Implosion method

There are two methods for assembling a supercritical mass The first one brings two sub-critical masses together (gun method) whereas the second one compresses a sub-critical mass into a supercritical one (implosion method). Some salient features of these methods are ... 

Implosion method Explosives are also used in nuclear weapons to generate the implosion required to bring the two halves of the radioactive device together. The implosion is achieved with the help of secondary explosives which surround the material and rapidly compress the mass to a supercritical state on their detonation. This encompasses two major assemblies (i) com-... 

The blast had knocked Kistiakowsky down at S-10000. He scrambled up to watch the fireball rise and darken and mushroom purple auras, then moved to claim his bet. I slapped Oppenheimer on the back and said, Oppie, you owe me ten dollars. The distracted Los Alamos director searched his wallet. It s empty, he told Kistiakowsky, you ll have to wait. Bainbridge went around congratulating the S-10000 leaders on the success of the implosion method. I finished by saying to Robert, Now we are all sons of bitches. ... [He] told my younger daughter later that it was the best thing anyone said after the test. ... 

A variation of the explosion method was designed for uranium. Bomb designers, imable to solve the purification problem, turned to the relatively unknown implosion method for plutonium. With implosion, symmetrical shockwaves directed inward would compress a subcritical mass of plutonium packed in a nickel casing (tamper), releasing neutrons and causing a chain reaction. 

Oppenheimer acted quickly to maximize the laboratory s efforts to master implosion. Only if the implosion method could be perfected would the plutoniiun produced at Hanford come into play. Without either a plutonium gun bomb or implosion weapon, the burden would fall entirely on uranium and the less efficient gun method. Oppenheimer directed a major reorganization of Los Alamos in July 1944 that prepared the way for the final development of an implosion bomb. Robert Bacher took over G Division (for gadget) to experiment with implosion and design a bomb George Kistiakowsky led X Division (for explosives) in work on the explosive components Hans Bethe continued to head up theoretic studies and Deke Parsons now focused on overall bomb construction and... 

The gun-type method is essentially obsolete and implosion technique is much more suitable in order to reduce weight of the weapon and consequently, increase weight of the fissionable material. Further, gun-type weapons also have some safety related problems. 

Many other affine equivariant and robust estimators of location and scatter have been presented in the literature. The first such estimator was proposed independently by Stahel [11] and Donoho [12] and investigated by Tyler [13] and Maronna and Yohai [14], Multivariate M-estimators [15] have a relatively low breakdown value due to possible implosion of the estimated scatter matrix. Together with the MCD estimator, Rousseeuw [16] introduced the minimum-volume ellipsoid. Davies [17] also studied one-step M-estimators. Other classes of robust estimators of multivariate location and scatter include S-estimators [6, 18], CM-estimators [19], T-estimators [20], MM-estimators [21], estimators based on multivariate ranks or signs [22], depth-based estimators [23-26], methods based on projection pursuit [27], and many others. 

A three-dimensional squeeze inward was implosion. Neddermeyer had just defined a possible new way to fire an atomic bomb. The idea had been suggested previously, but no one had carried it beyond conversation. At a meeting on ordnance problems late in April, records the Los Alamos technical history, Neddermeyer presented the first serious theoretical analysis of the implosion. His arguments showed that the compression of a. .. sphere by detonation of a surrounding high-explosive layer was feasible, and that it would be superior to the gun method both in its high velocity and shorter path of assembly. ... 

At that point it was just Seth and myself with a few helpers. The first cylindrical implosions were done at Bruceton. You take a piece of iron pipe, wrap the explosives around it, and ignite it at several points so that you get a converging wave and squash the < linder in. That was the birth of the experimental work on implosion, long before experimental work on the gun method. 

Carefully spaced prearranged wires contacted by the metal sphere as it imploded supplied information not only about the timing of the implosion but also about material velocities at various depths within the core. That provided direct, quantitative data which the Theoretical Division could use to check how well its hydrodynamic theory fit the facts. The Electric Method group began by measuring the high-explosive acceleration of flat metal plates. Early in 1945 it adapted its techniques to partial spheres and eventually to spheres surrounded by HE lens systems with only one lens removed to access the necessary wires. 

Disaster loomed again that day. The Creutz group at Los Alamos had fired the Chinese copy, measured the simultaneity of its implosion by the magnetic method and called Oppenheimer to report the dismaying news that the Trinity bomb was likely to fail So of course, says Kistiakowsky, I immediately became the chief villain and everybody lectured me. Groves flew in to Albuquerque in his official plane with Bush and Conant at noon they were appalled at the news and added their complaints to Kis-tiakowsky s full burden ... 

Chemists often use either high pressure or low pressure in various laboratory operations—it is an essential part of our work and often the preferred method of accomplishing our tasks. It is common to use glass vessels in many pressurized or vacuum systems because they are relatively inexpensive, relatively chemically inert, and easy to work with. Nevertheless, there is always the possibility of failure of these glass vessels from scratches, stress fractures, or accidental bumping. The result can be an explosion or implosion that puts you and others in harm s way. 

The symbols are p, gas mass density u, gas velocity p, gas pressure e, gas internal energy T, gas temperature Cf, friction coefficient Ch, heat transfer coefficient (Stanton number) Ty, wall temperature Cp, specific heat at constant pressure and w, channel radius or width. These equations were solved by the explicit Flux-Corrected Transport finite-difference method described by Oran and Boris.Computations were carried out on a coarse 100-point uniform mesh when the shock was in the vessel interior and on a 250-point variable mesh when the shock was near the walls or the center of symmetry. The variable mesh was used to increase the spatial resolution by a factor of 10 near the shock reflection or implosion point. 

When bubbles reach the resonance size range, they grow to a maximum size within one acoustic cycle and implode. Bubble implosion/collapse is a near adiabatic process. In simple thermodynamic terms, the volume of the bubble decreases instantaneously resulting in the generation of extreme heat within the bubble. Theoretical estimates predict greater than 15,000 K [44, 45]. However, experimental methods estimate about 1000-5000 K [46-50]. A number of techniques have been used to calculate the bubble temperatures. First, the bubble temperature could be theoretically calculated using Eq. (1.4). 

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