Time stays long enough for anyone who will use it. ~Leonardo Da Vinci
1854 – Henri Poincaré, French mathematician, physicist, and engineer is born.
Jules Henri Poincaré was a French mathematician, theoretical physicist, engineer, and a philosopher of science. He is often described as a polymath, and in mathematics as The Last Universalist by Eric Temple Bell, since he excelled in all fields of the discipline as it existed during his lifetime.
As a mathematician and physicist, he made many original fundamental contributions to pure and applied mathematics, mathematical physics, and celestial mechanics. He was responsible for formulating the Poincaré conjecture, which was one of the most famous unsolved problems in mathematics until it was solved in 2002–2003. In his research on the three-body problem, Poincaré became the first person to discover a chaotic deterministic system which laid the foundations of modern chaos theory. He is also considered to be one of the founders of the field of topology.
Poincaré made clear the importance of paying attention to the invariance of laws of physics under different transformations, and was the first to present the Lorentz transformations in their modern symmetrical form. Poincaré discovered the remaining relativistic velocity transformations and recorded them in a letter to Dutch physicist Hendrik Lorentz (1853–1928) in 1905. Thus he obtained perfect invariance of all of Maxwell’s equations, an important step in the formulation of the theory of special relativity.
The Poincaré group used in physics and mathematics was named after him.
1882 – The “Elektromote” – forerunner of the trolleybus – is tested by Ernst Werner von Siemens in Berlin.
The Electromote was the world’s first vehicle run like a trolleybus, which was first presented to the public on April 29, 1882, by its inventor Dr. Ernst Werner von Siemens in Halensee, a suburb of Berlin, Germany.
The Elektromote operated from April 29 to June 13, 1882, on a 540 m (591 yard) trail-track starting at Halensee railway station, and thence to “Straße No. 5”, today’s Joachim-Friedrich-Straße, and “Straße No. 13”, today’s Johann-Georg-Straße, crossing the upper Kurfürstendamm at former Kurfürstenplatz.
The Electromote built by the Siemens & Halske company was a converted four-wheel landau carriage, equipped with two 2.2 kW electric motors transmitting the power using a chain drive to the rear wheels. The voltage used was 550 V DC. The electric power transmission to the coach was by a flexible cable pulling a small eight-wheeled “contact car” (Kontaktwagen) that ran along the overhead power lines. In English language use, the Kontaktwagen was later named the “trolley”, giving the trolleybus its name.
This experimental vehicle already fulfilled all the technical criteria of a typical trolleybus. After the demonstration runs closed on June 13, the test track was dismantled on June 20, 1882.
1893 – Harold Urey, American chemist, Nobel Prize laureate is born.
Harold Clayton Urey was an American physical chemist whose pioneering work on isotopes earned him the Nobel Prize in Chemistry in 1934 for the discovery of deuterium. He played a significant role in the development of the atom bomb, but may be most prominent for his contribution to theories on the development of organic life from non-living matter.
Born in Walkerton, Indiana, Urey studied thermodynamics under Gilbert N. Lewis at the University of California. After he received his PhD in 1923, he was awarded a fellowship by the American-Scandinavian Foundation to study at the Niels Bohr Institute in Copenhagen. He was a research associate at Johns Hopkins University before becoming an associate professor of Chemistry at Columbia University. In 1931, he began work with the separation of isotopes that resulted in the discovery of deuterium.
During World War II Urey turned his knowledge of isotope separation to the problem of uranium enrichment. He headed the group located at Columbia University that developed isotope separation using gaseous diffusion. The method was successfully developed, becoming the sole method used in the early post-war period. After the war, Urey became professor of chemistry at the Institute for Nuclear Studies, and later Ryerson professor of chemistry at the University of Chicago.
Urey speculated that the early terrestrial atmosphere was probably composed of ammonia, methane, and hydrogen. One of his Chicago graduate students was Stanley L. Miller, who showed in the Miller–Urey experiment that, if such a mixture be exposed to electric sparks and water, it can interact to produce amino acids, commonly considered the building blocks of life. Work with isotopes of oxygen led to pioneering the new field of paleoclimatic research. In 1958, he accepted a post as a professor at large at the new University of California, San Diego (UCSD), where he helped create the science faculty. He was one of the founding members of UCSD’s school of chemistry, which was created in 1960. He became increasingly interested in space science, and when Apollo 11 returned moon rock samples from the moon, Urey examined them at the Lunar Receiving Laboratory.
1894 – Marietta Blau, Austrian physicist, is born.
Marietta Blau was an Austrian physicist. After having obtained the general certificate of education from the girls’ high school run by the Association for the Extended Education of Women, she studied physics and mathematics at the University of Vienna from 1914 to 1918; her Ph. D. graduation was in March 1919. Blau is credited with developing (photographic) nuclear emulsions that were usefully able to image and accurately measure high energy nuclear particles and events. Additionally, this established a method to accurately study reactions caused by cosmic ray events. Her nuclear emulsions significantly advanced the field of particle physics in her time. For her work she was nominated for the 1950 Nobel Prize in Physics by Erwin Schrödinger.
1953 – The first U.S. experimental 3D television broadcast showed an episode of Space Patrol on Los Angeles ABC affiliate KECA-TV.
3D television (3DTV) is television that conveys depth perception to the viewer by employing techniques such as stereoscopic display, multi-view display, 2D-plus-depth, or any other form of 3D display. Most modern 3D television sets use an active shutter 3D system or a polarized 3D system, and some are autostereoscopic without the need of glasses.
According to DisplaySearch, 3D televisions shipments have totaled 41.45 million units in 2012, compared with 24.14 in 2011 and 2.26 in 2010.
2009 – Tweet-a-watt in the news!
Tweet-a-Watt gets some attention from the press!
MAKE Volume 18: ReMake America
ReMake America! These challenging times have presented us with a rare chance to try out new ways of doing things. The opportunities for makers are terrific — we can start at home to remake manufacturing, education, food production, transportation, and recreation. In this volume you’ll learn how to make an automatic garden, heat your water with the sun, monitor and share your home energy usage, and more in MAKE Vol 18.
2011 – Warm white LED waterproof flexi-strip 60 LED is added to the Adafruit store!
These LED strips are fun and glowy. There are 60 warm white LEDs per meter, and you can control the entire strip at once with any microcontroller and a power transistor. The way they are wired, you will need a 9-12VDC power supply and connect directly. If you want to dim the strip, use any NPN or N-channel MOSFET (although the big powerful kind is good for a large strip) and PWM the input.
2013 – 3 new products and a new tutorial from Adafruit!
Can you believe that it’s only been 1 year since Adafruit added the Raspberry Pi? We’ve already moved on to a Model B! Also added this day last year: Maxbotix Ultrasonic Rangefinder – HR-USB-EZ1 – MB1413, SD/MicroSD Memory Card (8 GB SDHC), and our tutorial for an Affordable HAL 9000 Replica!
Have an amazing project to share? Join the SHOW-AND-TELL every Wednesday night at 7:30pm ET on Google+ Hangouts.
Join us every Wednesday night at 8pm ET for Ask an Engineer!
Learn resistor values with Mho’s Resistance or get the best electronics calculator for engineers “Circuit Playground” – Adafruit’s Apps!
Maker Business — Physical tutorials / video kiosks and more next to products in concept “store”
Wearables — 3D Print Authentic Cosplay Greebles
Electronics — Twist-tie Jumpers
Biohacking — “You can train your body into thinking it’s had medicine”
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