From melts area distribution

Figure 17 Comparison of model output for distribution of residue compositions with abyssal peridotites and harzburgites from Oman, (a) Distribution of clinopyroxene compositions in equilibrium with melts at the top of the melting column corresponding to Figure 15. This distribution is sampled uniformly by area (as if we were sampling residues from the top of the column) and is dominated by depleted inter-channel samples, (b) Clinopyroxene compositions in harzburgites from the mantle section of the Oman ophiohte (Kelemen et al., 1995a) superimposed on the range of cpx compositions from abyssal peridotites (Johnson et al., 1990 Johnson and Dick, 1992), showing the predominance of highly depleted samples.

Melting temperature of the samples was measured on a Perkin Elmer type-2 differential scanning calorimeter (DSC). The sample was premelted in DSC at 220 °C for 5 min. then rapidly cooled to room temperature. Thermogram was recorded by raising the temperature from 40° to 180 °C at a rate of 5 C/min. C NMR spectrum was obtained at 135°C on a JEOL FX-lOO pulsed Fourier transform NMR spectrometer. Experimental procedure and instrument conditions are described in a previous paper.Pentad tacticity was determined from the area of the resonance peaks of the methyl region. The molecular weight distribution of the samples was determined with GPC (Waters Associates type 150C) in o-dichlorobenzene at 140°C. 

To test the stability of polyvinyl alcohol (PVA) during preparation, PVA particles were prepared adapting the previously determined preparation conditions. SEM micrographs of an ion prepared PVA particle are pictured in Fig. 11.13. The porous PVA structure is completely existent after ion beam preparation process. Only minimal melting areas on pore edges are visible. From these results, the preparation and characterization of binder distributions within the granule structure should be no problem. 

The silica carrier of a sulphuric acid catalyst, which has a relatively low surface area, serves as an inert support for the melt. It must be chemically resistant to the very corrosive pyrosulphate melt and the pore structure of the carrier should be designed for optimum melt distribution and minimum pore diffusion restriction. Diatomaceous earth or synthetic silica may be used as the silica raw material for carrier production. The diatomaceous earth, which is also referred to as diatomite or kieselguhr, is a siliceous, sedimentary rock consisting principally of the fossilised skeletal remains of the diatom, which is a unicellular aquatic plant related to the algae. The supports made from diatomaceous earth, which may be pretreated by calcination or flux-calcination, exhibit bimodal pore size distributions due to the microstructure of the skeletons, cf. Fig. 5. 

The die manifold, which serves to distribute the incoming polymer melt stream over a cross-sectional area similar to that of the final product but different from that of the exit of the melt conveying equipment. 

The spinneret is a type of die principally used in fiber manufacture. It is usually a metal plate with many small holes (or oval, etc.) through which a melt is pulled and/or forced. They enable extrusion of filaments of one denier or less. Conventional spinneret orifices are circular and produce a fiber that is round in cross section. They can contain from about 50 to 110 very small holes. A special characteristic of their design is that the melt in a discharge section of a relatively small area is distributed to a large circle of spinnerets. Because of the smaller distance in the entry region of the distributor, dead spaces are avoided, and the greater distance between the exit orifices makes for easier threading.143... 

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