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Marine Mammals And Sonar
The interactions between marine mammals and sonar have been a subject of debate since the invention of the technology. Active sonar, the transmission equipment used on some ships to assist with navigation, is detrimental to the health and livelihood of some marine animals. Research has recently shown that beaked and blue whales are sensitive to mid-frequency active sonar and move rapidly away from the source of the sonar, a response that disrupts their feeding and can cause mass strandings. Some marine animals, such as whales and dolphins, use echolocation or "biosonar" systems to locate predators and prey. It is conjectured that active sonar transmitters could confuse these animals and interfere with basic biological functions such as feeding and mating. The study has shown whales experience decompression sickness, a disease that forces nitrogen into gas bubbles in the tissues and is caused by rapid and prolonged surfacing. Although whales were originally thought to be immu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humpback Whale Underwater Shot
Humpback may refer to: * Humpback whale * Humpback dolphin * Humpback salmon * Humpback bridge * Humpback, a common name for the fish ''Chanodichthys dabryi'' * Humpback, a variant of hunchback Kyphosis is an abnormally excessive convex curvature of the spine as it occurs in the thoracic and sacral regions. Abnormal inward concave ''lordotic'' curving of the cervical and lumbar regions of the spine is called lordosis. It can result fr ... {{disambiguation, fish Animal common name disambiguation pages ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waveguide
A waveguide is a structure that guides waves, such as electromagnetic waves or sound, with minimal loss of energy by restricting the transmission of energy to one direction. Without the physical constraint of a waveguide, wave intensities decrease according to the inverse square law as they expand into three-dimensional space. There are different types of waveguides for different types of waves. The original and most common meaningInstitute of Electrical and Electronics Engineers, “The IEEE standard dictionary of electrical and electronics terms”; 6th ed. New York, N.Y., Institute of Electrical and Electronics Engineers, c1997. IEEE Std 100-1996. d. Standards Coordinating Committee 10, Terms and Definitions; Jane Radatz, (chair)/ref> is a hollow conductive metal pipe used to carry high frequency radio waves, particularly microwaves. Dielectric waveguides are used at higher radio frequencies, and transparent dielectric waveguides and optical fibers serve as waveguides f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Spectrum
The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from below one hertz to above 1025 hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of the size of an atomic nucleus. This frequency range is divided into separate bands, and the electromagnetic waves within each frequency band are called by different names; beginning at the low frequency (long wavelength) end of the spectrum these are: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays at the high-frequency (short wavelength) end. The electromagnetic waves in each of these bands have different characteristics, such as how they are produced, how they interact with matter, and their practical applications. There is no known limit for long and short wavelengths. Extreme ultr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William A
William is a male given name of Germanic origin.Hanks, Hardcastle and Hodges, ''Oxford Dictionary of First Names'', Oxford University Press, 2nd edition, , p. 276. It became very popular in the English language after the Norman conquest of England in 1066,All Things William"Meaning & Origin of the Name"/ref> and remained so throughout the Middle Ages and into the modern era. It is sometimes abbreviated "Wm." Shortened familiar versions in English include Will, Wills, Willy, Willie, Bill, and Billy. A common Irish form is Liam. Scottish diminutives include Wull, Willie or Wullie (as in Oor Wullie or the play ''Douglas''). Female forms are Willa, Willemina, Wilma and Wilhelmina. Etymology William is related to the given name ''Wilhelm'' (cf. Proto-Germanic ᚹᛁᛚᛃᚨᚺᛖᛚᛗᚨᛉ, ''*Wiljahelmaz'' > German ''Wilhelm'' and Old Norse ᚢᛁᛚᛋᛅᚼᛅᛚᛘᛅᛋ, ''Vilhjálmr''). By regular sound changes, the native, inherited English form of the name shoul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Edward Schevill
William Edward "Bill" Schevill (July 2, 1906 – July 25, 1994) was an American paleontologist famous for his part in dynamiting out the nodules of the most complete skeleton of the short-necked pliosaur ''Kronosaurus queenslandicus'' discovered in Hughenden in Queensland, Australia, in 1932. He later became known as an authority on the sounds of whales. Schevill had the title of scientist emeritus at the Woods Hole Oceanographic Institution, where he had begun working in 1943, technically retiring in 1985. Early Education Born July 2, 1906 in Brooklyn, New York, William E. Schevill grew up in Manhattan, New York, and St Louis, Missouri. Prior to going to college he spent nearly a year in Silver City, New Mexico where, working a ranch, he earned the rank of wrangler. Graduating from Harvard College in 1927, he saw the rejuvenation of the Harvard Museum of Comparative Zoology (MCZ) as initiated by the new director Thomas Barbour and, in 1929 Bill Schevill earned an A.M. with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Russian Military
The Armed Forces of the Russian Federation (, ), commonly referred to as the Russian Armed Forces, are the military forces of Russia. In terms of active-duty personnel, they are the world's fifth-largest military force, with at least two million reserve personnel. Their branches consist of the Ground Forces, the Navy, and the Aerospace Forces, as well as three independent arms of service: the Strategic Rocket Forces, the Airborne Forces, and the Special Operations Forces. In 2021, Russia had the world's fifth-highest military expenditure at . The Russian Armed Forces possess the world's largest stockpile of nuclear weapons. They operate the second-largest fleet of ballistic missile submarines, and are one of only three national militaries (alongside those of the United States and China) that operate strategic bombers. With certain exceptions, Russian law mandates one year of military service for all male citizens aged 18–27, though conscripts are generally not deplo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whale Sound
