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๐ Alberto Santos-Dumont
Alberto Santos-Dumont (Brazilian Portuguese:ย [awหbษษพtu หsษฬtus duหmรต]; 20 July 1873ย โ 23 July 1932) was a Brazilian inventor and aviation pioneer, one of the very few people to have contributed significantly to the development of both lighter-than-air and heavier-than-air aircraft.
The heir of a wealthy family of coffee producers, Santos-Dumont dedicated himself to aeronautical study and experimentation in Paris, where he spent most of his adult life. In his early career he designed, built, and flew hot air balloons and early dirigibles, culminating in his winning the Deutsch de la Meurthe prize on 19 October 1901 for a flight that rounded the Eiffel Tower. He then turned to heavier-than-air machines, and on 23 October 1906 his 14-bis made the first powered heavier-than-air flight in Europe to be certified by the Aรฉro-Club de France and the Fรฉdรฉration Aรฉronautique Internationale. His conviction that aviation would usher in an era of worldwide peace and prosperity led him to freely publish his designs and forego patenting his various innovations.
Santos-Dumont is a national hero in Brazil, where it is popularly held that he preceded the Wright brothers in demonstrating a practical airplane. Countless roads, plazas, schools, monuments, and airports there are dedicated to him, and his name is inscribed on the Tancredo Neves Pantheon of the Fatherland and Freedom. He was a member of the Brazilian Academy of Letters from 1931 until his suicide in 1932.
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- "Alberto Santos-Dumont" | 2015-05-13 | 76 Upvotes 13 Comments
๐ There's Plenty of Room at the Bottom (1959)
"There's Plenty of Room at the Bottom: An Invitation to Enter a New Field of Physics" was a lecture given by physicist Richard Feynman at the annual American Physical Society meeting at Caltech on December 29, 1959. Feynman considered the possibility of direct manipulation of individual atoms as a more powerful form of synthetic chemistry than those used at the time. Although versions of the talk were reprinted in a few popular magazines, it went largely unnoticed and did not inspire the conceptual beginnings of the field. Beginning in the 1980s, nanotechnology advocates cited it to establish the scientific credibility of their work.
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- "There's Plenty of Room at the Bottom (1959)" | 2015-05-13 | 67 Upvotes 20 Comments
๐ Mechanism design
Mechanism design is a field in economics and game theory that takes an objectives-first approach to designing economic mechanisms or incentives, toward desired objectives, in strategic settings, where players act rationally. Because it starts at the end of the game, then goes backwards, it is also called reverse game theory. It has broad applications, from economics and politics (markets, auctions, voting procedures) to networked-systems (internet interdomain routing, sponsored search auctions).
Mechanism design studies solution concepts for a class of private-information games. Leonid Hurwicz explains that 'in a design problem, the goal function is the main "given", while the mechanism is the unknown. Therefore, the design problem is the "inverse" of traditional economic theory, which is typically devoted to the analysis of the performance of a given mechanism.' So, two distinguishing features of these games are:
- that a game "designer" chooses the game structure rather than inheriting one
- that the designer is interested in the game's outcome
The 2007 Nobel Memorial Prize in Economic Sciences was awarded to Leonid Hurwicz, Eric Maskin, and Roger Myerson "for having laid the foundations of mechanism design theory".
Discussed on
- "Mechanism design" | 2015-05-06 | 31 Upvotes 1 Comments
๐ Cognitive Distortion
A cognitive distortion is an exaggerated or irrational thought pattern involved in the onset and perpetuation of psychopathological states, especially those more influenced by psychosocial factors, such as depression and anxiety. Psychiatrist Aaron T. Beck laid the groundwork for the study of these distortions, and his student David D. Burns continued research on the topic. Burns, in The Feeling Good Handbook (1989), described personal and professional anecdotes related to cognitive distortions and their elimination.
Cognitive distortions are thoughts that cause individuals to perceive reality inaccurately. According to the cognitive model of Beck, a negative outlook on reality, sometimes called negative schemas (or schemata), is a factor in symptoms of emotional dysfunction and poorer subjective well-being. Specifically, negative thinking patterns reinforce negative emotions and thoughts. During difficult circumstances, these distorted thoughts can contribute to an overall negative outlook on the world and a depressive or anxious mental state.
