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🔗 Geology 🔗 Rocks and minerals

Cummingtonite ( KUM-ing-tə-nyte) is a metamorphic amphibole with the chemical composition (Mg,Fe²⁺
)
₂(Mg,Fe²⁺
)
₅Si
₈O
₂₂(OH)
₂, magnesium iron silicate hydroxide.

Monoclinic cummingtonite is compositionally similar and polymorphic with orthorhombic anthophyllite, which is a much more common form of magnesium-rich amphibole, the latter being metastable.

Cummingtonite shares few compositional similarities with alkali amphiboles such as arfvedsonite, glaucophane-riebeckite. There is little solubility between these minerals due to different crystal habit and inability of substitution between alkali elements and ferro-magnesian elements within the amphibole structure.

🔗 Military history 🔗 Military history/Military science, technology, and theory 🔗 Systems 🔗 Systems/Systems engineering

The OODA loop is the cycle observe–orient–decide–act, developed by military strategist and United States Air Force Colonel John Boyd. Boyd applied the concept to the combat operations process, often at the operational level during military campaigns. It is now also often applied to understand commercial operations and learning processes. The approach explains how agility can overcome raw power in dealing with human opponents. It is especially applicable to cyber security and cyberwarfare.

The OODA loop has become an important concept in litigation, business, law enforcement, management education, and military strategy. According to Boyd, decision-making occurs in a recurring cycle of observe–orient–decide–act. An entity (whether an individual or an organization) that can process this cycle quickly, observing and reacting to unfolding events more rapidly than an opponent, can thereby "get inside" the opponent's decision cycle and gain the advantage.

🔗 Philosophy 🔗 Classical Greece and Rome 🔗 Greece 🔗 Philosophy/Ancient philosophy 🔗 Philosophy/Epistemology

Pyrrhonism is an Ancient Greek school of philosophical skepticism which rejects dogma and advocates the suspension of judgement over the truth of all beliefs. It was founded by Aenesidemus in the first century BCE, and said to have been inspired by the teachings of Pyrrho and Timon of Phlius in the fourth century BCE. Pyrrhonism is best known today through the surviving works of Sextus Empiricus, writing in the late second century or early third century CE. The publication of Sextus' works in the Renaissance ignited a revival of interest in Skepticism and played a major role in Reformation thought and the development of early modern philosophy.

🔗 Physics 🔗 Philosophy 🔗 Philosophy/Philosophy of science 🔗 Sociology

The term physics envy is used to criticize modern writing and research of academics working in areas such as "softer sciences", liberal arts, business studies, and humanities. The term argues that writing and working practices in these disciplines have overused confusing jargon and complicated mathematics to seem more 'rigorous' and like mathematics-based subjects like physics.

🔗 Mathematics 🔗 Physics 🔗 Philosophy

Norton's dome is a thought experiment that exhibits a non-deterministic system within the bounds of Newtonian mechanics. It was devised by John D. Norton in 2003. It is a special limiting case of a more general class of examples from 1997 due to Sanjay Bhat and Dennis Bernstein. The Norton's dome problem can be regarded as a problem in physics, mathematics, or philosophy.

🔗 Germany 🔗 Songs 🔗 Anti-war

"99 Luftballons" (German: Neunundneunzig Luftballons, "99 balloons") is a song by the German band Nena from their 1983 self-titled album. An English-language version titled "99 Red Balloons", with lyrics by Kevin McAlea, was also released on the album 99 Luftballons in 1984 after widespread success of the original in Europe and Japan. The English version is not a direct translation of the German original and contains lyrics but with the same meaning. In the US, the English-language version did not chart, while the German-language recording became Nena's only US hit.

🔗 Chemicals

Aluminium oxynitride (marketed under the name ALON by Surmet Corporation) is a transparent ceramic composed of aluminium, oxygen and nitrogen. ALON is optically transparent (≥ 80%) in the near-ultraviolet, visible, and midwave-infrared regions of the electromagnetic spectrum. It is four times as hard as fused silica glass, 85% as hard as sapphire, and nearly 115% as hard as magnesium aluminate spinel. Since it has a cubic spinel structure, it can be fabricated to transparent windows, plates, domes, rods, tubes, and other forms using conventional ceramic powder processing techniques.

ALON is the hardest polycrystalline transparent ceramic available commercially. Because of its relatively low weight, distinctive optical and mechanical properties, and resistance to oxidation or radiation, it shows promise for applications such as bulletproof, blast-resistant, and optoelectronic windows. ALON-based armor has been shown to stop multiple armor-piercing projectiles of up to .50 BMG.

ALON is commercially available in sizes as large as 18-by-35-inch (460 mm × 890 mm; 46 cm × 89 cm) monolithic windows.

🔗 Physics

Separation of isotopes by laser excitation (SILEX) is a process for isotope separation that is being investigated to produce enriched uranium on an industrial scale using lasers. It was developed in the 1990s and is a variant of molecular laser isotope separation (MLIS). For uranium, it uses a cold molecular beam with UF₆ in a carrier cas, in which the ²³⁵UF₆ is selectively excited by an infrared laser near 16 µm. But in contrast to earlier MLIS techniques developed since the 1970s, it does not dissociate the molecule.

🔗 Aviation 🔗 Military history 🔗 Military history/Military aviation

Balloon busters were military pilots known for destroying enemy observation balloons. These pilots were noted for their fearlessness, as balloons were stationary targets able to receive heavy defenses, from the ground and the air. Seventy-seven flying aces in World War I were each credited with destroying five or more balloons, and thus were balloon aces.