Spherulite

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spherulite

[′sfir·ə‚līt]
(geology)
A spherical body or coarsely crystalline aggregate having a radial internal structure arranged about one or more centers.

Spherulite

 

a small sphere consisting of an aggregate of very fine acicular crystals radiating from a central point. Spherulites are found in magmatic and sedimentary rocks and vary in mineral composition and size. In magmatic rocks, spherulites are usually interpreted as endogenic contact formations in the marginal sections of diorites. In acidic lavas, they may occur through consolidation when the primary glassy mass cools; in basic lavas (variolites), such formations are called varióles. Spherulites also form in gas bubbles of already hardened rock during secondary precipitation of zeolites, quartz, and similar minerals; in such cases they may be called pseudospherulites. Carbonate, iron-manganese phosphate, chalcedonic, and other types of spherulites are found in sedimentary rocks. They usually result from the crystallization of material in colloidal nodules, and many are close in origin to concretions.

References in periodicals archive ?
This intensity may be absorbed (pigments with color, specific wavelengths), diffused with a polar diagram depending on size, contact of surfaces (pigment/polymer), and organization of polymer (spherulites, crystalline).
For Delrin, a quite distinct layer structure with numerous layers and very fine spherulites can be observed in Figure 8.
While the formation of spherulites and nanofibers can be clearly observed by eye in both F8BT and MEH-PPV samples, it is important to understand to which degree these structures are ordered and whether the addition of TCB to the spin-coated solution can force the crystallization of the two polymer materials.
However, individual spherulites, separated by approximately 100-300 [micro]m (Figs.
It was noted that surfaces were irregular, and contained a nonhomogeneous distribution of spherulites and the top and bottom of the samples were not uniform.
Thus, mixed GdCaHM crystal grows as single crystal with square platelet as well as spherulites.
The morphological investigation shows that spherulites develop and grow until the impingement occurs.
Both images show that big spherulites grow due to the isothermal Material Activation Energy [E.sub.A] [kJ/mol] PP 265,0 [+ or -] 24,3 PA12, PA2200 395,0 [+ or -] 216,2 PBT 521,5 [+ or -] 47,0 PE-HD 578,5 [+ or -] 70,0 PEK, PEEK-HP3 636,0 [+ or -] 21,3 POM 986,7 [+ or -] 29,5
The lamellae are typically organized into spherulites with the proper thermal history.
SCF induces the transcrystalline texture in the adjacent regions, while the morphology far from fibers remains spherulite. The classic Kolmogorov model can be used to calculate the crystallinity evolution of spherulites, as mentioned in the Introduction section.