Challenging and changing cognitive distortions is a key element of cognitive behavioral therapy (CBT).
Discussed on
- "Cognitive Distortion" | 2015-05-05 | 55 Upvotes 29 Comments
๐ Peak car
Peak car (also peak car use or peak travel) is a hypothesis that motor vehicle distance traveled per capita, predominantly by private car, has peaked and will now fall in a sustained manner. The theory was developed as an alternative to the prevailing market saturation model, which suggested that car use would saturate and then remain reasonably constant, or to GDP-based theories which predict that traffic will increase again as the economy improves, linking recent traffic reductions to the Great Recession of 2008.
The theory was proposed following reductions, which have now been observed in Australia, Belgium, France, Germany, Iceland, Japan (early 1990s), New Zealand, Sweden, the United Kingdom (many cities from about 1994) and the United States. A study by Volpe Transportation in 2013 noted that average miles driven by individuals in the United States has been declining from 900 miles (1,400ย km) per month in 2004 to 820 miles (1,320ย km) in July 2012, and that the decline had continued since the recent upturn in the US economy.
A number of academics have written in support of the theory, including Phil Goodwin, formerly Director of the transport research groups at Oxford University and UCL, and David Metz, a former Chief Scientist of the UK Department of Transport. The theory is disputed by the UK Department for Transport, which predicts that road traffic in the United Kingdom will grow by 50% by 2036, and Professor Stephen Glaister, Director of the RAC Foundation, who say traffic will start increasing again as the economy improves. Unlike peak oil, a theory based on a reduction in the ability to extract oil due to resource depletion, peak car is attributed to more complex and less understood causes.
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- "Peak car" | 2015-05-03 | 210 Upvotes 134 Comments
๐ Ryan Model 147
The Ryan Model 147 Lightning Bug is a jet-powered drone, or unmanned aerial vehicle, produced and developed by Ryan Aeronautical from the earlier Ryan Firebee target drone series.
Beginning in 1962, the Model 147 was introduced as a reconnaissance RPV (Remotely Piloted Vehicle, nomenclature of that era) for a United States Air Force project named Fire Fly. Over the next decade โ assisted with secret funding from the recently formed National Reconnaissance Office along with support of the Strategic Air Command and Ryan Aeronautical's own resources โ the basic Model 147 design would be developed into a diverse series of variants configured for a wide array of mission-specific roles, with multiple new systems, sensors and payloads used, modified and improved upon during the operational deployment of these drones in Southeast Asia. Missions performed by the Model 147 series RPVs included high- and low-altitude photographic and electronic aerial reconnaissance, surveillance, decoy, electronic warfare, signals intelligence, and psychological warfare.
The Ryan drones were designed without landing gear for simplicity and to save weight. Like its Firebee predecessor, the Model 147 could either be air-launched from a larger carrier aircraft or launched from the ground using a solid rocket booster; at completion of its mission the drone deployed its own recovery parachute which could be snatched in mid-air by a recovery helicopter (in a combat environment it was naturally not desired to recover the drone on, from or near enemy territory and ground or water impact could also cause damage to or loss of the drone or its payload).
At the end of the Vietnam War in 1975 the U.S. military's available funding and need for combat drones severely declined, even as Teledyne Ryan introduced further advanced developments of the Model 147 series such as the BGM-34 strike and defense suppression RPVs. Costs of maintaining the Lightning Bugs at full readiness could no longer be justified. Only by the 1990s did substantial interest, organization and funding again emerge from the U.S. Air Force and intelligence agencies to develop, acquire and widely deploy combat UAVs.
