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Underwater Acoustics
Underwater acoustics (also known as hydroacoustics) is the study of the propagation of sound in water and the interaction of the mechanical waves that constitute sound with the water, its contents and its boundaries. The water may be in the ocean, a lake, a river or a tank. Typical frequencies associated with underwater acoustics are between 10 Hz and 1 MHz. The propagation of sound in the ocean at frequencies lower than 10 Hz is usually not possible without penetrating deep into the seabed, whereas frequencies above 1 MHz are rarely used because they are absorbed very quickly. Hydroacoustics, using sonar technology, is most commonly used for monitoring of underwater physical and biological characteristics. Hydroacoustics can be used to detect the depth of a water body ( bathymetry), as well as the presence or absence, abundance, distribution, size, and behavior of underwater plants and animals. Hydroacoustic sensing involves " passive acoustics" (listening for soun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Acoustics
Physical acoustics is the area of acoustics and physics that studies interactions of acoustic waves with a gaseous, liquid or solid medium on macro- and micro-levels. This relates to the interaction of sound with thermal waves in crystals (phonons), with light (photons), with electrons in metals and semiconductors (acousto-electric phenomena), with magnetic excitations in ferromagnetic crystals ( magnons), etc. Some recently developed experimental techniques include photo-acoustics, acoustic microscopy and acoustic emission. A long-standing interest is in acoustic and ultrasonic wave propagation and scattering in inhomogeneous materials, including composite materials and biological tissues. There are two main classes of problems studied in physical acoustics. The first one concerns understanding how the physical properties of a medium (solid, liquid, or gas) influence the propagation of acoustic waves in this medium in order to use this knowledge for practical purposes. The seco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War I
World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting took place mainly in European theatre of World War I, Europe and the Middle Eastern theatre of World War I, Middle East, as well as in parts of African theatre of World War I, Africa and the Asian and Pacific theatre of World War I, Asia-Pacific, and in Europe was characterised by trench warfare; the widespread use of Artillery of World War I, artillery, machine guns, and Chemical weapons in World War I, chemical weapons (gas); and the introductions of Tanks in World War I, tanks and Aviation in World War I, aircraft. World War I was one of the List of wars by death toll, deadliest conflicts in history, resulting in an estimated World War I casualties, 10 million military dead and more than 20 million wounded, plus some 10 million civilian de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RMS Titanic
RMS ''Titanic'' was a British ocean liner that Sinking of the Titanic, sank in the early hours of 15 April 1912 as a result of striking Iceberg that struck the Titanic, an iceberg on her maiden voyage from Southampton, England, to New York City, United States. Of the Sinking of the Titanic#Casualties and survivors, estimated 2,224 passengers and crew aboard, approximately 1,500 died (estimates vary), making the incident one of List of accidents and disasters by death toll#Peacetime maritime, the deadliest peacetime sinkings of a single ship. ''Titanic'', operated by White Star Line, carried some of the wealthiest people in the world, as well as hundreds of emigrants from the British Isles, Scandinavia, and elsewhere in Europe who were seeking a new life in the United States and Canada. The disaster drew public attention, spurred major changes in maritime safety regulations, and inspired a Titanic in popular culture, lasting legacy in popular culture. It was the second time Whit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theory Of Sound
A theory is a systematic and rational form of abstract thinking about a phenomenon, or the conclusions derived from such thinking. It involves contemplative and logical reasoning, often supported by processes such as observation, experimentation, and research. Theories can be scientific, falling within the realm of empirical and testable knowledge, or they may belong to non-scientific disciplines, such as philosophy, art, or sociology. In some cases, theories may exist independently of any formal discipline. In modern science, the term "theory" refers to scientific theories, a well-confirmed type of explanation of nature, made in a way consistent with the scientific method, and fulfilling the criteria required by modern science. Such theories are described in such a way that scientific tests should be able to provide empirical support for it, or empirical contradiction (" falsify") of it. Scientific theories are the most reliable, rigorous, and comprehensive form of scientific k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annales De Chimie Et De Physique
