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Underwater Explosion
An underwater explosion (also known as an UNDEX) is a chemical or nuclear explosion that occurs under the surface of a body of water. While useful in anti-ship and submarine warfare, underwater bombs are not as effective against coastal facilities. Properties of water Underwater explosions differ from in-air explosions due to the properties of water: *Mass and incompressibility (all explosions) – water has a much higher density than air, which makes water harder to move (higher inertia). It is also relatively hard to compress (increase density) when under pressure in a low range (up to about 100 atmospheres). These two together make water an excellent conductor of shock waves from an explosion. *Effect of neutron exposure on salt water (nuclear explosions only) – most underwater blast scenarios happen in seawater, not fresh or pure water. The water itself is not much affected by neutrons but salt is strongly affected. When exposed to neutron radiation during the microsecond of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explosive Material
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An explosive charge is a measured quantity of explosive material, which may either be composed solely of one ingredient or be a mixture containing at least two substances. The potential energy stored in an explosive material may, for example, be * chemical energy, such as nitroglycerin or grain dust * pressurized gas, such as a gas cylinder, aerosol can, or BLEVE * nuclear energy, such as in the fissile isotopes uranium-235 and plutonium-239 Explosive materials may be categorized by the speed at which they expand. Materials that detonate (the front of the chemical reaction moves faster through the material than the speed of sound) are said to be "high explosives" and materials that deflagrate are said to be "low explosives". Explosives may a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
(n-p) Reaction
The (n-p) reaction, or (n,p) reaction, is an example of a nuclear reaction. It is the reaction which occurs when a neutron enters a nucleus and a proton leaves the nucleus simultaneously. For example, sulfur-32 (32S) undergoes an (n,p) nuclear reaction when bombarded with neutrons, thus forming phosphorus-32 (32P). The nuclide nitrogen-14 (14N) can also undergo an (n,p) nuclear reaction to produce carbon-14 (14C). This nuclear reaction 14N (n,p) 14C continually happens in the Earth's atmosphere, forming equilibrium amounts of the radionuclide 14C. Most (n,p) reactions have threshold neutron energies below which the reaction cannot take place as a result of the charged particle in the exit channel requiring energy (usually more than a MeV) to overcome the Coulomb barrier The Coulomb barrier, named after Coulomb's law, which is in turn named after physicist Charles-Augustin de Coulomb, is the energy barrier due to electrostatic interaction that two nuclei need to overcome so they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bubble Pulse
Bubble, Bubbles or The Bubble may refer to: Common uses * Bubble (physics), a globule of one substance in another, usually gas in a liquid ** Soap bubble * Economic bubble, a situation where asset prices are much higher than underlying fundamentals Arts, entertainment and media Fictional characters * Bubble, a character in ''Absolutely Fabulous'' * Bubbles, an oriole from the ''Angry Birds'' franchise * Bubble, in the video game ''Clu Clu Land'' * Bubbles (''The Wire'') * Bubbles (''Trailer Park Boys'') * Bubbles, a yellow tang fish in the ''Finding Nemo'' franchise * Bubbles, in ''Jabberjaw'' * Bubbles Utonium, in ''The Powerpuff Girls'' ** Bubbles (Miyako Gotokuji), in ''Powerpuff Girls Z'' * Bubbles (''The Adventures of Little Carp'') * Bubbles, in ''The Adventures of Timmy the Tooth'' * Bubbles the Clown, a doll used in the BBC's Test Card F * Cobra Bubbles, in ''Lilo & Stitch'' * Bubbles DeVere, in ''Little Britain'' * Bubbles Yablonsky, the protagonist in a series ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shockwave
In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a medium but is characterized by an abrupt, nearly discontinuous, change in pressure, temperature, and density of the medium. For the purpose of comparison, in supersonic flows, additional increased expansion may be achieved through an expansion fan, also known as a Prandtl–Meyer expansion fan. The accompanying expansion wave may approach and eventually collide and recombine with the shock wave, creating a process of destructive interference. The sonic boom associated with the passage of a supersonic aircraft is a type of sound wave produced by constructive interference. Unlike solitons (another kind of nonlinear wave), the energy and speed of a shock wave alone dissipates relatively quickly with distance. When a shock wave passes through ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-ship Missile
An anti-ship missile (AShM) is a guided missile that is designed for use against ships and large boats. Most anti-ship missiles are of the sea skimming variety, and many use a combination of inertial guidance and active radar homing. A good number of other anti-ship missiles use infrared homing to follow the heat that is emitted by a ship; it is also possible for anti-ship missiles to be guided by radio command all the way. The first anti-ship missiles, which were developed and built by Nazi Germany, used radio command guidance.https://airandspace.si.edu/collection-objects/bomb-guided-fritz-x-x-1/nasm_A19840794000#:~:text=The%20Fritz%20X%2C%20also%20known,the%20Henschel%20Hs%20293%20missile. These saw some success in the Mediterranean Theatre during 1943–44, sinking or heavily damaging at least 31 ships with the Henschel Hs 293 and more than seven with the ''Fritz X'', including the Italian battleship ''Roma'' and the light cruiser . A variant of the HS 293 had a TV ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermocline
