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🔗 Biography 🔗 Australia 🔗 Transport 🔗 Transport/Maritime 🔗 Australia/Australian maritime history 🔗 Australia/Western Australia 🔗 Australia/Australia, New Zealand and South Pacific military history

Frederick Benjamin "Ben" Carlin (27 July 1912 – 7 March 1981) was an Australian adventurer who was the first person to circumnavigate the world in an amphibious vehicle. Born in Northam, Western Australia, Carlin attended Guildford Grammar School in Perth, and later studied mining engineering at the Kalgoorlie School of Mines. After qualifying as an engineer, he worked on the Goldfields before in 1939 emigrating to China to work in a British coal mine. In the Second World War, Carlin was posted to the Indian Army Corps of Engineers, serving in India, Italy, and throughout the Middle East. After his discharge from service in 1946, he emigrated to the United States with his American wife, Elinore (née Arone).

Sparked by an idea he had had whilst in the military, Carlin proposed that the couple honeymoon by crossing the Atlantic Ocean in a modified Ford GPA (an amphibious version of the Ford GPW Jeep), which they named the Half-Safe. Beginning their trip in Montreal, Quebec, Canada, the Carlins finally completed the transatlantic crossing in 1951, after unsuccessful attempts. From there, they travelled to Europe, temporarily settling in Birmingham to raise more money. They resumed their journey in 1954, travelling overland through the Middle East before arriving in Calcutta. After a short fundraising trip to Australia, Carlin's wife left to return to the United States. He resumed the journey with new partners, travelling through South-East Asia and the Far East to the northern tip of Japan, and then to Alaska. After an extended tour through the United States and Canada, he and Half-Safe finally returned to Montreal, having travelled over 17,000 kilometres (11,000 mi) by sea and 62,000 kilometres (39,000 mi) by land during a ten-year journey. Following Carlin's death in 1981, Half-Safe was acquired by Guildford Grammar, his old school, where it remains on display.

🔗 Military history 🔗 Disaster management 🔗 Death 🔗 China/Chinese history 🔗 China 🔗 Astronomy 🔗 Geology 🔗 Military history/Asian military history 🔗 Geology/Meteorites 🔗 Military history/Chinese military history 🔗 Explosives 🔗 Astronomy/Solar System

The Wanggongchang Explosion (Chinese: 王恭廠大爆炸), also known as the Great Tianqi Explosion (天啟大爆炸), Wanggongchang Calamity (王恭廠之變) or Beijing Explosive Incident in Late Ming (晚明北京爆炸事件), was an unexplained catastrophic explosion that occurred on May 30 of the Chinese calendar in 1626 AD during the late reign of Tianqi Emperor, at the heavily populated Ming China capital Beijing, and had reportedly killed around 20,000 people. The nature of the explosion is still unclear to this day, as it is estimated to have released energy equivalent to about 10-20 kiloton of TNT, similar to that of the Hiroshima bombing.

🔗 United States 🔗 Companies 🔗 Business 🔗 Philately

The American Letter Mail Company was started by Lysander Spooner in 1844, competing with the presumed legal monopoly of the United States Post Office (USPO, now the USPS).

🔗 Chess

The Immortal Game was a chess game played by Adolf Anderssen and Lionel Kieseritzky on 21 June 1851 in London, during a break of the first international tournament. The bold sacrifices made by Anderssen to secure victory have made it one of the most famous chess games of all time. Anderssen gave up both rooks and a bishop, then his queen, checkmating his opponent with his three remaining minor pieces. In 1996, Bill Hartston called the game an achievement "perhaps unparalleled in chess literature".

🔗 Birds

Wisdom is a wild female Laysan albatross. She is the oldest confirmed wild bird in the world as well as the oldest banded bird in the world.

🔗 Computing 🔗 Computer science

Esterel is a synchronous programming language for the development of complex reactive systems. The imperative programming style of Esterel allows the simple expression of parallelism and preemption. As a consequence, it is well suited for control-dominated model designs.

The development of the language started in the early 1980s, and was mainly carried out by a team of Ecole des Mines de Paris and INRIA led by Gérard Berry in France. Current compilers take Esterel programs and generate C code or hardware (RTL) implementations (VHDL or Verilog).

The language is still under development, with several compilers out. The commercial version of Esterel is the development environment Esterel Studio. The company that commercialize it (Synfora) initiated a normalization process with the IEEE in April 2007 however the working group (P1778) dissolved March 2011. The Esterel v7 Reference Manual Version v7 30 – initial IEEE standardization proposal is publicly available.

🔗 Spaceflight

A porkchop plot (also pork-chop plot) is a chart that shows contours of equal characteristic energy (C₃) against combinations of launch date and arrival date for a particular interplanetary flight.

By examining the results of the porkchop plot, engineers can determine when launch opportunities exist (a launch window) that is compatible with the capabilities of a particular spacecraft. A given contour, called a porkchop curve, represents constant C₃, and the center of the porkchop the optimal minimum C₃. The orbital elements of the solution, where the fixed values are the departure date, the arrival date, and the length of the flight, were first solved mathematically in 1761 by Johann Heinrich Lambert, and the equation is generally known as Lambert's problem (or theorem).

🔗 Time

The ISO week date system is effectively a leap week calendar system that is part of the ISO 8601 date and time standard issued by the International Organization for Standardization (ISO) since 1988 (last revised in 2004) and, before that, it was defined in ISO (R) 2015 since 1971. It is used (mainly) in government and business for fiscal years, as well as in timekeeping. This was previously known as "Industrial date coding". The system specifies a week year atop the Gregorian calendar by defining a notation for ordinal weeks of the year.

The Gregorian leap cycle, which has 97 leap days spread across 400 years, contains a whole number of weeks (20871). In every cycle there are 71 years with an additional 53rd week (corresponding to the Gregorian years that contain 53 Thursdays). An average year is exactly 52.1775 weeks long; months (​¹⁄₁₂ year) average at exactly 4.348125 weeks.

An ISO week-numbering year (also called ISO year informally) has 52 or 53 full weeks. That is 364 or 371 days instead of the usual 365 or 366 days. The extra week is sometimes referred to as a leap week, although ISO 8601 does not use this term.

Weeks start with Monday. Each week's year is the Gregorian year in which the Thursday falls. The first week of the year, hence, always contains 4 January. ISO week year numbering therefore slightly deviates from the Gregorian for some days close to 1 January.

A precise date is specified by the ISO week-numbering year in the format YYYY, a week number in the format ww prefixed by the letter 'W', and the weekday number, a digit d from 1 through 7, beginning with Monday and ending with Sunday. For example, the Gregorian date Monday 23 December 2019 corresponds to Monday in the 52nd week of 2019, and is written 2019-W52-1 (in extended form) or 2019W521 (in compact form). The ISO year is slightly offset to the Gregorian year; for example, Monday 30 December 2019 in the Gregorian calendar is the first day of week 1 of 2020 in the ISO calendar, and is written as 2020-W01-1 or 2020W011.

🔗 Physics 🔗 Spectroscopy

Silicon drift detectors (SDDs) are X-ray radiation detectors used in x-ray spectrometry (XRF and EDS) and electron microscopy. Their chief characteristics compared with other X-ray detectors are:

• high count rates
• comparatively high energy resolution (e.g. 125 eV for Mn Kα wavelength)
• Peltier cooling

🔗 Computing

In computer science, the ostrich algorithm is a strategy of ignoring potential problems on the basis that they may be exceedingly rare. It is named for the ostrich effect which is defined as "to stick one's head in the sand and pretend there is no problem". It is used when it is more cost-effective to allow the problem to occur than to attempt its prevention.