Chicago Pile-1 was the world's first artificial nuclear reactor. On 2 December 1942, the first human-made self-sustaining nuclear chain reaction was initiated in CP-1, during an experiment led by Enrico Fermi; the secret development of the reactor was the first major technical achievement for the Manhattan Project, the Allied effort to create atomic bombs during World War II. Although the project's civilian and military leaders had misgivings about the possibility of a disastrous runaway reaction, they trusted Fermi's safety calculations and decided they could carry out the experiment in a densely populated area, it was built by the Metallurgical Laboratory at the University of Chicago, under the west viewing stands of the original Stagg Field. Fermi described the apparatus as "a crude pile of black bricks and wooden timbers"; the reactor was assembled in November 1942, by a team that included Fermi, Leo Szilard, Leona Woods, Herbert L. Anderson, Walter Zinn, Martin D. Whitaker, George Weil.
The reactor used natural uranium. This required a large amount of material in order to reach criticality, along with graphite used as a neutron moderator; the reactor contained 45,000 ultra-pure graphite blocks weighing 360 short tons, was fueled by 5.4 short tons of uranium metal and 45 short tons of uranium oxide. Unlike most subsequent nuclear reactors, it had no radiation shielding or cooling system as it operated at low power – about one-half watt; the pursuit for a reactor had been touched off by concern that Nazi Germany had a substantial scientific lead. The success of Chicago Pile-1 provided the first vivid demonstration of the feasibility of the military use of nuclear energy by the Allies, the reality of the danger that Nazi Germany could succeed in producing nuclear weapons. Estimates of critical masses had been crude calculations, leading to order-of-magnitude uncertainties about the size of a hypothetical bomb; the successful use of graphite as a moderator paved the way for progress in the Allied effort, whereas the German program languished because of the belief that scarce and expensive heavy water would have to be used for that purpose.
In 1943, CP-1 was moved to Red Gate Woods, reconfigured to become Chicago Pile-2. There, it was operated until 1954, when it was buried; the stands at Stagg Field were demolished in August 1957. The idea of chemical chain reactions was first suggested in 1913 by the German chemist Max Bodenstein for a situation in which two molecules react to form not just the final reaction products, but some unstable molecules which can further react with the original substances to cause more to react; the concept of a nuclear chain reaction was first hypothesized by the Hungarian scientist Leo Szilard on 12 September 1933. Szilard realized that if a nuclear reaction produced neutrons or dineutrons, which caused further nuclear reactions, the process might be self-perpetuating. Szilard proposed using mixtures of lighter known isotopes which produced neutrons in copious amounts, entertained the possibility of using uranium as a fuel, he filed a patent for his idea of a simple nuclear reactor the following year.
The discovery of nuclear fission by German chemists Otto Hahn and Fritz Strassmann in 1938, its theoretical explanation by their collaborators Lise Meitner and Otto Frisch, opened up the possibility of creating a nuclear chain reaction with uranium or indium, but initial experiments were unsuccessful. In order for a chain reaction to occur, fissioning uranium atoms had to emit additional neutrons to keep the reaction going. At Columbia University in New York, Italian physicist, Enrico Fermi, with Americans John Dunning, Herbert L. Anderson, Eugene T. Booth, G. Norris Glasoe, Francis G. Slack conducted the first nuclear fission experiment in the United States on 25 January 1939. Subsequent work confirmed. Szilard obtained permission from the head of the Physics Department at Columbia, George B. Pegram, to use a laboratory for three months, persuaded Walter Zinn to become his collaborator, they conducted a simple experiment on the seventh floor of Pupin Hall at Columbia, using a radium-beryllium source to bombard uranium with neutrons.
They discovered significant neutron multiplication in natural uranium, proving that a chain reaction might be possible. Fermi and Szilard still believed that enormous quantities of uranium would be required for an atomic bomb, therefore concentrated on producing a controlled chain reaction. Fermi urged Alfred O. C. Nier to separate uranium isotopes for determination of the fissile component, and, on 29 February 1940, Nier separated the first uranium-235 sample, after being mailed to Dunning at Columbia, was confirmed to be the isolated fissile material; when he was working in Rome, Fermi had discovered that collisions between neutrons and neutron moderators can slow the neutrons down, thereby make them more to be captured by uranium nuclei, causing the uranium to fission. Szilard suggested to Fermi; as a back-up plan, he considered heavy water. This contained deuterium, which would not absorb neutrons like ordinary hydrogen, was a better neutron moderator than carbon. Fermi estimated, it was enough, but a careful design was called for to minimize losses..
The American children's television series Sesame Street is known for its extensive merchandising. Licensees include a variety of companies which manufacture books, video/audio media, toys using the characters and themes of Sesame Street. Current licensees include Fisher-Price, Nakajima USA, Build-A-Bear Workshop, Wooly Willy, Betty Crocker, C&D Visionary and Children's Apparel Network. Former licences include Applause, Child Dimension, Gibson Greetings, Gorham Fine China, Ideal Toys, Milton Bradley Company, Palisades Toys, Radio Shack and the Western Publishing Company. Creative Wonders produced Sesame Street software for the Macintosh, since at least 1995 and on the PC since 1996. Before going bankrupt, Palisades Toys was to release a line of deluxe series action figures, for adults, as part of Sesame Workshop's push to expand into retro products for teens and adults; the Sesame Beginnings line, launched in mid-2005, consists of apparel and body, seasonal products. The products in this line are designed to accentuate the natural interactivity between infants and their parents.
