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In engineering and science, dimensional analysis is the analysis of the relationships between different physical quantities by identifying their base quantities and units of measurement and tracking these dimensions as calculations or comparisons are performed. The term dimensional analysis is also used to refer to conversion of units from one dimensional unit to another, which can be used to evaluate scientific formulae.
In classical mechanics, a harmonic oscillator is a system that, when displaced from its equilibrium position, experiences a restoring force F proportional to the displacement x: where k is a positive constant.
In physics, the kinetic energy of an object is the form of energy that it possesses due to its motion.
Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactive decay.
In nuclear physics, a nuclear chain reaction occurs when one single nuclear reaction causes an average of one or more subsequent nuclear reactions, thus leading to the possibility of a self-propagating series or "positive feedback loop" of these reactions. The specific nuclear reaction may be the fission of heavy isotopes. A nuclear chain reaction releases several million times more energy per reaction than any chemical reaction.
Nuclear Weapons Design are physical, chemical, and engineering arrangements that cause the physics package of a nuclear weapon to detonate. There are three existing basic design types:
- Pure fission weapons are the simplest, least technically demanding, were the first nuclear weapons built, and so far the only type ever used in warfare, by the United States on Japan in World War II.
- Boosted fission weapons increase yield beyond that of the implosion design, by using small quantities of fusion fuel to enhance the fission chain reaction. Boosting can more than double the weapon's fission energy yield.
- Staged thermonuclear weapons are arrangements of two or more "stages", most usually two. The first stage is normally a boosted fission weapon as above. Its detonation causes it to shine intensely with X-rays, which illuminate and implode the second stage filled with a large quantity of fusion fuel. This sets in motion a sequence of events which results in a thermonuclear, or fusion, burn. This process affords potential yields up to hundreds of times those of fission weapons.
Critical Mass is a form of direct action in which people travel as a group on bicycles at a set location and time. The idea is for people to group together to make it safe for each other to ride bicycles through their streets, based on the old adage: there's safety in numbers.
In nuclear engineering, a critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction. The critical mass of a fissionable material depends upon its nuclear properties, density, shape, enrichment, purity, temperature, and surroundings. The concept is important in nuclear weapon design.
Uranium-235 is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exists in nature as a primordial nuclide.
Soil mechanics is a branch of soil physics and applied mechanics that describes the behavior of soils. It differs from fluid mechanics and solid mechanics in the sense that soils consist of a heterogeneous mixture of fluids and particles but soil may also contain organic solids and other matter. Along with rock mechanics, soil mechanics provides the theoretical basis for analysis in geotechnical engineering, a subdiscipline of civil engineering, and engineering geology, a subdiscipline of geology. Soil mechanics is used to analyze the deformations of and flow of fluids within natural and man-made structures that are supported on or made of soil, or structures that are buried in soils. Example applications are building and bridge foundations, retaining walls, dams, and buried pipeline systems. Principles of soil mechanics are also used in related disciplines such as geophysical engineering, coastal engineering, agricultural engineering, and hydrology.
In physical systems, damping is the loss of energy of an oscillating system by dissipation. Damping is an influence within or upon an oscillatory system that has the effect of reducing or preventing its oscillation. Examples of damping include viscous damping in a fluid, surface friction, radiation, resistance in electronic oscillators, and absorption and scattering of light in optical oscillators. Damping not based on energy loss can be important in other oscillating systems such as those that occur in biological systems and bikes. Damping is not to be confused with friction, which is a type of dissipative force acting on a system. Friction can cause or be a factor of damping.
Critical mass is the amount of fissile material needed to sustain nuclear fission.
The Three Mile River or Threemile River is a river in Bristol County, Massachusetts. It is formed by the junction of the Rumford and Wading rivers in the town of Norton. It flows in a southeasterly direction for 13.5 miles (21.7 km) through the towns of Norton, Taunton and Dighton, where it joins the Taunton River.
The explosive yield of a nuclear weapon is the amount of energy released such as blast, thermal, and nuclear radiation, when that particular nuclear weapon is detonated, usually expressed as a TNT equivalent (the standardized equivalent mass of trinitrotoluene which, if detonated, would produce the same energy discharge), either in kilotonnes (kt—thousands of tonnes of TNT), in megatonnes (Mt—millions of tonnes of TNT), or sometimes in terajoules (TJ). An explosive yield of one terajoule is equal to 0.239 kilotonnes of TNT. Because the accuracy of any measurement of the energy released by TNT has always been problematic, the conventional definition is that one kilotonne of TNT is held simply to be equivalent to 1012 calories.
Critical Mass is a 2001 action film directed by Fred Olen Ray and released direct-to-video. It stars Treat Williams, Lori Loughlin, and Udo Kier. The film features scenes taken straight from other films such as Terminator 2: Judgment Day and Universal Soldier spliced into newly filmed scenes to make up its action sequences.
The Jeans instability is a concept in astrophysics that describes an instability that leads to the gravitational collapse of a cloud of gas or dust. It causes the collapse of interstellar gas clouds and subsequent star formation. It occurs when the internal gas pressure is not strong enough to prevent the gravitational collapse of a region filled with matter. It is named after James Jeans.
Conan and the Sorcerer is a fantasy novel written by Andrew J. Offutt and illustrated by Esteban Maroto. Featuring Robert E. Howard's sword and sorcery hero Conan the Barbarian, it is the first in a trilogy continuing with Conan the Mercenary and concluding with The Sword of Skelos. It was first published in paperback by Sunridge Press in October 1978, and reprinted in May 1979, 1982, and March 1984 by Ace Books.
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. Vibration may be deterministic if the oscillations can be characterised precisely, or random if the oscillations can only be analysed statistically.
Alternative tourism combines tourist products or individual tourist services, different from mass tourism by means of supply, organization and the human resources involved. Other examples of different terms include "intelligent" or "motivated tourism." In addition, "anti-tourism" or "participative tourism" are some others. That was just to name few of them. Natural, social, and community value in which allow both host and guest to enjoy positive, worthwhile and shared experience.
In the operation of a nuclear reactor, criticality is the state in which a nuclear chain reaction is self-sustaining—that is, when reactivity is zero. In supercritical states, reactivity is greater than zero.
References
- Red Herrings (1985), a BBC documentary broadcast on BBC2.
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