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Sound Mirrors
An acoustic mirror is a passive device used to reflect and focus (concentrate) sound waves. Parabolic acoustic mirrors are widely used in parabolic microphones to pick up sound from great distances, employed in surveillance and reporting of outdoor sporting events. Pairs of large parabolic acoustic mirrors which function as "whisper galleries" are displayed in science museums to demonstrate sound focusing. Between the World Wars, before the invention of radar, parabolic sound mirrors were used experimentally as early-warning devices by military air defence forces to detect incoming enemy aircraft by listening for the sound of their engines. During World War II on the coast of southern England, a network of large concrete acoustic mirrors was in the process of being built when the project was cancelled owing to the development of the Chain Home radar system. Some of these mirrors are still standing today. Acoustic aircraft detection Before World War II and the inventio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kilnsea
Kilnsea is a hamlet in the East Riding of Yorkshire, England, in an area known as Holderness. It is situated approximately south of the village of Easington, on the north bank of the Humber Estuary. The hamlet forms part of the civil parish of Easington. East of Kilnsea is the Grade II listed First World War concrete acoustic mirror used as an early warning device. Kilnsea has one public house, the Crown and Anchor. In 1823 Kilnsea was a civil parish in the Wapentake and Liberty of Holderness. The parish church, dedicated to Saint Helen, was close to the cliff and in a "state of dilapidation" and "dangerous condition". Repairs were considered useless with the expectation that the sea, which had already swept away the graveyard, would take the church "in a short time". Population in 1823 was 196. The old St Helen's Church was lost to the sea in 1826, and was replaced by a new church in 1865, at a cost of £420, that incorporated some salvaged remains of the old building. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ontario Science Centre
The Ontario Science Centre, formally the Centennial Museum of Science and Technology, is a science museum in Toronto, Ontario, Canada. It is located near the Don Valley Parkway about northeast of downtown on Don Mills Road just south of Eglinton Avenue East in the former city of North York. It is built down the side of a wooded ravine formed by one branch of the Don River located in Flemingdon Park. History Planning for the Science Centre started in 1961 during Toronto's massive expansion of the late 1950s and 1960s. In 1964, Toronto architect Raymond Moriyama was hired to design the site. Construction started in 1966 with plans to open the "Centennial Centre of Science and Technology" as part of the Canadian Centennial celebrations in 1967. However construction was not completed in 1967, and the Science Centre did not open to the public until two years later, on September 26, 1969. The buildings and design were part of a broader change in Canadian architecture, and remain an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
We The Curious
We The Curious (previously At-Bristol or "@Bristol") is a science centre, science and arts centre and Charitable organization, educational charity in Bristol, England. It features over 250 interactive exhibits over two floors, and members of the public and school groups can also engage with the Live Science Team over programming in the kitchen, studio and on live lab. We The Curious is also home of the United Kingdom's first 3D planetarium. The centre describes its aim as being "to create a culture of curiosity". As part of its charitable status, We The Curious has an extensive community engagement programme. In regular weekends throughout the year We The Curious hosts "Hello!" weekends for communities who are currently under-represented in their visitors while also providing a community membership for charities and groups working in and for the community. Alongside this, We The Curious is working with local schools and community groups to plan exhibits and programming for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whispering Dish, Jodrell Bank
Whispering is an unvoiced mode of phonation in which the vocal cords are abducted so that they do not vibrate; air passes between the arytenoid cartilages to create audible turbulence during speech. Supralaryngeal articulation remains the same as in normal speech. In normal speech, the vocal cords alternate between states of voice and voicelessness. In whispering, only the voicing segments change, so that the vocal cords alternate between whisper and voicelessness (though the acoustic difference between the two states is minimal). Because of this, implementing speech recognition for whispered speech is more difficult, as the characteristic spectral range needed to detect syllables and words is not given through the total absence of tone. More advanced techniques such as neural networks may be used, however, as is done by Amazon Alexa. There is no symbol in the IPA for whispered phonation, since it is not used phonemically in any language. However, a sub-dot under phonemic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Sansome Tucker
