Self-seeds

Figure 1 shows the DSC cooling scan of iPP in the bulk after self-nucleation at a self-seeding temperature Ts of 162 °C (in domain II). The self-nucleation process provides a dramatic increase in the number of nuclei, such that bulk iPP now crystallizes at 136.2 °C after the self-nucleation process this means with an increase of 28 °C in its peak crystallization temperature. In order to produce an equivalent self-nucleation of the iPP component in the 80/20 PS/iPP blend a Ts of 161 °C had to be employed. After the treatment at Ts, the cooling from Ts shows clearly in Fig. 1 that almost every iPP droplet can now crystallize at much higher temperatures, i.e., at 134.5 °C. Even though the fractionated crystallization has disappeared after self-nucleation, it should also be noted that the crystallization temperature in the blend case is nearly 2 °C lower than when the iPP is in the bulk this indicates that when the polymer is in droplets the process of self-nucleation is slightly more difficult than when it is in the bulk. In the case of block copolymers when the crystallization is confined in nanoscopic spheres or cylinders it will be shown that self-nucleation is so difficult that domain II disappears. 

Chen et al. [92] also performed self-nucleation experiments by DSC in PB-fr-PEO diblock copolymers and PB/PB-b-PEO blends. The cooling scans presented in their work showed that a classical self-nucleation behavior was obtained for PEO homopolymer and for the PB/PB-b-PEO blend where the weight fraction of PEO was 0.64 and the morphology was lamellar in the melt. For PB/PB-fr-PEO blends with cylinder or sphere morphology, the crystallization temperature remained nearly constant for several self-seeding temperatures evaluated. This observation indicates that domain II or the self-nucleation domain was not observable for these systems, as expected in view of the general trend outlined earlier. 

The plant shown here is a variegated version, with white-splashed green leaves. Like all the annual honesties, it self-seeds profusely. 

It is important to monitor the progress of more vigorous plants or those that self-seed in great guantity. Remove as necessary to prevent them from taking over completely. 

Herbaceous perennials from seed will take a year or two to reach flowering size. Raising perennials from seed is mostly restricted to true species seed sown from a plant with a cultivar name is unlikely to produce a plant identical to the parent. Some perennials, such as columbines, will self-seed freely. The flower color may bear no relation to the parent plant, but that is not necessarily a bad thing. 

Many hardy annuals, such as calendula (pot marigold), Phacelia tanacetifolia, and the poached-egg plant Limnanthes douglosii), will self-seed, reappearing year after year. Self-sown plants tend to be much sturdier, and flower earlier, than those you sow yourself. Unwanted seedlings can simply be hoed off, or transplanted to a more appropriate site. 

Fig. 4. Two contrasting spoil heaps in the Gardanne Coal Basin, Provence, France (a) Unrestored heap near Domaine de la Salle, showing largely bare spoil with characteristic development of scree and rills (cf. Nicolau 2002), with the only vegetation being a few self-seeding Mediterranean pines (b) Restored, thoroughly afforested spoil heap at Meyreuil, barely recognizable as a former mine waste disposal site.

Fig. 5.17 SAXS patterns for PEQwPBO.w showing (a) the ordered melt structure (T = 90 °C) (b) a metastable structure at T = 42 °C (c) the equilibrium once-folded structure grown at T - 50°C by a self-seeding process (Ryan et al. 1997). Numbers indicate the order of reflection from a lamellar structure and the arrow indicates the position of the peak in the ordered melt. The calculated repeat lengths for possible molecular conformations are indicated.

Fig. 5.20 Calculated lamellar spacings for copolymers with (/,g)-folded PEO and PBO blocks (loo) divided by measured lamellar spacings (d) and plotted against lm (Mai et al. 1997). Crystallization conditions are indicated by ( ) cooled at 10°Cmin T (o) quenched (a) annealed ( ) self-seeded. The symbol (v) denotes results from Yang et al. (1995). The dashed lines indicate the integral values of la)/d expected for the conformations with...

Sun, Y. and Xia, Y. (2002). Large-scale synthesis of uniform silver nanowires through a soft, self-seeding, polyol process. Adv. Mater. 14 833-837. 

Jiang, X. C., Zeng, Q. H. and Yu, A. B. (2006). A self-seeding coreduction method for shape control of silver nanoplates. Nanotechnology 17 4929-4935. 

Investigation Techniques. DSC measurements were carried out under nitrogen atmosphere. In order to destroy the self-seeding nuclei in the components, the samples were preheated for 5 min at least 35°C above the melting points of the higher melting component. Then, several crystallization and reheating runs were performed at a standard rate of 10°C/min. In some cases, other rates were used too. 

Glover JR, Kowal AS, Schirmer EC, Patino MM, Liu JJ, Lindquist S (1997) Self-seeded fibers formed by Sup35, the protein determinant of PSI+, a heritable prion-like factor of S. cerevisiae. Cell 89 811-819... 

BTF Pilot Self-seed MTBE removal from gas phase [28,103]... 

The base-line drawing procedure is the main reason for the relative low repeatability of the Hf-value determination. The self-seeding effect, clearly influencing the Tc-value, makes calculation of an average Tc-value meaningless. The He-, Tm2-and Hf2-values are hardly influenced, thus ... 

The higher the temperamre at which the blend is kept in the melt prior to crystallization, the less residual crystalline parts (otherwise leading to self-seeded nucleation) remain in the melt. As a result, fewer nuclei are available to nucleate the melt phase, thus leading to the formation of fewer, but larger spherulites. 

The ram is the sacrificial son-lover of the Goddess, the bush is the symbol of the Goddess Wisdom who tangles the lover to embrace him and the dog rose is the symbol of the womb of transformation that will produce the resurrected son. Dog roses peculiarly fruit by self-seeding to reproduce without cross-pollination from a mate. 

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