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Biography
William Friese-Greene
William Friese-Greene (born William Edward Green, 7 September 1855 – 5 May 1921) was a prolific English inventor and professional photographer. He is principally known as a pioneer in the field of motion pictures, creating a series of cameras in the period 1888–1891 with which he shot moving pictures in London. He went on to patent an early two-colour filming process in 1905. His inventions
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  • 02 Dec 2022
Biography
Patrick G. Forrester
Patrick Graham Forrester (born March 31, 1957) is a retired United States Army officer and a NASA astronaut. At the time of his retirement from the U.S. Army, Forrester had achieved the rank of colonel. He is married and has two children. Forrester has flown on three Space Shuttle missions, STS-105, STS-117 and STS-128. He is the current Chief of the Astronaut Office, having assumed the role fr
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  • 02 Dec 2022
Topic Review
Vision-Based Structural Vibration Tracking Using a Digital Camera
Computer-vision-based target tracking can be applied to structural vibration monitoring, but current target tracking methods suffer from noise in digital image processing. A new target-tracking method based on the sparse optical flow technique is introduced to improve the accuracy in tracking the target, especially when the target has a large displacement. The proposed method utilizes the ORB technique to maintain a variety of keypoints and combines the multi-level strategy with a sparse optical flow algorithm to search the keypoints with a large motion vector for tracking. Then, an outlier removal method based on Hamming distance and interquartile range (IQR) score is introduced to minimize the error. The proposed target tracking method is verified through a lab experiment---a three-story shear building structure subjected to various harmonic excitations. It is compared with existing sparse optical flow-based target tracking methods and target tracking methods based on three other types of techniques, i.e., feature matching, dense optical flow, and template matching. The results show that the performance of target tracking is greatly improved through the use of a multi-level strategy and the proposed outlier removal method. The proposed sparse optical flow-based target tracking method achieves the best accuracy compared to other existing target tracking methods.
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  • 01 Dec 2022
Topic Review
Solid State Transformers in Distribution System
Solid State Transformer (SST) is considered to be the most suitable and appropriate conversion device to replace the traditional prevailing transformer. In this device, the weight/volume savings, extensive efficiency enhancement and above all, the cost economization are taken to be the hallmarks. SST configuration comprises of three main stages (i.e., a rectifier, isolation through the HF transformer and finally the DC-AC converter to reproduce line frequency AC).
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  • 01 Dec 2022
Topic Review
M35 Series 2½-ton 6X6 Cargo Truck
The M35 2½-ton cargo truck is a long-lived 2½-ton 6x6 cargo truck initially used by the United States Army and subsequently utilized by many nations around the world. Over time it evolved into a family of specialized vehicles. It inherited the nickname "Deuce and a Half" from an older 2½-ton truck, the World War II GMC CCKW. The M35 started as a 1949 REO Motor Car Company design for a 2½-ton 6x6 off-road truck. This original 6-wheel M34 version with a single wheel tandem was quickly superseded by the 10-wheel M35 design with a dual tandem. The basic M35 cargo truck is rated to carry 5,000 pounds (2,300 kg) off-road or 10,000 pounds (4,500 kg) on roads. Trucks in this weight class are considered medium duty by the military and the Department of Transportation.
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  • 01 Dec 2022
Topic Review
Opening Credits
In a motion picture, television program or video game, the opening credits or opening titles are shown at the very beginning and list the most important members of the production. They are now usually shown as text superimposed on a blank screen or static pictures, or sometimes on top of action in the show. There may or may not be accompanying music. When opening credits are built into a separate sequence of their own, the correct term is a title sequence (such as the familiar James Bond and Pink Panther title sequences). Opening credits since the early 1980s, if present at all, identify the major actors and crew, while the closing credits list an extensive cast and production crew. Historically, however, opening credits have been the only source of crew credits and, largely, the cast, although over time the tendency to repeat the cast, and perhaps add a few players, with their roles identified (as was not always the case in the opening credits), evolved. The ascendancy of television movies after 1964 and the increasingly short "shelf-life" of films in theaters has largely contributed to the credits convention which came with television programs from the beginning, of holding the vast majority of cast and crew information for display at the end of the show. In movies and television, the title and opening credits may be preceded by a "cold open," or teaser (in other words, a brief scene prior to the main acts), that helps to set the stage for the episode or film.
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  • 01 Dec 2022
Topic Review
Shingled Magnetic Recording
Shingled magnetic recording (SMR) is a magnetic storage data recording technology used in hard disk drives (HDDs) to increase storage density and overall per-drive storage capacity. Conventional hard disk drives record data by writing non-overlapping magnetic tracks parallel to each other (perpendicular magnetic recording, PMR), while shingled recording writes new tracks that overlap part of the previously written magnetic track, leaving the previous track narrower and allowing for higher track density. Thus, the tracks partially overlap similar to roof shingles. This approach was selected because, if the writing head is made too narrow, it cannot provide the very high fields required in the recording layer of the disk.:7–9 The overlapping-tracks architecture complicates the writing process since writing to one track also overwrites an adjacent track. If adjacent tracks contain valid data, they must be rewritten as well. As a result, SMR drives are divided into many append-only (sequential) zones of overlapping tracks that need to be rewritten entirely when full, resembling flash blocks in solid state drives. Device-managed SMR devices hide this complexity by managing it in the firmware, presenting an interface like any other hard disk. Other SMR devices are host-managed and depend on the operating system to know how to handle the drive, and only write sequentially to certain regions of the drive. :11 ff. While SMR drives can use DRAM and flash memory caches to improve writing performance, continuous writing of large amount of data is noticeably slower than with PMR drives.
