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Thermal diffusivity

In heat transfer analysis, thermal diffusivity is the thermal conductivity divided by density and specific heat capacity at constant pressure. It measures the rate of transfer of heat of a material from the hot end to the cold end, it has the SI derived unit of m²/s. Thermal diffusivity is denoted α but a,h,κ, K, D are used; the formula is: α = k ρ c p where k is thermal conductivity c p is specific heat capacity ρ is density Together, ρ c p can be considered the volumetric heat capacity. As seen in the heat equation, ∂ T ∂ t = α ∇ 2 T,one way to view thermal diffusivity is as the ratio of the time derivative of temperature to its curvature, quantifying the rate at which temperature concavity is "smoothed out". In a sense, thermal diffusivity is the measure of thermal inertia. In a substance with high thermal diffusivity, heat moves through it because the substance conducts heat relative to its volumetric heat capacity or'thermal bulk'. Thermal diffusivity is measured with the flash method, it involves heating a strip or cylindrical sample with a short energy pulse at one end and analyzing the temperature change a short distance away.

Heat equation Laser flash analysis Thermodiffusion Thermal effusivity Thermal time constant

Norcross, Minnesota

Norcross is a city in Grant County, United States, along the Mustinka River. The population was 70 at the 2010 census. Norcross was platted in 1881; the city's name is Judson Newell Cross, the founders. A post office has been in operation at Norcross since 1881. According to the United States Census Bureau, the city has a total area of 1.56 square miles, all of it land. Minnesota State Highway 9 serves as a main route in the community; as of the census of 2010, there were 70 people, 29 households, 20 families living in the city. The population density was 44.9 inhabitants per square mile. There were 39 housing units at an average density of 25.0 per square mile. The racial makeup of the city was 74.3% White, 1.4% Native American, 20.0% from other races, 4.3% from two or more races. Hispanic or Latino of any race were 25.7% of the population. There were 29 households of which 27.6% had children under the age of 18 living with them, 58.6% were married couples living together, 10.3% had a female householder with no husband present, 31.0% were non-families.

31.0% of all households were made up of individuals and 13.8% had someone living alone, 65 years of age or older. The average household size was 2.41 and the average family size was 3.05. The median age in the city was 41.5 years. 28.6% of residents were under the age of 18. The gender makeup of the city was 62.9 % female. As of the census of 2000, there were 59 people, 33 households, 19 families living in the city; the population density was 37.7 people per square mile. There were 40 housing units at an average density of 25.5 per square mile. The racial makeup of the city was 100.00% White. There were 33 households out of which 21.2% had children under the age of 18 living with them, 48.5% were married couples living together, 9.1% had a female householder with no husband present, 39.4% were non-families. 39.4% of all households were made up of individuals and 27.3% had someone living alone, 65 years of age or older. The average household size was 1.79 and the average family size was 2.30. In the city, the population was spread out with 13.6% under the age of 18, 5.1% from 18 to 24, 13.6% from 25 to 44, 35.6% from 45 to 64, 32.2% who were 65 years of age or older.

The median age was 53 years. For every 100 females, there were 84.4 males. For every 100 females age 18 and over, there were 104.0 males. The median income for a household in the city was $11,875, the median income for a family was $34,375. Males had a median income of $52,500 versus $18,750 for females; the per capita income for the city was $14,507. There were 23.5% of families and 24.1% of the population living below the poverty line, including 50.0% of under eighteens and 15.0% of those over 64


Shitik is a small broad-bottomed vessel in which parts of the hull have been sewed with belts or juniper and fir-tree rods called vinya. There are two basic explanations for the origins of the name of this boat; the first involves the Russian: Сшивать word. This is a verb" and explains some design features of the boat; the second version associates the name with the shape of the boat being similar to larva Trichoptera, called Russian: Шитик or shitik. The term Shitik refers to two different vessel types: The Shitik was a keeled vessel, powered by sail and oars, it was used as a sea transport ship. The ship has a rounded-off bottom and, features a considerable expansion of the hull and disorder of boards; this design improves the ship's performance. Shitik had a single mast with a direct sail, a hinged wheel; the vessel had a canopy to protect the cargo from the rain although there is a bunkhouse below the deck. The underwater contours of the vessel allowed it to navigate in ice: when compressed it was squeezed out onto the surface.

