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Ultrasonic Metal Atomization
Ultrasound is sound with frequencies greater than 20 kilohertz. This frequency is the approximate upper audible limit of human hearing in healthy young adults. The physical principles of acoustic waves apply to any frequency range, including ultrasound. Ultrasonic devices operate with frequencies from 20 kHz up to several gigahertz. Ultrasound is used in many different fields. Ultrasonic devices are used to detect objects and measure distances. Ultrasound imaging or sonography is often used in medicine. In the nondestructive testing of products and structures, ultrasound is used to detect invisible flaws. Industrially, ultrasound is used for cleaning, mixing, and accelerating chemical processes. Animals such as bats and porpoises use ultrasound for locating prey and obstacles. History Acoustics, the science of sound, starts as far back as Pythagoras in the 6th century BC, who wrote on the mathematical properties of stringed instruments. Echolocation in bats was d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
First World War
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] |
Quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of Silicon dioxide, SiO2. Quartz is, therefore, classified structurally as a Silicate mineral#Tectosilicates, framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation from α-quartz to β-quartz takes place abruptly at . Since the transformation is accompanied by a significant change in volume, it can easily induce microfracturing of ceramics or rocks passing through this temperature threshold. There are many different varieties of quartz, several of which are classifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transducer
A transducer is a device that Energy transformation, converts energy from one form to another. Usually a transducer converts a signal in one form of energy to a signal in another. Transducers are often employed at the boundaries of automation, Measuring instrument, measurement, and control systems, where electrical signals are converted to and from other physical quantities (energy, force, torque, light, motion, position, etc.). The process of converting one form of energy to another is known as transduction. Types * Mechanical transducers convert physical quantities into mechanical outputs or vice versa; * Electrical transducers convert physical quantities into electrical outputs or signals. Examples of these are: ** a thermocouple that changes temperature differences into a small voltage; ** a linear variable differential transformer (LVDT), used to measure displacement (position) changes by means of electrical signals. Sensors, actuators and transceivers Transducers can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pierre Curie
Pierre Curie ( ; ; 15 May 1859 – 19 April 1906) was a French physicist, Radiochemistry, radiochemist, and a pioneer in crystallography, magnetism, piezoelectricity, and radioactivity. He shared the 1903 Nobel Prize in Physics with his wife, Marie Curie, and Henri Becquerel "in recognition of the extraordinary services they have rendered by their joint researches on the radiation phenomena discovered by Professor Henri Becquerel". With their win, the Curies became the Nobel Prize#Statistics, first married couple to win a Nobel Prize, launching the Nobel Prize#Family laureates, Curie family legacy of five Nobel Prizes. Early life Born in Paris on 15 May 1859, Pierre Curie was the son of Eugène Curie (1827–1910), a doctor of French Huguenot Protestant origin from Alsace, and Sophie-Claire Curie (née Depouilly; 1832–1897). He was educated by his father and in his early teens showed a strong aptitude for mathematics and geometry. When he was 16, he earned his Bachelor of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jacques Curie
Jacques Curie (29 October 1855 – 19 February 1941) was a French physicist and professor of mineralogy at the University of Montpellier. Along with his younger brother, Pierre Curie, he studied pyroelectricity in the 1880s, leading to their discovery of some of the mechanisms behind piezoelectricity. He is buried in the Saint-Lazare cemetery in Montpellier. Biography In 1883, Jacques Curie was appointed professor of mineralogy at the University of Montpellier. This appointment marked the end of his collaboration with his brother Pierre. He remained in Montpellier until his death in 1941 with the exception of the years 1887–1889, which he spent in Algeria, teaching at the School of Science of Algiers and conducting his research. It was not until 1903 that he was appointed to the chair of physics, a position he retained until his retirement in 1925. His son Maurice Curie was a physicist. Research and discoveries The major legacy of Jacques Curie is the discovery of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piezoelectric Effect
Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied stress (mechanics), mechanical stress. The piezoelectric effect results from the linear electromechanical interaction between the mechanical and electrical states in crystalline materials with no centrosymmetry, inversion symmetry. The piezoelectric effect is a reversible process (thermodynamics), reversible process: List of piezoelectric materials, materials exhibiting the piezoelectric effect also exhibit the reverse piezoelectric effect, the internal generation of a mechanical strain resulting from an applied electric field. For example, lead zirconate titanate crystals will generate measurable piezoelectricity when their static structure is Deformation (physics), deformed by about 0.1% of the original dimension. Conversely, those same crystals will change about 0.1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbine
A turbine ( or ) (from the Greek , ''tyrbē'', or Latin ''turbo'', meaning vortex) is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced can be used for generating electrical power when combined with a generator.Munson, Bruce Roy, T. H. Okiishi, and Wade W. Huebsch. "Turbomachines." Fundamentals of Fluid Mechanics. 6th ed. Hoboken, NJ: J. Wiley & Sons, 2009. Print. A turbine is a turbomachine with at least one moving part called a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades so that they move and impart rotational energy to the rotor. Gas, steam, and water turbines have a casing around the blades that contains and controls the working fluid. Modern steam turbines frequently employ both reaction and impulse in the same unit, typically varying the degree of reaction and impulse from the blade root to its periphery. History Hero of Alexandria demonstrat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sir Charles Parsons
Sir Charles Algernon Parsons (13 June 1854 – 11 February 1931) was an Anglo-Irish people, Anglo-Irish mechanical engineer and inventor who designed the modern steam turbine in 1884. His invention revolutionised marine propulsion, and he was also the founder of C. A. Parsons and Company. He worked as an engineer on dynamo and turbine design, and power generation, with great influence in the naval and electrical engineering fields. He also helped develop optical equipment for searchlights and telescopes. Parsons received the Faraday Medal and the Copley Medal for his work. Career and commercial activity Parsons was born into an aristocratic Anglo-Irish family on 13 June 1854 in London as the youngest son of the astronomer William Parsons, 3rd Earl of Rosse. The family seat is Birr Castle, County Offaly, Ireland, and the town of Birr, County Offaly, Birr was called Parsonstown, after the family, from 1620 to 1901. With his three brothers, Parsons was educated at home in Irelan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydraulic
Hydraulics () is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counterpart of pneumatics, which concerns gases. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on applied engineering using the properties of fluids. In its fluid power applications, hydraulics is used for the generation, control, and transmission of Power (physics), power by the use of pressure, pressurized liquids. Hydraulic topics range through some parts of science and most of engineering modules, and they cover concepts such as pipe Volumetric flow rate, flow, dam design, fluidics, and fluid control circuitry. The principles of hydraulics are in use naturally in the human body within the vascular system and erectile tissue. ''Free surface hydraulics'' is the branch of hydraulics dealing with free surface flow, such as occurring in rivers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titanic
RMS ''Titanic'' was a British ocean liner that sank in the early hours of 15 April 1912 as a result of striking an iceberg on her maiden voyage from Southampton, England, to New York City, United States. Of the estimated 2,224 passengers and crew aboard, approximately 1,500 died (estimates vary), making the incident one of 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 lasting legacy in popular culture. It was the second time White Star Line had lost a ship on her maiden voyage, the first being in 1854. ''Titanic'' was the largest ship afloat upon entering service and the second of three s built for White Star Line. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poulsen Arc
The arc converter, sometimes called the arc transmitter, or Poulsen arc after Danish engineer Valdemar Poulsen who invented it in 1903, was a variety of spark transmitter used in early wireless telegraphy. The arc converter used an electric arc to convert direct current electricity into radio frequency alternating current. It was used as a radio transmitter from 1903 until the 1920s when it was replaced by vacuum tube transmitters. One of the first transmitters that could generate continuous sinusoidal waves, it was one of the first technologies used to transmit sound (amplitude modulation) by radio. It is on the list of IEEE Milestones as a historic achievement in electrical engineering. History Elihu Thomson discovered that a carbon arc shunted with a series tuned circuit would "sing". This "singing arc" was probably limited to audio frequencies. Bureau of Standards credits William Duddell with the shunt resonant circuit around 1900. The English engineer William Duddell dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