A thermocline (also known as the thermal layer or the metalimnion in lakes) is a thin but distinct layer in a large body of fluid (e.g. water, as in an ocean or lake; or air, e.g. an atmosphere) in which temperature changes more drastically with depth than it does in the layers above or below. In the ocean, the thermocline divides the upper mixed layer from the calm deep water below. Depending largely on season, latitude, and turbulent mixing by wind, thermoclines may be a semi-permanent feature of the body of water in which they occur, or they may form temporarily in response to phenomena such as the radiative heating/cooling of surface water during the day/night. Factors that affect the depth and thickness of a thermocline include seasonal weather variations, latitude, and local environmental conditions, such as tides and currents. Oceans Most of the heat energy of the sunlight that strikes the Earth is absorbed in the first few centimeters at the ocean's surface, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subsidence Crater
__NOTOC__ A subsidence crater is a hole or depression left on the surface of an area which has had an underground (usually nuclear) explosion. Many such craters are commonly present at bomb testing areas; one notable example is the Nevada Test Site, which was historically used for nuclear weapons testing over a period of 41 years. Subsidence craters are created as the roof of the cavity caused by the explosion collapses. This causes the surface to depress into a sink (which subsidence craters are sometimes called; see sink hole). It is possible for further collapse to occur from the sink into the explosion chamber. When this collapse reaches the surface, and the chamber is exposed atmospherically to the surface, it is referred to as a ''chimney''. It is at the point that a chimney is formed through which radioactive fallout may reach the surface. At the Nevada Test Site, depths of were used for tests. When the material above the explosion is solid rock, then a mound may be fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Fallout
Nuclear fallout is the residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and the shock wave has passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes. The amount and spread of fallout is a product of the size of the weapon and the altitude at which it is detonated. Fallout may get entrained with the products of a pyrocumulus cloud and fall as black rain (rain darkened by soot and other particulates, which fell within 30–40 minutes of the atomic bombings of Hiroshima and Nagasaki). This radioactive dust, usually consisting of fission products mixed with bystanding atoms that are neutron-activated by exposure, is a form of radioactive contamination. Types of fallout Fallout comes in two varieties. The first is a small amount of carcinogenic material with a long half-life. The second, depending on the height of detonation, is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coral
Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton. A coral "group" is a colony of very many genetically identical polyps. Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in height. A set of tentacles surround a central mouth opening. Each polyp excretes an exoskeleton near the base. Over many generations, the colony thus creates a skeleton characteristic of the species which can measure up to several meters in size. Individual colonies grow by asexual reproduction of polyps. Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously overnight, often around a full moon. Fertilized eggs form planulae, a mobile early form of the coral polyp which, when m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorine-36
Chlorine-36 (36Cl) is an isotope of chlorine. Chlorine has two stable isotopes and one naturally occurring radioactive isotope, the cosmogenic isotope 36Cl. Its half-life is 301,300 ± 1,500 years. 36Cl decays primarily (98%) by beta-minus decay to 36 Ar, and the balance to 36 S. Trace amounts of radioactive 36Cl exist in the environment, in a ratio of about (7–10) × 10−13 to 1 with stable chlorine isotopes. This corresponds to a concentration of approximately 1 Bq/(kg Cl). 36Cl is produced in the atmosphere by spallation of 36 Ar by interactions with cosmic ray protons. In the top meter of the lithosphere, 36Cl is generated primarily by thermal neutron activation of 35Cl and spallation of 39 K and 40 Ca. In the subsurface environment, muon capture by 40 Ca becomes more important. The production rates are about 4200 atoms 36Cl/yr/mole 39K and 3000 atoms 36Cl/yr/mole 40Ca, due to spallation in rocks at sea level. The half-life of this isotope makes it suitable f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Half-life
Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive. The term is also used more generally to characterize any type of exponential (or, rarely, non-exponential) decay. For example, the medical sciences refer to the biological half-life of drugs and other chemicals in the human body. The converse of half-life (in exponential growth) is doubling time. The original term, ''half-life period'', dating to Ernest Rutherford's discovery of the principle in 1907, was shortened to ''half-life'' in the early 1950s. Rutherford applied the principle of a radioactive element's half-life in studies of age determination of rocks by measuring the decay period of radium to lead-206. Half-life is constant over the lifetime of an exponentially decaying quantity, and it is a characteristic unit for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium-24
There are 22 isotopes of sodium (11Na), ranging from to , and two isomers ( and ). is the only stable (and the only primordial) isotope. It is considered a monoisotopic element and it has a standard atomic weight of . Sodium has two radioactive cosmogenic isotopes (, with a half-life of ; and , with a half-life of ). With the exception of those two isotopes, all other isotopes have half-lives under a minute, most under a second. The shortest-lived is , with a half-life of seconds. Acute neutron radiation exposure (e.g., from a nuclear criticality accident) converts some of the stable in human blood plasma to . By measuring the concentration of this isotope, the neutron radiation dosage to the victim can be computed. is a positron-emitting isotope with a remarkably long half-life. It is used to create test-objects and point-sources for positron emission tomography. List of isotopes , - , , style="text-align:right" , 11 , style="text-align:right" , 6 , , , p , ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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