Fusion joining

Nuclear reactions involve fission (splitting) of a nucleus or fusion (joining) of two or more nuclei during which matter is converted into energy. 

Many of the above effects are empirical. Polymer physicists are now trying to understand and predict certain properties. The interface between addi-tive/polymer or polymer blends has received attention. One problem is how thick this interface has to be—several atoms or several thousand atoms thick Another problem is how energy is absorbed during fracture. Theoretical calculations have not been able to predict why some polymers are more difficult to fracture than others (this is not quite the same as saying that an amorphous polymer will incur brittle fracture below its Tg). The diffusion of polymer molecules at molten interfaces is another problem which has practical implications—crack annealing and fusion/joining of preformed parts. 

Electrofusion is another way to join plastic pipe with a fused joint. The main difference between electrofusion and regular fusion joining is the process of heating the materials. An electrofusion joint is made by heating internally rather than externally. This can be done with either a wire coil at the interface of the joint or by the use of a conductive polymer. Electrical current creates the heat needed to fuse a joint. 

Solid-State Welding. Sohd-state welding comprises a group of welding processes wherein a bond is made between two base materials upon the apphcation of pressure at a temperature below the soHdus of the base materials (Table 1). Interlayers are sometimes used. By joining materials in the sohd state, many of the difficulties of the fusion processes are avoided. 

Joining NonmetaUic Pipe Thermoplastic piping may be joined by a qiiahfied hot-gas welding procedure, a qnalined solvent-cement procedure, or by a qualified heat-fusion procedure. The general welding and heat-fiision procedures are described in ASTM D-2657 and solvent-cement procedures in ASTM D-2855. Two other techniques, for flared joints and elastomeric-sealed joints, are described in ASTM D-3140 and D-3139, respectively. 

Anelland, n. a ring joined to another by ortho fusion, anellated ring (see anellieren). anellieren, v.t. (Org. Chem.) join by ortho fusion" (as the two rings in naphthalene), aneUate. 

If and when projects producing energy on an industrial scale begin to appear in the middle of the twenty-first century, the theoretical advantages will be subject to confirmation. Fusion, magnetic or inertial, might then join the mix of energy resources. 

Also in 1950 Sakliarov and Tamm proposed an idea for a controlled thermonuclear fusion reactor, the TOKAMAK (acronym for the Russian phrase for toroidal chamber with magnetic coiF ), which achieved the highest ratio of output power to input power of any fusion device of the twentieth centuiy. This reactor grew out of interest in a controlled nuclear fusion reaction, since 1950. Sakharov first considered electrostatic confinement, but soon came to the idea of magnetic confinement. Tamm joined the effort with his work on particle motion in a magnetic field, including cyclotron motion, drifts, and magnetic surfaces. Sakharov and Tamm realized that... 

Human insulin Two peptide chains A, 21 amino acids long, and B, 30 amino acids long . coli Juvenile onset diabetes Approved for sale A and B chains made separately as fusion proteins and joined in vitro Compared with animal Insulins some undesirable side-effects have been noted... 

Extension of aromaticity. The extension of the aromatic ring system through fusion (as in naphthalene) or direct substitution (as in biphenyl) appears to increase log P, especially if the heteroaromatic atom is next to the juncture. If the ring-joining carbons are attached only to other aromatic carbons, electron delocalization is minimal the correction is -rO.lO for each 1C. If the ICs are also attached... 

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