 Military history/Medieval warfare 🔗 Industrial design 🔗 Military history/Italian military history 🔗 Former countries 🔗 Military history/European military history 🔗 Former countries/Italian historical states

The Venetian Arsenal (Italian: Arsenale di Venezia) is a complex of former shipyards and armories clustered together in the city of Venice in northern Italy. Owned by the state, the Arsenal was responsible for the bulk of the Venetian republic's naval power from the late Middle Ages to the early modern period. It was "one of the earliest large-scale industrial enterprises in history".

🔗 Physics

Landauer's principle is a physical principle pertaining to the lower theoretical limit of energy consumption of computation. It holds that "any logically irreversible manipulation of information, such as the erasure of a bit or the merging of two computation paths, must be accompanied by a corresponding entropy increase in non-information-bearing degrees of freedom of the information-processing apparatus or its environment".

Another way of phrasing Landauer's principle is that if an observer loses information about a physical system, the observer loses the ability to extract work from that system.

A so-called logically-reversible computation, in which no information is erased, may in principle be carried out without releasing any heat. This has led to considerable interest in the study of reversible computing. Indeed, without reversible computing, increases in the number of computations-per-joule-of-energy-dissipated must come to a halt by about 2050: because the limit implied by Landauer's principle will be reached by then, according to Koomey's law.

At 20 °C (room temperature, or 293.15 K), the Landauer limit represents an energy of approximately 0.0175 eV, or 2.805 zJ. Theoretically, room‑temperature computer memory operating at the Landauer limit could be changed at a rate of one billion bits per second (1Gbps) with energy being converted to heat in the memory media at the rate of only 2.805 trillionths of a watt (that is, at a rate of only 2.805 pJ/s). Modern computers use millions of times as much energy per second.

🔗 United States/U.S. Government 🔗 United States 🔗 Biography 🔗 International relations 🔗 Germany 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 United States/Military history - U.S. military history 🔗 Gerald Ford 🔗 Politics 🔗 Military history/Military biography 🔗 Biography/military biography 🔗 Military history/World War II 🔗 Military history/Cold War 🔗 Biography/politics and government 🔗 Politics/American politics 🔗 Cold War 🔗 Chile 🔗 Football 🔗 Football/American and Canadian soccer

Henry Alfred Kissinger (; German: [ˈkɪsɪŋɐ]; born Heinz Alfred Kissinger, May 27, 1923) is an American diplomat, political theorist, geopolitical consultant, and politician who served as United States Secretary of State and National Security Advisor under the presidential administrations of Richard Nixon and Gerald Ford. For his actions negotiating a ceasefire in Vietnam, Kissinger received the 1973 Nobel Peace Prize under controversial circumstances.

Kissinger was a Jewish refugee who fled Nazi Germany with his family in 1938. Upon arriving in the United States, he excelled academically and graduated from Harvard College in 1950, where he studied under William Yandell Elliott. He earned his M.A. and Ph.D. degrees at Harvard University in 1951 and 1954, respectively.

A practitioner of Realpolitik, Kissinger played a prominent role in United States foreign policy between 1969 and 1977, pioneering the policy of détente with the Soviet Union, orchestrating an opening of relations with the People's Republic of China, engaging in what became known as shuttle diplomacy in the Middle East to end the Yom Kippur War, and negotiating the Paris Peace Accords, which ended American involvement in the Vietnam War. Kissinger has also been associated with such controversial policies as the U.S. bombing of Cambodia during the Vietnam War, U.S. involvement in the 1973 Chilean military coup, a "green light" to Argentina's military junta for their Dirty War, and U.S. support for Pakistan during the Bangladesh Liberation War despite a genocide being perpetrated by Pakistan. After leaving government, he formed Kissinger Associates, an international geopolitical consulting firm. Kissinger has written over a dozen books on diplomatic history and international relations.

Kissinger remains a controversial and polarizing figure in U.S. politics, both venerated by some as a highly effective U.S. Secretary of State and condemned by others for allegedly tolerating or supporting war crimes committed by allied nation states during his tenure. A 2015 survey of top international relations scholars, conducted by College of William & Mary, ranked Kissinger as the most effective U.S. secretary of state in the 50 years to 2015. A centenarian, Kissinger is the oldest living former U.S. Cabinet member and the last surviving member of Nixon's Cabinet. The previous oldest cabinet member was George Shultz, who died at the age of 100 in February 2021.

🔗 United States 🔗 United States/Arizona 🔗 Invention 🔗 Ecology

Biosphere 2 is an American Earth system science research facility located in Oracle, Arizona. Its mission is to serve as a center for research, outreach, teaching, and lifelong learning about Earth, its living systems, and its place in the universe. It is a 3.14-acre (1.27-hectare) structure originally built to be an artificial, materially closed ecological system, or vivarium. It remains the largest closed ecological system ever created.

Constructed between 1987 and 1991, Biosphere 2 was originally meant to demonstrate the viability of closed ecological systems to support and maintain human life in outer space as a substitute for Earth's biosphere. It was designed to explore the web of interactions within life systems in a structure with different areas based on various biological biomes. In addition to the several biomes and living quarters for people, there was an agricultural area and work space to study the interactions between humans, farming, technology and the rest of nature as a new kind of laboratory for the study of the global ecology. Its mission was a two-year closure experiment with a crew of eight humans ("biospherians"). Long-term it was seen as a precursor to gaining knowledge about the use of closed biospheres in space colonization. As an experimental ecological facility it allowed the study and manipulation of a mini biospheric system without harming Earth's biosphere.