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  • 01 Dec 2022
Topic Review
Ionocraft
An ionocraft or ion-propelled aircraft (commonly known as a lifter or hexalifter) is a device that uses an electrical electrohydrodynamic (EHD) phenomenon to produce thrust in the air without requiring any combustion or moving parts. The term "ionocraft" dates back to the 1960s, an era in which EHD experiments were at their peak. In its basic form, it simply consists of two parallel conductive electrodes, one in the form of a fine wire and another which may be formed out of wire grid, tubes or foil skirts with a smooth round surface. When such an arrangement is powered by high voltage (in the range of a few kilovolts), it produces thrust. The ionocraft forms part of the EHD thruster family, but is a special case in which the ionisation and accelerating stages are combined into a single stage. The device is a popular science fair project for students. It is also popular among anti-gravity or so-called "electrogravitics" proponents, due to the research of Thomas Townsend Brown, who built these devices in the 1920s and incorrectly believed that he had found a way to modify gravity using electric fields. The term "lifter" is an accurate description because it is not an anti-gravity device; rather, it produces lift using the same basic principle as a rocket, i.e. from the equal but opposite force upward generated by the driving force downward, specifically by driving the ionized air downward in the case of the ionocraft. Much like a rocket or a jet engine (it can actually be much more thrust efficient than a jet engine), the force that an ionocraft generates is consistently oriented along its own axis, regardless of the surrounding gravitational field. Claims of the device also working in a vacuum have been disproved. Ionocraft require many safety precautions due to the high voltage required for their operation; nevertheless, a large subculture has grown up around this simple EHD thrusting device and its physics are now known to a much better extent.
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  • 01 Dec 2022
Topic Review
Air Source Heat Pumps
An air source heat pump (ASHP) is a system that transfers heat from outside to inside a building, or vice versa. Under the principles of vapor compression refrigeration, an ASHP uses a refrigerant system involving a compressor and a condenser to absorb heat at one place and release it at another. They can be used as a space heater or cooler, and are sometimes called "reverse-cycle air conditioners". In domestic heating use, an ASHP absorbs heat from outside air and releases it inside the building, as hot air, hot water-filled radiators, underfloor heating and/or domestic hot water supply. The same system can often do the reverse in summer, cooling the inside of the house. When correctly specified, an ASHP can offer a full central heating solution and domestic hot water up to 80 °C.
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  • 01 Dec 2022
Topic Review
ITER
International Thermonuclear Experimental Reactor is an international nuclear fusion research and engineering megaproject, which will be the world's largest magnetic confinement plasma physics experiment. It is an experimental tokamak nuclear fusion reactor that is being built next to the Cadarache facility in Saint-Paul-lès-Durance, in Provence, southern France. The ITER thermonuclear fusion reactor has been designed to produce a fusion plasma equivalent to 500 megawatts (MW) of thermal output power for around twenty minutes while 50 megawatts of thermal power are injected into the tokamak, resulting in a ten-fold gain of plasma heating power. Thereby the machine aims to demonstrate the principle of producing more thermal power from the fusion process than is used to heat the plasma, something that has not yet been achieved in any fusion reactor. The total electricity consumed by the reactor and facilities will range from 110 MW up to 620 MW peak for 30-second periods during plasma operation. Thermal-to-electric conversion is not included in the design because ITER will not produce sufficient power for net electrical production. The emitted heat from the fusion reaction will be vented to the atmosphere. The project is funded and run by seven member entities—the European Union, India , Japan , China , Russia , South Korea and the United States . The EU, as host party for the ITER complex, is contributing about 45 percent of the cost, with the other six parties contributing approximately 9 percent each. In 2016 the ITER organization signed a technical cooperation agreement with the national nuclear fusion agency of Australia , granting this country access to research results of ITER in exchange for construction of selected parts of the ITER machine. Construction of the ITER Tokamak complex started in 2013 and the building costs were over US$14 billion by June 2015. The construction of the facility is expected to be completed in 2025 when commissioning of the reactor can commence. Initial plasma experiments are scheduled to begin in 2025, with full deuterium–tritium fusion experiments starting in 2035. If ITER becomes operational, it will become the largest magnetic confinement plasma physics experiment in use with a plasma volume of 840 cubic meters, surpassing the Joint European Torus by almost a factor of 10. The goal of ITER is to demonstrate the scientific and technological feasibility of fusion energy for peaceful use. It is the largest of more than 100 fusion reactors built since the 1950s. ITER's planned successor, DEMO, is expected to be the first fusion reactor to produce electricity in an experimental environment. DEMO's anticipated success is expected to lead to full-scale electricity-producing fusion power stations and future commercial reactors.
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