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🔗 Spaceflight 🔗 Physics

Electrodynamic tethers (EDTs) are long conducting wires, such as one deployed from a tether satellite, which can operate on electromagnetic principles as generators, by converting their kinetic energy to electrical energy, or as motors, converting electrical energy to kinetic energy. Electric potential is generated across a conductive tether by its motion through a planet's magnetic field.

A number of missions have demonstrated electrodynamic tethers in space, most notably the TSS-1, TSS-1R, and Plasma Motor Generator (PMG) experiments.

🔗 Telecommunications 🔗 Radio 🔗 Electronics 🔗 Engineering

In radio communications, an evolved antenna is an antenna designed fully or substantially by an automatic computer design program that uses an evolutionary algorithm that mimics Darwinian evolution. This procedure has been used in recent years to design a few antennas for mission-critical applications involving stringent, conflicting, or unusual design requirements, such as unusual radiation patterns, for which none of the many existing antenna types are adequate.

🔗 Biography 🔗 England 🔗 Middle Ages 🔗 Middle Ages/History 🔗 Biography/arts and entertainment 🔗 East Anglia 🔗 East Anglia/Suffolk

Roland the Farter (known in contemporary records as Roland le Fartere, Roulandus le Fartere or Roland le Petour) was a medieval flatulist who lived in twelfth-century England. He was given Hemingstone manor in Suffolk and 12 hectares (30 acres) of land in return for his services as a jester for King Henry II. Each year he was obliged to perform "Unum saltum et siffletum et unum bumbulum" (one jump, one whistle, and one fart) for the King's court at Christmas.

Roland is listed in the thirteenth-century English Liber Feodorum (Book of Fees).

🔗 Books 🔗 Alternative Views 🔗 Chemistry 🔗 Psychoactive and Recreational Drugs

PiHKAL: A Chemical Love Story is a book by Dr. Alexander Shulgin and Ann Shulgin, published in 1991. The subject of the work is psychoactive phenethylamine chemical derivatives, notably those that act as psychedelics and/or empathogen-entactogens. The main title, PiHKAL, is an acronym that stands for "Phenethylamines I Have Known and Loved".

The book is arranged into two parts, the first part being a fictionalized autobiography of the couple and the second part describing 179 different psychedelic compounds (most of which Shulgin discovered himself), including detailed synthesis instructions, bioassays, dosages, and other commentary.

The second part was made freely available by Shulgin on Erowid while the first part is available only in the printed text. While the reactions described are beyond the ability of people with a basic chemistry education, some tend to emphasize techniques that do not require difficult-to-obtain chemicals. Notable among these are the use of mercury-aluminum amalgam (an unusual but easy to obtain reagent) as a reducing agent and detailed suggestions on legal plant sources of important drug precursors such as safrole.

🔗 Medicine 🔗 Ancient Egypt

The Ebers Papyrus, also known as Papyrus Ebers, is an Egyptian medical papyrus of herbal knowledge dating to circa 1550 BC. Among the oldest and most important medical papyri of ancient Egypt, it was purchased at Luxor in the winter of 1873–74 by Georg Ebers. It is currently kept at the library of the University of Leipzig, in Germany.

🔗 Poetry

"Fragments of Olympian Gossip" is a poem that Nikola Tesla composed in the late 1920s for his friend the German poet and mystic George Sylvester Viereck. It made fun of the scientific establishment of the day.

While listening on my cosmic phone
I caught words from the Olympus blown.
A newcomer was shown around;
That much I could guess, aided by sound.

"There's Archimedes with his lever
Still busy on problems as ever.
Says: matter and force are transmutable
And wrong the laws you thought immutable."

"Below, on Earth, they work at full blast
And news are coming in thick and fast.
The latest tells of a cosmic gun.
To be pelted is very poor fun.
We are wary with so much at stake,
Those beggars are a pest—no mistake."

"Too bad, Sir Isaac, they dimmed your renown
And turned your great science upside down.
Now a long haired crank, Einstein by name,
Puts on your high teaching all the blame.
Says: matter and force are transmutable
And wrong the laws you thought immutable."

