Have a deep view into what people are curious about.

🔗 Technology

A blast valve is used to protect a shelter, such as a fallout shelter or bunker, from the effects of sudden outside air pressure changes. A nuclear weapon creates a shock wave, which may produce sudden pressure changes of more than an atmosphere (about 1 bar) even several kilometres from the detonation point. After the shock wave passes, a sudden negative pressure follows.

If such pressure waves enter a shelter, they will likely do substantial harm to occupants and equipment. A blast valve is placed in air intake/exhaust pipes, that remains open normally, but automatically closes when strong pressure is applied in either direction. Blast dampers operate in the same fashion and are related or identical to blast valves, the former name however is generally used to describe blast mitigation devices, for more conventional explosive events.

A typical blast valve has entries of 15–30 cm diameter, and a larger centre section. Within the centre section is a disk mounted on an axle, with weak springs that keep it centred, away from both entries. Pressure displaces the disk along the axle, until it plugs one entry or the other. After the blast, the springs return the disk to the centre, re-opening the valve.

Another type of blast valve employs rounded metal tubes held in place by springs. As pressure rises it pushes the tubes against the frame of the valve closing the opening. These valves are typically unidirectional in airflow and are employed in large wall structures where large amounts of airflow is required.

One form of blast valve, popularized by the book Nuclear War Survival Skills and tested by ORNL is worn flat rubber tire treads nailed or bolted to frames strong enough to resist the maximum overpressure, with tested closing times cited as being identical to commercial grade blast valves, however the use of this form of blast valve design must also take the risk of the flammable rubber catching fire into consideration.

🔗 Biography 🔗 Aviation 🔗 Military history 🔗 Military history/Military aviation 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Military history/Military biography 🔗 Biography/military biography 🔗 Aviation/aerospace biography 🔗 Military history/World War II 🔗 Military history/Cold War 🔗 Pennsylvania

John Richard Boyd (January 23, 1927 – March 9, 1997) was a United States Air Force fighter pilot and Pentagon consultant during the second half of the 20th century. His theories have been highly influential in military, sports, business, and litigation strategies and planning.

As part of the Fighter Mafia, Boyd inspired the Lightweight Fighter program (LWF), which produced the successful General Dynamics F-16 Fighting Falcon and McDonnell Douglas F/A-18 Hornet, which are still in use by the United States and by several other military powers into the 21st century. Boyd, together with Thomas Christie, created the Energy–Maneuverability theory of aerial combat, which became the world standard for the design of fighter aircraft. He also developed the decision cycle known as the OODA loop, the process by which an entity reacts to an event.

🔗 Germany 🔗 Archaeology 🔗 Visual arts 🔗 Fashion

The Berlin Gold Hat or Berlin Golden Hat (German: Berliner Goldhut) is a Late Bronze Age artefact made of thin gold leaf. It served as the external covering on a long conical brimmed headdress, probably of an organic material. It is now in the Neues Museum on Museum Island in Berlin, in a room by itself with an elaborate explanatory display.

The Berlin Gold Hat is the best preserved specimen among the four known conical golden hats known from Bronze Age Europe so far. Of the three others, two were found in southern Germany, and one in the west of France. All were found in the 19th and 20th centuries. It is generally assumed that the hats served as the insignia of deities or priests in the context of a sun cult that appears to have been widespread in Central Europe at the time. The hats are also suggested to have served astronomical/calendrical functions.

The Berlin Gold Hat was acquired in 1996 by the Berlin Museum für Vor- und Frühgeschichte as a single find without provenance. A comparative study of the ornaments and techniques in conjunction with dateable finds suggests that it was made in the Late Bronze Age, circa 1,000 to 800 BC.

🔗 Holidays 🔗 Men's Issues

International Men's Day (IMD) is a global awareness day for many issues that men face, including parental alienation, abuse, homelessness, suicide, and violence, celebrated annually on November 19. The objectives of celebrating an International Men's Day are set out in 'All the Six Pillars of International Men's Day'. It is also an occasion to celebrate boys' and men's lives, achievements and contributions, in particular for their contributions to nation, union, society, community, family, marriage, and childcare.

🔗 Internet 🔗 Computing 🔗 Brands 🔗 Microsoft 🔗 Home Living

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.

🔗 Spaceflight

A diffractive solar sail, or diffractive lightsail, is a type of solar sail which relies on diffraction instead of reflection for its propulsion. Current diffractive sail designs use thin metamaterial films, containing micrometer-size gratings based on polarization or subwavelength refractive structures, causing light to spread out (i.e. diffract) and thereby exert radiation pressure when it passes through them.

