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Wolfgang Haack
Wolfgang Siegfried Haack (24 April 1902 – 28 November 1994) was a German mathematician and aerodynamicist. He in 1941 and William Sears in 1947 independently discovered the Sears–Haack body. Life Wolfgang Haack studied mechanical engineering at the Leibniz University Hannover and mathematics in Jena. He earned his doctorate in 1926 at the Friedrich Schiller University in Jena. After a short study and research period in Hamburg and a job as an assistant at the Technical University of Stuttgart he habilitated in 1929 at the TH Danzig (now Gdańsk). In 1935 he moved to the TH Berlin and in 1937, he followed the call to the TH Karlsruhe. During the Second World War he worked on projectile design. Although the TH Berlin did invite him to work there in 1944, Wolfgang Haack was unable to take up the post because of the war. In 1949 he became the successor to Georg Hamel as Professor of Mathematics and Mechanics at the TU Berlin Department of Mathematics and Mechanics. On h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gotha
Gotha () is the fifth-largest city in Thuringia, Germany, west of Erfurt and east of Eisenach with a population of 44,000. The city is the capital of the district of Gotha and was also a residence of the Ernestine Wettins from 1640 until the end of monarchy in Germany in 1918. The House of Saxe-Coburg and Gotha originating here spawned many European rulers, including the royal houses of the United Kingdom, Belgium, Portugal (until 1910) and Bulgaria (until 1946). In the Middle Ages, Gotha was a rich trading town on the trade route ''Via Regia'' and between 1650 and 1850, Gotha saw a cultural heyday as a centre of sciences and arts, fostered by the dukes of Saxe-Gotha. The first duke, Ernest the Pious, was famous for his wise rule. In the 18th century, the ''Almanach de Gotha'' was first published in the city. The publisher Justus Perthes and the encyclopedist Joseph Meyer made Gotha a leading centre of German publishing around 1800. In the early 19th century, Gotha was a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georg Hamel
Georg Karl Wilhelm Hamel (12 September 1877 – 4 October 1954) was a German mathematician with interests in mechanics, the foundations of mathematics and function theory. Biography Hamel was born in Düren, Rhenish Prussia. He studied at Aachen, Berlin, Göttingen, and Karlsruhe. His doctoral adviser was David Hilbert. He taught at Brünn in 1905, Aachen in 1912, and at the Technical University of Berlin in 1919. In 1927, Hamel studied the size of the key space for the Kryha encryption device. He was an Invited Speaker of the ICM in 1932 at Zurich and in 1936 at Oslo. He was the author of several important treatises on mechanics. He became a member of the Prussian Academy of Sciences in 1938 and the Bavarian Academy of Sciences in 1953. He died in Landshut, Bavaria. Selected publications * ("On the geometries in which the straight lines are the shortest", Hamel's doctoral dissertation on Hilbert's fourth problem. A version may be found in Mathematische Annalen 57, 1903.) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caliber
In guns, particularly firearms, caliber (or calibre; sometimes abbreviated as "cal") is the specified nominal internal diameter of the gun barrel bore – regardless of how or where the bore is measured and whether the finished bore matches that specification. It is measured in inches or in millimeters. In the United States it is expressed in hundredths of an inch; in the United Kingdom in thousandths; and elsewhere in millimeters. For example, a "45 caliber" firearm has a barrel diameter of roughly . Barrel diameters can also be expressed using metric dimensions. For example, a "9 mm pistol" has a barrel diameter of about 9 millimeters. Since metric and US customary units do not convert evenly at this scale, metric conversions of caliber measured in decimal inches are typically approximations of the precise specifications in non-metric units, and vice versa. In a rifled barrel, the distance is measured between opposing lands or between opposing grooves; groove mea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Resistance
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers (or surfaces) or between a fluid and a solid surface. Unlike other resistive forces, such as dry friction, which are nearly independent of velocity, the drag force depends on velocity. Drag force is proportional to the velocity for low-speed flow and the squared velocity for high speed flow, where the distinction between low and high speed is measured by the Reynolds number. Even though the ultimate cause of drag is viscous friction, turbulent drag is independent of viscosity. Drag forces always tend to decrease fluid velocity relative to the solid object in the fluid's path. Examples Examples of drag include the component of the net aerodynamic or hydrodynamic force acting opposite to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nose Cone Design