"I am much too ignorant, my son,
For grasping schemes so finely spun.
My followers are of stronger mind
And I am content to stay behind,
Perhaps I failed, but I did my best,
These masters of mine may do the rest.
Come, Kelvin, I have finished my cup.
When is your friend Tesla coming up."

"Oh, quoth Kelvin, he is always late,
It would be useless to remonstrate."

Then silence—shuffle of soft slippered feet—
I knock and—the bedlam of the street.

Nikola Tesla, Novice

🔗 Military history 🔗 Military history/African military history 🔗 British Empire 🔗 Military history/Maritime warfare 🔗 African diaspora 🔗 Military history/European military history 🔗 Military history/British military history

The British Royal Navy established the West Africa Squadron at substantial expense in 1808 after Parliament passed the Slave Trade Act of 1807, an Act for the Abolition of the Slave Trade. The squadron's task was to suppress the Atlantic slave trade by patrolling the coast of West Africa. With a home base at Portsmouth, England, it began with two small ships, the 32-gun fifth-rate frigate HMS Solebay and the Cruizer-class brig-sloop HMS Derwent. At the height of its operations, the squadron employed a sixth of the Royal Navy fleet and marines. In 1819 the Royal Navy established a West Coast of Africa Station and the West Africa Squadron became known as the Preventative Squadron. It remained an independent command until 1856 and then again 1866 to 1867. Between 1830 and 1865, more than 1,500 British sailors died on their mission of freeing slaves with the West Africa Squadron.

Between 1808 and 1860 the West Africa Squadron captured 1,600 slave ships and freed 150,000 Africans. It is considered the most costly international moral action in modern history.

The Squadron has been described as being poorly resourced and plagued by corruption; it only managed to capture around 6% of the transatlantic slave ships, but patrolling 3,000 miles of African coast from 1808 to 1860 it liberated 150,000 Africans.

🔗 Medicine 🔗 Psychology 🔗 Disability 🔗 Neuroscience

Aphantasia is a condition where one does not possess a functioning mind's eye and cannot voluntarily visualize imagery. The phenomenon was first described by Francis Galton in 1880 but has since remained largely unstudied. Interest in the phenomenon renewed after the publication of a study in 2015 conducted by a team led by Professor Adam Zeman of the University of Exeter, which also coined the term aphantasia. Research on the condition is still scarce.

🔗 Computing 🔗 Computing/Computer hardware

In the x86 architecture, the CPUID instruction (identified by a CPUID opcode) is a processor supplementary instruction (its name derived from CPU IDentification) allowing software to discover details of the processor. It was introduced by Intel in 1993 with the launch of the Pentium and SL-enhanced 486 processors.

A program can use the CPUID to determine processor type and whether features such as MMX/SSE are implemented.

🔗 Radio

A crystal detector is an obsolete electronic component used in some early 20th century radio receivers that consists of a piece of crystalline mineral which rectifies the alternating current radio signal. It was employed as a detector (demodulator) to extract the audio modulation signal from the modulated carrier, to produce the sound in the earphones. It was the first type of semiconductor diode, and one of the first semiconductor electronic devices. The most common type was the so-called cat whisker detector, which consisted of a piece of crystalline mineral, usually galena (lead sulfide), with a fine wire touching its surface.

The "asymmetric conduction" of electric current across electrical contacts between a crystal and a metal was discovered in 1874 by Karl Ferdinand Braun. Crystals were first used as radio wave detectors in 1894 by Jagadish Chandra Bose in his microwave experiments. Bose first patented a crystal detector in 1901. The crystal detector was developed into a practical radio component mainly by G. W. Pickard, who began research on detector materials in 1902 and found hundreds of substances that could be used in forming rectifying junctions. The physical principles by which they worked were not understood at the time they were used, but subsequent research into these primitive point contact semiconductor junctions in the 1930s and 1940s led to the development of modern semiconductor electronics.

The unamplified radio receivers that used crystal detectors were called crystal radios. The crystal radio was the first type of radio receiver that was used by the general public, and became the most widely used type of radio until the 1920s. It became obsolete with the development of vacuum tube receivers around 1920, but continued to be used until World War II and remains a common educational project today thanks to its simple design.