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Hans Benndorf
Hans Benndorf (13 December 1870 – 11 February 1953) was an Austrian physicist born in Zurich, and died in Graz. He made several contributions in the field of seismology and in his research of atmospheric electricity. He was the son of archaeologist Otto Benndorf (1838–1907) and the grandson of physiologist Rudolf Wagner (1805–1864). In 1895 he earned his doctorate from the University of Vienna, and subsequently became an assistant to Franz Serafin Exner (1849–1926). In 1904 he became an associate professor of meteorology at the University of Graz. In 1910 he replaced Leopold Pfaundler (1839–1920) as professor of physics, a position he kept until 1936 (forced retirement). In 1945 he resumed his duties in physics at Graz. In 1927 he was elected as a full member of the Austrian Academy of Sciences, and from 1932 to 1934 was university rector. From 1924 he worked closely with geophysicistAlfred Wegener (1880–1930) at Graz, also maintaining professional ties with physici ... [...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 phenomena, and usually frame their understanding in mathematical terms. Physicists work across a wide range of research fields, spanning all length scales: from sub-atomic and particle physics, through biological physics, to cosmological length scales encompassing the universe as a whole. The field generally includes two types of physicists: experimental physicists who specialize in the observation of natural phenomena and the development and analysis of experiments, and theoretical physicists who specialize in mathematical modeling of physical systems to rationalize, explain and predict natural phenomena. Physicists can apply their knowledge towards solving practical problems or to developing new technologies (also known as applie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alfred Wegener
Alfred Lothar Wegener (; ; 1 November 1880 – November 1930) was a German climatologist, geologist, geophysicist, meteorologist, and polar researcher. During his lifetime he was primarily known for his achievements in meteorology and as a pioneer of polar research, but today he is most remembered as the originator of continental drift hypothesis by suggesting in 1912 that the continents are slowly drifting around the Earth (German: '). His hypothesis was controversial and widely rejected by mainstream geology until the 1950s, when numerous discoveries such as palaeomagnetism provided strong support for continental drift, and thereby a substantial basis for today's model of plate tectonics. Wegener was involved in several expeditions to Greenland to study polar air circulation before the existence of the jet stream was accepted. Expedition participants made many meteorological observations and were the first to overwinter on the inland Greenland ice sheet and the first to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
German Wikipedia
The German Wikipedia (german: Deutschsprachige Wikipedia) is the German-language edition of Wikipedia, a free and publicly editable online encyclopedia. Founded on March 16, 2001, it is the second-oldest Wikipedia (after the English Wikipedia), and with articles, at present () the -largest edition of Wikipedia by number of articles, behind English Wikipedia and the mostly bot-generated Cebuano Wikipedia.] Alternative language Wikipedias, 16 March 2001List of Wikipedias/Table meta.wikimedia.org, Statistics It has the second-largest number of edits behind the English Wikipedia and over 260,000 disambiguation pages. On November 7, 2011, it became the second edition of Wikipedia, after the English edition, to exceed 100 million page edits. The German Wikipedia is criticized because of several ongoing p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refraction
In physics, refraction is the redirection of a wave as it passes from one medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commonly observed phenomenon, but other waves such as sound waves and water waves also experience refraction. How much a wave is refracted is determined by the change in wave speed and the initial direction of wave propagation relative to the direction of change in speed. For light, refraction follows Snell's law, which states that, for a given pair of media, the ratio of the sines of the angle of incidence ''θ1'' and angle of refraction ''θ2'' is equal to the ratio of phase velocities (''v''1 / ''v''2) in the two media, or equivalently, to the refractive indices (''n''2 / ''n''1) of the two media. :\frac =\frac=\frac Optical prisms and lenses use refraction to redirect light, as does the human eye. The refractive index of materials varies with the wavelengt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismometer
A seismometer is an instrument that responds to ground noises and shaking such as caused by earthquakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The output of such a device—formerly recorded on paper (see picture) or film, now recorded and processed digitally—is a seismogram. Such data is used to locate and characterize earthquakes, and to study the Earth's internal structure. Basic principles A simple seismometer, sensitive to up-down motions of the Earth, is like a weight hanging from a spring, both suspended from a frame that moves along with any motion detected. The relative motion between the weight (called the mass) and the frame provides a measurement of the vertical ground motion. A rotating drum is attached to the frame and a pen is attached to the weight, thus recording any ground motion in a seismogram. Any movement from the ground moves the frame. The mass tends not to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microseismic Event
