Enrico Fermi

Enrico Fermi was an Italian–American physicist and the creator of the world's first nuclear reactor, the Chicago Pile-1. He has been called the "architect of the nuclear age" and the "architect of the atomic bomb", he was one of few physicists to excel in both theoretical physics and experimental physics. Fermi held several patents related to the use of nuclear power, was awarded the 1938 Nobel Prize in Physics for his work on induced radioactivity by neutron bombardment and for the discovery of transuranium elements, he made significant contributions to the development of statistical mechanics, quantum theory, nuclear and particle physics. Fermi's first major contribution involved the field of statistical mechanics. After Wolfgang Pauli formulated his exclusion principle in 1925, Fermi followed with a paper in which he applied the principle to an ideal gas, employing a statistical formulation now known as Fermi–Dirac statistics. Today, particles that obey the exclusion principle are called "fermions".

Pauli postulated the existence of an uncharged invisible particle emitted along with an electron during beta decay, to satisfy the law of conservation of energy. Fermi took up this idea, developing a model that incorporated the postulated particle, which he named the "neutrino", his theory referred to as Fermi's interaction and now called weak interaction, described one of the four fundamental interactions in nature. Through experiments inducing radioactivity with the discovered neutron, Fermi discovered that slow neutrons were more captured by atomic nuclei than fast ones, he developed the Fermi age equation to describe this. After bombarding thorium and uranium with slow neutrons, he concluded that he had created new elements. Although he was awarded the Nobel Prize for this discovery, the new elements were revealed to be nuclear fission products. Fermi left Italy in 1938 to escape new Italian racial laws that affected his Jewish wife, Laura Capon, he emigrated to the United States, where he worked on the Manhattan Project during World War II.

Fermi led the team that designed and built Chicago Pile-1, which went critical on 2 December 1942, demonstrating the first human-created, self-sustaining nuclear chain reaction. He was on hand when the X-10 Graphite Reactor at Oak Ridge, went critical in 1943, when the B Reactor at the Hanford Site did so the next year. At Los Alamos, he headed F Division, part of which worked on Edward Teller's thermonuclear "Super" bomb, he was present at the Trinity test on 16 July 1945, where he used his Fermi method to estimate the bomb's yield. After the war, Fermi served under J. Robert Oppenheimer on the General Advisory Committee, which advised the Atomic Energy Commission on nuclear matters. After the detonation of the first Soviet fission bomb in August 1949, he opposed the development of a hydrogen bomb on both moral and technical grounds, he was among the scientists who testified on Oppenheimer's behalf at the 1954 hearing that resulted in the denial of Oppenheimer's security clearance. Fermi did important work in particle physics related to pions and muons, he speculated that cosmic rays arose when material was accelerated by magnetic fields in interstellar space.

Many awards and institutions are named after Fermi, including the Enrico Fermi Award, the Enrico Fermi Institute, the Fermi National Accelerator Laboratory, the Fermi Gamma-ray Space Telescope, the Enrico Fermi Nuclear Generating Station, the synthetic element fermium, making him one of 16 scientists who have elements named after them. Enrico Fermi was born in Rome, Italy, on 29 September 1901, he was the third child of Alberto Fermi, a division head in the Ministry of Railways, Ida de Gattis, an elementary school teacher. His sister, was two years older than him, his brother Giulio a year older. After the two boys were sent to a rural community to be wet nursed, Enrico rejoined his family in Rome when he was two and a half. Although he was baptised a Roman Catholic in accordance with his grandparents' wishes, his family was not religious; as a young boy he shared the same interests as his brother Giulio, building electric motors and playing with electrical and mechanical toys. Giulio died during an operation on a throat abscess in 1915 and Maria died in an airplane crash near Milan in 1959.

At a local market Fermi found a physics book, the 900-page Elementorum physicae mathematicae. Written in Latin by Jesuit Father Andrea Caraffa, a professor at the Collegio Romano, it presented mathematics, classical mechanics, astronomy and acoustics as they were understood at the time of its 1840 publication. With scientifically inclined friend, Enrico Persico, Fermi pursued projects such as building gyroscopes and measuring the acceleration of Earth's gravity. A colleague of Fermi's father gave him books on physics and mathematics which he assimilated quickly. Fermi graduated from high school in July 1918, at Amidei's urging applied to the Scuola Normale Superiore in Pisa. Having lost one son, his parents only reluctantly allowed him to live in the school's lodgings for four years. Fermi took first place in the difficult entrance exam, which included an essay on the theme of "Specific characteristics of Sounds". At the Scuola Normale Superiore Fermi played pranks with fellow student Franco Rasetti.

