Partial melting

Thermal Properties. Spider dragline silk was thermally stable to about 230°C based on thermal gravimetric analysis (tga) (33). Two thermal transitions were observed by dynamic mechanical analysis (dma), one at —75° C, presumed to represent localized mobiUty in the noncrystalline regions of the silk fiber, and the other at 210°C, indicative of a partial melt or a glass transition. Data from thermal studies on B. mori silkworm cocoon silk indicate a glass-transition temperature, T, of 175°C and stability to around 250°C (37). The T for wild silkworm cocoon silks were slightly higher, from 160 to 210°C. 

PVC Fusion (Gelation). The PVC piimaiy particle flow units (biUion molecule bundles) can partially melt, freeing some molecules of PVC... 

Fig. 7. Model for PVC fusion, accounting for molecular weight effects and processing temperature effects (a) unfused PVC primary particles (b) partially melted PVC primary particles (c) partially melted then recrysta11i2ed high molecular weight PVC, showing strong three-dimensional stmcture and (d) partially melted then recrysta11i2ed low molecular weight PVC, showing weak three-dimensional stmcture.

Lamination. la lamination a film is prepared by caleaderiag or extmsioa (see Laminated materials, plastic). It is thea adhered to a textile at a laminator by either an adhesive or sufficient heat which partially melts the film to obtain a mechanical bond. There are a variety of adhesives available for lamination, including solvent systems, water-base latex systems, and various forms of hot melt adhesives (qv). 

It may be noted that in the case of TMI-2, the core partially melted but did not get out of the pressure vessel. In the case of Chernobyl, there was no containment in the U.S. sense and what confinement there was, was disrupted by the nuclear excursion (like an explosion). 

While there is active core melt accident research, the TMI-2 accident demon.strated what happens in an accident that ends in partial core melt. Such a partial melt is in contradiction to the RSS assumption that if a melt starts, it will propagate to a full melt which were the only accidents considered in the RSS. 

According to Ellis, the melting-point is 19-5°. The specimen was partially melted and the liquid poured off three times, and the product was twice reciystallised from ether. Private communication from the laboratories of Messrs.. 4. Boake, Roberts, Co., Ltd.). 

J. Koike, M. Mabuchi, and K. Higashi, "In-Situ Observation of Partial Melting in Superplastic Aluminum Alloy Composites at x.igh Temperatures," Acta Metall Mater., 43(1) 199 (1994). 

Barium acetate decomposes [1050] with growth of planar product nuclei, E = 167 kJ mole-1 (720—750 K). Reactions of other Group II acetates are reported [1051] as being accompanied by at least partial melting. 

In the case on the left, a composition exists which in which a minimum melting point exists. Again, A and B form a which partially melts to form a + L. However, two forms of a edso exist, a compositional area known as a "miscibility gap", i.e.- " ai and aa". But at higher temperatures, both of these melt into the single phase, a. Finally, we obtain the melt plus a. Note that at about 80% ttj-20% Uj, a melting point minimum is seen where it melts directly instead of forming the two-phase system, a -i- L. 

Attree RW, Cabell MJ, Cushing RL, Pieroni JJ (1962) A calorimetric determination of the half-life of thorium-230 and a consequent revision to its neutron capture cross section. Can J Phys 40 194-201 Bateman H (1910) Solution of a system of differential equations occurring in the theory of radioactive transformations. Proc Cambridge Phil Soc 15 423-427 Beattie PD (1993) The generation of uranium series disequilibria by partial melting of spinel peridotite ... 

Barth MG, Foley SF, Horn 1 (2002) Partial melting in Archean subduction zones constraints from experimentally determined trace element partition coefficients between eclogitic minerals and tonahtic melts under upper mantle conditions. Precamb Res 113 323-340... 

Beattie P (1993a) The generation of uraiuum series disequilibria by partial melting of spinel peridotite Constraints from partitioiung studies. Earth Planet Sci Lett 117 379-391... 

Falloon TJ, Green DH (1987) Anhydrous partial melting of MORE pyrolite and other peridotite compositions at 10 kbar implications for the origin of primitive MORE glasses. Mineral Petrol 37 181-219... 

McKenzie D, O Nions RK (1991) Partial melt distribntions from inversion of rare earth element concentrations. J Petrol 32 1021-1091... 

U-series nuclides define their domain of application the longest-lived ( °Th, " " Pa, Ra), as discussed above, are appropriate to study partial melting in the mantle or deep crustal reservoirs, the shortest-lived give information on processes occurring in shallow magma chambers. 

---