Given the problem of the aerodynamic design of the nose cone section of any vehicle or body meant to travel through a compressible fluid medium (such as a rocket or aircraft, missile, shell or bullet), an important problem is the determination of the nose cone geometrical shape for optimum performance. For many applications, such a task requires the definition of a solid of revolution shape that experiences minimal resistance to rapid motion through such a fluid medium. Nose cone shapes and equations General dimensions In all of the following nose cone shape equations, is the overall length of the nose cone and is the radius of the base of the nose cone. is the radius at any point , as varies from , at the tip of the nose cone, to . The equations define the two-dimensional profile of the nose shape. The full body of revolution of the nose cone is formed by rotating the profile around the centerline . While the equations describe the 'perfect' shape, practical nose cones ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies of World War II, Allies and the Axis powers. World War II was a total war that directly involved more than 100 million Military personnel, personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Air warfare of World War II, Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the Atomic bombings of Hiroshima and Nagasaki, only two nuclear weapons ever used in war. World War II was by far the List of wars by death toll, deadliest conflict in hu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supersonic Speed
Supersonic speed is the speed of an object that exceeds the speed of sound (Mach 1). For objects traveling in dry air of a temperature of 20 °C (68 °F) at sea level, this speed is approximately . Speeds greater than five times the speed of sound (Mach 5) are often referred to as hypersonic. Flights during which only some parts of the air surrounding an object, such as the ends of rotor blades, reach supersonic speeds are called transonic. This occurs typically somewhere between Mach 0.8 and Mach 1.2. Sounds are traveling vibrations in the form of pressure waves in an elastic medium. Objects move at supersonic speed when the objects move faster than the speed at which sound propagates through the medium. In gases, sound travels longitudinally at different speeds, mostly depending on the molecular mass and temperature of the gas, and pressure has little effect. Since air temperature and composition varies significantly with altitude, the speed of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Dynamics
Compressible flow (or gas dynamics) is the branch of fluid mechanics that deals with flows having significant changes in fluid density. While all flows are compressible, flows are usually treated as being incompressible when the Mach number (the ratio of the speed of the flow to the speed of sound) is smaller than 0.3 (since the density change due to velocity is about 5% in that case).Anderson, J.D., ''Fundamentals of Aerodynamics'', 4th Ed., McGraw–Hill, 2007. The study of compressible flow is relevant to high-speed aircraft, jet engines, rocket motors, high-speed entry into a planetary atmosphere, gas pipelines, commercial applications such as abrasive blasting, and many other fields. History The study of gas dynamics is often associated with the flight of modern high-speed aircraft and atmospheric reentry of space-exploration vehicles; however, its origins lie with simpler machines. At the beginning of the 19th century, investigation into the behaviour of fired bullets led to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Applied Research
Applied science is the use of the scientific method and knowledge obtained via conclusions from the method to attain practical goals. It includes a broad range of disciplines such as engineering and medicine. Applied science is often contrasted with basic science, which is focused on advancing scientific theories and laws that explain and predict events in the natural world. Applied science can also apply formal science, such as statistics and probability theory, as in epidemiology. Genetic epidemiology is an applied science applying both biological and statistical methods. Applied research Applied research is the practical application of science. It accesses and uses accumulated theories, knowledge, methods, and techniques, for a specific state-, business-, or client-driven purpose. Applied Research can be better understood in any area when contrasting it with, basic, or pure, research. Basic geography research strives to create new theories and methods that aid in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Friedrich Pfaff
Johann Friedrich Pfaff (sometimes spelled Friederich; 22 December 1765 – 21 April 1825) was a German mathematician. He was described as one of Germany's most eminent mathematicians during the 19th century. He was a precursor of the German school of mathematical thinking, which under Carl Friedrich Gauss and his followers largely determined the lines on which mathematics developed during the 19th century. Biography He received his early education at the Carlsschule, where he met Friedrich Schiller, his lifelong friend. His mathematical capacity was noticed during his early years. He pursued his studies at Göttingen under Abraham Gotthelf Kästner, and in 1787 he went to Berlin and studied practical astronomy under J. E. Bode. In 1788, Pfaff became professor of mathematics in Helmstedt, and continued his work as a professor until that university was abolished in 1810. After this event, he became professor of mathematics at the University of Halle, where he stayed for the rest o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