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- "Ryan Model 147" | 2015-04-29 | 19 Upvotes 2 Comments
๐ ChandraโToueg consensus algorithm
The ChandraโToueg consensus algorithm, published by Tushar Deepak Chandra and Sam Toueg in 1996, is an algorithm for solving consensus in a network of unreliable processes equipped with an eventually strong failure detector. The failure detector is an abstract version of timeouts; it signals to each process when other processes may have crashed. An eventually strong failure detector is one that never identifies some specific non-faulty process as having failed after some initial period of confusion, and, at the same time, eventually identifies all faulty processes as failed (where a faulty process is a process which eventually fails or crashes and a non-faulty process never fails). The ChandraโToueg consensus algorithm assumes that the number of faulty processes, denoted by f, is less than n/2 (i.e. the minority), i.e. it assumes f < n/2, where n is the total number of processes.
๐ Golden hat
Golden hats (or Gold hats) (German: Goldhรผte, singular: Goldhut) are a very specific and rare type of archaeological artifact from Bronze Age Europe. So far, four such objects ("cone-shaped gold hats of the Schifferstadt type") are known. The objects are made of thin sheet gold and were attached externally to long conical and brimmed headdresses which were probably made of some organic material and served to stabilise the external gold leaf. The following Golden Hats are known as of 2012:
- Golden Hat of Schifferstadt, found in 1835 at Schifferstadt near Speyer, c. 1400โ1300 BC.
- Avanton Gold Cone, incomplete, found at Avanton near Poitiers in 1844, c. 1000โ900 BC.
- Golden Cone of Ezelsdorf-Buch, found near Ezelsdorf near Nuremberg in 1953, c. 1000โ900 BC; the tallest known specimen at c. 90ย cm.
- Berlin Gold Hat, found probably in Swabia or Switzerland, c. 1000โ800 BC; acquired by the Museum fรผr Vor- und Frรผhgeschichte, Berlin, in 1996.
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- "Golden hat" | 2015-04-20 | 87 Upvotes 28 Comments
๐ Rotary Rocket
Rotary Rocket Company was a rocketry company that developed the Roton concept in the late 1990s as a fully reusable single-stage-to-orbit (SSTO) crewed spacecraft. The design was initially conceived by Bevin McKinney, who shared it with Gary Hudson. In 1996, Rotary Rocket Company was formed to commercialize the concept. The Roton was intended to reduce costs of launching payloads into low earth orbit by a factor of ten.
The company gathered considerable venture capital from angel investors and opened a factory headquartered in a 45,000-square-foot (4,200ย m2) facility at Mojave Air and Space Port in Mojave, California. The fuselage for their vehicles was made by Scaled Composites, at the same airport, while the company developed the novel engine design and helicopter-like landing system. A full-scale test vehicle made three hover flights in 1999, but the company exhausted its funds and closed its doors in early 2001.
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- "Rotary Rocket" | 2015-04-15 | 30 Upvotes 13 Comments
๐ Relativistic kill vehicle
A projectile is any object thrown into space (empty or not) by the exertion of a force. Although any object in motion through space (for example a thrown baseball) may be called a projectile, the term more commonly refers to a ranged weapon. Mathematical equations of motion are used to analyze projectile trajectory. An object projected at an angle to the horizontal has both the vertical and horizontal components of velocity. The vertical component of the velocity on the y-axis given as Vy=USin(teta) while the horizontal component of the velocity Vx=UCos(teta). There are various terms used in projectiles at specific angle teta 1. Time to reach maximum height. It is symbolized as (t), which is the time taken for the projectile to reach the maximum height from the plane of projection. Mathematically, it is given as t=USin(teta)/g Where g=acceleration due to gravity(app 9.81m/sยฒ) U= initial velocity (m/s) teta= angle made by the projectile with the horizontal axis.
2. Time of flight (T): this is the total time taken for the projectile to fall back to the same plane from which it was projected. Mathematically it is given as T=2USin(teta)/g
3. Maximum Height (H): this is the maximum height attained by the projectile OR the maximum displacement on the vertical axis(y-axis) covered by the projectile. It is given as H= UยฒSinยฒ(teta)/2g
4. Range(R): The Range of a projectile is the horizontal distance covered (on the x-axis) by the projectile. Mathematically, R= UยฒSin2(teta)/g. The Range is maximum when angle teta= 45ยฐ I.e Sin2(teta)=1.
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- "Relativistic kill vehicle" | 2015-04-13 | 38 Upvotes 52 Comments