Whales use a variety of sounds for communication and sensation. The mechanisms used to produce sound vary from one family of cetaceans to another. Marine mammals, including whales, dolphins, and porpoises, are much more dependent on sound than land mammals due to the limited effectiveness of other senses in water. Sight is less effective for marine mammals because of the particulate way in which the ocean scatters light. Smell is also limited, as molecules diffuse more slowly in water than in air, which makes smelling less effective. However, the speed of sound is roughly four times greater in water than in the atmosphere at sea level. As sea mammals are so dependent on hearing to communicate and feed, environmentalists and cetologists are concerned that they are being harmed by the increased ambient noise in the world's oceans caused by ships, sonar and marine seismic surveys. The word "song" is used to describe the pattern of regular and predictable sounds made by some speci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid for the diameter of a sphere. In more modern usage, the length d of a diameter is also called the diameter. In this sense one speaks of diameter rather than diameter (which refers to the line segment itself), because all diameters of a circle or sphere have the same length, this being twice the radius r. :d = 2r \qquad\text\qquad r = \frac. For a convex shape in the plane, the diameter is defined to be the largest distance that can be formed between two opposite parallel lines tangent to its boundary, and the is often defined to be the smallest such distance. Both quantities can be calculated efficiently using rotating calipers. For a curve of constant width such as the Reuleaux triangle, the width and diameter are the same because all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Background Noise
Background noise or ambient noise is any sound other than the sound being monitored (primary sound). Background noise is a form of noise pollution or interference. Background noise is an important concept in setting noise levels. Background noises include environmental noises such as water waves, traffic noise, alarms, extraneous speech, bioacoustic noise from animals, and electrical noise from devices such as refrigerators, air conditioning, power supplies, and motors. The prevention or reduction of background noise is important in the field of active noise control. It is an important consideration with the use of ultrasound (e.g. for medical diagnosis or imaging), sonar, and sound reproduction. Other uses In astronomy, background noise or cosmic background radiation is electromagnetic radiation from the sky with no discernible source. In information architecture, irrelevant, duplicate or incorrect information may be called background noise. In physics and telecommunicat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fin Whales
The fin whale (''Balaenoptera physalus''), also known as finback whale or common rorqual and formerly known as herring whale or razorback whale, is a cetacean belonging to the parvorder of baleen whales. It is the second-longest species of cetacean on Earth after the blue whale. The largest reportedly grow to long with a maximum confirmed length of , a maximum recorded weight of nearly , and a maximum estimated weight of around . American naturalist Roy Chapman Andrews called the fin whale "the greyhound of the sea ... for its beautiful, slender body is built like a racing yacht and the animal can surpass the speed of the fastest ocean steamship." The fin whale's body is long and slender, coloured brownish-grey with a paler underside. At least two recognized subspecies exist, in the North Atlantic and the Southern Hemisphere. It is found in all the major oceans, from polar to tropical waters. It is absent only from waters close to the pack ice at the poles and relatively smal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roger Payne
Roger Searle Payne (born January 29, 1935) is an American biologist and environmentalist famous for the 1967 discovery (with Scott McVay) of whale song among humpback whales. Payne later became an important figure in the worldwide campaign to end commercial whaling. History Payne was born in New York, New York, and received his BA degree at Harvard University and his Ph.D. at Cornell. He spent the early years of his career studying echolocation in bats (and how their food, moths, avoid them) and auditory localization in owls. Desiring to work with something more directly linked to conservation he later focused his research on whales where, together with researcher Scott McVay, in 1967 they discovered the complex sonic arrangements performed by the male humpback whales during the breeding season. These findings were published in the article ''Songs of humpback whales'' in 1971. Payne describes the whale songs as "exuberant, uninterrupted rivers of sound" with long repeated "th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leonid Brekhovskikh
Leonid Maksimovich Brekhovskikh (6 May 1917 – 15 January 2005; russian: Леони́д Макси́мович Бреховски́х) was a Soviet and Russian scientist known for his work in acoustical and physical oceanography. Early life and education Brekhovskikh was born to a peasant family in Strunkino, a small village in Vologda Governorate (now Arkhangelsk Oblast), Russia. He graduated from Perm State University in 1939, from which he received his university degree, and studied under Igor Tamm at the Lebedev Physical Institute (FIAN). There, he received his Candidate of Sciences degree (PhD) in Physics in 1941 for his thesis on X-ray crystallography. After his PhD, he joined FIAN's acoustical laboratories and worked on a naval defence project to develop protection against acoustically triggered mines. He later developed a theory of the propagation of acoustical waves in layered media, for which he received his DSc in Physics and Mathematics from FIAN in 1947. Resear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