🔗 Physics 🔗 Meteorology 🔗 Skepticism

A sun dog (or sundog) or mock sun, formally called a parhelion (plural parhelia) in meteorology, is an atmospheric optical phenomenon that consists of a bright spot to one or both sides of the Sun. Two sun dogs often flank the Sun within a 22° halo.

The sun dog is a member of the family of halos, caused by the refraction of sunlight by ice crystals in the atmosphere. Sun dogs typically appear as a pair of subtly colored patches of light, around 22° to the left and right of the Sun, and at the same altitude above the horizon as the Sun. They can be seen anywhere in the world during any season, but are not always obvious or bright. Sun dogs are best seen and most conspicuous when the Sun is near the horizon.

🔗 Human rights 🔗 China 🔗 Islam 🔗 Correction and Detention Facilities

The Xinjiang re-education camps, officially called Vocational Education and Training Centers by the government of the People's Republic of China, are internment camps that have been operated by the Xinjiang Uygur Autonomous Region government for the purpose of indoctrinating Uyghurs since 2017 as part of a "people's war on terror" announced in 2014. The camps were established under General Secretary Xi Jinping's administration and led by party secretary, Chen Quanguo. These camps are reportedly operated outside the legal system; many Uyghurs have reportedly been interned without trial and no charges have been levied against them. Local authorities are reportedly holding hundreds of thousands of Uyghurs in these camps as well as other ethnic minority groups, for the stated purpose of countering extremism and terrorism and promoting sinicization.

As of 2018, it was estimated that the Chinese authorities may have detained hundreds of thousands, perhaps a million, Uyghurs, Kazakhs, Kyrgyz and other ethnic Turkic Muslims, Christians as well as some foreign citizens such as Kazakhstanis, who are being held in these secretive internment camps which are located throughout the region. In May 2018, Randall Schriver of the United States Department of Defense claimed that "at least a million but likely closer to three million citizens" were imprisoned in detention centers in a strong condemnation of the "concentration camps". In August 2018, a United Nations human rights panel said that it had received many credible reports that 1 million ethnic Uyghurs in China have been held in "re-education camps". There have also been multiple reports from media, politicians and researchers comparing the camps to the Chinese Cultural Revolution.

In 2019, the United Nations ambassadors from 22 nations, including Australia, Canada, France, Germany, Japan, and the United Kingdom signed a letter condemning China's mass detention of the Uyghurs and other minority groups, urging the Chinese government to close the camps. Conversely, a joint statement was signed by 37 states commending China's counter-terrorism program in Xinjiang, including Algeria, the DR Congo, Russia, Saudi Arabia, Syria, Iran, Iraq, Pakistan, North Korea, Egypt, Nigeria, the Philippines and Sudan.

🔗 Physics 🔗 Philosophy 🔗 Philosophy/Philosophy of science 🔗 Philosophy/Contemporary philosophy

In theoretical physics, the problem of time is a conceptual conflict between general relativity and quantum mechanics in that quantum mechanics regards the flow of time as universal and absolute, whereas general relativity regards the flow of time as malleable and relative. This problem raises the question of what time really is in a physical sense and whether it is truly a real, distinct phenomenon. It also involves the related question of why time seems to flow in a single direction, despite the fact that no known physical laws seem to require a single direction.

🔗 United States 🔗 Organized Labour 🔗 Record Labels 🔗 United States/American music

On August 1, 1942, the American Federation of Musicians, at the instigation of union president James C. Petrillo, began a strike against the major American record companies because of disagreements over royalty payments. Beginning at midnight, July 31, 1942, no union musician could make commercial recordings for any commercial record company. That meant that a union musician was allowed to participate on radio programs and other kinds of musical entertainment, but not in a recording session. The 1942–1944 musicians' strike remains the longest strike in entertainment history.

The strike did not affect musicians performing on live radio shows, in concerts, or, after October 27, 1943, on special recordings made by the record companies for V-Discs for distribution to the armed forces fighting World War II, because V-Discs were not available to the general public. However, the union did frequently threaten to withdraw musicians from the radio networks to punish individual network affiliates who were deemed "unfair" for violating the union's policy on recording network shows for repeat broadcasts.

The strike had a major impact on the American musical scene. At the time, union bands dominated popular music; after the strike, and partly as a result of it, the big bands began to decline and vocalists began to dominate popular music.