When docking the ship and hauling the anchor, Shitik needs the assistance of a vessel called osinovka boat. It is believed that in the 13th century, the Shitik was the most widespread coastal transport vessel. Shitiks were built between the 11th–17th centuries. Shitiks were built on the coast of the White Sea, the Northern Dvina, Vychegda and Tikhvinka rivers; the building of such boats spread in Siberia and the Far East, since Shitiks plied the Pacific Ocean. Shitiks were an important innovation on the Siberian rivers. Many shallows and reefs made a keel useless, a shortage of nails made it necessary to improve techniques of sewing the planks, it was operated throughout the 18th–20th centuries, being replaced with new types of ship. When artisan shipbuilders had the opportunity to use aluminium, the boat found a new niche, it is used by hunters and fishermen to reach inaccessible places in the taiga. Making Shitiks is popular on the Lena River in Russia; the design of the boat has been retained.

Shitiks now have pointed bows instead of sawn-off ends. Sails are no longer used. Shitiks are useful in overcoming shoals; the absence of a keel is a problem. Such a boat does not transfer a wave, every movement of a passenger risks capsizing the vessel, but this combination of features suits hunters and fishermen, who can use it to cross rivers of 30 centimetres – 40 centimetres depth. Well known Shitiks: on the First Kamchatka expedition under the command of Vitus Bering, an auxiliary vessel "Fortuna" boat-shitik was used Barge Flatboat Keelboat Riverboat

McMinnville UFO photographs

The McMinnville UFO photographs were taken on a farm near McMinnville, United States, in 1950. The photos were reprinted in Life magazine and in newspapers across the nation, are considered to be among the most famous taken of a UFO. UFO skeptics believe that the photos are a hoax, but many ufologists continue to argue that the photos are genuine, show an unidentified object in the sky. Although these images have become known as the "McMinnville UFO Photographs", Paul and Evelyn Trent's farm was just outside Sheridan, Oregon nine miles southwest of McMinnville, the nearest larger town. According to astronomer William K. Hartmann's account, on 11 May 1950 at 7:30 p.m. Evelyn Trent was walking back to her farmhouse after feeding rabbits on her farm. Before reaching the house she claimed to see a slow-moving, metallic disk-shaped object heading in her direction from the northeast, she yelled for her husband, inside the house. After a short time he went back inside their home to obtain a camera. Paul Trent's father claimed he viewed the object before it flew away.

Hartmann's version of the incident traces back to an interview the Trents gave to Lou Gillette, host of the radio station KMCM, quoted in The Oregonian newspaper on 10 June 1950. However, the Trents had given a different version of the incident to the local McMinnville newspaper, the Telephone Register, two days earlier on 8 June 1950. In that version, Evelyn Trent stated "We'd been out in the back yard. Both of us saw the object at the same time; the camera! Paul thought it was in the car but I was sure it was in the house. I was right—and the Kodak was loaded with film..." The roll of film in Paul Trent's camera was not used up, so Trent did not have the film developed immediately. The film was not developed until the remaining frames were used in shooting family photographs for Mother's Day. In a 1997 interview, the Trents claimed that they thought the object they had photographed was a secret military aircraft, feared the "photos might bring them trouble." When he mentioned his sighting and photographs to his banker, Frank Wortmann, the banker was intrigued enough to display them from his bank window in McMinnville.

Shortly afterwards Bill Powell, a local newspaper reporter, convinced Mr. Trent to loan him the negatives. Powell found no evidence that they were tampered with or faked. On June 8, 1950, Powell's story of the incident—accompanied by the two photos—was published as a front-page story in the McMinnville Telephone-Register; the headline read: "At Long Last—Authentic Photographs Of Flying Saucer"The story and photos were subsequently picked up by the International News Service and sent to other newspapers around the nation, thus giving them wide publicity. Life magazine published cropped versions of the photos on June 26, 1950, along with a photo of Trent and his camera; the Trents had been promised. In 1967 the negatives were found in the files of the United Press International, a news service which had merged with INS years earlier; the negatives were loaned to Dr. William K. Hartmann, an astronomer, working as an investigator for the Condon Committee, a government-funded UFO research project based at the University of Colorado Boulder.

The Trents were not informed that their "lost" negatives had been found. Hartmann was impressed by their sincerity. In Hartmann's analysis, he wrote to the Condon Committee that "This is one of the few UFO reports in which all factors investigated, geometric and physical, appear to be consistent with the assertion that an extraordinary flying object, metallic, disk-shaped, tens of meters in diameter, evidently artificial, flew within sight of two witnesses."One reason for this conclusion was due to the photometric analysis of the images. Hartmann noted that the brightness of the underside of the object appeared to be lighter than the underside of the oil tank seen in the images; this could be due to the effects of atmospheric extinction and scattering, the same effects that make distant mountains appear "washed out" and blue. This effect suggested the objects were further from the camera than the tank, not small, local objects."Hartmann did, however point out the possibility that the images were manufactured.