__NOTOC__ ''Annales de chimie et de physique'' (, ) is a scientific journal founded in Paris, France, in 1789 under the title ''Annales de chimie''. One of the early editors was the French chemist Antoine Lavoisier. Lavoisier, an aristocrat, was guillotined in May 1794, ostensibly for tax fraud: and the journal was not published from 1794 to 1796 while the Reign of Terror was at its height under the French Directory. In 1815, it became the ''Annales de chimie et de physique'', and was published under that name for the next 100 years. In 1914, it split into two successor journals. The first one, '' Annales de physique'', was latterly published by EDP Sciences under the same name up to 2009, when it became integrated in the '' European Physical Journal'' series as the '' European Physical Journal H – Historical Perspectives on Contemporary Physics''. The second successor, ''Annales de chimie'', later became '' Annales de chimie: Science des matériaux'' in 1978; from 1998 to 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Geneva
Lake Geneva is a deep lake on the north side of the Alps, shared between Switzerland and France. It is one of the List of largest lakes of Europe, largest lakes in Western Europe and the largest on the course of the Rhône. Sixty percent () of the lake belongs to Switzerland (the cantons of Vaud, Canton of Geneva, Geneva and Valais) and forty percent () to France (the department of Haute-Savoie). Name While the exact origins of the name are unknown, the name was in use during the time of Julius Caesar. comes from Ancient Greek () meaning "port's lake". In Medieval Latin it was known as , although this name was also used for Lausonius Lacus, a town or district on the lake, or ; the equivalent in Old French was . Following the rise of Geneva it became (translated into English as ''Lake Geneva''), but was the common name on all local maps and is the customary name in the French language. In contemporary English language, English, the name ''Lake Geneva'' has become predo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematician
A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematical model, models, and mathematics#Calculus and analysis, change. History One of the earliest known mathematicians was Thales of Miletus (); he has been hailed as the first true mathematician and the first known individual to whom a mathematical discovery has been attributed. He is credited with the first use of deductive reasoning applied to geometry, by deriving four corollaries to Thales's theorem. The number of known mathematicians grew when Pythagoras of Samos () established the Pythagorean school, whose doctrine it was that mathematics ruled the universe and whose motto was "All is number". It was the Pythagoreans who coined the term "mathematics", and with whom the study of mathematics for its own sake begins. The first woman math ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
France
France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlantic, North Atlantic, the French West Indies, and List of islands of France, many islands in Oceania and the Indian Ocean, giving it Exclusive economic zone of France, one of the largest discontiguous exclusive economic zones in the world. Metropolitan France shares borders with Belgium and Luxembourg to the north; Germany to the northeast; Switzerland to the east; Italy and Monaco to the southeast; Andorra and Spain to the south; and a maritime border with the United Kingdom to the northwest. Its metropolitan area extends from the Rhine to the Atlantic Ocean and from the Mediterranean Sea to the English Channel and the North Sea. Its Regions of France, eighteen integral regions—five of which are overseas—span a combined area of and hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Sturm
Charles is a masculine given name predominantly found in English and French speaking countries. It is from the French form ''Charles'' of the Proto-Germanic name (in runic alphabet) or ''*karilaz'' (in Latin alphabet), whose meaning was "free man". The Old English descendant of this word was '' Ċearl'' or ''Ċeorl'', as the name of King Cearl of Mercia, that disappeared after the Norman conquest of England. The name was notably borne by Charlemagne (Charles the Great), and was at the time Latinized as ''Karolus'' (as in ''Vita Karoli Magni''), later also as '' Carolus''. Etymology The name's etymology is a Common Germanic noun ''*karilaz'' meaning "free man", which survives in English as churl (James (wikt:Appendix:Proto-Indo-European/ǵerh₂-">ĝer-, where the ĝ is a palatal consonant, meaning "to rub; to be old; grain." An old man has been worn away and is now grey with age. In some Slavic languages, the name ''Drago (given name), Drago'' (and variants: ''Dragom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physicist
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate causes of Phenomenon, phenomena, and usually frame their understanding in mathematical terms. They work across a wide range of Physics#Research fields, research fields, spanning all length scales: from atom, sub-atomic and particle physics, through biological physics, to physical cosmology, cosmological length scales encompassing the universe as a whole. The field generally includes two types of physicists: Experimental physics, experimental physicists who specialize in the observation of natural phenomena and the development and analysis of experiments, and Theoretical physics, theoretical physicists who specialize in mathematical modeling of physical systems to rationalize, explain and predict natural phenomena. Physicists can apply their k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swiss People
The Swiss people (, , , ) are the citizens of the multi-ethnic Swiss Confederation (Switzerland) regardless of ethno-cultural background or people of self-identified Swiss ancestry. The number of Swiss nationals has grown from 1.7 million in 1815 to 8.7 million in 2020. More than 1.5 million Swiss citizens hold multiple citizenship. About 11% of citizens live abroad (0.8 million, of whom 0.6 million hold multiple citizenship). About 60% of those living abroad reside in the European Union (0.46 million). The largest groups of Swiss descendants and nationals outside Europe are found in the United States, Brazil, and Canada. Although the modern state of Switzerland originated in 1848, the period of romantic nationalism, Switzerland is not a nation-state and the Swiss are not a single ethnic group. Rather, Switzerland is a confederacy (') or ' ("nation of will", "nation by choice", that is, a consociational state), a term coined in conscious contrast to "nation" in the conv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