Most of the line is exclusive to a family of Canadian retailers that includes Loblaws and Zehrs. As Sesame Workshop, the licensor of these characters, is a non-profit organization, a percentage of the money from any Sesame Workshop product goes to help fund Sesame Street or its international co-productions. Tickle Me Elmo was one of the fastest selling toys of the 1996 season; that product line was and still is one of the most successful products Mattel has launched. Both it and its most notable successor, TMX, have caused in-store fights. Elmo starred in a Christmas special that year, in which he wished every day of the year was Christmas. After Fisher-Price recalled a large number of Sesame Street brand toys in 2007, Sesame Workshop announced that they would independently inspect the products of all manufacturers, it went so far as to threaten withdrawing from toy licensing, if it were not satisfied with the manufacturer's guarantees. Its fiction books are published on five continents by Random House in North America.
Over 18 million Sesame Street books and magazines were purchased in 2005. The books mention that children do not have to watch the show to benefit from its publications. In 1975, ice-skating show Sesame Street on Ice presented costumed actors and dancers as touring casts, each performing a unique-multimillion-dollar budget ice show, and Sesame Street on Ice ran from 1975–1980. Live touring show Sesame Street Live presents costumed actors and dancers as characters from the series, in original plots. In recent years, VEE has had four touring casts, each performing a unique multimillion-dollar budget show; each season, the tours reach 160 different cities across North America, reaching 2 million people annually. Since the first production of Sesame Street Live on September 17, 1980, 48 million children and their parents have seen the show performed, across the world. Busch Entertainment Corporation is the licence holder for Sesame Street in its U. S. amusement parks including a Sesame Street themed park, Sesame Place, in Langhorne, United States.
BEC has a stage show at SeaWorld Orlando Elmo and the Bookaneers. In 2009 Busch Entertainment's Busch Gardens Williamsburg in Williamsburg, Virginia opened "Sesame Street Forest of Fun" with plans to open "Sesame Street Safari of Fun" at its Busch Gardens Tampa Bay park in Tampa Florida in the 2010 operating season. Another theme park, Parque Plaza Sésamo, exists in Monterrey and Universal Studios Japan includes a three-dimensional movie based on the show. Although Sesame Street characters endorse non-educational products, they appear in their puppet form, to limit the suggestion to children that the characters are formally endorsing the product; the Muppets do appear in puppet form to endorse select causes. Big Bird has promoted safe seating practices and the wearing of seatbelts, for the Ford Motor Company, while Grover promoted a new course on children's informal learning, created by Harvard University with Sesame Workshop. Elmo has appeared before the US Education Appropriations Subcommittee to urge more spending on music in schools.
Barrio Sésamo, Plaza Sésamo, Sesamstraße, Sesame English and Sesamstraat have all had merchandise of their local characters. Shalom Sesame videos and books have been released. In 2004, Copyright Promotions Licensing Group became Sesame Workshop's licensing representative for The Benelux, adding to their United Kingdom representation
The first Belarusian round-the-world flight was conducted from 18 August to 15 September 2018 by a team of two aviators of Belarus. The flight was made on a Cessna 182 Skylane modified to hold extra fuel, covered 30,000 kilometers in 145 flying hours, over 30 flight days, landing in 10 countries. Alexander Tsenter and Andrey Borisevich became the first Belarusian pilots to fly around the world; the captain Alexandr Tsenter is the chairman of the Belarusian Federation of Air Sports, co-pilot Andrey Borisevich is the head of SkyEagle Aviation Academy in Florida, the United States. Flying across Russia was a challenge for pilots. Pilots had to send barrels of gasoline to projected landing points ahead of their trip. Russian air traffic control demanded their estimated distance from three points ahead, while some locations were not marked on the maps of pilots and from time to time there was no cell phone service in Syberian remote areas; the flight traveled from West to East, beginning in Belarus on 18 August 2018 and returning to its start point on 15 September 2018.
It flew northeast via Russia to the United States and across the Atlantic Ocean and Europe. Detailed itinerary: Lipki — Mahilyow — Ostafyevo — Bogorodsk — Pervushino — Kalachyovo — Mochishche — Yemelyanovo — Mostovoy — Irkutsk — Kadala — Tynda — Ayan — Sokol — Ugolny — Provideniya Bay — Nome — Talkeetna — Juneau — Ketchikan — Renton — Billings Logan — Yellowstone — Lake Tahoe — Mariposa-Yosemite — Page — Cheyenne — Dane — Greater Rochester — Nashua — Bangor — Goose Bay — Narsarsuaq — Reykjavík — Vágar — Wick — Schönhagen — Warsaw Modlin — Minsk — Lipki. First aerial circumnavigation List of circumnavigations: Aircraft Chronological listing of all known flights around the World Website of the first Belarusian round-the-world flight The first Belarusian round-the-world flight on YouTube The first Belarusian round-the-world flight on Instagram