Fermi was advised by Luigi Puccianti, director of the physics laboratory, who said t


HoloVID is a tool developed for the holographic dimensional measurement of the internal isogrid structural webbing of the Delta family of launch vehicles in 1981 by Mark Slater. Delta launch vehicles were produced by McDonnell Douglas Astronautics until the line was purchased by Boeing. Milled out of T6 Aluminum on 40-by-20-foot horizontal mills, the inspection of the huge sheets took longer than the original manufacturing, it was estimated that a real time in situ inspection device could cut costs so an Independent Research and Development budget was generated to solve the problem. Two solutions were worked by Mark Slater: a photo-optical technique utilizing a holographic lens and an ultrasonic technique utilizing configurable micro-transducer multiplexed arrays. A pair of HoloVIDs for simultaneous frontside and backside weld feedback was used at Martin Marietta to inspect the long weld seams which hold the External Tanks of the Space Shuttle together. By controlling the weld bead profile in real time as it was TIG generated, an optimum weight vs. performance ratio could be obtained, saving the rocket engines from having to waste thrust energy while guaranteeing the highest possible web strengths.

Many corporations use customized versions of the Six Dimensional Non-Contact Reader w/ Integrated Holographic Optical Processing for applications from supercomputer surface mount pad assessment to genetic biochemical assay analysis. HoloVID belongs to a class of sensor known as a structured-light 3D scanner device; the use of structured light to extract three-dimensional shape information is a well known technique. The use of single planes of light to measure the distance and orientation of objects has been reported several times; the use of multiple planes and multiple points of light to measure shapes and construct volumetric estimates of objects has been reported. The use of segmented phase holograms to selectively deflect portions of an image wavefront is unusual; the holographic optical components used in this device split tessellated segments of a returning wave front in programmable bulk areas and shaped patches to achieve a unique capability, increasing both the size of an object which can be read and the z-axis depth per point, measurable, while increasing the simultaneous operations possible, a significant advance in the previous state of art.

A laser beam is made to impinge onto a target surface. The angle of the nonlinear optical field can be non-orthogonal to the surface; this light beam is reflected by the surface in a wide conical spread function, geometrically related to the incidence angle, light frequency and relative surface roughness. A portion of this reflected light enters the optical system coaxially, where a'stop' shadows the edges. In a single point reader, this edge is viewed along a radius by a photodiode array; the output of this device is a boxcar output where the photodiodes are sequentially lit diode-by-diode as the object distance changes in relation to the sensor, until either no diodes are lit or all diodes are lit. The residual product charge dynamic value in each light diode cell is a function of the bias current, the dark current and the incident ionizing radiation. In the multipoint system, the HoloVID, the cursor point is acousto-optically scanned in the x-axis across a k θ monaxial transformer. A monaxial holographic lens collects the wave front and reconstructs the pattern onto the single dimensional photodiode array and a two dimensional matrix sensor.

Image processing of the sensor data derives the correlation between the compressed wave front and the actual physical object

Marin Hills

The Marin Hills are a series of steep high ridges and peaks in southern Marin County. They are a part of the long Pacific Coast Ranges mountain system; the centerpoint of these hills is the 2,571 foot Mount Tamalpais near Mill Valley. The hills are bordered to the north by Laguna de Santa Rosa. Parts of the hills are protected for their scenic beauty by Mount Tamalpais State Park and the Golden Gate National Recreation Area; the many ridges and peaks of these hills form a dramatic backdrop to the Golden Gate Bridge, the San Francisco skyline, several towns around Richardson Bay when viewed from the south. Since these hills lie near the Pacific Ocean, they force much of the incoming moisture out of the air and rainfall here is much greater than the bayside of Marin County. Due to this orographic rain effect, the Marin Municipal Water District has constructed several dams and reservoirs to store water for the population of Marin; the high rainfall makes these hills conducive for Coast redwood and Douglas-fir.

However, a side effect is that the eastern hills, where most of Marin's population lives, are drier and hotter due to the shielding of marine breezes. The low hills to the east support only California oak woodlands and grasslands; the western part of the hills once had extensive old growth forests, but in the 1800s they were a source of timber for the San Francisco Bay Area, thus logging took out most of the old growth stands. This stand is now the Muir Woods National Monument, part of the Golden Gate National Recreation Area; the parklands of these hills are popular with tourists and locals alike seeking to escape the urban areas of the Bay Area. The Black-tailed Deer is the most common large mammal of the Marin Hills