Its seven biome areas were a 1,900-square-meter (20,000 sq ft) rainforest, an 850-square-meter (9,100 sq ft) ocean with a coral reef, a 450-square-meter (4,800 sq ft) mangrove wetlands, a 1,300-square-metre (14,000 sq ft) savannah grassland, a 1,400-square-meter (15,000 sq ft) fog desert, and two anthropogenic biomes: a 2,500-square-meter (27,000 sq ft) agricultural system and a human habitat with living spaces, laboratories and workshops. Below ground was an extensive part of the technical infrastructure. Heating and cooling water circulated through independent piping systems and passive solar input through the glass space frame panels covering most of the facility, and electrical power was supplied into Biosphere 2 from an onsite natural gas energy center.

Biosphere 2 was only used twice for its original intended purposes as a closed-system experiment: once from 1991 to 1993, and the second time from March to September 1994. Both attempts ran into problems including low amounts of food and oxygen, die-offs of many animals and plants included in the experiment (though this was anticipated since the project used a strategy of deliberately "species-packing" anticipating losses as the biomes developed), group dynamic tensions among the resident crew, outside politics, and a power struggle over management and direction of the project. Nevertheless, the closure experiments set world records in closed ecological systems, agricultural production, health improvements with the high nutrient and low caloric diet the crew followed, and insights into the self-organization of complex biomic systems and atmospheric dynamics. The second closure experiment achieved total food sufficiency and did not require injection of oxygen.

In June 1994, during the middle of the second experiment, the managing company, Space Biosphere Ventures, was dissolved, and the facility was left in limbo. Columbia University assumed management of the facility in 1995 and used it to run experiments until 2003. It then appeared to be in danger of being demolished to make way for housing and retail stores, but was taken over for research by the University of Arizona in 2007. The University of Arizona took full ownership of the structure in 2011.

🔗 Visual arts 🔗 Belgium

Children's Games is an oil-on-panel by Flemish Renaissance artist Pieter Bruegel the Elder, painted in 1560. It is currently held and exhibited at the Kunsthistorisches Museum in Vienna. The entire composition is full of children playing a wide variety of games. Over 90 different games that were played by children at the time have been identified.

🔗 United States 🔗 Law 🔗 Politics 🔗 National Archives 🔗 Politics/American politics

The Alien and Sedition Acts were a set of four laws enacted in 1798 that applied restrictions to immigration and speech in the United States. The Naturalization Act increased the requirements to seek citizenship, the Alien Friends Act allowed the president to imprison and deport non-citizens, the Alien Enemies Act gave the president additional powers to detain non-citizens during times of war, and the Sedition Act criminalized false and malicious statements about the federal government. The Alien Friends Act and the Sedition Act expired after a set number of years, and the Naturalization Act was repealed in 1802. The Alien Enemies Act is still in effect.

The Alien and Sedition Acts were controversial. They were supported by the Federalist Party, and supporters argued that the bills strengthened national security during the Quasi-War, an undeclared naval war with France from 1798 to 1800. The acts were denounced by Democratic-Republicans as suppression of voters and violation of free speech under the First Amendment. While they were in effect, the Alien and Sedition Acts, and the Sedition Act in particular, were used to suppress publishers affiliated with the Democratic-Republicans, and several publishers were arrested for criticism of the Adams administration. The Democratic-Republicans took power in 1800, in part because of backlash to the Alien and Sedition Acts, and all but the Alien Enemies Act were eliminated by the next Congress. The Alien Enemies Act has been invoked several times since, particularly during World War II. The Alien and Sedition Acts are generally received negatively by modern historians, and the Supreme Court has since indicated that aspects of the laws would be found unconstitutional if challenged.

🔗 Biography 🔗 France 🔗 Philosophy 🔗 Biography/science and academia 🔗 Philosophy/Philosophers 🔗 Philosophy/Epistemology 🔗 Philosophy/Modern philosophy 🔗 Libertarianism

Michel Eyquem, Seigneur de Montaigne ( mon-TAYN; French: [miʃɛl ekɛm də mɔ̃tɛɲ]; 28 February 1533 – 13 September 1592), known as Michel de Montaigne, was one of the most significant philosophers of the French Renaissance. He is known for popularizing the essay as a literary genre. His work is noted for its merging of casual anecdotes and autobiography with intellectual insight. Montaigne had a direct influence on numerous Western writers; his massive volume Essais contains some of the most influential essays ever written.

During his lifetime, Montaigne was admired more as a statesman than as an author. The tendency in his essays to digress into anecdotes and personal ruminations was seen as detrimental to proper style rather than as an innovation, and his declaration that "I am myself the matter of my book" was viewed by his contemporaries as self-indulgent. In time, however, Montaigne came to be recognized as embodying, perhaps better than any other author of his time, the spirit of freely entertaining doubt that began to emerge at that time. He is most famously known for his skeptical remark, ''Que sçay-je?" ("What do I know?", in Middle French; now rendered as "Que sais-je?" in modern French).