He noted that "The object appears beneath a pair of wires, as is seen in Plates 23 and 24. We may question, whether it could have been a model suspended from one of the wires; this possibility is strengthened by the observation that the object appears beneath the same point in the two photos, in spite of their having been taken from two positions." And concludes "These tests do not rule out the possibility that the object was a small model suspended from the nearby wire by an unresolved thread."Hartmann noticed a discrepancy that would become the main point of objection for skeptics. He noticed that the overall lighting of the image was consistent with the lighting that would be expected around sunset, but noted that "There could be a possible discrepancy in view of the fact that the UFO, the telephone pole the garage at the left, the distant house gables are illuminated from the right, or east; the house, in particular, appe


Rüdlingen is a municipality in the canton of Schaffhausen in Switzerland. Rüdlingen is first mentioned in 827 as Ruodiningun. Rüdlingen has an area, as of 2006, of 5.5 km2. Of this area, 47.6 % is used for agricultural purposes. Of the rest of the land, 8.1% is settled and the remainder is non-productive. The municipality is located in the Schaffhausen district on the Rhine knee above Eglisau. With Buchberg, Rüdlingen forms an exclave of the Canton of Schaffhausen on the Rhine, bordered by the Canton of Zürich and Baden-Württemberg; the blazon of the municipal coat of arms is Per pale Azure an Oar and a in saltire Or and Or a Semi Mill Wheel Azure. A road border crossing into Germany's Lottstetten municipality, Baden-Württemberg state, is located at Ischläg; the town in Germany is Nack. Rüdlingen has a population of 665. Of the foreign population, 53.1% are from Germany, 46.9% are from another country. Over the last 10 years the population has grown at a rate of 7.9%. Most of the population speaks German, with French being second most English being third.

The age distribution of the population is children and teenagers make up 19.7% of the population, while adults make up 65.1% and seniors make up 15.2%. In the 2007 federal election the most popular party was the SVP; the next two most popular parties were the SP, the FDP. In Rüdlingen about 87.4% of the population have completed either non-mandatory upper secondary education or additional higher education. In Rüdlingen, as of 2007, 2.01% of the population attend kindergarten or another pre-school, 6.5% attend a Primary School, 2.63% attend a lower level Secondary School, 2.01% attend a higher level Secondary School. As of 2000, 14.3% of the population belonged to the Roman Catholic Church and 68.5% belonged to the Swiss Reformed Church. The historical population is given in the following table: The village of Rüdlingen with a number of half timbered houses is designated as part of the Inventory of Swiss Heritage Sites. Rüdlingen has an unemployment rate (as of 2007 of 0.75%. As of 2005, there were 56 people employed in the primary economic sector and about 19 businesses involved in this sector.

11 people are employed in the secondary sector and there are 7 businesses in this sector. 100 people are employed with 21 businesses in this sector. As of 2008 the mid year average unemployment rate was 0.7%. There were 34 non-agrarian businesses in the municipality and 19.1% of the population was involved in the secondary sector of the economy while 80.9% were involved in the third. At the same time, 55.9% of the working population was employed full-time, 44.1% was employed part-time. There were 136 residents of the municipality who were employed in some capacity, of which females made up 38.2% of the workforce. As of 2000 there were 102 residents who worked in the municipality, while 223 residents worked outside Rüdlingen and 40 people commuted into the municipality for work; as of 2008, there are 3 restaurants, 1 hotel with 68 beds. The hospitality industry in Rüdlingen employs 21 people

Joel J. Kupperman

Joel J. Kupperman is a professor of philosophy at the University of Connecticut and author of Six Myths about the Good Life, a popular philosophical volume centering on those values most worth engaging in human life, he is best known to the general public as a young math expert on the radio and television show Quiz Kids. He astounded audiences with his ability to do complex mathematics and "in his head." He had strong general knowledge, was the winner of the weekly competitions featured on the show. The 1944 film Chip Off the Old Block, starring Donald O'Connor, Peggy Ryan and Ann Blyth, featured Kupperman as the "Quiz Kid", representative of the group. During his initial Quiz Kids shows, 7, which emphasized his youth and endeared him to the listening audience. In one episode of Quiz Kids, Joel showed his ability to multiply any number times 99 "in his head." When asked how he was able to do this he replied "It's a theequit twick." When asked what the "secret trick" was, he explained that he multiplied the number he was given by one hundred subtracted the original number from that total to get the correct answer.

He received his bachelor's and master's degrees at the University of Chicago, his doctorate at Cambridge. He started teaching at the University of Connecticut in 1960 and was made a full professor in 1972, he is married to noted historian/author Karen Ordahl Kupperman. The couple have two children: a noted cartoonist. In 2018 Simon & Schuster published All the Answers, a graphic memoir by Michael Kupperman on his father Joel's rise to fame and his subsequent retreat from public life