A microearthquake (or microquake) is a very low intensity earthquake which is 2.0 or less in magnitude. They are very rarely felt beyond from their epicenter. In addition to having natural tectonic causes, they may also be seen as a result of underground nuclear testing or even large detonations of conventional explosives for producing excavations. They normally cause no damage to life or property, and are very rarely felt by people. Microquakes occur often near volcanoes as they approach an eruption, and frequently in certain regions exploited for geothermal energy , such as near Geyserville in Northern California Northern California (colloquially known as NorCal) is a geographic and cultural region that generally comprises the northern portion of the U.S. state of California. Spanning the state's northernmost 48 counties, its main population centers incl .... These occur so continuously that thcurrent USGS event map for that locationusually shows a substantial number of smal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earthquakes
An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from those that are so weak that they cannot be felt, to those violent enough to propel objects and people into the air, damage critical infrastructure, and wreak destruction across entire cities. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time period. The seismicity at a particular location in the Earth is the average rate of seismic energy release per unit volume. The word ''tremor'' is also used for non-earthquake seismic rumbling. At the Earth's surface, earthquakes manifest themselves by shaking and displacing or disrupting the ground. When the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismic Wave
A seismic wave is a wave of acoustic energy that travels through the Earth. It can result from an earthquake, volcanic eruption, magma movement, a large landslide, and a large man-made explosion that produces low-frequency acoustic energy. Seismic waves are studied by seismologists, who record the waves using seismometers, hydrophones (in water), or accelerometers. Seismic waves are distinguished from seismic noise (ambient vibration), which is persistent low-amplitude vibration arising from a variety of natural and anthropogenic sources. The propagation velocity of a seismic wave depends on density and elasticity of the medium as well as the type of wave. Velocity tends to increase with depth through Earth's crust and mantle, but drops sharply going from the mantle to Earth's outer core. Earthquakes create distinct types of waves with different velocities. When recorded by a seismic observatory, their different travel times help scientists locate the quake's hypocen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wave Propagation
Wave propagation is any of the ways in which waves travel. Single wave propagation can be calculated by 2nd order wave equation ( standing wavefield) or 1st order one-way wave equation. With respect to the direction of the oscillation relative to the propagation direction, we can distinguish between longitudinal wave and transverse waves. For electromagnetic waves, propagation may occur in a vacuum as well as in the material medium. Other wave types cannot propagate through a vacuum and need a transmission medium to exist. Reflection of plane waves in a half-space The propagation and reflection of plane waves—e.g. Pressure waves (P-wave) or Shear waves (SH or SV-waves) are phenomena that were first characterized within the field of classical seismology, and are now considered fundamental concepts in modern seismic tomography. The analytical solution to this problem exists and is well known. The frequency domain solution can be obtained by first finding the Helmholtz deco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lieben Prize
The Ignaz Lieben Prize, named after the Austrian banker , is an annual Austrian award made by the Austrian Academy of Sciences to young scientists working in the fields of molecular biology, chemistry, or physics. Biography The Ignaz Lieben Prize has been called the Austrian Nobel Prize. It is similar in intent but somewhat older than the Nobel Prize. The Austrian merchant Ignaz L. Lieben, whose family supported many philanthropic activities, had stipulated in his testament that 6,000 florins should be used “for the common good”. In 1863 this money was given to the Austrian Imperial Academy of Sciences, and the Ignaz L. Lieben Prize was instituted. Every three years, the sum of 900 florins was to be given to an Austrian scientist in the field of chemistry, physics, or physiology. This sum corresponded to roughly 40 per cent of the annual income of a university professor. From 1900 on, the prize was offered on a yearly basis. The endowment was twice increased by the Lieben fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