Major (United Kingdom), Major William Sansome Tucker (1877 Kidderminster, Worcestershire - 1955 Guelph, Ontario, Canada) was an England, English pioneer in acoustical research and inventor of the acoustic mirror Early life Tucker was born in Kidderminster, the son of William Tucker, an artist painter, and his wife Anna. Tucker married in Chorlton-on-Medlock, Lancashire, in 1906. Career Tucker lectured on physics in London. Following the outbreak of World War I, Tucker joined the British Army as a private soldier. He was posted to the Experimental Sound Ranging Station at Kemmel Hill in Belgium which was under the command of Lawrence Bragg. As part of the London Electrical Engineers, Territorial Force, Tucker was granted a commission, being promoted from lance corporal to temporary second lieutenant, General List in April 1916. At Kemmel Hill, Tucker undertook research into 'sound ranging': the process of using microphones and mathematics to determine the position of enemy artill ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arecibo Observatory
The Arecibo Observatory, also known as the National Astronomy and Ionosphere Center (NAIC) and formerly known as the Arecibo Ionosphere Observatory, is an observatory in Barrio Esperanza, Arecibo, Puerto Rico owned by the US National Science Foundation (NSF). The observatory's main instrument was the Arecibo Telescope, a spherical reflector dish built into a natural sinkhole, with a cable-mount steerable receiver and several radar transmitters for emitting signals mounted above the dish. Completed in 1963, it was the world's largest single-aperture telescope for 53 years, surpassed in July 2016 by the Five-hundred-meter Aperture Spherical Telescope (FAST) in China. Following two breaks in cables supporting the receiver platform in mid-2020, the NSF decommissioned the telescope. A partial collapse of the telescope occurred on December 1, 2020, before controlled demolition could be conducted. In 2022, the NSF announced the telescope will not be rebuilt, with an educational fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
English Channel
The English Channel, "The Sleeve"; nrf, la Maunche, "The Sleeve" (Cotentinais) or ( Jèrriais), (Guernésiais), "The Channel"; br, Mor Breizh, "Sea of Brittany"; cy, Môr Udd, "Lord's Sea"; kw, Mor Bretannek, "British Sea"; nl, Het Kanaal, "The Channel"; german: Ärmelkanal, "Sleeve Channel" ( French: ''la Manche;'' also called the British Channel or simply the Channel) is an arm of the Atlantic Ocean that separates Southern England from northern France. It links to the southern part of the North Sea by the Strait of Dover at its northeastern end. It is the busiest shipping area in the world. It is about long and varies in width from at its widest to at its narrowest in the Strait of Dover."English Channel". ''The Columbia Encyclopedia'', 2004. It is the smallest of the shallow seas around the continental shelf of Europe, covering an area of some . The Channel was a key factor in Britain becoming a naval superpower and has been utilised by Britain as a natural def ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focus (geometry)
In geometry, focuses or foci (), singular focus, are special points with reference to which any of a variety of curves is constructed. For example, one or two foci can be used in defining conic sections, the four types of which are the circle, ellipse, parabola, and hyperbola. In addition, two foci are used to define the Cassini oval and the Cartesian oval, and more than two foci are used in defining an ''n''-ellipse. Conic sections Defining conics in terms of two foci An ellipse can be defined as the locus of points for which the sum of the distances to two given foci is constant. A circle is the special case of an ellipse in which the two foci coincide with each other. Thus, a circle can be more simply defined as the locus of points each of which is a fixed distance from a single given focus. A circle can also be defined as the circle of Apollonius, in terms of two different foci, as the locus of points having a fixed ratio of distances to the two foci. A parabola is a li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microphone
A microphone, colloquially called a mic or mike (), is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public events, motion picture production, live and recorded audio engineering, sound recording, two-way radios, megaphones, and radio and television broadcasting. They are also used in computers for recording voice, speech recognition, VoIP, and for other purposes such as ultrasonic sensors or knock sensors. Several types of microphone are used today, which employ different methods to convert the air pressure variations of a sound wave to an electrical signal. The most common are the dynamic microphone, which uses a coil of wire suspended in a magnetic field; the condenser microphone, which uses the vibrating diaphragm as a capacitor plate; and the contact microphone, which uses a crystal of piezoelectric material. Microphones typically n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concrete
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most widely used building material. Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminum combined. Globally, the ready-mix concrete industry, the largest segment of the concrete market, is projected to exceed $600 billion in revenue by 2025. This widespread use results in a number of environmental impacts. Most notably, the production process for cement produces large volumes of greenhouse gas emissions, leading to net 8% of global emissions. Other environmental concerns include widespread illegal sand mining, impacts on the surrounding environment such as increased surface runoff or urban heat island effect, and potential public health implications from toxic ingredients. Significant research and development is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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